ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (185)
  • Taylor & Francis  (185)
  • 2010-2014  (73)
  • 2000-2004  (46)
  • 1995-1999  (45)
  • 1985-1989  (21)
  • 1
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Écoscience, 5 (3). pp. 361-394.
    Publication Date: 2020-04-20
    Description: It is well documented that animals take risk of predation into account when making decisions about how to behave in particular situations, often trading-off risk against opportunities for mating or acquiring energy. Such an ability implies that animals have reliable information about the risk of predation at a given place and time. Chemosensory cues are an important source of such information. They reliably reveal the presence of predators (or their presence in the immediate past) and may also provide information on predator activity level and diet. In certain circumstances (e.g., in the dark, for animals in hiding) they may be the only cues available. Although a vast literature exists on the responses of prey to predator chemosensory cues (or odours), these studies are widely scattered, from marine biology to biological control, and not well known or appreciated by behavioural ecologists. In this paper, we provide an exhaustive review of this literature, primarily in tabular form. We highlight some of the more representative examples in the text, and discuss some ecological and evolutionary aspects of the use of chemosensory information for prey decision making. Curiously, only one example illustrates the ability of birds to detect predator odours and we have found no examples for terrestrial insects, suggesting a fruitful area for future study.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  New Zealand Journal of Zoology, 13 (2). pp. 169-174.
    Publication Date: 2020-06-22
    Description: Food samples from 27 Buller’s mollymawks Diomedea bulleri from the New Zealand region showed that cephalopods were, by frequency of occurrence and by mass, their preferred food. Fish, crustaceans, and tunicates, in decreasing order of importance, also were taken. Seventeen species of Cephalopoda were identified by their beaks, with 78.5% of individuals belonging to the Ommastrephidae (77% Nototodarus spp.) and 10% to the Histioteuthidae. The diet was compared with that of four other small species of Diomedea, and found to be similar to that of D. chrysostoma, D. irrorata, and D. cauta, but different from that of D. melanophris, whose preferred food is euphausiids. Squid-fishing operations around New Zealand may come into competition with Buller’s mollymawk.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Marine Georesources & Geotechnology, 18 (1). pp. 43-76.
    Publication Date: 2017-05-09
    Description: The morphological features associated with Co-rich manganese deposits, the size variations of nodules, and the occurrence of different substrates have been analyzed, to evaluate the influence of various seabed slope angles on the distribution of these features. The coverage and size of the crusts depend on their surface morphology and seabed topography, resulting in cobble-type, lineated, or step-like outcrops. Small nodules (1–4 cm in diameter) dominate all seabed slopes, with a few locations having nodules ranging from 1 to 8 or 1 to 10 cm. Sediments invariably occur as substrates for nodules and as cover for crusts, their coverage being inversely proportional to that of the nodules and crust outcrops.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Geology Review, 52 (7-8). pp. 661-699.
    Publication Date: 2017-05-12
    Description: Biomineralized structures and tissues are composites, containing a biologically produced organic matrix and nano- or microscale amorphous or crystalline minerals. Two main examples of organic matrices – the amino-polysaccharide chitin and the asymmetric protein collagen – are presented and discussed as the basic structural modules and organo-templates for calcium and silica biomineralization in nature. Both serve as templates, providing preferential sites for nucleation and controlling the location and orientation of mineral phases. Here, for the first time, chitin and collagen are analysed from evolutionary, structural, and functional points of view with respect to their templating properties in calcification and silicification phenomena, using both in vivo and in vitro data. It is proposed that these biopolymers be characterized as fundamental templates in biomineralization, inasmuch as they are very ancient from an evolutionary point of view, common to many species and biological systems with a global distribution. The two polymers also exhibit very similar hierarchical structural organizations, in spite of the possible alternatives they provide in chemical nature and origin. In addition, the phenomenon of multi-phase mineralization – where two minerals, amorphous and crystalline CaCO3, form from one biomolecule, chitin – is also described, analysed, and discussed for the first time.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Marine Biology Research, 8 (3). pp. 300-306.
    Publication Date: 2017-06-20
    Description: Despite coelacanths, Latimeria chalumnae, being listed as either endangered by CITES or critically endangered by the IUCN, their population size within South Africa is unknown and still needs to be estimated. Their conservation status unfortunately excludes the use of conventional tagging to mark individual animals for a possible mark–recapture experiment. This study shows that because coelacanths have a unique spot patterning it is possible to quickly and accurately identify specific individuals photographically using computer-aided identification software. Without any manual intervention by an operator, the software accurately identified between 56 and 92% of the individuals. Indentification success increased to 100% if the operator could also manually select from other potential matching photographs. It was also shown that fish exhibiting a yaw angle not exceeding 60° could be accurately identified in photographs, although the percentage of fish correctly identified without operator-intervention decreased rapidly with increasing yaw angle. Computer-aided identification should therefore facilitate future coelacanth research as it is both efficient and accurate while also reducing potential stress on the animals observed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Marine Georesources & Geotechnology, 22 (1-2). pp. 103-114.
    Publication Date: 2017-07-20
    Description: The deep ocean floor between the Clarion and Clipperton fracture zones (NE equatorial Pacific) has the highest known manganese nodule abundance in the world oceans. A detailed analysis of MR1 (Mapping Researcher 1, 11–12 kHz) sonar images and free-fall grab data in the Korean manganese nodule field areas reveals a close relationship between side-scan sonar characteristics of the seafloor and manganese nodule abundance. Eight sonar facies are identified based on back-scattering intensity and distribution patterns. These sonar facies can be interpreted as (1) volcanic seamounts (facies I-1), (2) bounding faults of abyssal hills (facies I-2 and II-1), (3) lava flows or volcanoclastic mass-flow deposits around the volcanic seamounts (facies I-3 and II-2), (4) crests of abyssal hills (facies II-1), (5) abyssal troughs between abyssal hills (facies III-1), (6) relatively flat areas (facies II-3 and III-2). In the areas where facies II-1 (abyssal hill crests with thin sediment cover) and II-3 (relatively flat areas draped by thin sediments) are dominant, manganese nodules occur abundantly. In contrast, zones comprising facies III-1 (abyssal troughs with thick sediment cover) and III-2 (relatively flat areas covered by thick sediments) are characterized by low abundance of manganese nodules. This relationship between distribution of sonar facies and manganese nodule abundance implies that (1) the qualitative difference in acoustic reflectivity of long-range sidescan sonar with some ground truth data is useful for regional assessment of manganese nodule occurrence over wide areas in a reasonable time, and (2) seafloor topography and sediment thickness are important controlling factors for regional occurrences of manganese nodules.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2017-07-06
    Description: A semi-quantitative assessment is made of the animals observed in archived videotapes taken from the research submersible Jago, during diamond mining and exploratory surveys off the mouth of the Orange River on the west coast of southern Africa (28°15′S, 29°11′S) in November 1996. The seabed environment is described and nekton associations with substratum features are identified. The area is characterized by heterogeneity to its physical and biological struture. The variety of observed nekton is low, and communities are dominated by goby Sufflogobius bibarbatus, juvenile hake Merluccius spp. and cuttlefish Sepia spp. (on soft substrata), as well as false jacopever Sebastes capensis and kingklip Genypterus capensis (on rocky substrata).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Asian Natural Products Research, 3 (2). pp. 117-122.
    Publication Date: 2018-02-05
    Description: One kinds of glycolipid (SBI) have been isolated from the marine brown alga Sargassum hemiphyllum (Turn.) Ag. The structures of SBI have been determined as the sodium salt of 1-0-acyl-3-0-(6′-sulfo-α-D-quinovopyrannosyl) glycerol (acyl: tetradecanoyl, pentadecanoyl, 11-hexadecenoyl, hexadecanoyl, 10,13-octadecadienoyl, 9-octade cenoyl, 15-metylheptadecanoyl and 11-eicosenoyl 17:1.5:19:153:1:19:1:2) on the basis of chemical and spectral evidence and GC-MS analysis, respectively. Four constituents of the SBI were new compounds [the sodium salt of 1-0-(11″-hexadecenoyl)-3-0-(6′-sulfo-α-D-quinovopyrannosyl) glycerol, the sodium salt of 1-0-(10″,13″-octadecadienoyl)-3-0-(6′-sulfo-α-D-quinovopyrannosyl) glycerol, and the sodium salt of 1-0-(15″-metylhexadecenoyl)-3-0-(6′-sulfo-α-D-quinovopyrannosyl) glycerol, and the sodium salt of 1-0-(11″-eicosenoyl)-3-0-(6′-sulfo-α-D-quinovopyrannosyl) glycerol]. All compounds were isolated from marine brown alga for the first time.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Geology Review, 41 (3). pp. 243-262.
    Publication Date: 2017-11-24
    Description: A new image of the French continental crust between Brabant (Belgium) and the Basque province of Spain is presented on the basis of considerable recent geological and geophysical information as well as the compilation and reInterprétation of previously available data. The resulting section, which shows the main basement structures to a depth of 45 km, also is the first nonspeculative image of the westernmost part of the Variscan orogen. The French Global Geoscience Transect reveals a complete picture of this orogen between its remnant root and the surface. The divergent thrusts are bounded on the north and in the south by the old Brabant and Ebro-Aquitaine cratons, respectively; these thrusts also involve two previous plate boundaries. The lower part of the orogen is limited by a layered lower crust, probably of Permian age. Near the surface the Hercynian orogen is buried—near the northern end of the transect by the Paris Basin, which can be considered an eastward extension of the English Channel, and in the south by the South Armorican continental margin, which makes a transition between the oceanic crust of the Bay of Biscay and the axis of the Variscan orogen. In this area, the deep Parentis graben is located at the site of pronounced crustal thinning, since only 7 km of Hercynian crust are now preserved.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2018-01-24
    Description: A new compound, jolynamine (1), was isolated from the marine brown alga Jolyna laminarioides collected from the coast of Karachi, Pakistan. In addition, four known compounds, namely saringosterol (2), loliolide (3), methyl-4-hydroxybenzoate (4) and propyl-4-hydroxybenzoate (5), were isolated for the first time from the marine brown alga Iyengaria stellata, and two known compounds, namely 3,4,5-trimethylaniline (6) and harmine (7), were isolated for the first time from the marine brown alga Melanothamnus afaqhusainii. Compound 6 is synthetically known but was isolated for the first time from a natural source. The structures of these compounds were elucidated with the help of powerful spectroscopic techniques. Furthermore, the methanolic extracts of both algae showed anti-microbial activities against various bacteria and fungi.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Nonparametric Statistics, 24 (4). pp. 993-1006.
    Publication Date: 2018-03-26
    Description: In this paper, we empirically investigate the robustness of random forests for regression problems. We also investigate the performance of six variations of the original random forest method, all aimed at improving robustness. These variations are based on three main ideas: (1) robustify the aggregation method, (2) robustify the splitting criterion and (3) taking a robust transformation of the response. More precisely, with the first idea, we use the median (or weighted median), instead of the mean, to combine the predictions from the individual trees. With the second idea, we use least-absolute deviations from the median, instead of least-squares, as splitting criterion. With the third idea, we build the trees using the ranks of the response instead of the original values. The competing methods are compared via a simulation study with artificial data using two different types of contaminations and also with 13 real data sets. Our results show that all three ideas improve the robustness of the original random forest algorithm. However, a robust aggregation of the individual trees is generally more profitable than a robust splitting criterion.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2020-06-15
    Description: Squid regurgitated by Greyheaded and Yellownosed Albatrosses at the Prince Edward Islands were predominantly two onychoteuthid species, Kondakovia longimana and Moroteuthis knipovitchi. Both squid are characteristic of cold, Antarctic waters and may have been caught south of the Antarctic Convergence, some 350 km to the south of the breeding station. Both albatross species regurgitated similar squid (by species and size), and these squid were similar to those found in previous studies of the diet of Wandering, Sooty and Lightmantled Sooty Albatrosses at the Prince Edward Islands
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2016-12-14
    Description: The annual winter sardine run along the South African east coast impacts the KwaZulu-Natal (KZN) coastal system in a variety of ways. These include ecological impacts, such as enrichment of a largely oligotrophic environment, competition between migrant sardine Sardinops sagax, other migrant and resident small pelagic fish species, and interactions with predators, as well as the socio-economic impacts of the sardine run on the local people. Enrichment of KZN coastal waters with organic nitrogen contained within the sardine is compared with alternative sources of nitrogen such as upwelling, river, sewage and stormwater runoff, and groundwater discharge. The sardine run appears to contribute most nitrogen to this system—96 000 t compared to 500–3 300 t for each of the other significant sources at trophic level 2, although upwelling estimates are extremely wide. Nonetheless, the majority of surviving sardine, their young and predators return southwards, suggesting that the nett export of nitrogen to KZN waters during the run is likely to be of a similar order of magnitude as that from other sources. Further, whereas the sardine supply of nitrogen is exclusively during winter, the bulk of the riverine input is in summer, thus ensuring that nitrogen supply in the region is maintained at fairly constant levels throughout the year. Competition for food between small pelagic fish is minimised by resource partitioning, but further dietary data are needed for resident species. Although interactions between sardine and top predators must exist, further studies are needed to confirm links between top predator life cycles and the sardine run. The estimated value of sardine as a tourist spectacle is compared to that from a seasonal beach-seine or boat-based purse-seine fishery for this species. Whereas the estimated value of the sardine as a tourist attraction appears substantially higher than could be derived from catching them, the small-scale beach-seine fishery itself draws tourists and also provides limited, seasonal employment opportunities.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Critical Reviews in Biochemistry and Molecular Biology, 48 (5). pp. 430-445.
    Publication Date: 2020-07-29
    Description: Our understanding of the fundamental regulatory roles that tyrosine phosphatases play within cells has advanced significantly in the last two decades. Out-dated ideas that tyrosine phosphatases acts solely as the “off” switch counterbalancing the action of tyrosine kinases has proved to be flawed. PTP1B is the most characterized of all the tyrosine phosphatases and it acts as a critical negative and positive regulator of numerous signaling cascades. PTP1B’s direct regulation of the insulin and the leptin receptors makes it an ideal therapeutic target for type II diabetes and obesity. Moreover, the last decade has also seen several reports establishing PTP1B as key player in cancer serving as both tumor suppressor and tumor promoter depending on the cellular context. Despite many key advances in these fields one largely ignored area is what role PTP1B may play in the modulation of immune signaling. The important recognition that PTP1B is a major negative regulator of Janus kinase – signal transducer and activator of transcription (JAK-STAT) signaling throughout evolution places it as a key link between metabolic diseases and inflammation, as well as a unique regulator between immune response and cancer. This review looks at the emergence of PTP1B through evolution, and then explore at the cell and systemic levels how it is controlled physiologically. The second half of the review will focus on the role(s) PTP1B can play in disease and in particular its involvement in metabolic syndromes and cancer. Finally we will briefly examine several novel directions in the development of PTP1B pharmacological inhibitors.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Journal of Geographical Information Science, 26 (11). pp. 2083-2095.
    Publication Date: 2020-07-28
    Description: Species distribution models (SDMs) are an important tool in biogeography and ecology and are widely used for both fundamental and applied research purposes. SDMs require spatially explicit information about species occurrence and environmental covariates to produce a set of rules that identify and scale the environmental space where the species was observed and that can further be used to predict the suitability of a site for the species. More spatially accurate data are increasingly available, and the number of publications on the influence of spatial inaccuracies on the performance of modelling procedures is growing exponentially. Three main sources of uncertainty are associated with the three elements of a predictive function: the dependent variable, the explanatory variables and the algorithm or function used to relate these two variables. In this study, we review how spatial uncertainties influence model accuracy and we propose some methodological issues in the application of SDMs with regard to the modelling of fundamental and realized niches of species. We distinguish two cases suitable for different types of spatial data accuracy. For modelling the realized distribution of a species, particularly for management and conservation purposes, we suggest using only accurate species occurrence data and large sample sizes. Appropriate data filtering and examination of the spatial autocorrelation in predictors should be a routine procedure to minimize the possible influence of positional uncertainty in species occurrence data. However, if the data are sparse, models of the potential distribution of species can be created using a relatively small sample size, and this can provide a generalized indication of the main regional drivers of the distribution patterns. By this means, field surveys can be targeted to discover unknown populations and species in poorly surveyed regions in order to improve the robustness of the data for later modelling of the realized distributions. Based on this review, we conclude that (1) with data that are currently available, studies performed at a resolution of 1–100 km2 are useful for hypothesizing about the environmental conditions that limit the distribution of a species and (2) incorporating coarse resolution species occurrence data in a model, despite an increase in sample size, lowers model performance.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  South African Journal of Marine Science, 15 (1). pp. 207-223.
    Publication Date: 2020-05-26
    Description: A model is presented which tests the representation of the maturity process in terms of gonadosomatic indices (GSI) in chokka squid Loligo vulgaris reynaudii. It assumes that the true maturation process is reflected by the results of histological investigation, which cannot be used in large-scale ecological work in the field. However, the maturity scales used in ecological studies define some morphological categories which can be linked directly to microscopic development. Therefore, the overlap of GSI ranges for each morphological maturity category may be used to judge how well the GSIs represent the histological stages. Results have shown that the overlap is large and that GSI cannot be recommended as adequately reflecting the maturation process in squid. A morphological scale of maturity with possible broad applications in exploited families of squid is proposed as a better representation of the maturation process than GSI.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  South African Journal of Marine Science, 15 (1). pp. 1-7.
    Publication Date: 2020-05-26
    Description: Morphological differences between paralarvae of two loliginid squid species common in southern African waters (Loligo vulgaris reynaudii and Lolliguncula mercatoris) are described. The differences are: Loligo — "cheek patches" consisting of four dark chromatophores, nine large dark dorsal chromatophores on the mantle, tentacular clubs broad and much wider than tentacle stalks, proximal row of three club suckers with others tetraserial, suckers large enough to appear crowded on the club surface; Lolliguncula — "cheek patches" with three dark chromatophores, two pairs of" large, dark dorsal chromatophores on the mantle, tentacular clubs narrow, proximal club suckers arranged in three pairs, suckers small, not particularly crowded. Relationships with other myopsids are briefly discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2017-06-20
    Description: Cereopsis studeri was described by G. von Koch in 1891 with material from Naples. However, it was subsequently synonymized, erroneously identified, and overlooked in subsequent soft coral literature of the twentieth century. After the original description, this species was not recorded or correctly described for 120 years. The study of newly collected material from the North Western Mediterranean permits the re-description of this forgotten species and its assignation to the genus Nidalia in the family Nidaliidae. The main features of Nidalia studeri com. nov. are: colony torch-like, a capitulum light orange in colour, not laterally flattened, dome-shaped and not distinctly projecting beyond the stalk, introvert with sclerites transversally placed in two longitudinal rows per interseptal space, anthocodial crown with 28–38 sclerite rows, points separated from polyps distally, formed by 6–9 pairs of sclerites, and the presence of intermediate points (secondary points) between principal (interseptal) ones. Nidalia studeri is here compared with its closest congeners, especially with the Indonesian species N. simpsoni, species from the West Indian Region N. dissidens, N.occidentalis, N. deichmannae, and the recently described Nidalia aurantia from the Mid-Atlantic Ocean. This is the first time that the genus Nidalia and the family Nidaliidae have been reported with certainty for the Mediterranean Sea.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Biotechnic & Histochemistry, 78 (3-4). pp. 191-199.
    Publication Date: 2017-06-27
    Description: Siliceous and calcareous sponges commonly are treated with acid to remove the spicules prior to embedding and cutting for histological investigations. Histology of spiculated sponge tissue represents a challenging problem in sponge histotechnology. Furthermore, fluorescence in situ hybridization (FISH), a key method for studying sponge-associated microbes, is not possible after acid treatment. For a broad range of siliceous sponge species, we developed and evaluated methods for embedding in paraffin, methylmethacrylate resins, LR White resin and cryomatrix. Different methods for cutting tissue blocks as well as mounting and staining sections also were tested. Our aim was to enable histological investigations and FISH without prior removal of the spicules. To obtain an overview of tissue and skeleton arrangement, we recommend embedding tissue blocks with LR White resin combined with en bloc staining techniques for large specimens with thick and numerous spicules, but paraffin embedding and subsequent staining for whole small specimens. For FISH on siliceous sponges, we recommend Histocryl embedding if the spicule content is high, but paraffin embedding if it is low. Classical histological techniques are used for detailed tissue examinations.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Dispersion Science and Technology, 34 (7). pp. 974-984.
    Publication Date: 2017-09-25
    Description: The changes in global temperatures as a result of carbon dioxide (CO2) emissions has suggested that cumulative CO2 emissions will continue to increase over time. Many countries are looking for ways to reduce or alter the amount of CO2 harming our environment; therefore, this review is a compilation of CO2 adsorption on biomass-derived-biochar (BDB). This suggests that effective measures to mitigate the risk of dangerous climate change will need to limit cumulative emissions of CO2. Further, if cumulative CO2 emissions overshoot acceptable limits, it will become necessary to remove CO2 from the air, that is, the so-called “negative emissions.” In this review, we discuss the definitions and classes of technologies for capturing CO2 from the air and the application of biochar in the improvement of soil fertility. We also discuss the economic tradeoff between biochar and bio-oil, agricultural nutrient leaching, the novel magnetic property of biochar and its durability.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Geology Review, 42 . pp. 445-469.
    Publication Date: 2017-09-29
    Description: The chief host of cadmium in zinc deposits is sphalerite, the cadmium content of which depends on the type of deposit. Sphalerite from Mississippi Valley-type (MVT) deposits has high cadmium concentrations whereas sphalerite from exhalative deposits has low cadmium concentrations. The Cd content of sphalerite depends on the Cd/Zn ratio, ligand activities, and temperature of the ore-forming fluids. The combined effect of variation of temperature, pH, total activity of reduced sulfur, and activity of Cl- cannot by itself account for either Cd depletion (exhalative deposits) or Cd enrichment (MVT deposits). Variations in the Cd/Zn ratio of the fluid have a significant effect in determining that of sphalerite. Basinal brines, which can considered to be the recent equivalents of MVT fluids, have high Cd/Zn ratios, and active exhalative systems are characterized by low Cd/Zn ratios. Probably the differences in sphalerite composition between the different deposit types are less a function of temperature and ligand activities than Cd/Zn ratio of the ore-forming fluids. In the hydrothermal environment, the Cd/Zn ratio is generally not high enough to allow crystallization of cadmium sulfides (greenockite or hawleyite). The abundance of greenockite in the supergene alteration zone of hydrothermal zinc deposits can be explained on the basis of Zn scavenging by crystallizing smithsonite.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Asian Natural Products Research, 14 (7). pp. 647-651.
    Publication Date: 2018-01-24
    Description: Three new compounds, 4′-(4,5-dimethyl-1,3-dioxolan-2-yl)methyl-phenol (1), (3′-hydroxybutan-2′-yl)5-oxopyrrolidine-2-carboxylate (2), and atroviridetide (3), have been isolated from the marine-derived fungus Trichoderma atroviride G 20-12. Their structures were determined on the basis of chemical and spectroscopic methods.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Applied Statistics, 39 (1). pp. 151-160.
    Publication Date: 2018-07-13
    Description: It is well known that random forests reduce the variance of the regression predictors compared to a single tree, while leaving the bias unchanged. In many situations, the dominating component in the risk turns out to be the squared bias, which leads to the necessity of bias correction. In this paper, random forests are used to estimate the regression function. Five different methods for estimating bias are proposed and discussed. Simulated and real data are used to study the performance of these methods. Our proposed methods are significantly effective in reducing bias in regression context.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2018-04-11
    Description: A histological study of the reproductive cycle of male and female shore crabs, Carcinus maenas (Linnaeus), was performed monthly on the South West coast of Ireland (from December 2006 to July 2008). The calculated sex ratio deviated from equality, 1:0.53, revealing a strong male bias. A system was devised, based on screening of tissue sections, to describe and stage gametogenic development. Histological examinations revealed that ovarian development occurred biannually, with a primary winter cycle in which the larger crabs reproduced and a secondary summer cycle, when smaller crabs reproduced. An association was observed where more of the larger specimens were caught in the summer months and the smaller specimens in the winter months, which inversely correlated with the segregated breeding cycles. There was strong evidence that mature male crabs could potentially copulate year round since all mature specimens, collected throughout the year, contained viable spermatozoa. Developmental stages of oogenesis and spermatogenesis were described to develop a practical gonadal index for this portunid crab, providing information on the biology of this species, which will be of benefit for fisheries management.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Advanced Robotics, 17 (9). pp. 863-878.
    Publication Date: 2016-12-14
    Description: Fault tolerance is an important aspect in the development of control systems for multi-legged robots since a failure in a leg may lead to a severe loss of static stability of a gait. In this paper, an algorithm for tolerating a locked joint failure is described in gait planning for a quadruped robot with crab walking. A locked joint failure is one for which a joint cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue walking maintaining static stability. A strategy for fault-tolerant gaits is described and, especially, a periodic gait is presented for crab walking of a quadruped. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The adjustment procedure from a normal gait to the proposed fault-tolerant crab gait is shown to demonstrate the applicability of the proposed scheme.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Marine and Freshwater Behaviour and Physiology, 37 (4). pp. 235-251.
    Publication Date: 2020-07-08
    Description: The torque generated by a rotating joint comprises the useful force exerted by the joint on the external environment, and both the magnitude and distribution of torque through the step cycle during walking are important variables in understanding the mechanics of walking. The mechanics of the American lobster (Homarus americanus) and snow crab (Chionoecetes opilio) during walking were modelled to examine the relative roles of flexor versus extensor apodeme–muscle complexes, investigate which legs of these decapods likely contribute the greatest to locomotion, determine scaling effects of torque generation, and assess the relative roles of various model variables on torque production. Force generated along the length of the apodeme by the muscle was modelled based on apodeme surface area, muscle stress, and muscle fibre pinnation angle. Torque was then calculated from this estimated force and the corresponding moment arm. The flexor apodeme–muscle complex is calculated to generate consistently greater forces than the extensor, and generally this results in flexor torque being larger than extensor, though the snow crab does illustrate the opposite in two of its legs. This greater torque generation in flexion suggests that, in addition to the pushing of the trailing legs, the pulling action of the leading legs may play a significant role, at least during lateral walking. Leg 4 of both species appears to generate greater torques and thus provide the greatest forces for locomotion. Torque generation as a function of body size shows a second order response due to the increase in apodeme surface area. The pinnation angle of the muscle fibre is found to be insignificant in force generation, apodeme surface area (representing muscle cross sectional area) likely plays the most influential role in total force production, and moment arm controls the distribution of this force through the step cycle. Muscle stress remain a largely unknown quantity however, and may significantly affect both magnitude and distribution through step cycle of forces, and thus torque. Despite the uncertainty associated with the muscle stress parameter, the modelled results fit well with previously published force measurements.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2020-06-15
    Description: The diet of Northern Rockhopper Penguins Eudyptes chrysocome moseleyi breeding on Gough Island, south Atlantic Ocean was studied, during November 1984, 1985 and 1986 by stomach content analysis. Rockhopper Penguins fed chiefly on the euphausiids Thysanoessa gregaria, Euphausia lucens and E. similis. Fish and squid were of minor importance by mass but constituted the largest individual prey items.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Ophelia, 24 (1). pp. 65-74.
    Publication Date: 2020-06-15
    Description: The feeding biology of the nectobenthic, sepiolid squid, Sepietta oweniana is treated based on behavioural observations in aquaria and stomach content analyses on 859 trawl caught squid. Juvenile squid in aquaria catch free-swimming prey, preferably the mysid Praunus flexuosus, day and night using the bottom only for shorter resting periods. Adult squid forage from dusk till dawn from positions close to the bottom and spend the day buried in the bottom. Praunus flexuosus is preferred as prey in comparison with demersal and benthic crustaceans as Palaemon elegans and Crangon crangon. Stomach analyses show that in daytime catches, only 16% of all analyzed specimens had stomach contents. Low frequencies were consistent throughout most sampled months in 1979 and 1982. Of the specimens with stomach contents most (50–100%) contained fragments of the euphausiid Meganyctiphanes norvegica. Specimens with remains of decapod shrimps were found in late spring and early summer. It is concluded that S. oweniana feeds in the hyperbenthic habitat at very low light intensities mostly on Meganyctiphanes norvegica in northern waters. A tentative ecological trade off explanation for this apparently inefficient feeding pattern is briefly discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2017-05-22
    Description: Introduction: Nanocarriers are considered to be one of the most innovative drug delivery systems, owing to their high potential in drug protection, delivery and targeting to the diseased site. Unfortunately, their applicability is hampered mainly by their uptake, due to macrophagic recognition and lack of specificity, if not properly engineered. Areas covered: Sialic acid (SA) and its derivatives have recently been studied in order to govern their stealthness as carriers and their effectiveness as targeting moieties. In this review, the most outstanding research (in vitro and in vivo) dealing with the use of SA or its derivatives to modify the surface carriers, in order to achieve targeted or stealth nanosystems, is summarized. Moreover, the application of SA or its derivatives as modifiers in cancer targeting and therapy, and in recognition purposes, is considered. Expert opinion: The application of SA-based strategies for nanocarrier engineering represents one of the most stimulating challenges in drug delivery and drug targeting. Both in vivo and in vitro results on stealth or targeted nanocarriers, modified with different kinds of SA or SA derivative, have highlighted the great potential of this approach. These studies have drawn attention to both the advantages (stealth properties, targeting ability, cancer inhibition, viral and inflammation recognition, brain targeting) and the possible disadvantages (i.e., presence of possible multi-target side effect outputs) of this strategy, and overall suggests that further investigations on this strategy are required.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2018-01-16
    Description: There has been debate in the literature about whether jellyfish abundance has increased in the northern Benguela upwelling system, or not, over the past five decades and what impact they are having on pelagic fish. Here we review old expedition literature as well as more recent spatial and temporal patterns in distribution of jellyfish off Namibia at a number of different scales, using both published and previously unpublished data. Specifically, we have used data from fishery-dependent sources of both the demersal (359 638 trawls) and pelagic fisheries (11 324 purse-seine sets) that cover the period 1992–2006, supported by data from fishery-independent demersal (6 109 trawls) and pelagic trawls (1 817 trawls) from 1996 to 2006. Using frequency of capture as an index of abundance, it is clear that jellyfish are not randomly distributed within the northern Benguela ecosystem, but show specific areas of concentration that broadly reflect regional oceanography and the distribution of other zooplankton. Although jellyfish are present throughout the year, peaks in abundance are shown that often coincide with peaks in the spawning activity of fish of commercial importance. Interannual changes in jellyfish abundance observed from all sources do not agree, with some showing increases, others declines, and still others showing no change, which suggests caution should be exercised in their interpretation. Based on the multiple lines of evidence synthesised here, we conclude that jellyfish abundance has increased concomitant with a decline of pelagic fish stocks. We conclude that future recovery of the pelagic fishery off Namibia is likely to be considerably challenged because of significant overlaps in space and time between fish and jellyfish, and through the effects of competition and predation effects of jellyfish on fish.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Geomechanics and Geoengineering, 7 (3). pp. 159-174.
    Publication Date: 2018-04-17
    Description: In this paper, drained behaviour of cemented sand under high pressure is studied. A recently developed high pressure triaxial apparatus is used. The test results indicate the significance of degree of cementation and confining pressure on the isotropic compression, volumetric change, stress-strain behaviour and stress-dilatancy relationship of cemented sand at high confining pressures. The results suggest that the influence of cementation is greater at low confining stresses and it reduces with increasing confining stress where the effect of the confining pressure becomes dominant. A Scanning Electron Microscope analysis has also been included in the paper. It revealed that the particle and cement bonding breakage at high pressure is dependent on the stress level and the cement content. The higher the confining pressure the more significant particle and cement bonding breakage is observed. The higher the cement content the fewer sand particles and cement bonds are broken.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Applied Earth Science, 120 (1). pp. 31-38.
    Publication Date: 2018-04-24
    Description: The abundance of gold in crustal rocks is an important constraint on the formation of gold deposits. Gold concentrations in unmineralised igneous, sedimentary and metamorphic rocks range from 0.05 to 20 ppb with average concentrations commonly between 0.5 and 5 ppb. Analytical methods with ultra-low detection limits are required to observe the full range of concentrations. Gold concentrations in igneous rocks are strongly controlled by the behaviour of sulphur. Higher gold concentrations occur in sulphur-undersaturated rocks compared to sulphur saturated igneous rocks. Mid ocean ridge basalt has lower gold concentration than ocean-island and volcanic-arc basalt, due mainly to lower oxygen fugacity at MOR settings that causes sulphur saturation. Gold concentrations in sedimentary rocks increase with increasing abundance of diagenetic sulphide minerals and organic matter. Gold concentrations in metamorphic rocks decrease systematically with increasing metamorphic grade. Amphibolite facies rocks commonly contain between 50 and 80% less gold than their unmetamorphosed protolith rocks.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  African Journal of Marine Science, 32 (2). pp. 271-277.
    Publication Date: 2016-12-14
    Description: This paper provides an introduction to, and overview of, the natural phenomenon known as the KwaZulu-Natal sardine run. Previous literature on this topic and hypotheses about the reasons why, and the mechanisms how, the run occurs are briefly synthesised and described. Papers contributing to this suite that detail more recent work on a variety of aspects of the sardine run, ranging from physical oceanography through sardine biology and ecology to socio-economic and ecological consequences, are outlined. Such studies will lead to improved understanding of the factors that regulate the timing and intensity of the run, which may permit predictions of whether it will occur, when fish will arrive on the KZN beaches, and how long it will persist. Such predictions would have substantial benefits for this ecologically and economically important event.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2020-07-09
    Description: A study of the echo peak amplitudes from known nodule areas is initiated to observe the acoustic response for varying nodule abundances and number densities. A statistical study of the peak amplitudes from different nodule areas confirms that the coefficient of variation is the highest for medium nodule abundance and number density. Echo fluctuation study based on the Rician probability density function (PDF) establishes that the non‐nodule sediment bottom contributes to less scattering, i.e., it is a microtopographic type, whereas scattering is dominant in the nodule‐bearing areas. The spectral studies are conducted on depth data of different areas. This study ensures that the signal scattering in the nodule bottom area is due to the nodules lying on the seabed rather than the large / small‐scale topographic variations. The study based on Poisson PDF for nodule area confirms this fact again. Agreement between the nodule distribution and the Poisson distribution parameter is clearly seen. Such a relation is not observed in the case of Rician density functions.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  New Zealand Journal of Marine and Freshwater Research , 21 . pp. 315-326.
    Publication Date: 2020-06-22
    Description: Two species of arrow squid, Nototodarus (Oegopsida: Ommastrephidae), are caught in New Zealand waters. The close similarity in most morphometric characters has lead to confusion over the status of the two species. They are distinguished by the number of pairs of suckers on the first right arm; adult males are distinguished by the number of proximal tubercles and the morphology of the distal part of the hectocotylised arm; fresh or frozen specimens can be identified by gel elec‐trophoresis of the enzyme glycerol‐3‐phosphate dehydrogenase. Nototodarus sloanii is found in southern waters and N. gouldi in more northerly waters around New Zealand as well as southern waters of Australia. Differences between the two species are described and notes presented on their biology, abundance, and exploitation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2020-07-30
    Description: The Imperial Cormorant Phalacrocorax atriceps is an inshore foraging, diving seabird (Cooper 1985) distributed throughout the southern hemisphere south of 45°S (Watson 1975). A brief description of the diet of the Imperial Cormorant at Marion Island has been published (Blankley 1981). We present here a more comprehensive report based on food samples collected throughout the year.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Journal of Remote Sensing, 32 (16). pp. 4527-4543.
    Publication Date: 2017-07-18
    Description: In this article, wave refraction and shoaling in coastal areas were investigated and used to derive the bathymetry. With its high spatial resolution, which can achieve up to 1 m in SpotLight mode, and its low cut-off wavelength, the TerraSAR-X satellite provides images that are particularly suitable for the observation of wave behaviour in transient and shallow waters. By computing the two-dimensional (2D) spectra, shoaling waves were tracked from the open sea to the shoreline. The observed wave refraction and shoaling were compared with wave refraction laws and first-order wave theory (Airy theory). The retrieved bathymetry was compared against depth data from other sources such as ETOPO1, the US Coastal Relief Model and sea charts from the British Admiralty. A further aim of this article was the investigation of breaking waves showing up as near-shore image patterns. A theory is presented of how to derive the height of breaking waves by use of this pattern. Synthetic aperture radar (SAR) images with azimuth as well as range travelling waves were investigated. As test sites, we chose the entrance of Port Phillip near Melbourne (Australia) and the Duck Research Pier in North Carolina (USA).
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2017-07-25
    Description: Seafloor morphology and ferromanganese nodule occurrence were studied using a multibeam side scan sonar (SeaBeam, 2000) and a deep-sea camera system in the Korea Deep-sea Environmental Study (KODES) area, northeast equatorial Pacific. Seafloor morphology and nodule abundance are highly variable even in this small study area. The NNE-SSW oriented hills are parallel and about 100–200 m high. Valleys are very flat-floored, while hilltops are rugged with depressions of tens of meters. Cliffs to about 100 m bound the valleys and the hills. The study area can be classified into three types based both on nodule occurrence and seafloor morphology, mostly G- and B-types and some M-type. G-type is characterized by high nodule abundance, ubiquitous bioturbation, and flat seafloor morphology, while B-type is characterized by irregular-shaped nodules, variable nodule abundance, occurrence of giant nodules and sediment lumps, rugged bottom morphology with depressions, and white calcareous surface sediments. Medium nodule abundance and a generally flat seafloor characterize M-type. G-type occurs mostly in the valley regions, while B-type is on the hilltop areas. M-type is located between the hilltop and the valley. Tectonic movement of the Pacific plate resulted in the elongated abyssal hills and cliffs. The rugged morphology on hilltops resulted from erosion and redistribution of surface siliceous sediments on hilltops by bottom currents, outcropping of underlying calcareous sediments, and dissolution of the carbonate sediments by corrosive bottom water undersaturated with CaCO3. Sediment eroded from the hills, which is relatively young and organic-rich, is deposited in the valleys, and diagenetic metal supply to manganese nodules in the valley area is more active than on the hills. We suggest that tectonic movement ultimately constrains morphology, surface sediment facies, bottom currents and sediment redistribution, bioturbation, thickness of the sedimentary layer, and other conditions, which are all interrelated and control nodule occurrence. The best potential area for mining in the study area is the G-type valley zones with about 3–4 km width and NNW-SSE orientation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2020-07-28
    Description: Mineral exploration activities require robust predictive models that result in accurate mapping of the probability that mineral deposits can be found at a certain location. Random forest (RF) is a powerful machine data-driven predictive method that is unknown in mineral potential mapping. In this paper, performance of RF regression for the likelihood of gold deposits in the Rodalquilar mining district is explored. The RF model was developed using a comprehensive exploration GIS database composed of: gravimetric and magnetic survey, a lithogeochemical survey of 59 elements, lithology and fracture maps, a Landsat 5 Thematic Mapper image and gold occurrence locations. The results of this study indicate that the use of RF for the integration of large multisource data sets used in mineral exploration and for prediction of mineral deposit occurrences offers several advantages over existing methods. Key advantages of RF include: (1) the simplicity of parameter setting; (2) an internal unbiased estimate of the prediction error; (3) the ability to handle complex data of different statistical distributions, responding to nonlinear relationships between variables; (4) the capability to use categorical predictors; and (5) the capability to determine variable importance. Additionally, variables that RF identified as most important coincide with well-known geologic expectations. To validate and assess the effectiveness of the RF method. Statistical measures of map quality indicate that the RF method performs better than LR, with mean square errors equal to 0.12 and 0.19, respectively. The efficiency of RF is also better, achieving an optimum success rate when half of the area predicted by LR is considered.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Environmental Technology, 18 . pp. 195-202.
    Publication Date: 2017-09-26
    Description: Plastic debris accumulates in the marine environment following its use in agricultural, industrial and social activities. Its ultimate fate is accomodation in sediments where it may persist for times up to centuries or longer. There appears to be an increasing flux of materials with time and an increased areal coverage of the benthos. Impacts upon bottom organisms can take many forms. Systematic monitoring tactics for the extent of seafloor coverage by plastics are yet to be incorporated into national programs.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2019-02-27
    Description: The development of natural plankton populations in tanks (1000l) and in Kiel Bight is compared with special references to mechanisms affecting species composition in spring and early summer. In a first experiment, three tanks filled with surface water just prior to the bloom (February 1983) were held under different light conditions. Exponential growth coincided with onset of the growth in the field. Growth in the two darkened tanks was retarded. In the field, a bloom of mainly Thalassiosira polychorda was observed, whereas in the light tank Thlassiosira 'pseudonana' and in the two darker tanks Skeletonema costatum were the domninant species. The observed shift in species compositions between tanks and in the field can be attributed partly to differences in growth strategies of species involved but also to the specific effect of population enclosure. In a second experiment (May/ June 1983) the influence of grazing pressure was studied in two tanks with different abundance of metazooplankton. Nauplii as well as large protozoans were grazed down more rapidly than the samller phytoflagellates, which confirmed earlier hypotheses based on field observations. After decline of grazers, possibly due to starvation, a succession from bacteria to nanoflagellates and then ciliates was observed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Natural History, 37 (11). pp. 1281-1327.
    Publication Date: 2018-06-01
    Description: The family Forskaliidae (Siphonophora, Physonectae) contains a single genus, Forskalia, whose species are, in general, poorly known. However, in recent years many Forskalia specimens have been collected by scuba divers or by using submersibles. These specimens have allowed a comprehensive review of the species within the genus to be carried out. In addition two new species are described.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 62 (4). pp. 469-480.
    Publication Date: 2016-06-15
    Description: A thorough knowledge of global ocean precipitation is an indispensable prerequisite for the understanding of the water cycle in the global climate system. However, reliable detection of precipitation over the global oceans, especially of solid precipitation, remains a challenging task. This is true for both, passive microwave remote sensing and reanalysis based model estimates. The optical disdrometer ODM 470 is a ground validation instrument capable of measuring rain and snowfall on ships even under high wind speeds. It was used for the first time over the Nordic Seas during the LOFZY 2005 campaign. A dichotomous verification of precipitation occurrence resulted in a perfect correspondence between the disdrometer, a precipitation detector and a shipboard observer's log. The disdrometer data is further point-to-area collocated against precipitation from the satellite based Hamburg Ocean Atmosphere Parameters and fluxes from Satellite data (HOAPS) climatology. HOAPS precipitation turns out to be overall consistent with the disdrometer data resulting in a detection accuracy of 0.96. The collocated data comprises light precipitation events below 1 mm h–1. Therefore two LOFZY case studies with high precipitation rates are presented that indicate plausible HOAPS satellite precipitation rates. Overall, this encourages longer term measurements of ship-to-satellite collocated precipitation in the near future.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2020-06-19
    Description: Many Penicillium species produce enzyme systems with good performances in lignocellulose degradation. In our laboratory, lignocellulolytic enzyme-producing Penicillium oxalicum (formerly classified as Penicillium decumbens) strains have been studied for more than 30 years. High cellulase-producing mutants have been obtained through random mutagenesis and genetic engineering, and the components in the enzyme systems have been elucidated using systems biology tools. The effects of different carbon sources on the production level of lignocellulolytic enzymes have been studied, and the related molecular mechanisms have been investigated. When compared with the widely used cellulase producer Trichoderma reesei, some unique features have been found in P. oxalicum, including higher β-glucosidase activity, higher numbers of lignocellulolytic enzyme gene, and different response of cellulase gene expression to some disaccharides. To boost the economic potential of the biorefineries using lignocellulosic biomass, P. oxalicum strains need to be further improved regarding the performance and production level of the enzyme systems.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Journal of Remote Sensing, 32 (14). pp. 3967-3984.
    Publication Date: 2014-12-09
    Description: The temporal and spatial variability of sea-ice radar signatures in the Southern Ocean during late winter, spring and early summer from QuikSCAT data is presented. We observe a circumpolar and broad band of sea-ice close to the marginal ice zone that is characterized by very high radar backscatter. This feature is explained through detailed in situ observations of snow and sea-ice properties as well as in relation to meteorological conditions, which were derived from US National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. Our results indicate that high backscatter regions are caused by metamorphous snow, which forms through re-freezing after short-term melt events. This process is connected with the episodic passes of low-pressure systems entraining warmer air from the north. South of the Antarctic Circumpolar Trough, sea-ice is not affected by this influence and shows spatially homogenous microwave signatures with low backscatter.
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2015-01-22
    Description: Palaeoenvironmental records from permafrost sequences complemented by infrared stimulated luminescence (IRSL) and 230Th/U dates from Bol'shoy Lyakhovsky Island (7320'N, 14130'E) document the environmental history in the region for at least the past 200 ka. Pollen spectra and insect fauna indicate that relatively wet grass-sedge tundra habitats dominated during an interstadial c. 200–170 ka BP. Summers were rather warm and wet, while stable isotopes reflect severe winter conditions. The pollen spectra reflect sparser grass-sedge vegetation during a Taz (Late Saalian) stage, c. 170–130 ka BP, with environmental conditions much more severe compared with the previous interstadial. Open Poaceae and Artemisia plant associations dominated vegetation at the beginning of the Kazantsevo (Eemian) c. 130 ka BP. Some shrubs (Alnus fruticosa, Salix, Betula nana) grew in more protected and wetter places as well. The climate was relatively warm during this time, resulting in the melting of Saalian ice wedges. Later, during the interglacial optimum, shrub tundra with Alnus fruticosa and Betula nana s.l. dominated vegetation. Climate was relatively wet and warm. Quantitative pollen-based climate reconstruction suggests that mean July temperatures were 4–5 C higher than the present during the optimum of the Eemian, while late Eemian records indicate significant climate deterioration.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus B: Chemical and physical meteorology, 51 (2). pp. 461-476.
    Publication Date: 2016-06-14
    Description: The assessment of direct effects of anthropogenic CO2 increase on the marine biota has received relatively little attention compared to the intense research on CO2-related responses of the terrestrial biosphere. Yet, due to the rapid air–sea gas exchange, the observed past and predicted future rise in atmospheric CO2 causes a corresponding increase in seawater CO2 concentrations, [CO2], in upper ocean waters. Increasing [CO2] leads to considerable changes in the surface ocean carbonate system, resulting in decreases in pH and the carbonate concentration, [CO2−3]. These changes can be shown to have strong impacts on the marine biota. Here we will distinguish between CO2-related responses of the marine biota which (a) potentially affect the ocean's biological carbon pumps and (b) are relevant to the interpretation of diagnostic tools (proxies) used to assess climate change on geological times scales. With regard to the former, three direct effects of increasing [CO2] on marine plankton have been recognized: enhanced phytoplankton growth rate, changing elemental composition of primary produced organic matter, and reduced biogenic calcification. Although quantitative estimates of their impacts on the oceanic carbon cycle are not yet feasible, all three effects increase the ocean's capacity to take up and store atmospheric CO2 and hence, can serve as negative feedbacks to anthropogenic CO2 increase. With respect to proxies used in palaeo-reconstructions, CO2-sensitivity is found in carbon isotope fractionation by phytoplankton and foraminifera. While CO2- dependent isotope fractionation by phytoplankton may be of potential use in reconstructing surface ocean pCO2 at ancient times, CO2-related effects on the isotopic composition of foraminiferal shells confounds the use of the difference in isotopic signals between planktonic and benthic shells as a measure for the strength of marine primary production. The latter effect also offers an alternative explanation for the large negative swings in δ13C of foraminiferal calcite between glacial and interglacial periods. Changes in [CO2−3] affect the δ18O in foraminiferal shells. Taking this into account brings sea surface temperature estimates for the glacial tropics closer to those obtained from other geochemical proxies.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2019-01-21
    Description: A model of the interactive effects of disturbance and productivity on diversity predicts peak diversity to shift towards higher disturbance regimes as productivity increases, confining the Intermediate Disturbance Hypothesis to intermediate productivity levels. We conducted a two-factorial (disturbance, nutrients) field experiment to test the validity of this model for two subtropical intertidal rocky shores. Treatment responses varied between distinct community types at two sites. Intensified disturbance increased evenness, and under high nutrient enrichment decreased species richness of communities dominated by encrusting algae, whereas turf-dominated communities remained unaffected. Nutrient additions increased biomass and modulated community composition at both sites, in addition to increasing species richness in encrusting-algal and decreasing evenness of turf-forming assemblages. Thus, only highly enriched encrusting-algal communities followed the model predictions. Different mechanisms appear to control species coexistence in different types of communities, some violating the assumptions of the tested model, i.e. resource limitation and competitive exclusion.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2019-01-21
    Description: Prevention of epibiosis is of vital importance for most aquatic organisms, which can have consequences for their ability to invade new areas. Surface microtopography of the shell periostracum has been shown to have antifouling properties for mytilid mussels, and the topography shows regional differences. This article examines whether an optimal shell design exists and evaluates the degree to which shell microstructure is matched with the properties of the local fouling community. Biomimics of four mytilid species from different regional provenances were exposed at eight different sites in both northern and southern hemispheres. Tendencies of the microtopography to both inhibit and facilitate fouling were detected after 3 and 6 weeks of immersion. However, on a global scale, all microtopographies failed to prevent fouling in a consistent manner when exposed to various fouling communities and when decoupled from other shell properties. It is therefore suggested that the recently discovered chemical anti-microfouling properties of the periostracum complement the anti-macrofouling defence offered by shell microtopography.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  South African Journal of Marine Science, 20 . pp. 421-428.
    Publication Date: 2019-01-24
    Description: The capture of 52 specimens of the cirrate octopod Grimpoteuthis glacialis (Robson, 1930), of dorsal mantle length 20-165 mm during a 1996 trawling survey near the Antarctic Peninsula allowed the basic biology of the species to be examined. Their presence in bottom trawls at depths of 333-879 m, but their absence from benthopelagic and pelagic trawls, is consistent with a primarily benthic habitat. The largest single sample, 40 animals, came from a soft mud bottom and highlights the patchy nature of the distribution. Males tended to be bigger in total length and mass than females of similar mantle length. The males, however, were mature at a smaller size. Mature males have tiny sperm packets, rather than typical cephalopod spermatophores, in their distal reproductive tract. Mature females have large, smooth eggs in the proximal oviduct, in the huge oviducal gland and in the distal oviduct. Eggs in the distal oviduct have a thick, sticky coating that hardens in seawater into a secondary egg case. Ovarian eggs vary greatly in size, possibly indicating protracted egg laying. Observations on live animals indicate that the species swims primarily by fin action, rather than by jetting or medusoid pulses with the arm/web complex. It may be capable of limited changes in colour pattern, especially on the oral surface of the web. Three pairs of surface structures that appear superficially to be white spots anterior to the eyes and near the bases of the fins are actually transparent patches in the skin. When considered in association with the transparent subdermal layer and the anatomy of the eyes, optic nerves and optic lobes, these clear patches seem to function in detecting unfocused light on the horizontal plane of the benthic animal.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 66 . p. 22830.
    Publication Date: 2015-11-25
    Description: Mid-latitudinal cyclones are a key factor for understanding regional anomalies in primary meteorological parameters such as temperature or precipitation. Extreme cyclones can produce notable impacts on human society and economy, for example, by causing enormous economic losses through wind damage. Based on 41 annually initialised (1961–2001) hindcast ensembles, this study evaluates the ability of a single-model decadal forecast system (MPI-ESM-LR) to provide skilful probabilistic three-category forecasts (enhanced, normal or decreased) of winter (ONDJFM) extra-tropical cyclone frequency over the Northern Hemisphere with lead times from 1 yr up to a decade. It is shown that these predictions exhibit some significant skill, mainly for lead times of 2–5 yr, especially over the North Atlantic and Pacific. Skill for intense cyclones is generally higher than for all detected systems. A comparison of decadal hindcasts from two different initialisation techniques indicates that initialising from reanalysis fields yields slightly better results for the first forecast winter (month 10–15), while initialisation based on an assimilation experiment provides better skill for lead times between 2 and 5 yr. The reasons and mechanisms behind this predictive skill are subject to future work. Preliminary analyses suggest a strong relationship of the model’s skill over the North Atlantic with the ability to predict upper ocean temperatures modulating lower troposphere baroclinicity for the respective area and time scales.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2015-04-21
    Description: The bright colouration of the cytoplasm in intertidal rotaliid foraminifera and their particle-gathering activity reliably reveals live specimens in fresh samples, without any fixatives or dyes applied. Using this approach, we demonstrate that live representatives of three rotaliid species, all belonging to the genus Elphidium, were common on intertidal mud and sand beaches. Two species, E. excavatum clavatum and E. albiumbilicatum, lived close to freshwater outflows, whereas E. williamsoni occupied beaches bathed by waters with normal salinity (surface 26–27‰ in the western White Sea). A least 13 species were found alive in the intertidal zone. Among non-calcareous foraminifera, Miliammina fusca, Ammotium cassis and Ovammina opaca were the most numerous.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Journal of Remote Sensing, 25 (7-8). pp. 1449-1453.
    Publication Date: 2015-10-14
    Description: The Space Information Laboratory (SIL) of the Tropical Center for Earth and Space Studies of the University of Puerto Rico at Mayagu¨ ez (UPRM) has been collecting and processing satellite data since December of 1996. Satellite imagery from the Advanced Very High Resolution Radiometer (AVHRR) and the Sea viewing Wide Field of view Sensor (SeaWiFS) provides us with a new understanding of phytoplankton dynamics in the Caribbean region. SeaWiFS shows the intrusion of waters into the eastern Caribbean Sea from the Orinoco River during fall and from the Amazon River during spring–summer. Strong coastal upwelling in Venezuela produced by the trade winds during winter– spring is detected with the AVHRR. The satellite data suggest that these seasonal events may play an important role in phytoplankton fertilization of the eastern Caribbean Sea. SeaWiFS and hydrological data are also combined to evaluate the impact of hurricanes on phytoplankton distribution. The development of models for estimation of ocean primary productivity using SeaWiFS and AVHRR data is now in progress.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  North American Journal of Fisheries Management, 21 (1). pp. 1-9.
    Publication Date: 2020-06-19
    Description: The use of precautionary management actions within a fisheries context has generally been limited to reducing fishing mortality. By the use of quantitative models, overfishing thresholds can be determined and actions can be taken to reduce the probability of further population declines and to allow rebuilding. Within this context, four management approaches have been defined (i.e., preventive approach, corrective approach, precautionary approach, and precautionary principle) on the basis of levels of uncertainty in the information used to make decisions and the potential cost of errors as a result of those decisions. In this paper, I apply these approaches to developing a precautionary and adaptive habitat management framework. Fishing effort metrics are used to develop estimates of the area of seafloor impacted by fishing, and thresholds are proposed to trigger specific types of management actions. Information needs include the cumulative area impacted by all gears, the distribution of habitats and diversity of key taxa, effects of gears on habitat and patterns of diversity, and linkages between habitat and the dynamics of exploited populations. Incentives for the fishing industry that will improve the information available to make decisions and reduce the level of precaution required for managing exploitation of wild populations are discussed. This framework is a starting point for management agencies to develop precautionary and adaptive habitat management programs that promote both the sustainability of exploited populations and the maintenance of biological diversity.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2020-04-20
    Description: According to historical data, the glacial relict higher crustaceans, Mysis relicta and Pallaseopsis quadrispinosa, as well as a plankton crustacean Limnocalanus macrurus had earlier been recorded in Lake Drüksiai. Our data and investigations of other authors evidence that these crustaceans no longer inhabit the lake. What are the prospects for the recovery of these crustaceans after restoring the natural thermal regime in Lake Drüksiai? One of the possibilities is to reintroduce these species after restoring the natural thermal regime in the lake and improving dissolved oxygen level in the hypolimnion, which would provide conditions for long-term survival and recovery of populations of these crustaceans. As reintroduction of relict species is rather costly, it is necessary to assess effectiveness of such works.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2015-03-23
    Description: Permafrost deposits were studied along the Olenyeksky and the Arinsky distributaries in the western Lena delta using a multidisciplinary approach that included sedimentological, mineralogical, stable-isotope, and paleoecological analyses in order to reconstruct the Late Quaternary landscape and environmental history of this Northeast.
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Expert Opinion on Drug Metabolism & Toxicology, 9 (5). pp. 551-558.
    Publication Date: 2020-07-31
    Description: Cytochromes P450 (P450) and associated monooxygenases are a family of heme proteins involved in metabolism of endogenous compounds (arachidonic acid, eicosanoids and prostaglandins) as also xenobiotics including drugs and environmental chemicals. Liver is the major organ involved in P450-mediated metabolism and hepatic enzymes have been characterized. Extrahepatic organs, such as lung, kidney and brain have the capability for biotransformation through P450 enzymes. Brain, including human brain, expresses P450 enzymes that metabolize xenobiotics and endogenous compounds. AREAS COVERED: An overview of P450-mediated metabolism in brain is presented focusing on distinct differences seen in expression of P450 enzymes, generation of unique P450 enzymes in brain through alternate splicing and their consequences in terms of metabolism of psychoactive drugs and inflammatory prompts, such as leukotrienes, thus modulating inflammatory response. EXPERT OPINION: The brain possesses unique P450s that metabolize drugs and endogenous compounds through pathways that are markedly different from that seen in liver indicating that extrapolation directly from liver to brain is not appropriate. It is therefore necessary to characterize the unique brain P450s and their ability to metabolize xenobiotics and endogenous compounds to better understand the functions of this important class of enzymes in brain, especially human brain.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2017-05-30
    Description: Exposure of Fucus spiralis germlings to precise copper concentrations (0 to 844 nM Cu2+) in chemically defined medium demonstrated a relationship between urltrastructural changes and growth retardation with increasing copper concentration. Electron-translucent vesicles, present in ova, which normally disappear after fertilization, accumulated in germlings exposed to Cu2+ above 10.6 nM, suggesting that copper may inhibit a metabolic pathway involved in cell wall formation which is initiated by fertilization No membrane damage was observed during the exposure period. During a post-exposure period in copper-free medium, recovery occurred (rhizoid extension, apical hair formation) in germlings previously exposed to concentrations below 106 nM Cu2+ and electron-translucent vesicles became granular and disappeared. It is proposed that the electron-translucent vesicles contain a cell wall precursor and that copper inhibits its incorporation into the cell wall, preventing growth and development of the zygote.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Biofouling, 29 (6). pp. 661-668.
    Publication Date: 2019-09-23
    Description: The important role of marine epibiotic biofilms in the interactions of the host with its environment has been acknowledged recently. Previous studies with the temperate brown macroalga Fucus vesiculosus have identified polar and non-polar compounds recovered from the algal surface that have the potential to control such biofilms. Furthermore, both the fouling pressure and the composition of the epibiotic bacterial communities on this macroalga varied seasonally. The extent to which this reflects a seasonal fluctuation of the fouling control mechanisms of the host is, however, unexplored in an ecological context. The present study investigated seasonal variation in the anti-settlement activity of surface extracts of F. vesiculosus against eight biofilm-forming bacteria isolated from rockweed-dominated habitats, including replication of two populations from two geographically distant sites. The anti-settlement activity at both sites was found to vary temporally, reaching a peak in summer/autumn. Anti-settlement activity also showed a consistent and strong difference between sites throughout the year. This study is the first to report temporal variation of antifouling defence originating from ecologically relevant surface-associated compounds.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Oceanography and Marine Biology: an Annual Review, 41 . pp. 115-159.
    Publication Date: 2015-12-11
    Description: This review provides an overview of the importance of beach accumulations of macrophytes and other organic beach-cast material on the ecology of sandy beach ecosystems. It describes the composition of these allochthonous subsidies, their abundance on beaches in relation to seasonal, lunar, tidal and spatial trends, their decomposition and utilisation by bacterial, meio- and macrofaunal communities. The paper then analyses the community structure and the species succession in both macrophyte wrack and carrion and reports the most important findings on individual wrack-inhabiting species (amphipods, isopods, dipterans). Other aspects, such as feeding and microclimatic preferences of certain species and their interactions in wracks, are also discussed. Links to vertebrate species and other secondary consumers that exploit beach-cast macrophytes and carrion as trophic resource are considered, and the importance of wrack in recycling nutrients to nearshore coastal ecosystems is stressed. The beneficial and detrimental effects of organic beach-cast material on both plants and animals of beach and nearshore communities and on the geomorphology of coastal beach-dune systems are pointed out. Another section is dedicated to human use of beach-cast macrophytes through harvesting of economically important species and of other stranded material through its exploitation for traditional reasons. The effects of harvesting on local faunal communities and on the stability of the dunes is discussed. A final section of the paper includes the positive and negative effects of man-made debris on sandy-beach ecosystems and briefly reviews the major findings.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2015-09-10
    Description: The mussel Mytilus galloprovincialis is a common aquaculture species, and also a major fouling organism that has negative economic impacts. There are no standard assay conditions for this important species and therefore, this study quantified the effect of key factors on the settlement of pediveligers and plantigrades. Density dependent settlement did not occur for either pediveligers or plantigrades. Settlement increased in drop assays in a 12 h light:12 h dark cycle, while bottom shade had no effect of any magnitude. In addition, settlement was significantly enhanced by storing pediveligers for between 4 and 24 days at 4 °C. Overall, these data provide the template to optimise and standardise static laboratory settlement assays for mussels in order to develop materials that either enhance settlement for the aquaculture industry, or deter settlement for antifouling applications. Furthermore, simple mechanisms such as storage at 4 °C can enhance settlement beyond current methods used in aquaculture hatcheries.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2020-05-28
    Description: A single living specimen of Stenocyathus vermiformis was collected with a grab from the distal rubble zone of a Lophelia bank at 276 m depth on the Sula Ridge, Norwegian Shelf.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  European Journal of Phycology, 30 (2). pp. 87-94.
    Publication Date: 2018-08-15
    Description: The mean pressures required to collapse gas vesicles in turgid cells of cyanobacteria from the Baltic Sea were 0·91 MPa (9·1 bar) in Aphanizomenon flos-aquae, 0·83 MPa in Nodularia sp. collected from the main deep basins and 0·34 MPa in Nodularia from shallower coastal regions. The gas vesicles were strong enough to withstand the depth of winter mixing, down to the permanent halocline (60 m in the Bornholm Sea, 90 m in the Eastern Gotland Sea) or to the sea bottom (30 m or less in the shallow Arkona Sea and Mecklenburg Bight). The cyanobacteria had low cell turgor pressures, within the range 0·08–0·18 MPa. The colonies were highly buoyant: the Aphanizomenon colonies floated up at a mean velocity of 22 m per day and the Nodularia colonies at 36 m per day. The colonies remained floating when up to half of the gas vesicles had been collapsed. In summer the cyanobacteria were mostly restricted to the water above the thermocline and in calm conditions their concentration increased towards the top of the water column. A series of colony concentration profiles indicated that, following a deep mixing event, the population of colonies moved upward with a net velocity of 22 m per day, similar to the colony floating velocity. This demonstrated that the buoyancy provided by gas vesicles would give a selective advantage to populations of cyanobacteria by enabling them to float into the higher irradiance of the near-surface water.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2015-10-02
    Description: Current antifouling technologies rely on metal-based paints, but due to their toxicity, an expected worldwide ban of organotin-containing paints is now prompting the quest for safe and effective alternatives. One of these is antifouling coatings whose active components are naturally occurring compounds in marine organisms. A number of laboratory bioassays has been designed to search for antifouling compounds. However, there is no evidence to date that these assays provide results reproducible through ecologically realistic field experiments. Natural concentrations of the extracts from the Brazilian seaweeds Laurencia obtusa and Stypopodium zonale were tested in the laboratory through the 'mussel test' and in the field through the 'phytagel method' in order to compare the efficiency of these methods in assessing antifouling activity. L. obtusa extract significantly inhibited fouling in both the laboratory and field assays, while S. zonale stimulated fouling in both assays. Major compounds from the extracts were identified. The findings suggest that the 'mussel test' is a reliable time and cost-saving screening method for antifouling substances, although field assays are more sensitive for detection of their activity spectrum.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  International Journal of Remote Sensing, 25 (7-8). pp. 1337-1340.
    Publication Date: 2015-10-08
    Description: The hydrographic conditions in the south-east Atlantic were investigated during the cruise of R/V Poseidon in April 1999. The area of investigation covers the two major eastern boundary currents of the Southern Atlantic and its convergence in the Angola-Benguela Frontal Zone (ABFZ). Hydrographic measurements have been carried out in combination with current measurements and are supplemented with remote sensing data of sea surface temperature (SST) and wind stress. The Angola Current transported in its surface part less saline water from the great rivers in the north towards the ABFZ. At the same time, south of the front, strong coastal upwelling in the Benguela was observed. At the beginning of April 1999 the ABFZ was found at an unusual southern position. The rapid dynamic response of the ABFZ to wind forcing is discussed on the basis of satellite SST images combined with hydrographic measurements.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 63 . pp. 338-347.
    Publication Date: 2019-09-23
    Description: The buoyancy flux at the air/sea interface plays a key role in water mass transformation and mixing as it modifies surface water density and in turn drives overturning and enhances stratification. It is the interplay of these two independent heat and freshwater buoyancy flux components that is of central importance when analysing mechanisms of the ocean/atmosphere interaction. Here, a diagnostic quantity (ΘB) is presented that allows to capture the relative contribution of both components on the buoyancy flux in one single quantity. Using NCEP reanalysis of heat and freshwater fluxes (1948–2009) demonstrates that ΘB is a convenient tool to analyse both the temporal and spatial variability of their corresponding buoyancy fluxes. For the global ocean the areal extent of buoyancy gain and loss regions changed by 10%, with the largest extent of buoyancy gain during the 1970–1990 period. In the subpolar North Atlantic, and likewise in the South Pacific, decadal variability in freshwater flux is pronounced and, for the latter region, takes control over the total buoyancy flux since the 1980s. Some of the areal extent time series show a significant correlation with large-scale climate indices.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2019-09-23
    Description: The chemical defence against microfouling in the brown seaweed Fucus vesiculosus was investigated and an inhibitor of bacterial settlement was isolated by bioassay-guided fractionation of non-polar surface extracts. UV-vis and mass spectrometry were used to identify the compound as the carotenoid fucoxanthin. The metabolite was tested at the natural concentration (in a surface volume based assay) against the settlement of four bacterial strains isolated from F. vesiculosus and 11 strains isolated from co-occurring algae and marine sediment. Surface concentrations between 1.4 and 6 μg cm-2 resulted in 50% inhibition of four of these isolates, which were studied in more detail using a surface area-based assay, while a fifth isolate proved to be less sensitive. The presence of fucoxanthin on the surface of F. vesiculosus was demonstrated with two different surface extraction methods. Fucoxanthin was detected at concentrations between 0.7 and 9 μg cm-2 on the algal surface. Fucoxanthin was still present at the algal surface after removal of associated diatoms through mechanical cleaning and germanium dioxide treatment and was thus mainly produced by F. vesiculosus rather than by diatoms. Thus, the photosynthetic pigment fucoxanthin appears to be ecologically relevant as a surface-associated antimicrobial agent, acting against the settlement of bacteria on the surface of the macroalga F. vesiculosus.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2020-06-19
    Description: The “rugophilic”; behaviour (e.g. the preference for settling in concavities) of barnacles is well documented. In contrast, little is known about settlement preferences of other species with regard to surface microtopography. In a randomized block design, five different rugosities (smooth, 0.1 mm, 0.5 mm, 1 mm, 5 mm) were exposed to natural fouling in the Baltic Sea. In four experiments, test panels were colonized by Mytilus edulis, Polydora dliata, Balanus improvisus, diatoms, hydrozoa, bryozoa, and several ciliates. Settlement densities and microtopographical preferences for pits or elevations as a function of grain size were evaluated. Rugosities influenced settlement densities and the microtopographical preferences of almost all investigated species. Settlement densities were generally lowest on smooth panels, with most species showing distinct preferences for different rugosities. While a preference for pits was frequent, in some species the proportion of individuals settling on elevations significantly increased with roughness. These data on microtopographical preferences of different species give new insights into interactions between settlement behaviour, surface roughness, boundary layer hydrodynamics and community structure.
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 54 (3). pp. 299-316.
    Publication Date: 2019-09-23
    Description: Due to the ephemeral nature of the atmospheric conditions over the Baltic Sea, the flow field is highly variable, and thus, changes in the resulting circulation and upwelling are difficult to observe. However, three-dimensional models, forced by realistic atmospheric conditions and river runoff, have reached such a state of accuracy that the highly fluctuating current field and the associated evolution of the temperature and salinity field can be described. In this work, effects of remote and local atmospheric forcing on circulation and upwelling in the Baltic Sea are investigated. Changes in the characteristics of the large-scale atmospheric wind field over the central and eastern North Atlantic can be described by the North Atlantic Oscillation (NAO). The NAO is related to the strength and geographical position of weather systems as they cross the North Atlantic and thus has a direct impact on the climate in Europe. To relate the local wind field over the Baltic Sea to the large-scale atmospheric circulation, we defined a Baltic Sea Index (BSI), which is the difference of normalised sea level pressures between Oslo in Norway and Szczecin in Poland. The NAO is significantly related to the BSI. Furthermore, the BSI is highly correlated with the storage variation of the Baltic Sea and the volume exchange through the Danish Sounds. Based on three-dimensional model calculations, it is shown that different phases of the NAO during winter result in major changes of horizontal transports in the deep basins of the Baltic Sea and in upwelling along the coasts as well as in the interior of the basins. During NAO+ phases, strong Ekman currents are produced with increased up- and downwelling along the coasts and associated coastal jets, whereas during NAO− phases, Ekman drift and upwelling are strongly reduced, and the flow field can almost entirely be described by the barotropic stream function. The general nature of the mean circulation in the deep basins of the Baltic Sea, obtained from a 10-yr model run, can be described by the depth integrated vorticity balance derived from the transport equation for variable depth.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Natural History, 47 (5-12). pp. 265-288.
    Publication Date: 2019-03-13
    Description: The copepod family Oncaeidae is widely distributed in the world's oceans and includes many small and abundant species. Due to their small size and the existence of sister and sibling species in different parts of the ocean, species identification is very difficult. Quantitative studies on copepod communities usually consider oncaeids at the family level only, or present uncertain species names, when based on regional identification keys not established for the study area. This paper aims to develop the basis for an improved taxonomic resolution of oncaeids in ecological studies. It summarizes the most relevant morphological elements to characterize the seven presently known genera and to define in addition 16 species groups within the paraphyletic taxon Oncaea s.l. On this basis, a worldwide identification key for oncaeids is presently being developed, restricted to genera and species groups, with species included as far as the state of knowledge allows.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 51 (5). pp. 964-978.
    Publication Date: 2016-06-14
    Description: A quantitative relationship between observed sea-ice roughness and simulated large-scale deformation work is established in order to provide new means for model validation and a better representation of the sea-ice component in climate modelling. Sea-ice roughness is introduced as an additional prognostic variable in a dynamic–thermodynamic sea-ice model with a viscous-plastic rheology. It is defined as the accumulated work of internal forces acting upon an ice volume, given in energy per area. A fraction of this total deformation work is transferred to the potential energy stored in pressure ridges. Using ridge geometries and distribution functions from observations, observable quantities like mean pressure ridge height, ridge frequency as well as volumetric and areal fractions of deformed ice are derived from the simulated ice roughness. Comparisons of these simulated quantities with measurements (submarine-borne sonars, laser altimeters on helicopters) show good agreement. Satellite-borne observations of sea-ice roughness now under development will provide an even larger data set which will be used for model verification. Additionally roughness-dependent drag coefficients are introduced to account for the effect on the momentum exchange between ocean and atmosphere due to the form drag of roughness elements. The simulations indicate that the inclusion of sea-ice roughness provides for a more realistic representation of the boundary layer processes in climate models.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Marine Biology Research, 6 (1). pp. 25-52.
    Publication Date: 2021-08-16
    Description: A two-leg cruise of R/V G. O. Sars in summer of 2004 along the Mid-Atlantic Ridge explored the diversity and distribution patterns of pelagic and non-hydrothermal bottom communities in the vicinity of the northern Mid-Atlantic Ridge. In total, 1295 cephalopods were caught, representing 56 species. Differences in species composition and size were apparent among the various types of trawls used. The Aakra trawl and bottom trawl caught the largest numbers of species (38 and 34, respectively); size of cephalopods was directly related to the size of the net. Many more species were caught in the southern part of the study area than farther north. The most abundant species was Gonatus steenstrupi, found mostly in the northern part of the study area. A few abundant species, such as Mastigoteuthis agassizii, were found throughout the region, with no clear indication that their northern or southern distributional limits occur within the area sampled. Several benthic and one pelagic species, all taken in small numbers, were captured only in the region of the Charlie Gibbs Fracture Zone. We found many species at very low numbers (i.e. 37 species with 〈10 specimens in all gear types combined).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  European Journal of Phycology, 38 . pp. 171-180.
    Publication Date: 2017-09-12
    Description: Development of biomass and density in experimental monospecific stands of Fucus serratus, F. vesiculosus and F. spiralis was followed on Helgoland (southern North Sea) in plots with three different initial germling densities. As biomass increased over time, considerable mortality occurred. Mortality was significantly higher in stands with higher initial densities, leading to similar final densities. The self-thinning law, which describes boundary conditions for combinations of biomass and density of plants, was refuted in two ways for all three Fucus species: (i) several data points on a bi-logarithmic plane lay considerably above self-thinning lines with conventional parameters from terrestrial plant ecology; however, ‘overall boundaries’ (i.e. a self-thinning line that constrains all lines found) from terrestrial plant ecology were not significantly transgressed, (ii) lines fitted with principal components analysis (PCA) revealed a positive correlation between stand biomass and density. Reasons are proposed why seaweeds generally seem to show higher maximum biomass for a given density than terrestrial plants. Size distributions at the end of the experiment were positively skewed with high Gini coefficients that lay in the range found in other seaweed studies. Inequality decreased with individual mass and increased with density. Gini coefficients were highly correlated with other measurements of inequality (coefficient of variation, skewness).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2016-06-17
    Description: In a midoceanic region of the northeast Atlantic, patches of freshly deposited phytodetritus were discovered on the sea floor at a 4500 m depth in July/August 1986. The color of phytodetritus was variable and was obviously related to the degree of degradation. Microscopic analyses showed the presence of planktonic organisms from the euphotic zone, e.g., cyanobacteria, small chlorophytes, diatoms, coccolithophorids, silicoflagellates, dinoflagellates, tintinnids, radiolarians, and foraminifers. Additionally, crustacean exuviae and a great number of small fecal pellets, “minipellets,” were found. Although bacteria were abundant in phytodetritus, their number was not as high as in the sediment. Phytodetrital aggregates also contained a considerable number of benthic organisms such as nematodes and special assemblages of benthic foraminifers. Pigment analyses and the high content of particulate organic carbon indicated that the phytodetritus was relatively undegraded. Concentrations of proteins, carbohydrates, chloroplastic pigments, total adenylates, and bacteria were found to be significantly higher in sediment surface samples when phytodetritus was present than in equivalent samples collected at the same stations in early spring prior to phytodetritus deposition. Only the electron transport system activity showed no significant difference between the two sets of samples, which may be caused by physiological stress during sampling (decompression, warming). The chemical data of phytodetritus samples displayed a great variability indicative of the heterogeneous nature of the detrital material. The gut contents of various megafauna (holothurians, asteroids, sipunculids, and actiniarians) included phytodetritus showing that the detrital material is utilized as a food source by a wide range of benthic organisms. Our data suggest that the detrital material is partly rapidly consumed and remineralized at the sediment surface and partly incorporated into the sediment. Incubations of phytodetritus under simulated in situ conditions and determination of the biological oxygen demand under surface water conditions showed that part of its organic matter can be biologically utilized. Based on the measured standing stock of phytodetritus, it is estimated that 0.3–3% of spring primary production sedimented to the deep-sea floor. Modes of aggregate formation in the surface waters, their sedimentation, and distribution on the seabed are discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2019-09-23
    Description: This study investigated whether surface-associated compounds isolated from the macroalga Fucus vesiculosus had the potential to mediate microbial and/or macrobial epibiosis similar to that on the natural alga. To selectively yield thallus-associated compounds and avoid contamination by intracellular algal compounds, cell lysis was monitored by surface microscopy of algal cells and chemical profiling of algal surface extracts by coupled gas chromatography mass spectroscopy. The optimized extraction resulted in polar and non-polar algal surface extracts. The non-polar surface extract was immobilized in hydrogel, the polar surface extract was homogeneously perfused through the gel to ensure a temporally constant delivery of polar extract components. During a 7day field trial, bacterial biofilms were formed on control gels and gels featuring polar and/or non-polar extract components. PERMANOVA revealed that bacterial community profiles on controls and on gels featuring polar or non-polar extract were significantly different from the profile on F. vesiculosus, while the profile on the gels bearing both polar and non-polar extracts was not. Moreover, the polar surface extracts inhibited the settlement of barnacle cyprids. Considering the pronounced effects of bacterial biofilms on invertebrate larval settlement, these results suggest that algal surface chemistry affects macrofouling not only directly but also indirectly, via its control of biofilm formation and composition
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2019-09-23
    Description: It was demonstrated previously that polar and non-polar surface extracts of the brown alga Fucus vesiculosus collected during winter from the Kiel Bight (Germany) inhibited bacterial attachment at natural concentrations. The present study describes the bioassay-guided identification of the active metabolites from the polar fraction. Chromatographic separation on a size-exclusion liquid chromatography column and bioassays identified an active fraction that was further investigated using nuclear magnetic resonance spectroscopy and mass spectrometry. This fraction contained the metabolites dimethylsulphopropionate (DMSP), proline and alanine. DMSP and proline caused the anti-attachment activity. The metabolites were further quantified on the algal surface together with its associated boundary layer. DMSP and proline were detected in the range 0.12–1.08 ng cm−2 and 0.09–0.59 ng cm−2, respectively. These metabolites were tested in the concentration range from 0.1 to 1000 ng cm−2 against the attachment of five bacterial strains isolated from algae and sediment co-occurring with F. vesiculosus. The surface concentrations for 50% inhibition of attachment of these strains were always 〈0.38 ng cm−2 for DMSP and in four cases 〈0.1 ng cm−2 for proline, while one strain required 1.66 ng cm−2 of proline for 50% inhibition. Two further bacterial strains that had been directly isolated from F. vesiculosus were also tested, but proved to be the least sensitive. This study shows that DMSP and proline have an ecologically relevant role as surface inhibitors against bacterial attachment on F. vesiculosus.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2019-09-23
    Description: Bacteria associated with Fucus vesiculosus and Delesseria sanguinea, two macroalgae from the Kiel Fjord were investigated seasonally over two years by cultivation-based methods. A total of 166 bacterial strains were isolated from the macroalgae, affiliated to seven classes of bacteria (Actinobacteria, Bacilli, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Cytophagia and Flavobacteria). According to 16S rRNA gene sequence similarities they were arranged in 82 phylotypes of〉99.0% sequence identity. Assuming that chemical factors rule the bacteriamacroalga and bacteriabacteria interactions on algal surfaces, we tested the antibiotic activity of the bacterial isolates not only against a panel of four standard test organisms (Bacillus subtilis, Candida glabrata, Escherichia coli and Staphylococcus lentus) but also four macroalga-associated microorganisms: Algicola bacteriolytica and Pseudoalteromonas elyakovii (macroalgal pathogens), and Bacillus algicola and Formosa algae (strains associated with algal surfaces). Organic extracts of more than 51% of the isolates from the two macroalgae inhibited the growth of at least one of the tested microorganisms. As much as 46% and 45% of the isolates derived from F. vesiculosus and D. sanguinea, respectively, showed antimicrobial activity against the set of macroalga-associated bacteria, compared with 13 and 19% against a standard set of microorganisms. High antibacterial activity against macroalgal pathogens and bacterial competitors support the assumption that complex chemical interactions shape the relationships of bacteria associated with macroalgae and suggest that these bacteria are a rich source of antimicrobial metabolites.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2016-06-14
    Description: Changes apparent in the arctic climate system in recent years require evaluation in a century-scale perspective in order to assess the Arctic's response to increasing anthropogenic greenhouse-gas forcing. Here, a new set of century- and multidecadal-scale observational data of surface air temperature (SAT) and sea ice is used in combination with ECHAM4 and HadCM3 coupled atmosphere-ice-ocean global model simulations in order to better determine and understand arctic climate variability. We show that two pronounced twentieth-century warming events, both amplified in the Arctic, were linked to sea-ice variability. SAT observations and model simulations indicate that the nature of the arctic warming in the last two decades is distinct from the early twentieth-century warm period. It is suggested strongly that the earlier warming was natural internal climate-system variability, whereas the recent SAT changes are a response to anthropogenic forcing. The area of arctic sea ice is furthermore observed to have decreased similar to8 x 10(5) km(2) (7.4%) in the past quarter century, with record-low summer ice coverage in September 2002. A set of model predictions is used to quantify changes in the ice cover through the twenty-first century, with greater reductions expected in summer than winter. In summer, a predominantly sea-ice-free Arctic is predicted for the end of this century.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2016-06-14
    Type: Article , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Journal of Natural History, 45 (39-40). pp. 2419-2441.
    Publication Date: 2016-08-30
    Description: Two brachyurans of the varunid genus Hemigrapsus from the northwestern Pacific Ocean have invaded coastal regions of the north Atlantic – Hemigrapsus takanoi (sibling species of Hemigrapsus penicillatus) and Hemigrapsus sanguineus in Europe and the latter in the USA. Parasites are known from these crabs in their native habitats, but except for an undescribed larval nematode, none has been found in those examined from their new locations. These parasites include metacercariae of eight species of microphallid trematode, the rhizocephalan barnacles Polyascus polygenea, Sacculina nigra and Sacculina senta, and the obligate gut-inhabiting mesomycetozoan Enteromyces callianassae (potential parasite). The following have been identified in four of the other eight Pacific crabs within the genus (Hemigrapsus nudus and Hemigrapsus oregonensis, northern hemisphere; Hemigrapsus crenulatus and Hemigrapsus sexdentatus, southern hemisphere), none of which have been geographically displaced: metacercariae of two microphallid trematodes; cystacanths of three acanthocephalans Profilicollis antarcticus, Profilicollis botulus and Profilicollis novaezelandensis; larval nematode Ascarophis sp.; nematomorph Nectonema zealandica; entoniscid isopod Portunion conformis; mesomycetozoan Taeniella carcini; and nemertean egg predator Carcinonemertes epialti. The likelihood of the displaced species of shore crabs being rejoined with their native parasites or their susceptibility to becoming infected by similar parasites in their new locations is discussed. In future global displacements of parasitized Hemigrapsus species it is possible that their most serious parasites, rhizocephalans and entoniscid isopods, may infect previously uninfected species. For example, the two eastern Pacific species of Hemigrapsus (H. nudus and H. oregonensis) may be vulnerable to the rhizocephalans and may in turn be a source of entoniscids transported elsewhere.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2020-06-19
    Description: In this study the antifouling activity was investigated of a series of chemically related, halogenated furanones isolated from Delisea pulchra (Greville) Montagne, a red alga which is rarely fouled in the field. The metabolites were tested in laboratory assays against representatives of the three major groups of fouling organisms, the barnacle Baianus amphitrite amphitirite Darwin, the macroalga Ulva lactuca Linnaeus and a marine bacterium (strain SW 8). Settlement of barnacle cyprid larvae was strongly inhibited, with an EC50 of 〈 25 ng·mr1 (25 ppb) for some compounds. The settlement and growth of algal gametes was also strongly inhibited, in some cases at concentrations as low as 25 ng·cm-2 • Growth of the marine bacterium SW8 was inhibited more strongly than by the common antibiotic gentamicin. Overall, activity of the D. pulchra metabolites was comparable to that of the heavy metals and biocides currently used in antifouling paints. However, no single compound was most active in all tests and some metabolites effective against one organism showed Iittle or no activity a·gainst the others. The high but variable level of activity of the D. pulchra metabolites, coupled with their small size, relative stability, and ability tobe synthesized suggest their potential use as active ingredients in antifouling coatings.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  South African Journal of Marine Science, 5 (1). pp. 557-564.
    Publication Date: 2020-05-26
    Description: Change of colour, consistency and pH in contents of the caecum and the stomach of laboratory-maintained long-finned squid Loligo vulgaris reynaudii were determined. There was relatively little variability in any of these parameters of the specimens investigated. Colour and consistency of food or emulsion were used as a basis of analysis of stomach-caecum contents of wild squid. Most squid fed late during the night and/or during the early morning, and the frequency of caecum colour categories did not change much between trawls. Wild squid preyed upon different organisms according to their size. Squid of 69–125 mm dorsal mantle length fed mainly on euphausiids (95% by frequency of occurrence, 87,5% by mass) and those of 126–240 mm mainly on fish (78 and 74,3% respectively) with Bregmaceros?macclellandii and hake as important components. Unidentified fish in the stomachs (i.e. those from which no otoliths were available) probably also belonged to these two species.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  South African Journal of Marine Science, 20 . pp. 363-373.
    Publication Date: 2019-01-24
    Description: Beaks of 133 specimens of Todarodes sagittatus caught in the central East Atlantic were studied. Relationships between several measurements of the upper and lower beaks and dorsal mantle length (DML) and total mass were calculated. The darkening process or pigmentation of both beaks was investigated and a qualitative scale of eight degrees of pigmentation developed. Except for the hood of the lower beak, the growth of both beaks was allometrically negative in relation to DML in males, whereas the growth of several parts of both beaks of females was allometrically positive. The hood grew faster than all other parts of the male beak and faster than all parts of the lower beak of females. Regression coefficients calculated for the growth of the beaks revealed differences between the growth patterns of females and males (p 〈 0.05). The results relating to darkening and the maturing process suggest that they are related and that they take place over a very short period in the life of the squid.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Biofouling, 20 (1). pp. 43-51.
    Publication Date: 2019-03-06
    Description: Multiple antifouling strategies of marine organisms may consist of combinations of physical, chemical and mechanical mechanisms. In this study, the role of surface microtopography (〈500 mum) of different marine organisms, such as Cancer pagurus , Mytilus edulis , Ophiura texturata and the eggcase of Scyliorhinus canicula , has been investigated as a possible component of their defence systems. High resolution resin replicates of these natural surface structures were exposed to natural fouling in field experiments. Abundances of recruits were determined and compared to those on untextured, but otherwise identical, control surfaces to quantify the influence of the different microtopographies on fouling rates. Antifouling effects of microtopographies varied with type of microtopography and coloniser species. The surface microtopography of C. pagurus significantly rejected macrofoulers. The surface structures of the eggcase and O. texturata had repellent effects on microfoulers. Barnacle settlement was temporarily reduced on surface microtopographies of M. edulis and the eggcase. These results emphasise the promising non-toxic antifouling properties of microtextured surfaces
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 48 . pp. 324-341.
    Publication Date: 2019-01-21
    Description: The free surface version of the GFDL model is used to study inflow and outflow through the Danish Straits, which connect the Baltic with the North Sea. Three problems are addressed: (i) the piling up of inflowing water in the Arkona basin; (ii) the transport ratios between Belt and Sound; (iii) the dominance of hydraulic or geostrophic control. Model results show that a cyclonic eddy (dome) is formed by the inflowing saline water that prevents this water from passing rapidly into the Bornholm basin. This eddy is enforced with increasing inflow due to a sea level difference between Kattegat and western Baltic. If density gradients along the straits are weak and the flow is dominantly driven by sea level differences between Kattegat and Baltic, the well-known ratio of 70% : 30% for the transports through Belt and Sound are confirmed. Strong density gradients can change this ratio considerably, especially in the outflow case, when the light water of the Baltic flows against the heavier water of the Kattegat. Under variable wind conditions, no fixed ratio is found. The flow in the Straits is geostrophically controlled; however, the strong baroclinic density field does not allow us to derive the transport simply from sea level inclination.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  European Journal of Phycology, 37 . pp. 1-17.
    Publication Date: 2017-01-04
    Description: A compilation of data on the elemental composition of marine phytoplankton from published studies was used to determine the range of C:N:P. The N:P ratio of algae and cyanobacteria is very plastic in nutrient-limited cells, ranging from 〈5 mol N:mol P when phosphate is available greatly in excess of nitrate or ammonium to 〈100 mol N:mol P when inorganic N is present greatly in excess of P. Under optimal nutrient-replete growth conditions, the cellular N:P ratio is somewhat more constrained, ranging from 5 to 19 mol N:mol P, with most observations below the Redfield ratio of 16. Limited data indicate that the critical N:P that marks the transition between N- and P-limitation of phytoplankton growth lies in the range 20–50 mol N:mol P, considerably in excess of the Redfield ratio. Biochemical composition can be used to constrain the critical N:P. Although the biochemical data do not preclude the critical N:P from being as high as 50, the typical biochemical composition of nutrient-replete algae and cyanobacteria suggests that the critical N:P is more likely to lie in the range between 15 and 30. Despite the observation that the overall average N:P composition of marine particulate matter closely approximates the Redfield ratio of 16, there are significant local variations with a range from 5 to 34. Consistent with the culture studies, lowest values of N:P are associated with nitrate- and phosphate-replete conditions. The highest values of N:P are observed in oligotrophic waters and are within the range of critical N:P observed in cultures, but are not so high as to necessarily invoke P-limitation. The C:N ratio is also plastic. The average C:N ratios of nutrientreplete phytoplankton cultures, oceanic particulate matter and inorganic N and C draw-down are slightly greater than the Redfield ratio of 6.6. Neither the analysis of laboratory C:N:P data nor a more theoretical approach based on the relative abundance of the major biochemical molecules in the phytoplankton can support the contention that the Redfield N:P reflects a physiological or biochemical constraint on the elemental composition of primary production.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 51 (5). pp. 698-710.
    Publication Date: 2016-06-14
    Description: To study the variability of the thermohaline circulation in the North Atlantic on decadal time scales, the atmospheric regional model REMO is currently investigated as a component of a fully-coupled atmosphere–ice–ocean model for the Arctic/North Atlantic. A comparison of a 5-year uncoupled simulation of the regional model with a 5-year NCEP/NCAR reanalysis period is carried out in order to assess the performance of the regional model in polar and subpolar regions. The model simulates basic structures realistically. It performs well in middle latitudes but shows some problems in the region of the marginal ice zone and in continental regions with extreme temperature amplitudes. The high elevations of Greenland in the central part of the model domain give rise to problems in the model dynamics, resulting in moderate deviations from NCEP/NCAR reanalysis.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 55 . pp. 426-437.
    Publication Date: 2016-06-14
    Description: The Baltic Sea Experiment BALTEX is the European regional project of GEWEX. The aim of BALTEX is to improve the knowledge of the water and energy cycle of the Baltic Sea including its catchment area (the BALTEX area). In this study the NCEP/NCAR reanalysis data (Kalnay et al. Bull. Am. Meteorol. Soc., 1996, 77, 437–471) are used to derive the mean atmospheric water budget over the BALTEX area. For this purpose the horizontal water vapour fluxes are calculated. In the long-term mean (here 1948 – 2000) the vertically integrated divergence of these fluxes must balance evaporation minus precipitation. The latter two are provided by the NCEP/NCAR reanalyses. The water budget over the BALTEX area is, however, not closed. An error estimation is performed. The divergence of the water vapour flux is corrected due to the mass balance correction technique (Alestalo, Tellus, 1981, 33, 360–371). Large differences are obtained between the precipitation given by the NCEP/NCAR reanalysis and by the analysis of the observations by Rubel and Hantel (Meteorol. Atmos. Phys., 2001, 77, 155–166). With these analysed precipitation data and the corrected divergence of the water vapour fluxes the imbalance of the water vapour budget could be remarkably reduced.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus B: Chemical and physical meteorology, 51 (2). pp. 562-571.
    Publication Date: 2019-01-24
    Description: Recent progress in research of the global carbon cycle is reviewed and research needs for the immediate future are discussed, in light of the challenge posed to society to come to grips with the problem of man-made climate change. The carbon cycle in the oceans and on the land is reviewed, and how the atmosphere functions to couple them together. Major uncertainties still exist for any projection of the future atmospheric burden of carbon dioxide resulting from postulated emission scenarios of CO2. We present some ideas on how future policies designed to limit emissions or to sequester carbon can possibly be supported by scientific evidence of their effectiveness.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Geomicrobiology Journal, 27 (6). pp. 585-595.
    Publication Date: 2019-02-27
    Description: A number of studies are providing increasing genomic and transcriptomic information on the molecular components of transport, and biochemical control in the cell biology of calcification in coccolithophores. In this review we summarise recent evidence for molecular components involved in the trans-cellular transport of Ca2+, inorganic carbon and H+ between the external medium and the intracellular calcification compartment. We present new hypotheses for the transport of substrates to the site of calcification and for the removal of products, highlighting key gaps in our current knowledge. We also discuss how a cellular and molecular approach will improve abilities to understand and predict responses and adaptation to changing ocean chemistry of this important group of microorganisms.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2018-06-25
    Description: The study presents results on the composition and vertical distribution of the near-bottom plankton community at an abyssal site in the NE Atlantic. Plankton samples were collected at 1, 15, 50 and 100 m above bottom (mab). Whereas the composition within the upper three layers was very similar, a major shift occurred in the immediate vicinity of the seafloor. Between 100 and 15 mab, the plankton was dominated by Copepoda, making up more than 75% of the total abundance and biomass (without gelatinous organisms). At 1 mab, Copepoda were still abundant, but their share decreased to ca. 50%, while Polychaeta, Malacostraca and Chaetognatha became important groups. Within the Copepoda, the predominance of the genus Metridia (Calanoida) in the upper layers was replaced by the genus Benthomisophria (Misophrioida) at 1 mab. Despite enrichment in organic particles towards the bottom, the total abundance and biomass of plankton did not show marked differences between the four layers investigated. Several hypotheses are discussed which may explain why the presumably higher food concentrations near the deep-sea floor do not lead to increased standing stocks of the plankton community.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2019-09-23
    Description: A comparative study about the removability of four potentially harmful ozone-produced oxidants (free bromine, bromamines, free chlorine and chloramines) by activated carbon filtration was performed under identical conditions in small-scale filter experiments. Removability was high and similar among the oxidants with the exception of chloramines which showed the least removability. Results proved activated carbon filtration to be very efficient in removing the dominating brominated oxides formed during the ozonation of natural and most artificial seawaters. In contrast, removability of chloramines, sometimes present in ozonated bromide-free artificial saltwater, was shown to be significantly lower. To improve removal of persistent chloramines by activated carbon filtration, a comparative evaluation of 3 different activated carbon types was conducted. Granulated activated carbon on coal basis was suggested to be the most cost-effective carbon for removing chloramines as it possessed highest removal capacity, while being the cheapest of the carbons tested.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2020-06-22
    Description: Subtle sexual dimorphism and its perception in apparently monomorphic bird species warrant assessment of how birds identify the sex of conspecifics, particularly of prospective mates. Visual sensitivity and its potential co-variation with cryptic sexual dichromatism are still uninvestigated in most avian taxa. Using molecular sexing, reflectance spectrometry and perceptual modelling based on the sequencing of short wavelength visual pigments, we assessed the sex-specificity of coloration and colour perception in the red-tailed tropicbird Phaethon rubricauda. We also measured morphological dimorphism at a previously unstudied breeding locality for this species. Our data are in line with both physical and avian-perceived monochromatism with a potential indication of achromatic sex differences in plumage reflectance. The moderate extent of size dimorphism is consistent with reports from other Pacific breeding populations, and morphological measurements from live specimens in this study are in line with reports on museum specimens from the same sample location. Potential differences between individuals of the same sex in size and coloration warrant the assessment of sexual dimorphism in larger sample sizes of this species.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Australian Journal of Earth Sciences, 59 (6). pp. 953-964.
    Publication Date: 2018-06-08
    Description: Altered lavas have been dredged from three locations on the Resolution Ridge, west of New Zealand's South Island. On the basis of whole-rock geochemistry, Sr, Nd and Pb isotope data and Ar–Ar ages, they can be divided into two suites: 62–60 Ma enriched mid-ocean ridge basalt (E-MORB), and 57 Ma trachybasalt and trachyandesite of ocean island basalt (OIB) affinity. The E-MORBs from the Resolution Ridge are only the second place from which Tasman Sea abyssal oceanic crust has ever been sampled, they have Indian MORB-like isotope compositions, and their ages support a recent interpretation of a 100 km sinistral offset of the southern part of the Tasman Sea spreading ridge. The slightly younger OIB suite erupted shortly after oceanic crust formation and has FOZO to HIMU source characteristics similar to the well-known SW Pacific Diffuse Alkaline Magmatic Province (DAMP). The close occurrence and isotopic mixing relationships of both Paleocene volcanic suites on the Resolution Ridge may be explained by a heterogeneous upper mantle in which the more fertile OIB component was extracted during a later melting event away from the spreading ridge. The dredged lavas predate formation of Southeast Tasman oceanic crust that borders the Resolution Ridge to the south.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Geodinamica Acta, 2 (2). pp. 63-73.
    Publication Date: 2017-05-16
    Description: The western margin of the Tauera Window (Eastern Alps) is defined by a low angle westward dipping fault zone of potently We disp lacement. Ductile deformation of the fault rocks results in a carpet of mylonites up to 400 metres thick. Evidence from shear criteria and the excision of part of the Cretaceous-Tertiary metamorphic edifice both indicate normal displacements, and relative movement of Austroalpine nappe complex towards the west. The Sterzing-Steinach mylonite zone overprints the Alpine nappe edifice. Movements occurred on the cooling path of the Tauern metamorphism, and may be as recent as Middle Miocene. The Kinematics and geometry of the mylonite zone constrain two likely t ectonic explanations that are both compatible with secondary thining of a thick orogenic wedge. (1) Ute the Austroalpine nappe pile due to tectonic unroofing of the Tauern window. (2) Continental escape by east-west stretching of the Alpine orogenic wedge in response to continental collision.
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2019-03-14
    Description: We compared pelagic copepod communities at three (400+ m) stations adjacent to Scott Reef (14°S), a shelf-break reef in Australia's Indian Ocean territory, with those within the shallow (c.50 m) atoll lagoon. The metazooplankton assemblage sampled by our 100-μm multinet system was dominated by small (〈 1.0 mm) copepods. We identified over 220 copepod species, belonging to five of the nine orders. Of these, 68 (31%) are new records for Australian waters and at least 14 are likely to be undescribed. Redundancy analysis indicated that depth stratum was the most important determinant of community structure: distinct communities were associated with the epipelagic (within which the atoll lagoon community was further distinguished by reef-associated copepods), the chlorophyll maximum/thermocline, the upper mesopelagic and the hyper-benthos. The family Oncaeidae was highly speciose (〉 52 taxa) and progressively more important with increasing depth.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Tellus B: Chemical and physical meteorology, 64 . p. 17160.
    Publication Date: 2019-09-23
    Description: Radiation measurements in the area off Northwest Africa (research cruise, February 2008) and at Mindelo (Cape Verde Islands, May 2009) were used to investigate the impacts of Saharan dust and clouds on solar irradiance and on photosynthetically available radiation, to derive a relationship between dust aerosol optical depth (AOD) and photosynthetically available radiation and to determine the annual variations of photosynthetically available radiation. Three different kinds of atmospheric conditions were considered: cloudy skies, which decreased or increased the irradiance and dusty skies. The reduction by clouds was up to 67.2% at 400 nm and up to 84.4% at 700 nm. Enhancements of up to 21.9% at 400 nm and 34.0% at 700 nm were observed. The decrease by dust was up to 19.7% at 400 nm and up to 4.1% at 700 nm. Clouds decreased or increased the photosynthetically available radiation by up to 79.9% or up to 31.2%. The reduction by dust depended on the dust AOD and was between 3.6% and 12.3%. A linear relationship confirmed a decrease of photosynthetically available radiation of 1.2% by an increase of dust AOD of 0.1.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    facet.materialart.
    Unknown
    Taylor & Francis
    In:  Atmosphere-Ocean, 51 (2). pp. 213-225.
    Publication Date: 2019-09-23
    Description: We present a new method for the statistical downscaling of coarse-resolution General Circulation Model (GCM) fields to predict local climate change. Most atmospheric variables have strong seasonal cycles. We show that the prediction of the non-seasonal variability of maximum and minimum daily surface temperature is improved if the seasonal cycle is removed prior to the statistical analysis. The new method consists of three major steps. First, the average seasonal cycles of both predictands and predictors are removed. Second, a principal component-based multiple linear regression model between the deseasonalized predictands and predictors is developed and validated. Finally, the regression is used to make projections of future changes in maximum and minimum daily surface temperature at Shearwater, Nova Scotia. This projection is made using the local grid-scale variables of the Canadian General Circulation Model Version 3 (CGCM3) climate model as predictors. Our statistical downscaling method indicates significant skill in predicting the observed distribution of temperature using GCM predictors. Projections suggest minimum and maximum temperatures at Shearwater will be up to about five degrees warmer by 2100 under the current “business-as-usual” scenario. RÉSUMÉ [Traduit par la rédaction] Nous présentons une nouvelle méthode pour la réduction d'échelle statistique des champs des modèles de circulation générale (MCG) à faible résolution pour prévoir les changements du climat local. La plupart des variables atmosphériques ont des cycles saisonniers bien marqués. Nous démontrons que la prédiction de la variabilité non saisonnière de la température de surface quotidienne minimum et maximum est meilleure si on retranche le cycle saisonnier avant de procéder à l'analyse statistique. Voici les trois grandes étapes de cette nouvelle méthode. D'abord, nous retirons les cycles saisonniers moyens des prédictants et des prédicteurs. Ensuite, nous concevons et validons un modèle de régression linéaire multiple sur composantes principales entre les prédictants et les prédicteurs désaisonnalisés. Enfin, nous nous servons de la régression afin d'établir des projections pour les changements à venir dans la température de surface quotidienne minimum et maximum à Shearwater en Nouvelle-Écosse. Cette projection est établie au moyen des variables locales à l'échelle du maillage de la troisième version du modèle canadien de circulation générale (MCCG3). Notre méthode de réduction d'échelle statistique se révèle très efficace pour prédire la répartition observée de la température au moyen des prédicteurs du MCG. D'après les projections, les températures minimum et maximum à Shearwater connaîtront une augmentation d'environ cinq degrés d'ici 2100 dans le scénario actuel de type « statu quo ».
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2020-08-03
    Description: Natural re-colonisation events are rare so it can be important to monitor newly establishing populations to understand and characterise such events. As re-colonising populations are often freed from spatial and competitive constraints, documenting the sex-ratio of offspring may provide insights in sex-allocation theory. We studied a re-establishing population of Black-winged Petrels (Pterodroma nigripennis) on Raoul Island, in the Kermadec Group, New Zealand, where all predators have recently been removed. Wemeasured, and took DNA samples from 20 chicks in four new colonies in 2007, when the colonies first re-established, 25 chicks from seven colonies in 2008, and 25 adults captured across both years, including seven that were caught nearby at sea, and two adults caught at a colony where no chicks were sampled. We found the developmental stage of chicks to have no differences between sexes, and recorded no sexual differences in the morphometrics of chicks or adults. We report a significantly biased sex-ratio towards male offspring in the first year of re-colonisation. In contrast, the sex-ratios of offspring in the second year of re-colonisation and of adults in both years were even. We suggest that biases in offspring sex-ratios towards the more philopatric sex may be adaptive when under release from spatial or competitive constraints in re-colonising birds. Continued monitoring of the populations of Black-winged Petrels re-establishing on Raoul Island, as well as comparable data from adjacent islets with long-established breeding colonies of Black-winged Petrels will be critical to identify the realised ecological role of variation in offspring sex-ratio and of sex-biased natal philopatry.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2017-01-04
    Description: Bacteria associated with 2 macroalgae growing in the Kiel Fjord (Baltic Sea) were investigated seasonally over two years by scanning electron microscopy and cultivation methods. Seasonal variations and significant differences between both macroalgal species with respect to the associated bacteria were observed. 166 bacterial strains were isolated from the macroalgae and classified by phylogenetic analysis of 16S rRNA gene sequences. The strains formed 82 phylotypes according to sequence similarities of499.0%. Samples from Fucus vesiculosus revealed 43 and from Delesseria sanguinea 57 bacterial phylotypes. They affiliated to Actinobacteria, Alphaproteobacteria, Bacilli, Betaproteobacteria, Flavobacteria, Gammaproteobacteria, and Sphingobacteria. Following the assumption that chemical interactions rule the bacteria-macroalga associations, we tested the biological activity of both macroalgae and isolated bacterial strains against a panel comprising standard and ecologically relevant microorganisms (Gram-positive and Gram-negative bacteria, including macroalgal pathogens and surface associated strains, and a yeast). Both macroalgae presented inhibitory activity against at least one microorganism, but overall the inhibitory activities were low. In contrast, all extracts stimulated growth of many of the tested bacteria. While growth stimulation was common concerning bacteria associated with macroalgae, no stimulation was shown for the standard set of bacteria (with exception of one case of stimulation of the plant pathogen Erwinia amylovora). Regarding the potential biological activity of microorganisms associated with macroalgae, more than 60% of the bacterial phylotypes inhibited the growth of at least one microorganism. A higher proportion of strains showed antimicrobial activity against the set of bacteria associated with macroalgae as compared to standard set of microorganisms. Certain phylotypes are consistently found as epiphytes, suggesting their specific association with macroalgae. The presented positive and negative effects of macroalgal extracts on growth of macroalga-associated bacteria, significant bacterial activity against macroalgal pathogens and competitors, and potential degradative capabilities support the assumption that complex chemical interactions shape the bacteria-macroalga relationships.
    Type: Article , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...