ALBERT

Description: This chapter aims at introducing the reader to general concepts about the main forcings of the Mediterranean Sea, in terms of exchanges through the Strait of Gibraltar, and air-sea exchanges of heat, freshwater, and momentum. These forcings are also responsible for the peculiar characteristics of Mediterranean water masses. Therefore, the chapter continues with giving a general explanation on water mass analysis, and then it describes the properties and vertical and horizontal distributions of the main Mediterranean water masses. To conclude, the reader is introduced to the use of other (biogeochemical, and chemical) tracers of water masses, with a focus on the Mediterranean Sea.

Description: Wildfires are natural or anthropogenic phenomena increasing at alarming rates globally due to land-use alterations, droughts, climatic warming, hunting and biological invasions. Whereas wildfire effects on terrestrial ecosystems are marked and relatively well-studied, ash depositions into aquatic ecosystems have often remained overlooked but have the potential to significantly impact bottom-up processes. This study assessed ash-water-phytoplankton biomass dynamics using six plant species [i.e., three natives (apple leaf Philenoptera violacea, Transvaal milk plum Englerophytum magalismontanum, quinine tree Rauvolfia caffra) and three aliens (lantana Lantana camara, gum Eucalyptus camaldulensis, guava Psidium guajava)] based on a six-week mesocosm experiment with different ash concentrations (1 and 2 g L-1). We assessed concentrations of chemical elements, i.e., N, P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn and B from ash collected, and we have observed significant differences among the species. High concentrations of P, K, Mn, Fe, Cu, Zn and B were recorded from Transvaal milk plum ash and low concentrations of P, K, Ca, Mg, Cu and Zn were recorded from apple leaf. An increase in phytoplankton biomass (using chlorophyll-a concentration as a proxy) for all treatments i.e., 1 and 2 g L-1 for all plant species ash was observed a week after, followed by decreases in the following weeks, with the exception of 2 g L-1 for lantana, gum and control. Silicate concentrations (i.e., used as a proxy for diatom abundance) showed increasing patterns among all ash treatments, with exception of controls. However, no clear patterns were observed between native and alien plant ash on both chl-a and silicate concentrations. We found that ash has notable effects on water chemistry, particularly nitrate, which increased throughout the weeks, whereas, pH and conductivity were high at low ash concentrations. The impacts of ash on water chemistry, chl-a and silicate concentrations vary with individual species and the amount of ash deposited into the system.

Description: Phytoplankton form the base of the pelagic food web in inland waters. Unlike rooted plants with access to nutrients in the sediment, phytoplankton depend on the open water as their sole direct source of minerals. Phytoplankton comprise cyanobacteria and phylogenetically diverse eukaryotic algae that convert light energy and mineral nutrients into organic matter. Many species also exploit the elements and energy within dissolved organic compounds and particles produced in the catchment or within the water. Here, we describe the nutrient requirements of phytoplankton, their different modes of nutrition, the mechanisms they employ to acquire nutrients and the ecological consequences of their varying ability to exploit an often scarce and spatially and temporally variable resource. When nutrients are abundant, often as a result of human disruption of nutrient cycles, phytoplankton productivity, and often biomass, increases to the point that it causes a range of ecological consequences that reduce the value of the water resource for mankind.

Description: Quantification of phthalates or phthalic acid esters (PAEs) might be problematic due to matrix overlap, auto-self absorbance and background scattering noise by the plastic lab materials although plastics have been reported in the release of PAEs. These materials (ambient air, reagents bottles, sampling devices, and various analytical instruments), are ubiquitous in the laboratory environment, thereby making it more difficult to reliably analyze of trace concentration of PAEs. Thus, in the current study, a straight forward and reliable protocol has been established for the analysis of PAEs including control of blank contamination, and the experimental conditions such as extraction time and temperature were optimized. The mass of PAEs in blank tests of selected materials ranged from 3±0.7 to 35±6 ng for liquid-liquid extraction (LLE) and from 5±1.8 to 63±15 ng for solid-phase extraction (SPE). For both extraction methods, higher blank values were measured for dibutyl phthalate (DBP) (35±6 ng, 12±3 ng), and DEHP (63±12 ng, 23±5 ng) in LLE and SPE, respectively. Average recoveries of PAEs in LLE were 90-97% and obtained with successive aliquots of 2 mL, 1 mL, and 1 mL dichloromethane (DCM). For SPE, recoveries up to 86-90% were achieved with successive aliquots of 5, 3, and 2 mL DCM at a sample flow rate of 5 mL min -1 . Under the optimized conditions, the method quantification limits (MQL) for PAEs was 10-20 ng L -1 for LLE and 10-35 ng L -1 for SPE. Moreover, the dissolved concentrations of PAEs from LDPE measured by the LLE method ranged 〈 1.5 to 5.83 ng cm -2, and those measured by SPE ranged from 1.0to256ngL -1 , in seawater samples of Sharm Obhur. The method has lower MQL values for LLE and SPE than average reported values of 10-100 ng L -1 and 30-100 ng L -1 , respectively.

Description: A key requirement for geological CO2 storage is site integrity management and monitoring during operation through to the post decommissioning period. This paper focuses on monitoring deformation of the ground surface and seabed as a proxy for overall deformation in the reservoir and surrounding layers. The objective is to inform, based on deformation data, on how the reservoir is responding to CO2 injection and to ensure any issues with regard to storage integrity are rapidly detected. The magnitude and pattern of deformation at the surface reveals geomechanical/hydromechanical processes that occur in reservoir due to CO2 injection. We acquired deformation data from the In Salah CO2 injection site and from four additional study cases during the course of this study; one in the onshore UK, the other a combined campaign onshore Norway and offshore Germany, and the third in onshore Japan. Significant developments in measurement techniques, processing tools and interpretation algorithms were developed through this project. Models were then developed to simulate the observed data and to couple surface deformation to displacement in the subsurface. The results show millimeter-scale deformations in the subsurface have a signature at the surface that can be captured by the tools and workflows developed in this project. These deformations, particularly the patterns, are important factors to consider when monitoring a CO2 storage site.

Description: New sedimentological data of facies and diagenesis as well as chronological data including strontium (87Sr/86Sr)-isotope ratios and uranium (U)-series dating, radiocarbon (14C) accelerator mass spectrometry (AMS) dating and biostratigraphy from elevated reef terraces (makatea) in the southern Cook Islands of Mangaia, Rarotonga and Aitutaki contribute to controversial discussions regarding age and sea-level relationships of these occurrences during the Neogene and Quaternary. The oldest limestones of the uplifted makatea island of Mangaia include reef-related facies which are mid-Miocene in age, based on new Sr-isotope and biostratigraphical data. In between these older deposits and the lowest coastal reef terrace of marine isotope stage (MIS) 5e, various older Pleistocene reef-related facies were identified. Based on Sr-isotope ratios, these were deposited during earlier Pleistocene highstands (as old as 2.28 Ma). Rare reef terraces on Rarotonga belong to the Plio-Pleistocene and the late Miocene, according to 87Sr/86Sr ratios. The late Miocene age is enigmatic as it exceeds the age of subaerially exposed volcanic rocks of Rarotonga island. The fossil reef could have formed on an older submarine volcanic high that was later displaced by younger volcanism to its present position, or the Sr-age could be too old due to diagenetic resetting. The Plio-Pleistocene Rarotonga reef terraces are overlain irregularly by Holocene reef deposits that are interpreted as storm rubble. Reef terraces on Aitutaki represent evidence of a higher-than-present (up to 1 m) sea-level during the late Holocene, based on 14C AMS age data. They are very similar to elevated late Holocene reefs of adjacent French Polynesia with regard to composition, elevation and age.

Description: The oceans' role in climate and climate change is manifold. The Ocean circulation transports large amounts of heat and freshwater on hemispheric space scales which have significant impacts on regional climate in the ocean itself but also noticeable consequences via atmospheric teleconnections on land. Due to the high heat capacity of seawater and the relatively slow ocean circulation, the oceans provide a significant “memory” for the climate system. Bodies of water that descend from the sea surface may reside in the ocean interior for decades and centuries, while preserving their temperature and salinity signature, before they surface again to interact with the overlying atmosphere. The residence time of water in the atmosphere is about ten days and the persistence of dynamical states of the atmospheric circulation may last up to a few weeks. Thus, on long time scales ocean dynamics becomes important for climate, which implies that climate variations and climate change can only partially be understood without consideration of ocean dynamics and the intricate ocean-atmosphere interaction. Since 1960 the heat uptake of the oceans has been 20 times larger than that of the atmosphere. Thus the oceans have been able to reduce the otherwise much more pronounced temperature rise in the atmospheric climate. Also, over the last 200 years the oceans have absorbed about half of the CO2 release into the atmosphere by human activities (fossil fuel combustion, de-forestation, cement production), thereby reducing the direct effect of greenhouse gases on atmospheric temperatures.This chapter aims to describe and explain fundamental principles of the ocean dynamics and gathers information about past, present and future states the world’s ocean and its role in climate change.

Description: Highlights • Continuous CH4 bioelectrosynthesis from CO2 demonstrated with 80% or higher Coulombic Efficiency • At pH values below 8 CH4 cathodic off-gas contains up to 85% CH4 • At pH above 8.5, production of acetate and then ethanol (up to 8 g L−1) was obtained • Coulombic efficiency remained above 80% • 16S sequencing showed proliferation of Clostridium, Methanosaeta, Methanobrevibacter and Methanobacterium spp at the cathode This study demonstrates the continuous conversion of CO2 to methane, acetate, and ethanol in a Microbial Electrosynthesis Cell (MESC) with a carbon felt biocathode. The MESC was inoculated with a mixed anaerobic microbial consortium and operated at a mesophilic temperature of 30 °C. In situ deposition of Ni and Fe was achieved by introducing 0.2 g L−1 of NiSO4 or FeSO4, respectively, into the cathode compartment influent stream. In response, a considerable improvement in MESC performance was observed with a current density of 6.4 mA cm−2 (per separator area) and a CH4 production of 0.83 L (LR d)−1 (R = cathode volume). Once Ni and Fe were removed from the influent solution, the performance remained unchanged. Electron dispersive spectroscopy confirmed Ni and Fe electrodeposition. A shift from CH4 to acetate and ethanol production with concentrations reaching 5 and 8 g L−1, respectively, was observed upon increasing the cathode compartment pH to 8.5–9.0. 16S rRNA gene sequencing showed significant changes in the bacterial population at the cathode with Clostridia representing almost two-thirds of the population. Methanosaeta, Methanobrevibacter, and Methanobacterium species dominated the archaeal community.

Description: Rivers are viewed as major pathways of microplastic transport from terrestrial areas to marine ecosystems. However, there is paucity of knowledge on the dispersal pattern and transport of microplastics in river sediments. In this study, a three dimensional hydrodynamic and particle transport modelling framework was created to investigate the dispersal and transport processes of microplastic particles commonly present in the environment, namely, polyethylene (PE), polypropylene (PP), polyamide (PA), and polyethylene terephthalate (PET) in river sediments. The study outcomes confirmed that sedimental microplastics with lower density would have higher mobility. PE and PP are likely to be transported for a relatively longer distance, while PA and PET would likely accumulate close to source points. High water flow would transport more microplastics from source points, and high flow velocity in bottom water layer are suggested to facilitate the transport of sedimental microplastics. Considering the limited dispersal and transport, the study outcomes indicated that river sediments would act as a sink for microplastic pollutants instead of being a transport pathway. The patchiness associated with the hotspots of different plastic types is expected to provide valuable information for microplastic source tracking.

Description: The present study aims to valorize the apple peels (AP) and grape seeds (GS) by the fortification of the yogurts using their powder. Firstly, the optimization of the extraction parameters for assessing maximum of total phenolic content (TPC) was achieved. Under the optimized conditions, the experimental maximum yields of TPC were 19.33 ± 2.33 and 240.59 ± 4.77 mg Gallic Acid Equivalents (GAE)/100 g Dry Weight (DW) for AP and GS, respectively, which was in close agreement with predicted values (19.32 ± 0.91 and 242.26 ± 11.08 mg GAE/100 g DW for AP and GS, respectively). The antioxidant capacity of GS extract was better with IC50 of 12.22 ± 0.89 and 225.47 ± 7.10 µg/ml in DPPH and phosphomolybdenum assays, respectively. Besides, powder from these by-products was incorporated into yogurt samples. The classification test revealed that the yogurt prepared with GS powder was the preferred one.

Description: Microbially catalyzed corrosion of metals is a substantial economic concern. Aerobic microbes primarily enhance Fe0 oxidation through indirect mechanisms and their impact appears to be limited compared to anaerobic microbes. Several anaerobic mechanisms are known to accelerate Fe0 oxidation. Microbes can consume H2 abiotically generated from the oxidation of Fe0. Microbial H2 removal makes continued Fe0 oxidation more thermodynamically favorable. Extracellular hydrogenases further accelerate Fe0 oxidation. Organic electron shuttles such as flavins, phenazines, and possibly humic substances may replace H2 as the electron carrier between Fe0 and cells. Direct Fe0-to-microbe electron transfer is also possible. Which of these anaerobic mechanisms predominates in model pure culture isolates is typically poorly documented because of a lack of functional genetic studies. Microbial mechanisms for Fe0 oxidation may also apply to some other metals. An ultimate goal of microbial metal corrosion research is to develop molecular tools to diagnose the occurrence, mechanisms, and rates of metal corrosion to guide the implementation of the most effective mitigation strategies. A systems biology approach that includes innovative isolation and characterization methods, as well as functional genomic investigations, will be required in order to identify the diagnostic features to be gleaned from meta-omic analysis of corroding materials. A better understanding of microbial metal corrosion mechanisms is expected to lead to new corrosion mitigation strategies. The understanding of the corrosion microbiome is clearly in its infancy, but interdisciplinary electrochemical, microbiological, and molecular tools are available to make rapid progress in this field.

Description: Highlights: • Transcriptional response to hypoxia-reoxygenation was studied in an OMZ bivalve. • Anaerobic glycolysis and protein quality control pathways were transcriptionally upregulated in hypoxia. • Hypoxia elevated mRNA levels of UCP2 but had no effect on thiol-dependent antioxidants. • No impact of hypoxia-reoxygenation was found on aerobic marker enzymes. • Responses of an OMZ bivalve show parallels to other hypoxia-tolerant bivalves. Abstract: Benthic animals inhabiting the edges of marine oxygen minimum zones (OMZ) are exposed to unpredictable large fluctuations of oxygen levels. Sessile organisms including bivalves must depend on physiological adaptations to withstand these conditions. However, as habitats are rather inaccessible, physiological adaptations of the OMZ margin inhabitants to oxygen fluctuations are not well understood. We therefore investigated the transcriptional responses of selected key genes involved in energy metabolism and stress protection in a dominant benthic species of the northern edge of the Namibian OMZ, the nuculanid clam Lembulus bicuspidatus,. We exposed clams to normoxia (~5.8 ml O2 l−1), severe hypoxia (36 h at ~0.01 ml O2 l−1) and post-hypoxic recovery (24 h of normoxia following 36 h of severe hypoxia). Using newly identified gene sequences, we determined the transcriptional responses to hypoxia and reoxygenation of the mitochondrial aerobic energy metabolism (pyruvate dehydrogenase E1 complex, cytochrome c oxidase, citrate synthase, and adenine nucleotide translocator), anaerobic glycolysis (hexokinase (HK), phosphoenolpyruvate carboxykinase (PEPCK), phosphofructokinase, and aldolase), mitochondrial antioxidants (glutaredoxin, peroxiredoxin, and uncoupling protein UCP2) and stress protection mechanisms (a molecular chaperone HSP70 and a mitochondrial quality control protein MIEAP) in the gills and the labial palps of L. bicuspidatus. Exposure to severe hypoxia transcriptionally stimulated anaerobic glycolysis (including HK and PEPCK), antioxidant protection (UCP2), and quality control mechanisms (HSP70 and MIEAP) in the gills of L. bicuspidatus. Unlike UCP2, mRNA levels of the thiol-dependent mitochondrial antioxidants were not affected by hypoxia-reoxygenation stress. Transcript levels of marker genes for aerobic energy metabolism were not responsive to oxygen fluctuations in L. bicuspidatus. Our findings highlight the probable importance of anaerobic succinate production (via PEPCK) and mitochondrial and proteome quality control mechanisms in responses to oxygen fluctuations of the OMZ bivalve L. bicuspidatus. The reaction of L. bicuspidatus to oxygen fluctuations implies parallels to that of other hypoxia-tolerant bivalves, such as intertidal species.

Description: Despite the growing concern of scyphozoan jellyfish blooms and their associated threats, there is an acute lack of baseline knowledge regarding the trophic ecology of scyphozoans in tropical waters where blooms of several species sometimes occur at once or successively. Therefore, this study was conducted from June 2010 to December 2011 in the Klang Strait (Malaysia) to elucidate the trophic ecology of eight sympatric species of scyphozoan that occurred in a conjoint mangrove-mudflat habitat. The species diet, trophic position and the relative contribution of primary producers to their nutrition were determined by integrating stomach content examination with stable isotope analysis. Scyphozoans in the Klang Strait are principally carnivores and can be grouped into three major trophic guilds: specialized copepod feeder, copepod and macrozooplankton feeder, and mixed plankton feeder. Bayesian mixing model of δ13C isotope values indicates that the scyphozoans mainly derived their basal carbon source from microphytobenthos and phytoplankton. Analysis of δ15N isotope values reveals that all species are positioned at the third trophic level after mixed zooplankton groups (second) and primary producers (first) in the food web. Scyphozoans thus represent an important trophic link coupling benthic and pelagic primary production to higher-level predators and humans, and are important carbon exporters from nearshore to neritic and offshore waters.

Description: Being integral primary producers in diverse ecosystems, microalgal genomes could be mined for ecological insights, but representative genome sequences are lacking for many phyla. We cultured and sequenced 107 microalgae species from 11 different phyla indigenous to varied geographies and climates. This collection was used to resolve genomic differences between saltwater and freshwater microalgae. Freshwater species showed domain-centric ontology enrichment for nuclear and nuclear membrane functions, while saltwater species were enriched in organellar and cellular membrane functions. Further, marine species contained significantly more viral families in their genomes (p = 8e–4). Sequences from Chlorovirus, Coccolithovirus, Pandoravirus, Marseillevirus, Tupanvirus, and other viruses were found integrated into the genomes of algal from marine environments. These viral-origin sequences were found to be expressed and code for a wide variety of functions. Together, this study comprehensively defines the expanse of protein-coding and viral elements in microalgal genomes and posits a unified adaptive strategy for algal halotolerance.

Description: A major highlight of restoration efforts is to improve the ecological structure and function of the natural ecosystem in the restored habitat. Assessment of restoration success is a crucial component of an optimal ecological management strategy. In studies to determine the restoration success of a transplanted seagrass habitat by assessing trophic recovery, we examined carbon and nitrogen stable isotope ratios of organic matter sources and macrobenthic assemblages in a transplanted eelgrass Zostera marina bed. The eelgrass bed was restored about 2 years after transplantation in a southern coastal bay of Korea, and consequently, the food web structure in the bed was compared with that in a natural reference site. Our results revealed no significant differences in isotopic values of both macrobenthic consumers and their putative food sources between the transplanted and natural seagrass beds. These isotopic similarities in florae and faunae in the two beds suggest a uniformity in food web structure formed by the diversity and availability of resources, and thereby suggest similarities in the resource–consumer relationship. Isotopic niche indices and high dietary overlaps of feeding guilds in the transplanted and natural beds further suggest the transplanted habitat provides similar ecological functions and ecosystem services to its natural counterpart. Collectively, our results suggest the eelgrass transplantation led to successful restoration of a common seagrass bed, with recovery of the functional properties of the food web structure. Finally, our findings support the idea that stable isotope measures can provide a better understanding of the functioning of restored ecosystems, and improve post-transplantation monitoring efforts for the future planning and managing of successful habitat restoration.

Description: Micro- and nano-scale plastic particles in the environment result from their direct release and degradation of larger plastic debris. Relative to macro-sized plastics, these small particles are of special concern due to their potential impact on marine, freshwater, and terrestrial systems. While microplastic (MP) pollution has been widely studied in geographic regions globally, many questions remain about its origins. It is assumed that urban environments are the main contributors but systematic studies are lacking. The absence of standard methods to characterize and quantify MPs and smaller particles in environmental and biological matrices has hindered progress in understanding their geographic origins and sources, distribution, and impact. Hence, the development and standardization of methods is needed to establish the potential environmental and human health risks. In this study, we investigated stable carbon isotope ratio mass spectrometry (IRMS), attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy, and micro-Raman spectroscopy (μ-Raman) as complementary techniques for characterization of common plastics. Plastic items selected for comparative analysis included food packaging, containers, straws, and polymer pellets. The ability of IRMS to distinguish weathered samples was also investigated using the simulated weathering conditions of ultraviolet (UV) light and heat. Our IRMS results show a difference between the δ13C values for plant-derived and petroleum-based polymers. We also found differences between plastic items composed of the same polymer but from different countries, and between some recycled and nonrecycled plastics. Furthermore, increasing δ13C values were observed after exposure to UV light. The results of the three techniques, and their advantages and limitations, are discussed.

Description: Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) has become a well-established technique for the detection, size characterization and quantification of inorganic nanoparticles but its use for the analysis of micro- and nanoparticles composed of carbon has been scarce. Here, the analysis of a microplastic suspensions by ICP-MS operated in single particle mode using microsecond dwell times is comprehensively discussed. The detection of polystyrene microparticles down to 1.2 μm was achieved by monitoring the 13C isotope. Plastic microparticles of up to 5 μm were completely volatized and their components atomized, which allowed the detection of microplastics, their quantification using aqueous dissolved carbon standards, and the measurement of the size-distribution of the detected particles. Limits of detection of 100 particles per milliliter were achieved for an acquisition time of 5 min. The method developed was applied to the screening of microplastics in personal care products and released from food packagings. The chemical identity of the detected microplastics was confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy.

Description: Favorable interspecies associations prevail in natural microbial assemblages. Some of these favorable associations are co-metabolic dependent partnerships in which extracellular electrons are exchanged between species. For such electron exchange to occur, the cells must exhibit electroactive interfaces and get involved in direct cell-to-cell contact (Direct Interspecies Electron Transfer/DIET) or use available conductive mineral grains from their environment (Conductive-particle-mediated Interspecies Electron Transfer/CIET). This review will highlight recent discoveries and knowledge gaps regarding DIET and CIET interspecies associations in artificial co-cultures and consortia from natural and man-made environments and emphasize approaches to validate DIET and CIET. Additionally, we acknowledge the initiation of a movement towards applying electric syntrophies in biotechnology, bioremediation and geoengineering for natural attenuation of toxic compounds. Next, we have highlighted the urgent research needs that must be met to develop such technologies.

Description: Highlights • A total of 1455 crustal events in Santorini-Amorgos zone have been relocated. • The seismogenic layer along the zone is found to be 12.5 km thick. • Expected moment magnitude of future earthquakes is in the range of 6.3 to 7.2. • High Vp/Vs ratios in northern part of Santorini caldera indicate the presence of melt. • Upward migrating fluids exist at areas with vertical earthquake clusters. The Santorini-Amorgos zone is located in the central part of the Hellenic volcanic arc and is hosting eight large faults as well as Kolumbo and Santorini volcanic centers. The largest earthquake (Mw ~ 7.1) in the southern Aegean during the 20th century also occurred in this area on 9 July 1956. A total of 1868 crustal events were recorded by temporary networks during September 2002 to July 2004 and October 2005 to March 2007, and also by the permanent network from 2011 to 2019. We relocated 1455 of these events by using HypoDD and revealed clusters of earthquakes beneath Kolumbo, Anydros graben, and Santorini-Amorgos ridge. Only the faults in the SW of Anydros, SE of Ios, and along the south coast of Amorgos were delineated by the relocated events. Nearly vertical clusters were observed beneath the island of Anydros, south of Amorgos, and in NE end of Amorgos fault, indicating possible pathways of upward migrating fluids. The seismogenic layer thickness calculated based on the depth distribution of the relocated events was 12.5 km. We combined this thickness with geometrical properties of the faults to calculate the expected moment magnitude of future earthquakes, resulting in a range of 6.3–7.2. In an effort to map the distribution of fluids, the Vp/Vs ratio distribution was estimated by utilizing the event-station travel time data along with crack density, fluid saturation, and Poisson's ratio. The petrophysical parameters observed in the northern part of the Santorini caldera suggest the existence of melt, while those observed in Anydros and in the NE of Amorgos fault support the suggestion of upward migrating fluids in these areas.

Description: The Santorini-Amorgos zone is an area rich in microseismicity at the center of the Hellenic volcanic arc. The microseismicity of the zone is distributed along the Santorini-Amorgos ridge and Kolumbo submarine volcano. In this study, we utilized crustal events that were recorded by temporary networks during September 2002 to July 2004 and October 2005 to March 2007, and also by the permanent network from 2011 to 2020. These events were inverted for their moment tensors by using P-wave polarities as well as SV/P and SH/P amplitude ratios, yielding 74 well-constrained moment tensor solutions. Most of these moment tensors have significant CLVD and isotropic components that are positively correlated to each other (R2 = 0.68). Tensile faulting due to high pore pressure is considered as the most likely cause of the observed non-DC components. The positive and negative non-DC components observed in Kolumbo may be generated by the opening and closing of cracks beneath the shallow (6–7 km) magma chamber due to a steady migration of magmatic fluids from the deep reservoir into the chamber. In Anydros, most of the microearthquakes have positive non-DC components associated with the opening of cracks. It is possible that the extensional deformation and high pore fluid pressure in the area opens subvertical cracks that become pathways for upward migrating fluids. The upward migration of magmatic fluids in an extensional regime such as the Santorini-Amorgos zone can also be viewed as an indication of emerging volcanic activity in this area.

Description: Chemical pollutants, such as pesticides, often leach into aquatic environments and impact non-target organisms. Marine invertebrates have complex life cycles with multiple life-history stages. Exposure to pesticides during one life-history stage potentially influences subsequent stages; a process known as a carry-over effect. Here, we investigated carry-over effects on the jellyfish Aurelia coerulea. We exposed polyps to individual and combined concentrations of atrazine (2.5 μg/L) and chlorpyrifos (0.04 μg/L) for four weeks, after which they were induced to strobilate. The resultant ephyrae were then redistributed and exposed to either the same conditions as their parent-polyps or to filtered seawater to track potential carry-over effects. The percentage of deformities, ephyrae size, pulsation and respiration rates, as well as the metabolic profile of the ephyrae, were measured. We detected a subtle carry-over effect in two metabolites, acetoacetate and glycerophosphocholine, which are precursors of the neurotransmitter acetylcholine, important for energy metabolism and osmoregulation of the ephyrae. Although these carry-over effects were not reflected in the other response variables in the short-term, a persistent reduction of these two metabolites could have negative physiological consequences on A. coerulea jellyfish in the long-term. Our results highlight the importance of considering more than one life-history stage in ecotoxicology, and measuring a range of variables with different sensitivities to detect sub-lethal effects caused by anthropogenic stressors. Furthermore, since we identified few effects when using pesticides concentrations corresponding to Australian water quality guidelines, we suggest that future studies consider concentrations detected in the environment, which are higher than the water quality guidelines, to obtain a more realistic scenario by possible risk from pesticide exposure.

Description: The Kerguelen Islands are part of the French Southern Territories, located at the limit of the Indian and Southern oceans. They are highly impacted by climate change, and coastal marine areas are particularly at risk. Assessing the responses of species and populations to environmental change is challenging in such areas for which ecological modelling can constitute a helpful approach. In the present work, a DEB-IBM model (Dynamic Energy Budget – Individual-Based Model) was generated to simulate and predict population dynamics in an endemic and common benthic species of shallow marine habitats of the Kerguelen Islands, the sea urchin Abatus cordatus. The model relies on a dynamic energy budget model (DEB) developed at the individual level. Upscaled to an individual-based population model (IBM), it then enables to model population dynamics through time as a result of individual physiological responses to environmental variations. The model was successfully built for a reference site to simulate the response of populations to variations in food resources and temperature. Then, it was implemented to model population dynamics at other sites and for the different IPCC climate change scenarios RCP 2.6 and 8.5. Under present-day conditions, models predict a more determinant effect of food resources on population densities, and on juvenile densities in particular, relative to temperature. In contrast, simulations predict a sharp decline in population densities under conditions of IPCC scenarios RCP 2.6 and RCP 8.5 with a determinant effect of water warming leading to the extinction of most vulnerable populations after a 30-year simulation time due to high mortality levels associated with peaks of high temperatures. Such a dynamic model is here applied for the first time to a Southern Ocean benthic and brooding species and offers interesting prospects for Antarctic and sub-Antarctic biodiversity research. It could constitute a useful tool to support conservation studies in these remote regions where access and bio-monitoring represent challenging issues.

Description: Methane generation from seagrass contributes to green-house gases emissions but can also be a potential controlled biogas source. Understanding the natural fluctuations of emissions and the biotic and abiotic factors underlying such variations is essential. In this work, CH4 emission from beach-cast seagrass from the High-Adriatic coast was analysed. Biochemical methane potential (BMP) tests were used to evaluate CH4 generation at different temperatures (30 °C and 35 °C) and salinity levels (from 0‰ to 35‰), consistent with the typical observed environmental conditions. The changes in the microorganism community composition were investigated by means of amplicon metagenomics sequencing. The results underlined a specific CH4 emission in the range of 0.90–1.37 NmL CH4/g Volatile Solids (VS) d at 35 °C and 0.36–0.50 NmL CH4/g VS d at 30 °C. The most intense methane generation was observed at intermediate salinity levels of 18‰ at 35 °C and 9‰ at 30 °C. The total seasonal emission from the investigated beach-cast seagrass was estimated as 0.1399 mmol CH4/m2g. The microbial community analysis highlighted that Rhodobacteraceae was the most abundant family, coherently with its abundance in the marine environment. Low salinity (0–9‰) samples showed a prevalence of carbohydrate–degrading Ruminococcaceae, while the carbohydrate-fermenting Petrotogaceae were more abundant in high salinity (18–35‰) samples. The total lack of an important functional class was not noticed in any salinity level, except for sulphate-reducing bacteria, which were virtually absent when salinity was 0‰. The present study allows a better understanding of the environmental conditions resulting in a higher methanogenic potential and an enhanced comprehension of the bacterial communities associated to this process. The obtained information can be of help for designing efficient systems for producing methane from seagrass wrack, as well as for selecting the most appropriate managing route among the currently available technologies (such as on-site environmental preservation, composting, anaerobic digestion).

Description: Transdisciplinary research is a promising approach to address sustainability challenges arising from global environmental change, as it is characterized by an iterative process that brings together actors from multiple academic fields and diverse sectors of society to engage in mutual learning with the intent to co-produce new knowledge. We present a conceptual model to guide the implementation of environmental transdisciplinary work, which we consider a “science with society” (SWS) approach, providing suggested activities to conduct throughout a seven-step process. We used a survey with 168 respondents involved in environmental transdisciplinary work worldwide to evaluate the relative importance of these activities and the skills and characteristics required to implement them successfully, with attention to how responses differed according to the gender, geographic location, and positionality of the respondents. Flexibility and collaborative spirit were the most frequently valued skills in SWS, though non-researchers tended to prioritize attributes like humility, trust, and patience over flexibility. We also explored the relative significance of barriers to successful SWS, finding insufficient time and unequal power dynamics were the two most significant barriers to successful SWS. Together with case studies of respondents’ most successful SWS projects, we create a toolbox of 20 best practices that can be used to overcome barriers and increase the societal and scientific impacts of SWS projects. Project success was perceived to be significantly higher where there was medium to high policy impact, and projects initiated by practitioners/other stakeholders had a larger proportion of high policy impact compared to projects initiated by researchers only. Communicating project results to academic audiences occurred more frequently than communicating results to practitioners or the public, despite this being ranked less important overall. We discuss how these results point to three recommendations for future SWS: 1) balancing diverse perspectives through careful partnership formation and design; 2) promoting communication, learning, and reflexivity (i.e., questioning assumptions, beliefs, and practices) to overcome conflict and power asymmetries; and 3) increasing policy impact for joint science and society benefits. Our study highlights the benefits of diversity in SWS - both in the types of people and knowledge included as well as the methods used - and the potential benefits of this approach for addressing the increasingly complex challenges arising from global environmental change.

Description: The Quaternary history of the Atlantic Canadian inner shelf shares some similarities with the North Sea and northern United States of America (US) Atlantic coast, with the influence of large-scale glaciation and subsequent sea level transgression being the main drivers of seafloor morphology, sedimentology, and uppermost stratigraphy. The geology of the inner shelf, generally confined to 100 m water depth for this study, is an important constraint on the development of offshore renewables, in particular wind energy. Offshore wind has seen rapid growth, particularly in Europe and Asia, where the industry has now experienced decades of production. In the US, one small-scale production farm and many hundreds of MW are in the production pipeline. In contrast, offshore wind in Canada, despite onshore installed wind capacity that ranks highly globally, lacks any operating turbines and there are no plans for development in the wind resource-rich Atlantic Canadian region. In this study, the geological constraints on offshore wind in Atlantic Canada are explored. Generally, the available offshore wind resource is high, and thus the main geophysical constraint on the development of offshore wind energy converters is the inner shelf geology. Several sites with available high-resolution geophysical data are selected for in-depth analysis and comparison with production and planned offshore wind farm sites found elsewhere. In general, a lack of sufficiently thick Quaternary sedimentation—necessary for the most common bottom-fixed foundations for wind turbines—will make developing offshore wind in Atlantic Canada challenging when compared with North Sea and US Atlantic Coast locations. A few locations may be suitable geologically, such as Sable Island Bank in Nova Scotia (thick package of sands), Northumberland Strait between Prince Edward Island and Nova Scotia (shallow firm seabed and sandbanks), Baie des Chaleurs in New Brunswick/Québec (thick, low relief fine sediments), and St. George's Bay, Newfoundland (shallow, postglacially modified moraine). Highlights • Glaciated shelves in Atlantic Canada present distinct challenges for offshore wind foundations. • Few analogies exist between Atlantic Canadian shelf sites and offshore wind sites elsewhere. • Piles—typical offshore wind foundations—require thick sediments, rare in Atlantic Canada. • Thin sand/cobble blankets over bedrock are ubiquitous but thick sand banks/mud basins exist. • The inner shelf seabed geology is variable and historically data collection has focused elsewhere.

Description: The occurrence of neurotoxicity caused by xenobiotics such as pesticides (dichlorodiphenyltrichloroethane, organophosphates, pyrethroids, etc.) or metals (mercury, lead, aluminum, arsenic, etc.) is a growing concern around the world, particularly in vulnerable populations with difficulties on both detection and symptoms treatment, due to low economic status, remote access, poor infrastructure, and low educational level, among others features. Despite the numerous molecular markers and questionnaires/clinical evaluations, studying neurotoxicity and its effects on cognition in these populations faces problems with samples collection and processing, and information accuracy. Assessing cognitive changes caused by neurotoxicity, especially those that are subtle in the initial stages, is fundamentally challenging. Finding accurate, non-invasive, and low-cost strategies to detect the first signals of brain injury has the potential to support an accelerated development of the research with these populations. Saliva emerges as an ideal pool of biomarkers (with interleukins and neural damage-related proteins, among others) and potential alternative diagnostic fluid to molecularly investigate neurotoxicity. As a source of numerous neurological biomarkers, saliva has several advantages compared to blood, such as easier storage, requires less manipulation, and the procedure is cheaper, safer and well accepted by patients compared with drawing blood. Regarding cognitive dysfunction, neuropsychological batteries represent, with their friendly interface, a feasible and accurate method to evaluate the eventual cognitive deficits associated with neurotoxicity in people from diverse cultural and educational backgrounds. The association of these two tools, saliva and neuropsychological batteries, to cover the molecular and cognitive aspects of neurotoxicity in vulnerable populations, could potentially increase the prevalence of early intervention and successful treatment.

Description: The reaction surface area of hydrate (RSAH) inherently controls the reaction rate of hydrate dissociation in the pore spaces, which further affects the gas production behaviour of the hydrate-bearing sediments. The objective of this work is to measure and describe the RSAH evolution during MH dissociation and analyse its implications for gas production. The CT images obtained from different dissociation stages showed the RSAH decreased slowly in the early stage of dissociation and rapidly in the later stage. By considering the pore structure features of sediment, a fractal method was proposed to predict the relationship between RSAH and hydrate saturation, which showed better agreement with the CT experimental results than that of Yousif's model. Further hydrate production numerical simulations embedded with different RSAH predictions indicated that the hydrate production process was significantly influenced by the variations in RSAH. The simulated gas production rate based on the fractal model was lower than that of Yousif's model, the far-field pressure drop in the fractal model was slower, and the advance of the dissociation front and the transfer of the pressure field in Yousif's model was faster than that of the fractal model. Highlights • The changes in hydrate reaction surface area during hydrate dissociation are experimentally measured and analysed. • A fractal model considering the pore structure characteristics of porous media is proposed and experimentally validated. • A comparison of the hydrate dissociation rate predicted by the proposed fractal model and by Yousif’s model is made. • Implications of reaction surface evolution during the hydrate dissociation for hydrate productions are modeled.

Description: Adaptive sampling and situational awareness for autonomous underwater vehicles (AUVs) is a major improvement in ocean research. By only sampling the feature of interest in a feature-relevant domain instead of a covering a whole area expensive ship time can be saved and at the same time a more comprehensive data set can be obtained. A classical marine example where adaptive sampling is useful is sampling of boundary layers such as the thermocline because the boundary layer thickness is very small compared to the depth of the water column. These boundary layers play an important role in many ocean related disciplines such as marine biology, physical oceanography and underwater acoustics. In this paper an unscented Kalman filter (UKF) based extremum seeking control (ESC) approach is presented to detect and track such boundary layers. Simulation results for different use cases are presented to show its effectiveness.

Description: Pa.ra.rho.do.spi.ril'lum. Gr. pref. para-, beside, alongside of, near, like; N.L. neut. n. Rhodospirillum, a bacterial generic name; N.L. neut. n. Pararhodospirillum, resembling Rhodospirillum. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Pararhodospirillum Pararhodospirillum species are spiral-shaped, mesophilic, and phototrophic freshwater bacteria of the Rhodospirillaceae family. Cells are motile by polar flagella, and photosynthetic pigments are located in internal photosynthetic membranes present as lamellar stacks. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series with spirilloxanthin itself lacking. Ubiquinone-9 and rhodoquinone-9 are the major quinones. All species are sensitive to oxygen and require anoxic or microoxic conditions for growth. They grow photoheterotrophically under anoxic conditions in the light. Photoautotrophic growth, aerobic chemotrophic growth, and fermentative growth have not been demonstrated. Growth factors are required. DNA G + C content (mol%): 60.2–65.8 (Bd and HPLC) and 64.7–67 (GA). Type species: Pararhodospirillum photometricum Lakshmi et al. 2014VP (basonym: Rhodospirillum photometricum Molisch 1907AL).

Description: Rho.do.ci'sta Gr. neut. n. rhodon, rose; L. fem. n. cista a basket; N.L. fem. n. Rhodocista, red basket. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Azospirillaceae / Rhodocista Rhodocista centenaria is a well-characterized thermotolerant, phototrophic purple bacterium growing optimally at a temperature of 40–45°C and a maximal growth temperature of 48°C. Under low nutrient conditions, Rhodocista forms desiccation-, heat-, and UV-resistant cysts, which enable survival under severe drought and salt stress. Cells are motile by a single polar flagellum in liquid culture but in addition form lateral flagella on agar surfaces and under these conditions may show a characteristic phototactic movement. Rhodocista species grow under photoheterotrophic conditions and also are able to perform a chemotrophic aerobic metabolism. They encode enzymes for autotrophic carbon dioxide fixation and fixation of dinitrogen, although autotrophic growth has so far not been demonstrated. In the type species, bacteriochlorophyll biosynthesis occurs under both aerobic and anaerobic growth conditions. Aerobically grown cells are fully pigmented. In other species, oxygen may inhibit photosynthetic pigment biosynthesis, and aerobically grown cells are colorless. DNA G + C content (mol%): 68.8–69.9 (Tm), 70.5 (WGS). Type species: Rhodocista (Rcs.) centenaria Kawasaki et al. 1992, VL48 (basonym: Rhodospirillum centenum Favinger et al. 1989, VL48).

Description: Rho.do.pi'la. Gr. neut. n. rhodon the rose; N.L. fem. n. pila a ball or sphere; N.L. fem. n. Rhodopila red sphere. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Acetobacteraceae / Rhodopila Rhodopila globiformis is one of the very few anaerobic phototrophic purple bacteria that can grow below pH 6 with an optimum depending on the organic carbon substrate from 4.8 to 5.6. Growth occurs preferably photoheterotrophically under anoxic conditions in the light. Cells are sensitive to oxygen but grow by respiration under microoxic conditions in the dark. Growth factors are required. They are acidophilic freshwater bacteria that inhabit acidic warm sulfur springs. Cells are spherical to ovoid, motile by means of polar flagella, and divide by binary fission. They stain Gram-negative and have internal photosynthetic membranes of the vesicular type. Rhodopila is classified within the Acetobacteraceae family and Rhodospirillales order of the Alphaproteobacteria. The photosynthetic pigments are bacteriochlorophyll a and carotenoids. The major fatty acids are C18:1 (∼75%) and C16:0. Ubiquinones, menaquinones, and rhodoquinones with 9 and 10 isoprene units are produced. DNA G + C content (mol%): 67.1 (genome analysis). Type species: Rhodopila globiformis Imhoff et al. 1984VP (basonym: Rhodopseudomonas globiformis Pfennig 1974AL).

Description: Rho.do.pla'nes. Gr. neut. n. rhodon rose; Gr. masc. n. planos a wanderer; N.L. masc. n. Rhodoplanes a red wanderer. Proteobacteria / Alphaproteobacteria / Rhizobiales / Hyphomicrobiaceae / Rhodoplanes The genus Rhodoplanes accommodates species of anoxygenic facultative phototrophic bacteria that grow optimally under anaerobic conditions in the light. They belong to the family Hyphomicrobiaceae of the order Rhizobiales within the class Alphaproteobacteria. Cells are Gram-stain-negative rods and multiply by budding and asymmetric cell division. Motile by means of polar, subpolar, or lateral flagella. Internal photosynthetic membranes are present as lamellar stacks parallel to the cytoplasmic membrane. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Photoorganotrophy with pyruvate and some other organic acids is the best mode of growth. Straight-chain, monounsaturated C18:1 ω7c is the main component of the cellular fatty acids and C16:0 is a second major component. Ubiquinones and rhodoquinones with 10 isoprene units (Q-10 and RQ-10) are present. The main components of polar lipids are phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, and diphosphatidylglycerol. Terrestrial and freshwater bacteria having a preference for mesophilic to moderately thermophilic habitats and neutral pH. DNA G + C content (mol%): 67.2–70.4. Type species: Rhodoplanes roseus Hiraishi and Ueda 1994 (Rhodopseudomonas rosea Janssen and Harfoot 1991).

Description: Rho.do.pi'la. Gr. neut. n. rhodon the rose; N.L. fem. n. pila a ball or sphere; N.L. fem. n. Rhodopila red sphere. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Acetobacteraceae / Rhodopila Rhodopila globiformis is one of the very few anaerobic phototrophic purple bacteria that can grow below pH 6 with an optimum depending on the organic carbon substrate from 4.8 to 5.6. Growth occurs preferably photoheterotrophically under anoxic conditions in the light. Cells are sensitive to oxygen but grow by respiration under microoxic conditions in the dark. Growth factors are required. They are acidophilic freshwater bacteria that inhabit acidic warm sulfur springs. Cells are spherical to ovoid, motile by means of polar flagella, and divide by binary fission. They stain Gram-negative and have internal photosynthetic membranes of the vesicular type. Rhodopila is classified within the Acetobacteraceae family and Rhodospirillales order of the Alphaproteobacteria. The photosynthetic pigments are bacteriochlorophyll a and carotenoids. The major fatty acids are C18:1 (∼75%) and C16:0. Ubiquinones, menaquinones, and rhodoquinones with 9 and 10 isoprene units are produced. DNA G + C content (mol%): 67.1 (genome analysis). Type species: Rhodopila globiformis Imhoff et al. 1984VP (basonym: Rhodopseudomonas globiformis Pfennig 1974AL).

Description: Rho.do.spi.ril'lum. Gr. neut. n. rhodon, the rose; N.L. neut. n. Spirillum, a bacterial genus; N.L. neut. n. Rhodospirillum, the rose Spirillum. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Rhodospirillum The genus Rhodospirillum has harbored a diverse set of spiral-shaped phototrophic bacteria, most of which have been reclassified as species of other genera, families, and even orders and phyla since the 1980s. The heterogeneity has been long known, but only the faith into sequence-based information gave strong support for taxonomic rearrangements. Currently, the genus Rhodospirillum contains a single species, which is characterized by spiral-shaped cells, motility by bipolar flagella, and internal membranes as vesicles. It performs anaerobic photosynthesis, which is restricted to anoxic light conditions due to the oxygen-sensitive biosynthesis of bacteriochlorophyll and thus the phototrophic apparatus. It can grow photoheterotrophically as well as photoautotrophically. The key enzyme of autotrophic carbon dioxide fixation in Rhodospirillum rubrum, ribulose bisphosphate carboxylase (RubisCO) type-II, is well characterized and forms a homodimer that is also encoded in some related genera of Rhodospirillaceae. Chemotrophic growth may also occur under microoxic to oxic conditions in the dark and anaerobically by fermentation. The genus comprises mesophilic freshwater bacteria. Ubiquinones and rhodoquinones with 10 isoprene units and fatty acids typical of other Alphaproteobacteria with C18:1, C16:0, and C16:1 as major components are present. DNA G + C content (mol%): 64.6–65.7, type 65.4 (genome analysis), 63.8–65.8 (Bd). Type species: Rhodospirillum (Rsp.) rubrum Molisch 1907AL (basonym: Spirillum rubrum Esmarch 1887).

Description: Rho.do.ci'sta Gr. neut. n. rhodon, rose; L. fem. n. cista a basket; N.L. fem. n. Rhodocista, red basket. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Azospirillaceae / Rhodocista Rhodocista centenaria is a well-characterized thermotolerant, phototrophic purple bacterium growing optimally at a temperature of 40–45°C and a maximal growth temperature of 48°C. Under low nutrient conditions, Rhodocista forms desiccation-, heat-, and UV-resistant cysts, which enable survival under severe drought and salt stress. Cells are motile by a single polar flagellum in liquid culture but in addition form lateral flagella on agar surfaces and under these conditions may show a characteristic phototactic movement. Rhodocista species grow under photoheterotrophic conditions and also are able to perform a chemotrophic aerobic metabolism. They encode enzymes for autotrophic carbon dioxide fixation and fixation of dinitrogen, although autotrophic growth has so far not been demonstrated. In the type species, bacteriochlorophyll biosynthesis occurs under both aerobic and anaerobic growth conditions. Aerobically grown cells are fully pigmented. In other species, oxygen may inhibit photosynthetic pigment biosynthesis, and aerobically grown cells are colorless. DNA G + C content (mol%): 68.8–69.9 (Tm), 70.5 (WGS). Type species: Rhodocista (Rcs.) centenaria Kawasaki et al. 1992, VL48 (basonym: Rhodospirillum centenum Favinger et al. 1989, VL48).

Description: Rho.do.tha.las.si.a.ce'ae. N.L. neut. n. Rhodothalassium, type genus of the family; suff. -aceae, ending to denote a family; N.L. fem. pl. n. Rhodothalassiaceae, the family of Rhodothalassium. Proteobacteria / Alphaproteobacteria / Rhodothalassiales / Rhodothalassiaceae Cells are vibrioid to spiral shaped, are motile by means of polar flagella, and multiply by binary fission. They belong to the class Alphaproteobacteria and stain Gram-negative. An unusual protein-rich cell wall with only low amounts of peptidoglycan may be present. Internal photosynthetic membranes are present as lamellar stacks lying parallel to the cytoplasmic membrane. The photosynthetic pigments are bacteriochlorophyll a and carotenoids. The major ubiquinone and menaquinone components are Q-10 and MK-10. Growth occurs preferably photoheterotrophically under anoxic conditions in the light but also may be possible under microoxic to oxic conditions in the dark. Obligately halophilic bacteria that require NaCl or sea salt for growth. Habitats are anoxic zones of hypersaline environments such as salterns, salt lakes, and evaporated coastal lagoons that are exposed to light. At present, the family includes a single genus. DNA G + C content of the type species and genus (mol%): 68.5–69.0 (genome analysis), 60.0–62.8 (HPLC analysis). Type genus: Rhodothalassium Imhoff et al. 1998VP.

Description: Phae.o.spi.ril'lum. Gr. masc. adj. phaeos, brown; N.L. neut. n. Spirillum, a bacterial genus; N.L. neut. n. Phaeospirillum, brown Spirillum. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Phaeospirillum Phaeospirillum species are vibrioid to spiral shaped and motile Alphaproteobacteria. They are strictly anaerobic and anoxygenic phototrophic bacteria with a reaction center and light-harvesting complexes located in the internal membrane stacks formed at a sharp angle with the cytoplasmic membrane. The photosynthetic pigments are bacteriochlorophyll a esterified with phytol and carotenoids of the spirilloxanthin series, with spirilloxanthin itself lacking. They have a photoheterotrophic metabolism and depend on anoxic conditions for biosynthesis of bacteriochlorophyll and photosynthesis. The preferred carbon substrates are fatty acids including longer chains up to pelargonate. The longer chain fatty acids provide a selective advantage for several of the species. Chemotrophic growth may be possible at controlled and very low oxygen tensions (〈1.5 kPa) in the dark. Ammonia and dinitrogen serve as nitrogen sources. Assimilatory sulfate reduction is present. Growth factors may be required. Phaeospirillum species are mesophilic freshwater bacteria with a preference for neutral pH that live in stagnant and anoxic freshwater habitats. DNA G + C content (mol%): 60.5–65.3 (Bd), 62.1–62.8 (Tm), 61.5–64.7 (WGS). Type species: Phaeospirillum (Phs.) fulvum Imhoff et al. 1998VP (basonym: Rhodospirillum fulvum van Niel 1944AL).

Description: Rho.do.tha.las.si.a'les. N.L. neut. n. Rhodothalassium, type genus of the order; suff. -ales, ending denoting an order; N.L. fem. pl. n. Rhodothalassiales, the Rhodothalassium order. Proteobacteria / Alphaproteobacteria / Rhodothalassiales The order currently comprises a single family and genus, which is characterized by halophilic anoxygenic phototrophic bacteria having spiral-shaped cells and containing lamellar photosynthetic membranes. The properties of the order are determined by the characteristics of the Rhodothalassiaceae family.

Description: Rho.do.tha.las'si.um. Gr. neut. n. rhodon, the rose; Gr. masc. adj. thalassios, belonging to the sea; N.L. neut. n. Rhodothalassium, the rose belonging to the sea. Proteobacteria / Alphaproteobacteria / Rhodothalassiales / Rhodothalassiaceae / Rhodothalassium The genus Rhodothalassium is represented by a single species and is the only genus of the Rhodothalassiaceae family and Rhodothalassiales order. It is characterized by vibrioid- to spiral-shaped cells which multiply by binary fission and are motile by means of flagella. Internal photosynthetic membranes are present as lamellar stacks lying parallel to the cytoplasmic membrane. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Ubiquinones and menaquinones with 10 isoprene units (Q-10 and MK-10) are present. Growth occurs preferably photoheterotrophically under anoxic conditions in the light. Most strains also grow chemoorganotrophically under oxic conditions in the dark. Rhodothalassium species are obligately halophilic, require NaCl or sea salt for growth, and live in anoxic zones of hypersaline environments such as salterns, salt lakes, and evaporated coastal lagoons that are exposed to the light. DNA G + C content (mol%): 68.5–69.0 (WGS), 60.0–62.8 (HPLC). Type species: Rhodothalassium salexigens Imhoff et al. 1998VP (basonym: Rhodospirillum salexigens Drews 1981, VL9).

Description: Rho.do.pla'nes. Gr. neut. n. rhodon rose; Gr. masc. n. planos a wanderer; N.L. masc. n. Rhodoplanes a red wanderer. Proteobacteria / Alphaproteobacteria / Rhizobiales / Hyphomicrobiaceae / Rhodoplanes The genus Rhodoplanes accommodates species of anoxygenic facultative phototrophic bacteria that grow optimally under anaerobic conditions in the light. They belong to the family Hyphomicrobiaceae of the order Rhizobiales within the class Alphaproteobacteria. Cells are Gram-stain-negative rods and multiply by budding and asymmetric cell division. Motile by means of polar, subpolar, or lateral flagella. Internal photosynthetic membranes are present as lamellar stacks parallel to the cytoplasmic membrane. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Photoorganotrophy with pyruvate and some other organic acids is the best mode of growth. Straight-chain, monounsaturated C18:1 ω7c is the main component of the cellular fatty acids and C16:0 is a second major component. Ubiquinones and rhodoquinones with 10 isoprene units (Q-10 and RQ-10) are present. The main components of polar lipids are phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, and diphosphatidylglycerol. Terrestrial and freshwater bacteria having a preference for mesophilic to moderately thermophilic habitats and neutral pH. DNA G + C content (mol%): 67.2–70.4. Type species: Rhodoplanes roseus Hiraishi and Ueda 1994 (Rhodopseudomonas rosea Janssen and Harfoot 1991).

Description: Pa.ra.rho.do.spi.ril'lum. Gr. pref. para-, beside, alongside of, near, like; N.L. neut. n. Rhodospirillum, a bacterial generic name; N.L. neut. n. Pararhodospirillum, resembling Rhodospirillum. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Pararhodospirillum Pararhodospirillum species are spiral-shaped, mesophilic, and phototrophic freshwater bacteria of the Rhodospirillaceae family. Cells are motile by polar flagella, and photosynthetic pigments are located in internal photosynthetic membranes present as lamellar stacks. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series with spirilloxanthin itself lacking. Ubiquinone-9 and rhodoquinone-9 are the major quinones. All species are sensitive to oxygen and require anoxic or microoxic conditions for growth. They grow photoheterotrophically under anoxic conditions in the light. Photoautotrophic growth, aerobic chemotrophic growth, and fermentative growth have not been demonstrated. Growth factors are required. DNA G + C content (mol%): 60.2–65.8 (Bd and HPLC) and 64.7–67 (GA). Type species: Pararhodospirillum photometricum Lakshmi et al. 2014VP (basonym: Rhodospirillum photometricum Molisch 1907AL).

Description: Ro.se.o.spi'ra. L. masc. adj. roseus, rosy; Gr. fem. n. spira, the spiral; N.L. fem. n. Roseospira the rosy spiral. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Roseospira Roseospira species are vibrioid to spiral shaped, anoxygenic, and phototrophic bacteria of the Rhodospirillaceae family that live in various types of marine and slightly saline habitats all over the world. The photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series, and internal photosynthetic membranes are present as vesicles. They perform a phototrophic way of life using organic substrates (photoheterotrophic growth) or inorganic reduced sulfur compounds (photoautotrophic growth) as electron donors for photosynthesis. Bacteriochlorophyll biosynthesis depends on anoxic to microoxic conditions, and chemotrophic growth is possible under microoxic to oxic conditions in the light. Nitrogenase and ribulose bisphosphate carboxylase may be present. Vitamins or yeast extracts are required as growth factors. The G + C content of the DNA is 67.8–71.2 (GA), and the genome size ranges from 4.19 to 4.61 Mb. DNA G + C content (mol%): 67.8–71.2 (GA) (type species 66.6 Tm). Type species: Roseospira mediosalina Imhoff et al. 1998VP (synonym: “Rhodospirillum mediosalinum” Kompantseva and Gorlenko 1984).

Description: The Q10 temperature coefficient, which is widely used in scientific literature, is a measure of the temperature sensitivity of chemical reaction rates or biological processes. However, the conclusions drawn from applying this coefficient to experimental data obtained from biological processes are not universal. In many biological processes, Q10 values are often discordant with the results predicted by the Arrhenius law. The hypothesis tested in the present study is that this problem arises mainly from the fact that the Q10 coefficient is defined by the ratio between rates described by exponential laws instead of power laws. Considering this hypothesis and the need to review the mathematical laws and models currently used to describe rates and Q10 coefficients, we propose a model beyond the usual Arrhenius theory or exponential decay law herein. The proposed mathematical model is based on the theory of deformed exponential functions, with the ordinary Q10 model representing the conventional exponential function. Therefore, all results following the standard model remain valid. Moreover, we include a Q10 free open-source code, written in Python, and compatible with Windows, Linux and macOS platforms. The validation of the proposed model and confirmation of the given hypothesis were performed based on the following temperature-dependent biological processes: soil organic carbon (SOC) decomposition (which is essential to forecast the impact of climate change on terrestrial ecosystems); the metabolism of Arctic zooplankton; physiological processes of the respiratory and cardiovascular systems; rate of oxygen consumption in mitochondria of the eurythermal killifish Fundulus heteroclitus, and leaf respiration.

Description: Since 2010, the Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors the earth emission at L-Band. It provides the longest time series of Sea Surface Salinity (SSS) from space over the global ocean. However, the SSS retrieval at high latitudes is a challenge because of the low sensitivity L-Band radiometric measurements to SSS in cold waters and to the contamination of SMOS measurements by the vicinity of continents, of sea ice and of Radio Frequency Interferences. In this paper, we assess the quality of weekly SSS fields derived from swath-ordered instantaneous SMOS SSS (so called Level 2) distributed by the European Space Agency. These products are filtered according to new criteria. We use the pseudo-dielectric constant retrieved from SMOS brightness temperatures to filter SSS pixels polluted by sea ice. We identify that the dielectric constant model and the sea surface temperature auxiliary parameter used as prior information in the SMOS SSS retrieval induce significant systematic errors at low temperatures. We propose a novel empirical correction to mitigate those sources of errors at high latitudes. Comparisons with in-situ measurements ranging from 1 to 11 m depths spotlight huge vertical stratification in fresh regions. This emphasizes the need to consider in-situ salinity as close as possible to the sea surface when validating L-band radiometric SSS which are representative of the first top centimeter. SSS Standard deviation of differences (STDD) between weekly SMOS SSS and in-situ near surface salinity significantly decrease after applying the SSS correction, from 1.46 pss to 1.28 pss. The correlation between new SMOS SSS and in-situ near surface salinity reaches 0.94. SMOS estimates better capture SSS variability in the Arctic Ocean in comparison to TOPAZ reanalysis (STDD between TOPAZ and in-situ SSS = 1.86 pss), particularly in river plumes with very large SSS spatial gradients.

Description: The exhumation of peridotite rocks in oceanic transform zones passes by the rheological transition between the ductile and brittle deformation until the complete emplacement in the oceanic lithosphere. The São Pedro and São Paulo Archipelago (SPSPA), in the Equatorial Atlantic, records the deformational products of ductile, brittle and the rocks/fluid interaction generating specific structures in each domain. The deformational stages are related to the transpressional and transtensional geodynamics of São Paulo Transform Fault. Firstly, during transpression, exhumation occurs associated with the ductile domain causing intense mylonitization in temperatures between ~700° and 800 °C, defined by olivine and orthopyroxene recrystallization. The interaction with fluids initially originated from the mantle generates amphibole and oxide-rich layers marking the passage to a semi-brittle deformation. The continuation of peridotite exhumation, associated with an NW-SE shortening and transpressional led to a higher availability of hydrothermal fluids. As a consequence, four serpentinization episodes are recorded, which are associated with semi-brittle to brittle transition under temperatures between 300° and 400 °C. Finally, the complete exhumation and establishment of brittle mechanisms led to carbonatation phase near the surface, with temperatures ranging from 300° to 150 °C. The active NW-SE tectonic stress generated E-W strike-slip faults that were filled by carbonates recording the final exhumation stage.

Description: The present state of constantly increasing plastic pollution is the major concern of scientific researchers. The conventional techniques applied (i.e., burning and landfilling) to get plastic degraded from the environment are inadequate due to harmful byproducts and limited to its recycling. In this review, we have recapitulated recent biotechnological approaches, including synthetic microbial consortia, systems biology tools, and genetic engineering techniques which can pave the path towards the plastic bioremediation and degradation. Moreover, potential plastic degrader microbes and their degradation pathways are also summarized. Lastly, this review focuses on enhancing the understanding of the degradation ability of microorganisms using contemporary biotechnological tools.

Description: Atmospheric deposition of aerosols to the ocean provides an important pathway for the supply of vital micronutrients, including trace metals. These trace metals are essential for phytoplankton growth, and therefore their delivery to marine ecosystems can strongly influence the ocean carbon cycle. The solubility of trace metals in aerosols is a key parameter to better constrain their potential impact on phytoplankton growth. To date, a wide range of experimental approaches and nomenclature have been used to define aerosol trace metal solubility, making data comparison between studies difficult. Here we investigate and discuss several laboratory leaching protocols to determine the solubility of key trace metals in aerosol samples, namely iron, cobalt, manganese, copper, lead, vanadium, titanium and aluminium. Commonly used techniques and tools are also considered such as enrichment factor calculations and air mass back-trajectory projections and recommendations are given for aerosol field sampling, laboratory processing (including leaching and digestion) and analytical measurements. Finally, a simple 3-step leaching protocol combining commonly used protocols is proposed to operationally define trace metal solubility in aerosols. The need for standard guidelines and protocols to study the biogeochemical impact of atmospheric trace metal deposition to the ocean has been increasingly emphasised by both the atmospheric and oceanographic communities. This lack of standardisation currently limits our understanding and ability to predict ocean and climate interactions under changing environmental conditions.

Description: Highlights • Regional brain iron concentrations are heterogenous. • Regional distribution of iron is most consistent with ferritin mRNA expression. • SEC-ICP-MS reveals the protein masses that cytosolic iron is associated with. • More than 50 % of cytosolic iron is associated with ferritin. Iron is essential for brain development and health where its redox properties are used for a number of neurological processes. However, iron is also a major driver of oxidative stress if not properly controlled. Brain iron distribution is highly compartmentalised and regulated by a number of proteins and small biomolecules. Here, we examine heterogeneity in regional iron levels in 10 anatomical structures from seven post-mortem human brains with no apparent neuropathology. Putamen contained the highest levels, and most case-to-case variability, of iron compared with the other regions examined. Partitioning of iron between cytosolic and membrane-bound iron was generally consistent in each region, with a slightly higher proportion (55 %) in the ‘insoluble’ phase. We expand on this using the Allen Human Brain Atlas to examine patterns between iron levels and transcriptomic expression of iron regulatory proteins and using quantitative size exclusion chromatography-inductively coupled plasma-mass spectrometry to assess regional differences in the molecular masses to which cytosolic iron predominantly binds. Approximately 60 % was associated with ferritin, equating to approximately 25 % of total tissue iron essentially in storage. This study is the first of its kind in human brain tissue, providing a valuable resource and new insight for iron biologists and neuroscientists, alike.

Description: The aim of this study was to investigate the syntrophic methanogenesis from the perspective of energy transfer and competition. Effects of redox materials and redox potential on direct interspecies electron transfer (DIET) were examined through thermodynamic analysis based on the energy distribution principle. Types of redox materials could affect the efficiency of DIET via changing the total energy supply of the syntrophic methanogenesis. Decreasing system redox potential could facilitate DIET through increasing the total available energy. The competition between hydrogenotrophic methanogens and DIET methanogens might be the reason for the low proportion of the DIET pathway in the syntrophic methanogenesis. A facilitation mechanism of DIET was proposed based on the energy distribution. Providing sufficient electrons, inhibiting hydrogenotrophic methanogens and adding more competitive redox couples to avoid hydrogen generation might be beneficial for the facilitation of DIET.

Description: Highlights • NH4NO3, Tris-HCl, and NH4CH3COO are optimal buffers for use in SEC-ICP-MS metalloprotein analyses. • Optimal range of buffer concentration is 50–200 mM in SEC-ICP-MS. • 100 mM concentration reduces both protein column interactions and ICP-MS maintenance. • Dextran-based columns are best suited for the analysis of apo-copper proteins. The correct identification of the metalloproteins present in human tissues and fluids is essential to our understanding of the cellular mechanisms underpinning a host of health disorders. Separation and analysis of biological samples are typically done via size exclusion chromatography hyphenated with inductively coupled plasma-mass spectrometry (SEC-ICP-MS). Although this technique can be extremely effective in identification of potential metalloproteins, the choice of mobile phase may have a marked effect on results, results by adversely affecting metal-protein bonds of the metalloproteins of interest. To assess the choice of mobile phase on SEC-ICP-MS resolution and the resulting metalloproteome pattern, we analysed several different sample types (brain homogenate; Cu/Zn-superoxide dismutase (SOD1); a molecular weight standard mix containing ferritin (Ft), ceruloplasmin (Cp), cytochrome c (CytC), vitamin B12 (B12) and thyroglobulin (Tg) using six different mobile phase conditions (200 mM, pH 7.5 solutions of ammonium salts nitrate, acetate, and sulfate; HEPES, MOPS and Tris-HCl). Our findings suggest that ammonium nitrate, ammonium acetate and Tris-HCl are optimal choices for the mobile phase, with the specific choice being dependent on both the number of samples and method of detection that is hyphenated with separation. Furthermore, we found that MOPS, HEPES and ammonium sulfate mobile phases all caused significant changes to peak resolution, retention time and overall profile shape. MOPS and HEPES, in particular, produced additional Fe peaks that were not detected with any of the other mobile phases that were investigated. As well as this, MOPS and HEPES both caused significant concentration dependent matrix suppression of the internal standard.

Description: Symbiotic relationships range from parasitic to mutualistic, yet all endosymbionts face similar challenges, including evasion of host immunity. Many symbiotic organisms have evolved similar mechanisms to face these challenges, including manipulation of the host's transforming growth factor-beta (TGFβ) pathway. Here we investigate the TGFβ pathway in scelaractinian corals which are dependent on symbioses with dinoflagellates from the family Symbiodiniaceae. Using the Caribbean coral, Orbicella faveolata, we explore the effects of enhancement and inhibition of the TGFβ pathway on host gene expression. Following transcriptomic analyses, we demonstrated limited effects of pathway manipulation in absence of immune stimulation. However, manipulation of the TGFβ pathway significantly affects the subsequent ability of host corals to mount an immune response. Enhancement of the TGFβ pathway eliminates transcriptomic signatures of host coral immune response, while inhibition of the pathway maintains the response. This is, to our knowledge, the first evidence of an immunomodulatory role for TGFβ in a scelaractinian coral. These findings suggest variation in TGFβ signaling may have implications in the face of increasing disease prevelance. Our results suggest that the TGFβ pathway can modulate tradeoffs between symbiosis and immunity. Further study of links between symbiosis, TGFβ, and immunity is needed to better understand the ecological implications of these findings.

Description: Highlights • Microplastics act as anthropogenic vectors of trace metals in freshwaters. • Adsorption capacity of microplastics is enhanced by biofilms but is not strong as natural substrates. • Biofilms alter the adsorption kinetics and mechanisms of trace metals onto microplastics. • Microplastics enhance exchange rates of trace metals between water and solid materials. • Anthropogenic substrate is necessary in evaluation of migration and fate of trace metals. Microplastics (MPs) are ubiquitous in freshwater environments, and represent an emerging anthropogenic vector for contaminants, such as trace metals. In this study, virgin expanded polystyrene (PS) particles were placed in a eutrophic urban lake and a reservoir serving as the resource of domestic water for 4 weeks, to develop biofilms on the surface. For comparison, natural adsorbents in the form of suspended particles and surficial sediment were also sampled from these waterbodies. The trace metal adsorption properties of anthropogenic (virgin and biofilm covered microplastics) and natural substrates were investigated and compared via batch adsorption experiments. The adsorption isotherms fitted the Langmuir model, revealed that biofilms could enhance the trace metal adsorption capacity of MPs. However, natural substrates still had a greater adsorption capacity. Biofilms also alter the adsorption kinetics of trace metals onto MPs. The process of adsorption onto virgin MPs was dominated by intraparticle diffusion, whereas film diffusion governed adsorption onto biofilm covered microplastics and natural substrates. The trace metal adsorption of all the substrates was significantly dependent on pH and ionic strength. The adsorption mechanisms were further analyzed by SEM-EDS and FT-IR. The enhancement of adsorption was mainly attributed to complexation with functional groups contained in the biofilms, including carboxyl, amino, and phenyl-OH. Collectively, biofilm development intensifies the role of MPs in the migration and fate of trace metals in freshwater, since it does not give MPs an edge over natural substrates in adsorption.

Description: Highlights • New insights of CH4 and CO2 hydrates are explored using MD strategy. • The bubble evolution appears to be important over dissociation process. • RDF, MSD, AOP, and diffusion coefficient can be used to examine hydrate stability. • The most stable structure of CH4 and CO2 molecules in the gas hydrate is found. • A promising match is noticed between the MD and literature findings. A comprehensive knowledge and precise estimation of the dynamic, structural, and thermodynamic characteristics of hydrates are needed to assess the stability of gas hydrates. Thermodynamic model and experimental studies can be utilized to compute the physical and dynamic properties of hydrate structures. The use of molecular dynamic (MD) simulation is a well-established approach in gas hydrate studies at the atomic level where the properties of interest are obtained from the numerical solution of Newtonian equations. The present work uses MD simulations by employing the constant temperature-constant pressure (NPT), constant temperature-constant volume (NVT) conditions, and the consistent valence force field (CVFF) to monitor the stability and decomposition of methane and carbon dioxide gas hydrates with different compositions. The effects of temperature and composition on the hydrate stability are investigated. In this study, we also compute the radial distribution function, mean square displacement, diffusion coefficient, lattice parameter, potential energy, dissociation enthalpy as well as the density of methane and carbon dioxide under various thermodynamic and process conditions. The formation of methane and carbon dioxide bubbles is studied to investigate bubble evolution during hydrate dissociation. The sizes of methane and carbon dioxide bubbles are not the same due to different solubility conditions of methane and carbon dioxide in liquid water. In addition, the influences of pressure and temperature on the lattice parameter and density of clathrate hydrates are discussed. The obtained results are consistent with previous theoretical and experimental findings, implying that the methodology followed in this work is reliable. The most stable arrangement of methane and carbon dioxide molecules in the gas hydrate is found. The insights/findings of this study might be useful to further understand detailed transport phenomena (e.g., molecular interactions, gas production rate, carbon dioxide replacement, and carbon dioxide capture) involved in the process of carbon dioxide injection into gas hydrate reservoirs.

Description: Deep-ocean islands have long been associated with the generation of oceanic eddies in their wakes. However, their interaction with incoming eddies has seldom been considered. This study focuses on the characterization of background and locally generated mesoscale eddies in the Cabo Verde archipelago between 2003 and 2014. Special attention is given to the interaction of incoming eddies with the bathymetry of the islands, along with their impacts on the local generation of eddies. Island-induced wind-shear effects are also considered. In addition, some examples of the biological response to background and locally generated eddies are discussed. This is achieved by combining remote-sensing satellite observations for wind, sea surface height, and chlorophyll-a (Chla) surface concentrations. The results show that the interaction between incoming background eddies and the archipelago is a recurrent phenomenon, which results in eddy deflection, splitting, merging, intensification, and termination (sorted by highest to lowest number of occurrences). Local island-induced disturbances are also significant, mainly due to atmospheric effects. Such processes result in the generation of island-induced eddies and in wind-mediated eddy intensification and confinement, more often observed in the leeward group. Nonetheless, it is strongly suggested that many of the locally generated eddies are a direct product or by-product of the interaction of background eddies with the islands. With respect to the biological realm, a locally generated cyclonic eddy is observed to originate a pronounced phytoplankton bloom in the vicinity of the tallest island. Nonetheless, background eddies generated off the African coast are often associated with enhanced Chla concentrations when they intersect the archipelago. Such observations challenge the idea that local biological productivity in deep oceanic islands is exclusively driven by island-induced mechanisms.

Description: In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.

Description: Rho.do.mi.cro' bi.um. Gr. neut. n. rhodon the rose; Gr. masc. adj. micros small; Gr. masc. n. bios life; N.L. neut. n. Rhodomicrobium red microbe. Proteobacteria / Alphaproteobacteria / Rhizobiales / Hyphomicrobiaceae / Rhodomicrobium Most characteristic for Rhodomicrobium species is the polar cell growth and the characteristic vegetative growth cycle which includes the formation of peritrichously flagellated swarmer cells and nonmotile “mother cells,” which form prosthecae from one to several times the length of the mother cell. Daughter cells originate as spherical buds at the end of the prosthecae and may undergo differentiation in various ways. They are Gram-negative ovoid to elongate-ovoid bacteria belonging to the Alphaproteobacteria. Internal photosynthetic membranes are of the lamellar type. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The predominant cellular fatty acid is C18:1, which comprises more than 80% of the membrane-bound fatty acids. Ubiquinone and rhodoquinone with 10 isoprene units are present, and the lipopolysaccharides are characterized by a glucosamine-containing, phosphate-free lipid A with amide-bound C16:0 3 OH. DNA G + C content (mol%): 61.8–63.8. Type species: Rhodomicrobium vannielii Duchow and Douglas 1949.

Description: Proteobacteria Alphaproteobacteria Rhizobiales Hyphomicrobiaceae Blas.to.chlo'ris. Gr. masc. n. blastos bud shoot; Gr. masc. adj. chloros green; N.L. fem. n. Blastochloris green bud shoot. Proteobacteria / Alphaproteobacteria / Rhizobiales / Hyphomicrobiaceae / Blastochloris Blastochloris species are anoxygenic phototrophic Alphaproteobacteria that have bacteriochlorophyll b in their photosynthetic reaction centers. Crystals of the photosynthetic reaction centers of Blastochloris viridis were the first that have been studied in high-resolution structure analysis at 3 Å resolution. Internal photosynthetic membranes are present as lamellae underlying and parallel to the cytoplasmic membrane. Cells are rod shaped to ovoid and exhibit polar growth, budding, and asymmetric cell division and form rosette-like cell aggregates. They are motile by means of subpolar flagella and stain Gram-negative. Straight-chain monounsaturated C18:1 is the predominant component of cellular fatty acids. Ubiquinones and menaquinones are present, and the lipopolysaccharides are characterized by a 2,3-diamino-2,3-deoxy-d-glucose (DAG)-containing, phosphate-free lipid A with amide-bound C14:0 3OH. DNA G + C content (mol%): 63.8–68.3. Type species: Blastochloris viridis (Drews and Giesbrecht 1966) Hiraishi 1997 (Rhodopseudomonas viridis Drews and Giesbrecht 1966).

Description: Rho.do.mi.cro' bi.um. Gr. neut. n. rhodon the rose; Gr. masc. adj. micros small; Gr. masc. n. bios life; N.L. neut. n. Rhodomicrobium red microbe. Proteobacteria / Alphaproteobacteria / Rhizobiales / Hyphomicrobiaceae / Rhodomicrobium Most characteristic for Rhodomicrobium species is the polar cell growth and the characteristic vegetative growth cycle which includes the formation of peritrichously flagellated swarmer cells and nonmotile “mother cells,” which form prosthecae from one to several times the length of the mother cell. Daughter cells originate as spherical buds at the end of the prosthecae and may undergo differentiation in various ways. They are Gram‐negative ovoid to elongate‐ovoid bacteria belonging to the Alphaproteobacteria. Internal photosynthetic membranes are of the lamellar type. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The predominant cellular fatty acid is C18:1, which comprises more than 80% of the membrane‐bound fatty acids. Ubiquinone and rhodoquinone with 10 isoprene units are present, and the lipopolysaccharides are characterized by a glucosamine‐containing, phosphate‐free lipid A with amide‐bound C16:0 3 OH. DNA G + C content (mol%): 61.8–63.8. Type species: Rhodomicrobium vannielii Duchow and Douglas 1949.

Description: One of the best-known greenhouse gases, CO2, has been increasing in the last decade of about 1.7%. To overcome the well-known global problems related to this gas, researchers of all over the world are working very hard in order to develop any strategies to seriously solve this issue. In this chapter, the authors focus their attention on one of the possible solutions to the problem: bacteria that are CO2 capture cells which have carried out this task since ancient times. In our work we make an excursus on all the biochemical processes of CO2 capture carried out by bacteria, ending with a detailed comparison of the most studied enzymes. One of the alternatives will be to genetically modify the organisms known to date to speed up their conversion process.

Description: The availability of dissolved iron (dFe) exerts an important control on primary production. Recent ocean observation programs have provided information on dFe in many parts of the ocean, but knowledge is still limited concerning the rates of processes that control the concentrations and cycling of dFe in the ocean and hence the role of dFe as a determinant of global primary production. We constructed a three-dimensional gridded dataset of oceanic dFe concentrations by using both observations and a simple model of the iron cycle, and estimated the difference of processes among the ocean basins in controlling the dFe distributions. A Green's function approach was used to integrate the observations and the model. The reproduced three-dimensional dFe distribution indicated that iron influx from aeolian dust and from shelf sediment were 7.6 Gmol yr and 4.4 Gmol yr in the Atlantic Ocean and 0.4 Gmol yr and 4.1 Gmol yr in the Pacific Ocean. The residence times were estimated to be 12.2 years in the Atlantic and 80.4 years in the Pacific. These estimates imply large differences in the cycling of dFe between the two ocean basins that would need to be taken into consideration when projecting future iron biogeochemical cycling under different climate change scenarios. Although there is some uncertainty in our estimates, global estimates of iron cycle characteristics based on this approach can be expected to enhance our understanding of the material cycle and hence of the current and future rates of marine primary production.

Description: The book presents multivariate statistical methods useful in geological analysis. The essential distinction between multivariate analysis as applied to full-space data (measurements on lengths, heights, breadths etc.) and compositional data is emphasized with particular reference to geochemical data. Each of the methods is accompanied by a practically oriented computer program and backed up by appropriate examples. The computer programs are provided on a compact disk together with trial data-sets and examples of the output. An important feature of this book is the graphical system developed by Dr. Savazzi which is entitled Graph Server.

Description: 1 Zonation is often seen in environments with a strong physico-chemical gradient, such as salt marshes. It has been hypothesized that plant species are limited in their distribution by abiotic factors towards the more extreme end of the gradient, and by competition towards the more favourable end. Invasion of the native clonal grass genus Elymus in many Wadden Sea marshes may be due to increasing atmospheric nitrogen input into a nitrogen-limited environment. However, at Thmlauer Bay, Germany, Elymus athericus does not occur in lower salt marsh communities that are dominated by a dwarf shrub (Atriplex portulacoides). We therefore hypothesized that at this site the downslope (= more extreme) distributional boundary of E. athericus is a result of competition with A. portulacoides rather than of physiological limits. 2 A factorial experiment was set up to investigate the effects of removal of each competitor and fertilization. The reciprocal effects of the species on each other were measured in terms of vegetation cover and above-ground biomass. The impact of the tidal regime on plant zonation was investigated by calculating inundation frequencies at the boundary between the two plant populations from water level recordings. 3 Elymus athericus extended its distribution into the lower salt marsh when A. portulacoides was removed. The latter increased in cover but not in biomass after the removal of E. athericus. Neither species showed a response to nitrogen fertilization. The boundary between the two species in the control plots varied considerably in elevation and inundation frequency. 4 The lower distributional boundary of E. athericus can be interpreted as the result of competition with A. portulacoides. Improvement of nitrogen availability in concentrations of the same order of magnitude as annual atmospheric input had no detectable effect on plant zonation and growth. Elevation and inundation frequency were not strictly correlated with plant zonation.

Description: The sea-ice export out of the central Arctic through the Fram Strait is a key variable in the Arctic climate system. Satellite data provide the only basis for mapping ice features with a high spatial and temporal resolution in polar regions. An automatic drift algorithm has been employed and optimized to monitor the sea-ice drift velocity in the Greenland Sea with AVHRR data. The combination of the ice drift and the spatial ice distribution provides an insight into the ice transport processes along the coast of Greenland. The combination with sea-ice thickness measurements allows an estimation of the spatial distribution of the sea-ice mass flux. The seasonal and spatial variability of the mass flux allows further predictions of the meridional melting and freezing processes along the East Greenland Current. This investigation covers the years 1993 and 1994. Seasonal and spatial distributions of the sea-ice drift were derived. The derived absolute values in this study are in good agreement with estimates proposed by other authors.

Description: Heavy mineral studies of East Siberian river sediments, Laptev Sea surface sediments, and a sediment core of the western Laptev Sea were carried out in order to reconstruct the pathways of modern and ancient sediment transport from the Siberian hinterland to the Laptev Sea. The modern heavy mineral distribution of Laptev Sea surface sediments reflects mainly the riverine input. While the eastern and central part of the Laptev Sea is dominated by amphibole, which is supplied by the Lena River, the western part is dominated by pyroxene imported from the Siberian Trap basalts by the Khatanga River. The distribution of garnet and opaque minerals is additionally influenced by hydrodynamic processes. As a consequence of their high density, these minerals are predominantly deposited close to the river mouths. Heavy mineral and sedimentological studies of a sediment core of the western Laptev Sea were applied to reconstruct the postglacial history of the shelf area during the last 11 ka. In the lowermost interval of the core (〉c. 10 ka), high accumulation rates and a heavy mineral composition similar to that of the modern Khatanga river indicate fluvial conditions. Additionally, the high mica content in this interval may indicate meltwater inflow from the Byrranga mountains. Strong variations in accumulation rates, grain-size distribution, and heavy mineral composition are observed in the time interval between c. 10 and 6 ka, which represents the main transgression of the Laptev Sea shelf. During the uppermost interval (〈6 ka), rather stable conditions similar to the modem situation prevailed.

Description: High-resolution Nd- and Pb-isotope time series for the last 8 Myr are reported for four Atlantic ferromanganese crusts, dated by 10Be/9Be chronology. These are compared to new high-resolution and high-precision Pb-isotope time series and recently published Nd-isotope time series for two previously studied crusts from the NW Atlantic Ocean. These records allow a more detailed examination of Atlantic deepwater variability over the time period of intensification of Northern Hemisphere Glaciation (NHG). Changes in the Pb-isotope time series started after 3 Ma, but were most dramatic over the last 1.8 Myr, coinciding with changes of Pb-isotopes in the Arctic Ocean. This latter change post-dates the intensification of NHG at 3.1 to 2.5 Ma and reflects an increase in the input of material eroded from the Archean Shield of Canada and Greenland. Shifts in Nd- and Pb-isotope compositions in a crust from the Blake Plateau occur before ∼5 Ma and most prominent at ∼8 Ma suggest that water masses from either the Pacific or Southern Ocean influenced the isotope composition of this crust. The relatively high εNd values around 8 Ma recorded by the Blake Plateau crust are explained by a contribution of eastward flowing Pacific water through the Panama Gateway into the Caribbean Sea. This high εNd signal decreased between 8 and 5 Ma suggesting that the supply of Pacific water into the Caribbean became restricted. This is earlier than the Caribbean seawater salinity increase at 4.2 Ma deduced from δ18O data, and may indicate that there was only a surface water connection between the Caribbean and Pacific between ∼5 and 4.2 Ma. The closure of the Panama Gateway to intermediate and deep water exchange (〉200 m depth) apparently occurred much earlier than the intensification of Northern Hemisphere Glaciation at 3.1–2.5 Ma, and cannot therefore have been a direct cause of this climatic change, but may, as recently argued, only have been a necessary precondition

Description: The influence of mixing frequency and depth on phytoplankton functional group composition (mobile versus immobile species) was studied by enclosure experiments in a shallow, stratified lake. Mixing events were artificially induced at intervals from 2–12 d. The mixing depth was increased from the natural level (4 m) to 6 and 9 m. The mobile phytoplankton in the experiments consisted of cyanobacteria and flagellates. Among the latter, large and rapid swimming species were represented by dinoflagellates. An increase of the relative abundance of gas vacuolated cyanobacteria occurred with increasing frequency of mixing. Additionally Reynolds' hypothesis predicting the occurrence of certain mobile phytoplankton genera in response to the mixing regime could be confirmed for the condition when mixing depth exceeds the euphoric depth.

Description: Ship speed may have an important effect on the results of seabird surveys. We counted seabirds on a 20.5 X 0.3 km transect in the Kattegat that was sailed nine times with the RV "Heincke." Ship speed alternated between 9 knots and 5 knots. The numbers of the most common species, the Lesser Black-backed Gull (Larusfuscus), were significantly higher when the ship was sailing at lower speed similar to that of commercial fishing vessel when trawling in the area. It is postulated that scavenging species( e.g., gulls) are attracte to the low speed of vessels whereas non-scavengers (e.g. auks) are not

Description: Mixed methane–sulfide hydrates and carbonates are exposed as a pavement at the seafloor along the crest of one of the accretionary ridges of the Cascadia convergent margin. Vent fields from which methane-charged, low-salinity fluids containing sulfide, ammonia, 4He, and isotopically light CO2 escape are associated with these exposures. They characterize a newly recognized mechanism of dewatering at convergent margins, where freshening of pore waters from hydrate destabilization at depth and free gas drives fluids upward. This process augments the convergence-generated overpressure and leads to local dewatering rates that are much higher than at other margins in the absence of hydrate. Discharge of fluids stimulates benthic oxygen consumption which is orders of magnitude higher than is normally found at comparable ocean depths. The enhanced turnover results from the oxidation of methane, hydrogen sulfide, and ammonia by vent biota. The injection of hydrate methane from the ridge generates a plume hundreds of meters high and several kilometers wide. A large fraction of the methane is oxidized within the water column and generates δ13C anomalies of the dissolved inorganic carbon pool.

Description: The identification of developmental stages in fish eggs from plankton samples is often complicated by deformation of the embryos due to mechanical stress during the sampling procedure and by dehydration during formaldehyde fixation. The effects of formaldehyde fixation and mechanical stress on Baltic cod eggs (Gadus morhua callarias L.) were examined separately by visually comparing the morphological features of treated vs. live eggs of identical ontogenetic age. Microphotographs were made concurrently for documentation. In stage IA eggs, mechanical treatment resulted in scattered blastodiscs surrounded by single cells, while in further advanced stages the yolk membrane collapsed entirely, the yolk coagulated and the embryo extending over the yolk shrank. Formaldehyde fixation caused the yolk and the blastodisc or embryo to darken, and in some cases crystalline enclosures occurred. Eggs mechanically deformed during handling were clearly distinguishable from those that died prior to catching; however, staging was generally less accurate for formaldehyde-preserved eggs when compared with living specimens.

Description: Controversy surrounding the mechanisms and controls on argon diffusion in K-feldspar has led us to undertake direct diffusion measurements on a crystal with simple microtextures, over a range of temperatures. Measurements of argon diffusion profiles in a gem-quality iron-rich orthoclase heated in a cold seal apparatus, have been undertaken in situ using an ultra-violet laser ablation microprobe (UVLAMP) technique. The results agree very closely with the previously determined bulk values for Benson Mines orthoclase (activation energy ( E)=43.8±1 kcal mol -1) and vacuum furnace cycle-heating studies of K-feldspars ( E=46±6 kcal mol -1). However, instead of defining a single activation energy ( E) and diffusion coefficient ( Do), the data yield two sets of parameters: a low-temperature (550-720°C) array with an E of 47.2±2.5 kcal mol -1 (198.2±10.5 kJ mol -1) and a Do of 0.0374 +0.1123-0.0281 cm 2 s -1, and a high-temperature (725-1019°C) array with an E of 63.8±3.4 kcal mol -1 (268.0±14.3 kJ mol -1) and a Do of 55.0 +225.5-44.2 cm 2 s -1. The new results closely reproduce two sets of apparent activation energies previously measured in cycle-heating studies of Madagascar K-feldspar (40±3 and 57±3 kcal mol -1). Previous interpretations of the two arrays have included multiple domains with variable activation energies and fast track diffusion. However, the UV depth profile analyses indicate simple diffusion to the grain surface and importantly, diffusion radii calculated by combining the UVLAMP and cycle-heating data, are the same as the physical grain sizes used in the experiments, around 1 mm. Vacuum furnace stepped heating experiments on slowly cooled K-feldspars have been interpreted as showing diffusion radii of around 6 μm and indicate complex populations of sub-grains. This study indicates that Madagascar K-feldspar and thus probably all gem-quality K-feldspars act as single diffusion domains and that short-circuit (or pipe) diffusion was not an important loss mechanism. An apparent diffusion compensation relationship in the stepped heating data for Madagascar K-feldspar implies that similar relationships seen in other K-feldspars are a result of a range of diffusion mechanisms.

Description: The holocene depositional setting of the Laptev Sea was studied using three marine sediment cores from water depths between 77 and 46 m. Based on sedimentary parameters (TOC content, delta(13)C(org) Sedimentation rates) controlled by radiocarbon age models the palaeoenvironment of a strongly coupled river-shelf system was reconstructed since similar to 11 ka SP. Caused by a transgressing sea after the last glaciation, all cores reveal progressive decreases in sedimentation rates. Using the sedimentary records of a core from the Khatanga-Anabar river channel in the western Laptev Sea, several phases of change are recognized: (1) an early period lasted until similar to 10 ka BP characterized by an increased deposition of plant debris due to shelf erosion and fluvial runoff; (2) a transitional phase with consistently increasing marine conditions until 6 ka BP, which was marked at its beginning near 10 ka BP by the first occurrence of marine bivalves, high TOC content and an increase in delta(13)C(org); (3) a time of extremely slow deposition of sediments, commencing at,6 ka BP and interpreted as Holocene sea-level highstand, which caused a southward retreat of the depositional centres within the now submerged river channels on the shelf; (4) a final phase with the establishment of modern conditions after similar to 2 ka BP.

Description: Sediment proxy data from the Norwegian, Greenland, and Iceland seas (Nordic seas) are presented to evaluate surface water temperature (SST) differences between Holocene and Eemian times and to deduce from these data the particular mode of surface water circulation. Records from planktic foraminiferal assemblages, CaCO3 content, oxygen isotopes of foraminifera, and iceberg-rafted debris form the main basis of interpretation. All results indicate for the Eemian comparatively cooler northern Nordic seas than for the Holocene due to a reduction in the northwardly flow of Atlantic surface water towards Fram Strait and the Arctic Ocean. Therefore, the cold polar water flow from the Arctic Ocean was less influencial in the southwestern Nordic seas during this time. As can be further deduced from the Eemian data, slightly higher Eemian SSTs are interpreted for the western Iceland Sea compared to the Norwegian Sea (ca. south of 70°N). This Eemian situation is in contrast to the Holocene when the main mass of warmest Atlantic surface water flows along the Norwegian continental margin northwards and into the Arctic Ocean. Thus, a moderate northwardly decrease in SST is observed in the eastern Nordic seas for this time, causing a meridional transfer in ocean heat. Due to this distribution in SSTs the Holocene is dominated by a meridional circulation pattern. The interpretation of the Eemian data imply a dominantly zonal surface water circulation with a steep meridional gradient in SSTs.

Description: The growth of Fucus vesiculosus L, germlings in chemically defined culture media containing a range of Cu concentrations (20-1000 nM) was monitored simultaneously with measurement of the Cu speciation in the media by competitive equilibrium-adsorptive cathodic stripping voltammetry, Fucus vesiculosus germlings were found to exude Cu-complexing Ligands with conditional stability constants of the order of 1.6 x 10(11), Ligand concentrations increased with increasing total dissolved Cu concentrations (Cu-T) until a concentration of 500-800 neq Cu.L-1 was reached. Concentrations of the ligand exceeded Cu-T in treatments containing 20 and 100 nM Cu-T were similar to Cu-T in the 500-nM Cu treatment, but were less than Cu-T in the 1000-nM treatment. Therefore, [Cu2+] were calculated to be at concentrations of 10(-11) - 10(-10) M in the 20- and 100-nM treatments, 10(-9) M in the 500-nM treatment, and 10(-7) M in the 1000-nM treatment, Growth rates were lowest at Cu2+ concentration 〉 10(-9). These results are discussed within the context of the potential roles for exuded copper-complexing ligands

Description: The widespread view that scleractinian corals in cold and deep waters of high latitudes are slow growing organisms that do not form reefs is challenged by the discovery of a huge coral reef over 13 km in length, 10 to 35 m in height and up to 300 m in width formed by the coral Lophelia pertusa in water depths of 270 to 310 m at 64°N on the Sula Ridge, Mid-Norwegian Shelf. Cruises in 1994, 1995 and manned submersible operations in May 1997 provide data and observations from which the structure and development of the Sula Ridge coral reef have been determined. The Fennoscandian icesheet retreated from the Mid-Norwegian shelf prior to 12,000 years before present and modern oceanographic conditions were established at 8000 years before present. Coral growth since that time has resulted in a large deep-water shelf reef for which recent stable isotopic studies have demonstrated high growth rates for these azooxanthellate cold-water corals. Information on the geometry of deep-water coral reefs and their environmental controls is still fragmentary, controversial and raises issues of conservation in this area of active fishing and oil exploration. This paper reports on the discovery of what is probably one of the largest deep-water coral reefs existing in the northeast Atlantic and indicates that its siting is due to post-glacial structures (iceberg plough marks), events (the second Storegga Slide) and local conditions on the seafloor. Surprisingly, reef accumulation rates on the Sula Ridge are comparable with those measured on tropical coral reefs.

Description: The possibilities of defining and computing an approximately neutral density variable are reexamined in this paper. There are three desirable properties that a neutral density variable should possess. Firstly, the isosurfaces of this variable should coincide with (approximately) neutral surfaces. This would facilitate the analysis of hydrographic data on the most appropriate mixing and spreading surfaces. Secondly, the horizontal gradients of the neutral density should agree with the gradients of the in situ density, and thirdly the vertical gradient of the neutral density variable should be proportional to the static stability of the water column. A density variable that approximates the latter two properties can be used in ocean circulation models based on layer coordinates, and would reduce substantial errors in present isopycnal models due to the use of a potential density variable. No variable can possess all the three properties simultaneously. The variable γn introduced by Jackett and McDougall (1997, J. Phys. Oceanogr. 27, 237–263) satisfies the first of the properties exactly but is not designed for the use in models. Based on climatological data in the North Atlantic, an alternative neutral density variable ν̃(S, Θ) is defined, which is shown to approximate the two gradient criteria much better than any potential density. We suggest that this neutral density variable may be useful in isopycnal ocean models as an alternative to potential density, since it could significantly reduce errors in thermal wind relation and vertical stability

Description: To investigate patch selectivity in aspidochirotide holothurians, individuals of five species (Holothuria (Halodeima) atra Jäger, H. (H.) edulis Lesson, H. (Microthele) nobilis Selenka, Stichopus chloronotus Brandt and S. variegatus Semper) were subjected to multiple choice experiments. As a food source, sediments were pre-cultivated in petri dishes under different light and nutrient regimes. This resulted in four sediment treatments with different levels of microalgal biomass (measured as chlorophyll a and phaeophytin concentrations). Only two sediment treatments were used for experiments with H. nobilis and S. variegatus. The sediments were offered simultaneously to individual holothurians (six per experiment), and the weights of the sediment in each petri dish at the start and after 48 h were used to calculate a selection index together with confidence intervals for each food type. In experiments with H. atra and H. edulis, the animals exhibited no preference for any food type. In contrast, S. chloronotus significantly selected sediments with the highest contents of microalgae and avoided the sediment with the lowest pigment concentrations. These results were supported by field collections of sediments found directly underneath holothurians. Sediment underneath H. edulis did not differ from the average sediment of the habitat, while H. atra was found on sediments only slightly higher in chlorophyll a. Chlorophyll a concentrations underneath S. chloronotus were distinctly higher than in the adjacent sediment and that underneath H. atra. H. nobilis showed only a weak preference for sediments with higher pigment concentrations in aquarium experiments, and no patch selectivity in this species was found in the field. Stichopus variegatus exhibited a very distinct patch selectivity towards sediments with more nutritional value in both aquaria experiments and field measurements. Thus members of the genus Holothuria had no, or only a weak, tendency to select their food source, whereas both Stichopus species appeared to carefully select the sediment patch to feed on.

Description: In an extended deep-sea study the response of the benthic community to seasonally varying sedimentation rates of organic matter were investigated at a fixed abyssal site in the NE Atlantic (BIOTRANS station or JGOFS station L2 at 47°N–20°W, water depth 〉4500 m) on four legs of METEOR expedition 21 between March and August 1992. The vertical flux at 3500 m depth and temporal variations in the chloroplastic pigment concentration, a measure of phytodetritus deposition, and of total adenylates and total phospholipids, measures of benthic biomass, and of activity of hydrolytic enzymes were observed. The flux patterns in moored sediment traps of total chlorophyll, POC and total flux showed an early sedimentation peak in March/April 1992, followed by low fluxes in May and intermediate ones from June to August. Thus 1992 differed from other years, in which one large flux peak after the spring phytoplankton bloom was observed. Unusually high concentrations of chloroplastic pigments were consistently observed in March 1992, reflecting the early sedimentation input. At the same time biomass of small benthic organisms (bacteria to meiobenthos) and activity of hydrolytic enzymes were higher compared to values from March 1985 and from the following months in 1992. In May and August 1992 pigment concentrations and biomass and activity parameters in the sediment were lower than during previously observed depositions of phytodetrital matter in summer. The data imply that the deep ocean benthic community reacts to small sedimentation events with transient increases in metabolic activity and only small biomass production. The coupling between pelagic and benthic processes is so close that interannual variability in surface water production is “mirrored” by deep-sea benthic processes.

Description: This is the first detailed investigation of the distribution and ecology of living (stained) shallow water (0–6 m) foraminifera along the Skagerrak–Kattegat coast, eastern North Sea. A total of 25 species (13 agglutinated; 12 calcareous) are common in the 169 sediment surface samples which were collected from 27 geographic areas. The sediment grain size and total organic carbon (TOC) content are strongly variable and the salinity and temperature ranges were 10–31‰ and 9–30°C, respectively, at the time of sampling (July to October) but temperatures down to freezing occur during the winter. The species are divided into six environmental categories of which the first five comprise euryhaline and the sixth essentially stenohaline taxa: (1) species associated only with marsh plants, (2) species basically, but not entirely, associated with marsh plants, (3) species basically, but not entirely, restricted to non-marsh areas, (4) species solely recorded in non-marsh intertidal to subtidal environments, (5) species restricted to subtidal areas, (6) species basically living in the most open marine areas. In this region, marshes have a patchy distribution and they are small and compressed due to low tidal ranges (〈40 cm). Balticammina pseudomacrescens (not reported here before) lives in the most elevated, landward, terrestrial parts of marshes and thus defines the uppermost limit of the influence of marine water. However, the marshes are generally dominated by Jadammina macrescens and Miliammina fusca at the landward and seaward sides, respectively. Jadammina macrescens is observed living epiphytically on decaying Carex leaf debris. The most widely distributed euryhaline species are Elphidium williamsoni, Miliammina fusca, Ammonia beccarii, and Haynesina germanica. The former two are common only in sediments with a mud content less than about 60%, whereas the latter two are common even in sediments with 〉80% mud. Ammoscalaria runiana is common only in coarse-grained sediments (〈20% mud) with low TOC (≤0.7%). There are no marked biogeographic boundaries within the Skagerrak–Kattegat area but 10 of the 25 commonly occurring species have not been reported from the adjacent Baltic Sea, probably partly due to the brackish character of the water there. The southern limits of distribution of the northern species, Elphidium albiumbilicatum, Ammotium cassis, and Ophthalmina kilianensis, are in the Kattegat–Baltic Sea.

Description: Although much of the deep sea is physically tranquil, some regions experience near-bottom flows that rework the surficial sediment. During periods of physical reworking, animals in the reworked layer risk being suspended, which can have both positive and negative effects. Reworking can also change the sediment in ecologically important ways, so the fauna of reworked sites should differ from that of quiescent locations. We combined data from two reworked, bathyal sites on the summit of Fieberling Guyot (32°27.631′N, 127°49.489′W; 32°27.581′N, 127°47.839′W) and compared the results with those of more tranquil sites. We tested for differences in the following parameters, which seemed likely to be sensitive to the direct or indirect effects of reworking: (1) the vertical distribution of the meiofauna in the sea bed, (2) the relative abundance of surface-living harpacticoids, (3) the proportion of the fauna consisting of interstitial harpacticoids, (4) the ratio of harpacticoids to nematodes. We found that the vertical distributions of harpacticoid copepods, ostracods, and kinorhynchs were deeper on Fieberling. In addition, the relative abundance of surface-living harpacticoids was less, the proportion of interstitial harpacticoids was greater, and the ratio of harpacticoids to nematodes was greater on Fieberling. These differences between Fieberling and the comparison sites suggest that physical reworking affects deep-sea meiofauna and indicate the nature of some of the effects.

Description: The percentage of the structural Fe(II) in clay minerals that is readily oxidized to Fe(III) upon contact with atmospheric oxygen was determined across the downcore tan–green color change in Peru Basin sediments. This latent fraction of reactive Fe(II) was only found in the green strata, where it proved to be large enough to constitute a deep reaction layer with respect to the pore water O2 and NO3−. Large variations were detected in the proportion of the reactive Fe(II) concentration to the organic matter content along core profiles. Hence, the commonly observed tan–green color change in marine sediments marks the top of a reactive Fe(II) layer, which may represent the major barrier to the movement of oxidation fronts in pelagic subsurface sediments. This is also demonstrated by numerical model simulations. The findings imply that geochemical barriers to pore water oxidation fronts form diagenetically in the sea floor wherever the stage of iron reduction is reached, provided that the sediments contain a significant amount of structural iron in clay minerals.

Description: A coulometrically-based SOMMA system for the determination of total dissolved carbon dioxide (TCO2) in a continuous mode was designed and tested at sea. The new continuous technique approached the same high accuracy and reliability associated with prior discrete TCO2 measurements. During three cruises encompassing more than 19 weeks and 6000 continuous TCO2 measurements none of the three different systems tested exhibited any hardware-related failures. We found that coulometer cell lifetimes can greatly exceed prior expectations with many of the titration cells in the continuous mode remaining accurate for up to 72 h at carbon ages exceeding 50 mg C. We suggest a practical definition based on the CRM analyses for changing coulometer cells in the continuous mode. Systematic deviations of the SOMMA pipette volume from a theoretical temperature dependence were identified both from field data comparisons and pipette calibrations. Hence pipettes should be kept at constant temperature or they must be gravimetrically calibrated over the expected temperature range. Comparison of the continuous TCO2 data together with simultaneously measured additional CO2 system parameters showed that the refitted “Mehrbach” dissociation constants for carbonic acid best-represent fCO2 when calculated from TCO2 and alkalinity over a wide range of sea-surface temperatures and salinities. Some remaining systematic differences of calculated–measured fCO2 of up to 9 μatm likely reflect uncertainty in the temperature-dependence of the “Mehrbach” constants as well as possible uncertainty in the alkalinity–salinity relationship used to estimate alkalinity in the consistency checks.

Description: An unrealistically high-salinity maximum is found to develop in a high-resolution model of the north and equatorial Atlantic below the shallow halocline in the Gulf of Guinea. The spurious water mass with salinities too high by as much as 1 psu is formed when the vertical advection is treated by the standard central-differencing advection scheme. The problem is considerably reduced either by increasing the vertical resolution of the numerical grid, or by switching to a higher-order upwind-weighted scheme for vertical advection. This note stresses the need for a careful consideration of vertical discretization even in typical high-resolution ocean general circulation models (OGCMs). Particular attention is needed for studying heat and salt budgets or transports of biogeochemical tracers.

Description: Data on the carbonate system of the Northwestern Indian Ocean obtained on a cruise of F.S. Meteor during SW monsoon in July/August 1995 were compared with those of George et al. [George, M.D., Kumar, M.D., Naqvi, S.W.A., Banerjee, S., Narvekar, P.V., de Sousa, S.N., Jayakumar, D.A., 1994. A study of the carbon dioxide system in the northern Indian Ocean during premonsoon. Mar. Chem. 47, 243–254] collected during intermonsoon. In general, deep water values agreed well between the two expeditions. Surface waters, however, showed a substantial increase in dissolved inorganic carbon (CT) in the coastal regions due to strong upwelling in the SW monsoon. This was also accompanied by very high CO2 partial pressures in surface waters. The north–south gradients in vertical profiles of the measured parameters in the Arabian Sea are discussed by comparing profiles from the oligotrophic equatorial region with those from the highly productive central Arabian Sea. The effect of denitrification on regenerated CT and AT is minor, with contributions of 〈9 and 〈8 μmol kg−1, respectively, to the total amount regenerated also utilizing oxygen. The dissolution of biogenic carbonates is discussed; different approaches to define the depth, where the dissolution starts (lysocline(s), carbonate critical depth (CCrD)), are compared together with the calculation of saturation depth from carbonate concentrations. It is shown, that small differences in measured CT and AT (found between our data and those measured during GEOSECS) and different calculation approaches to the CO2 system (different dissociation constants for species involved and taking into account phosphate and silicate concentrations) can produce pronounced differences in the calculated saturation depths. However, CT and AT data suggest substantial dissolution of biogenic carbonate in the water column even above the calcite lysocline, irrespective of the procedures followed to calculate this horizon.

Description: The aim of this study was to evaluate the potential of a compound diet as a live prey substitute for feeding European sea bass larvae (Dicentrarchus labrax L.). The effect of a commercial diet (Nippai ML feed) and live prey (Artemia nauplii) on tryptic enzyme activity, protein content, growth (standard length) and survival rates of sea bass larvae were tested during a 27-day rearing experiment. Sea bass larvae were divided into two groups. The live food group (control group) was fed exclusively on newly hatched Artemia nauplii (Inve AF grade), the test group was fed exclusively with the compound diet from day 15 onwards. As trypsin has been demonstrated to be a useful indicator for evaluating digestibility of food and the nutritional condition of fish larvae, individual tryptic enzyme activity was determined in both feeding groups. Larvae older than 14 days after hatching and fed on live food showed a significantly higher tryptic enzyme activity than larvae fed the compound diet. A similar relationship between tryptic activity and standard length in both test groups was detected only in small larvae (standard length 〈 7 mm). The usefulness of proteolytic enzyme activity measurements in larval fish research, as well as its use in aquaculture nutrition research, was confirmed. Protein content, increase in length and survival rates of the sea bass larvae were additionally determined in order to evaluate an influence on the diet. The protein content of larvae fed the Artemia nauplii was higher and the growth of larvae fed the compound diet was reduced. Larval mortality was not affected by the diet given.

Description: Microalgal biovolume is commonly calculated to assess the relative abundance (as biomass or carbon) of co‐occurring algae varying in shape and/or size. However, a standardized set of equations for biovolume calculations from microscopically measured linear dimensions that includes the entire range of microalgal shapes is not available yet. In comparison with automated methods, the use of microscopical measurements allows high taxonomic resolution, up to the species level, and has fewer sources of error. We present a set of geometric shapes and mathematical equations for calculating biovolumes of 〉850 pelagic and benthic marine and freshwater microalgal genera. The equations are designed to minimize the effort of microscopic measurement. The similarities and differences between our proposal for standardization and previously published proposals are discussed and recommendations for quality standards given.

Description: We compare the time series of major element geochemical and Pb- and Nd-isotopic composition obtained for seven hydrogenous ferromanganese crusts from the Atlantic, Indian, and Pacific Oceans which cover the last 60 Myr. Average crust growth rates and age-depth relationships were determined directly for the last about 10 Myr using Be-10/Be-9 profiles. In the absence of other information these were extrapolated to the base of the crusts assuming constant growth rates and constant initial Be-10/Be-9 ratios due to the lack of additional information. Co contents have also been used previously to estimate growth rates in Co-rich Pacific and Atlantic seamount crusts (Puteanus and Halbach, 1988). A comparison of Be-10/Be-9- and Co-based dating of three Co-rich crusts supports the validity of this approach and confirms the earlier chronologies derived from extrapolated Be-10/Be-9-based growth rates back to 60 Ma. Our data show that the flux of Co into Co-poor crusts has been considerably lower. The relationship between growth rate and Co content for the Co-poor crusts developed from these data is in good agreement with a previous study of a wider range of marine deposits (Manheim, 1986). The results suggest that the Co content provides detailed information on the growth history of ferromanganese crusts, particularly prior to 10-12 Ma where the Be-10-based method is not applicable. The distributions of Pb and Nd isotopes in the deep oceans over the last 60 Myr are expected to be controlled by two main factors: (a) variations of oceanic mixing patterns and flow paths of water masses with distinct isotopic signatures related to major paleogeographic changes and (b) variability of supply rates or provenance of detrital material delivered to the ocean, linked to climate change (glaciations) or major tectonic uplift. The major element profiles of crusts in this study show neither systematic features which are common to crusts with similar isotope records nor do they generally show coherent relationships to the isotope records within a single crust. Consequently, any interpretation of time series of major element concentrations of a single crust in terms of paleoceanograghic variations must be considered with caution. This is because local processes appear to have dominated over more basin wide paleoceanographic effects. In this study Co is the only element which shows a relationship to Pb and Nd isotopes in Pacific crusts. A possible link to changes of Pacific deep water properties associated with an enhanced northward advection of Antarctic bottom water from about 14 Ma is consistent with the Pb but not with the Nd isotopic results. The self-consistent profiles of the Pb and Nd isotopes suggest that postdepositional diagenetic processes in hydrogenous crusts, including phosphatization events, have been insignificant for particle reactive elements such as Pb, Be, and Nd. Isotope time series of Pb and Nd show no systematic relationships with major element contents of the crusts, which supports their use as tracers of paleo-seawater isotopic composition

Description: Variations of intensity and composition of biogenic particle flux at the northern boundary of the present PolarFrontal Zone in the Atlantic sector of the Southern Ocean are indicators of major changes of paleoenvironmentalconditions on glacial/interglacial time scales during the Late Quaternary. In order to estimate those pastchanges, sediment accumulation patterns of two piston cores, one from just north and one just south of thepresent day position of the Subantarctic Front were reconstructed. Using the 230Thex method large contributionsof laterally supplied material were quantified and used to correct sediment accumulation rates. During the lastglacial focussing of biogenic opal-dominated material exceeded the original contribution from the surfacewater above by a maximum factor of 8.7. The initial activity ratio of 231Paex/230Thex was used as tracer forbiogenic particle flux and composition and indicates that during the glacial stages 2 and 4 the area of high opalproductivity was situated above the location of the southern core whereas the northern core has not beenreached by this northward shift during the last 130 kyr as shown by the pattern of focussing-corrected bulkaccumulation rates. If the position of the Antarctic Polar Front has remained at the northern boundary of thehigh opal productivity area during the last 130 kyr, the results suggest that was located exactly between thetwo core sites during glacial stages 2 and 4. A two-box modeling approach involving particle flux and boundaryscavenging intensity of 231Pa was applied to estimate the possible range of the 231Paex/230Thex ratio recordedin Southern Ocean sediments. Previous estimates on the export of 231Pa from the Atlantic into the SouthernOcean are corroborated but the model suggests a low sensitivity of the 231Paex/230Thex ratio in Southern Oceansediments to variations of the residence time of North Atlantic Deep Water in the Atlantic Ocean.

Description: Tens of thousands of synthetic substances are in existence today and hundreds of new compounds are being introduced every year. Because of the complexity of the physico-chemical interactions between pollutants and the marine environment, the potential toxicity of contaminants can be assessed adequately only by means of bioassays with living organisms. From a practical point of view, a bioassay needs to be sensitive and scientifically valid, yield rapid results at moderate cost, and the organism in question must be readily available. Ecotoxicological bioassays with bivalve embryos and larvae fulfil these criteria better than most other tests. They have increasingly come into use during the past three decades and are now commonly employed to ascertain the biological effects of pure chemicals, as well as to determine the quality of effluents, coastal waters and sediments sampled in the field. There do not appear to be very great differences between bivalve species with regard to larval sensitivity to toxicants. The principal species for bioassays are oysters (Crassostrea gigas and C. virginica), and mussels (Mytilus edulis and M. galloprovincialis). Bioassays are conducted with gametes and larvae of ail ages: sperm and unfertilized eggs, embryos, young D-larvae, intermediate umboned larvae, and pediveligers towards the end ofthe pelagic period. Embryos are usually the most sensitive stage. Recent advances now also permit bioassays on metamorphosing pediveligers, a method particularly suited to investigate the effects of adsorbate-contaminated surfaces. There are various criteria for the assessment oftoxic effects, including embryogenesis success (abnormalities), larval growth, mortality, physiology (e.g. feeding or swimming activity), and metamorphosis success. Chronic toxicity studies may be carried out over periods ofseveral weeks, but larval rearing in the laboratory requires considerable effort (e.g. cultivation of algal food). The method of choice for investigations of acute toxicity and for routine monitoring studies is the embryo bioassay because it is very sensitive, relatively simple, and produces results within 24 or 48 hours. The data obtained by different investigators are often difficult to compare, however, because of differences in methodology. There is no firmly established procedure, and further simplification and standardization of techniques is required. In bioassays with a single pollutant, the effective toxic concentration may span several orders of magnitude, depending on bioassay procedures, larval stage and choice of response. Tributyl-tin (TBT) is the most toxic compound ever bioassayed with bivalve larvae, with effective concentrations (EC50) as low as a few nanograms per litre (i.e. 10−3 ppb). Heavy metals (particularly mercury, silver and copper) are next in order of toxicity, with EC50 values between a few micrograms per litre (ppb) and several hundred ppb. Chlorine and some organochlorine pesticides may also have EC50 values of less than 100 ppb, while detergents and petroleum products are generally less toxic

Description: Sensitivities of cirrus cloud radiative forcing as well as solar albedo and infrared emittances to ice crystal size spectrum and ice crystal shape were examined using a coupled cloud-radiation model. The single- and bi-modal crystal size distribution were considered and simulated based on field measurements. Optical parameters of ice crystals shaped as hexagonal columns and random polycrystals (being frequently found in cirrus clouds) were calculated with a ray-tracing method. Both solar and infrared cirrus radiative forcing are influenced by the pattern of crystal size spectra. The net radiative forcing is lower for bi-modal than for single-modal spectra. The solar radiative forcing of cirrus cloud is reduced by nonspherical ice crystals, due to larger albedo effects of nonspherical crystals compared to those of equivalent spherical crystals. Moreover, this reduction in solar radiative forcing by random polycrystals is even larger than that by hexagonal column crystals. The cloud radiative forcing, solar albedo and infrared emittance are changed significantly as the mean crystal size approaches the smaller size end. Furthermore, net cloud radiative forcing is positive in most cirrus cases. Exceptions are cirrus clouds with a large number (〉107 m−3) of small (mean maximum dimension 〈30 μm) ice crystals and cirrus clouds with bi-modal crystal size distribution and large particle size for the second maximum peak.

Description: We looked at the routes taken by Magellanic Penguins up the beach while moving between the sea and the colony at a breeding site in San Julian, Argentina. Birds swam parallel to the shore for a period before leaving the water to cross the beach but trajectories over the beach were not perpendicular to the water's edge but at an angle of 39°. We examined the premise that birds might be optimizing for a trade off between time or energy by adopting this procedure and found that birds can gain little or no time by walking obliquely but can, under particular circumstances, save energy. These circumstances require that the previously-calculated costs of transport for walking have been over-estimated by a factor of two

Description: Various discretization methods exist for the numerical simulation of multiphase flow in porous media. In this paper, two methods are introduced and analyzed—a full-upwind Galerkin method which belongs to the classical finite element methods, and a mixed-hybrid finite element method based on an implicit pressure–explicit saturation (IMPES) approach. Both methods are derived from the governing equations of two-phase flow. Their discretization concepts are compared in detail. Their efficiency is discussed using several examples.

Description: Colonization of new habitats, which have been established as a result of a catastrophic disturbance of the environment, is one of the characteristic repetitive events throughout the Phanerozoic. In recent years, much attention has been paid to investigations focusing on biological recovery of benthic habitats severely disturbed by human activity. In order to improve our environmental and stratigraphical interpretations of such events, we need a more thorough understanding of the processes involved in colonization by one of the most abundant and useful fossil groups, the benthic foraminifera. The present review focuses on processes governing benthic foraminiferal dispersion and colonization patterns in modern environments. For benthic foraminifera, the only active dispersal mechanism is through self-locomotion on or within the sediment and this is considered to be efficient over short distances only. Several passive dispersal methods have been suggested but two seem to be of more general importance. These are dispersal through release and transport of embryonic juveniles and passive suspension and transport of various growth stages. Both are probably important for most benthic foraminifera but the former is likely to be the main mechanism for attached, tubular and larger foraminifera, which are not easily entrained at a later life stage. The latter seems to be a more important dispersion mechanism for benthic foraminifera than previously realized. The colonization rate of soft-bottom substrates is closely related to the hydraulic regime in, and the transit time from, the source area inhabited by species capable of colonizing the new habitat (as long as food and other environmental characteristics are not limiting factors). The transit time depends on the speed of the transporting medium and the distance from the source area. There seems to be two end-processes which can operate during the colonization, depending on whether physically induced or biological processes are allowed to dominate. They are characterized by different colonization patterns. In high energy environments (bottom current velocities often 〉20 cm/s), a short transit time may cause the major components of the nearest ambient seafloor assemblages to colonize the new habitat within days. In this case the colonization is simply through a physical transfer of parts of the source community to the new habitat, allowing no time for pioneer, opportunistic assemblages to develop. In low energy environments (bottom current velocities generally 〈10 cm/s), the transit time is long for most species. Here, colonization follows the classic metazoan successional pattern with an initial, high abundance pioneer assemblage strongly dominated by small opportunists followed by development of assemblages with increasing numbers of specialized species and recovery can take from one to several years. Initial lack of food (e.g., volcanic ash) or `hostile' substrate properties (e.g., recently reoxygenated or severely contaminated sediments) may delay colonization by months or even years. Small, infaunal species (both calcareous and agglutinated) are among the first and most successful colonizers of soft bottom habitats from shallow waters to the deep sea. Throchospiral agglutinated taxa are among the most abundant colonizers on deep sea hard substrates.

Description: The excretion of siderophores and the reduction of organic iron-complexes at the cell surface are common reactions of terrestrial plants, fungi and bacteria in response to low availability of iron. However, there is much less evidence for the use of these strategies by marine phytoplankton. It has been argued that siderophore excretion is inefficient in an aquatic environment due to rapid diffusion. This study examines how diffusion and chemical reactions in the microenvironment of a phytoplankton cell influence the efficiency of both strategies to increase the bioavailability of iron and to reduce iron stress. A numerical model of the cell surroundings is presented that calculates the concentration distribution for different iron species and allows to study the effect of siderophores or surface reductases. It calculates the efficiency of these mechanisms, defined as the quotient between the increase in iron uptake rate and the excretion rate of siderophores or electrons, needed to obtain this increase. The dependence of this efficiency on rates of iron coordination reactions, on diffusivity, and on the kinetics of iron uptake is discussed with the aid of some analytical calculations.

Description: Laboratory feeding experiments were conducted to elucidate size-relationships in the seastar-mussel (Asterias rubens-Mytilus edulis) predator-prey interaction. This is one of the most well-known predator-prey relationships in marine benthic ecology and the dependence of seastar feeding rates and prey size selection are crucial for modelling. Moreover, the hypothesis should be tested that large individuals of M. edulis enjoy a size-refuge from seastar predation in the Baltic sea. Ingestion rates showed an allometric relationship to seastar size. They increased slightly more than cubically (b = 3.62) with the linear size of the seastars and slightly more than linearly (b = 1.27) with the body mass of the seastars. Somatic growth rates were linearly related to ingestion rates. Larger seastars tended to eat larger mussels. This relationship was significant for the largest size of mussels eaten and for the mean size of mussels eaten, but not for the minimal size. Size selection of seastars did not depend on the spatial arrangement of mussel sizes relative to the initial position of the seastars in the aquarium. Mussels of 〉 48 mm in length are safe from predation by the largest seastars found in the western Baltic sea.