ALBERT

Description: The Fram Strait between Greenland and Spitsbergen is the only deep-water connection between the Arctic Ocean and its surrounding water bodies. Here, the WSC (West Spitsbergen Current) transports warm Atlantic Water into the Arctic, which accounts for a major part of the warming trend measured there in the past. The northern part of the Fram Strait is strongly influenced by the MIZ (Marginal Ice Zone), which causes a stratification of the water column that retains nutrients at the surface. These sustain intense algal blooms, leading to high abundances of zooplankton, linking the primary production and higher trophic levels. Changes in the position of the MIZ and the timing of the algae blooms might affect the zooplankton community and thus the entire Arctic food chain. The aim of this study was to investigate the effect of the ice edge on the zooplankton community in the Fram Strait. Zooplankton samples were taken at the northern (ice influenced) stations N4/5 and the southern (ice-free) station S3 of the Long-Term Ecological Research Observatory HAUSGARTEN established by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in the Fram Strait in 1999. MultiNet samples of both stations were collected in 6 years. For 2015, 2017 and 2018, samples covered a depth of 1,000 m with 4 depth intervals (0-50-200-500-1,000 m). Additionally, surface samples (0-50 m) from 2011, 2012 and 2016 were added to the analysis. CTD data and ice parameters were included to test for correlations between species occurrences and the shifting ice edge. It was hypothesized 1) that the plankton community differs between the northern stations N4/5 and the southern station S3, 2) that these differences are caused by the influence of the ice edge and 3) that interannual differences are stronger at N4/5 due to the shifting ice edge. Furthermore, the zooplankton camera LOKI (Lightframe On-sight Key species Investigation) was deployed at S3 in 2017. This approach offers continuous abundance data combined with simultaneously measured environmental parameters and thus allows a closer insight into small-scale zooplankton distributions. Here, it is hypothesized 4) that the results of the LOKI and the MultiNet will differ regarding zooplankton abundance and community composition. An ANOSIM revealed sampling depth to be the only significant factor for differences between samples. Year and location both tested insignificant. While the northern station showed a higher interannual variability of environmental parameters than the southern station, this was not reflected in the zooplankton communities. It is likely that the WSC which transports Atlantic species northwards is the major factor determining the community composition while the influence of the ice edge is minor. Abundances ranged from 4,500 ind.m-3 at the surface level (0-50 m) at N5 in 2015 to almost 14,000 ind.m-3 at the surface at N4 in 2018, with copepods being the most abundant taxon in all samples. While overall abundances were higher at the surface, the number of taxa increased with depth. In general, there was no trend with time or location. However, in 2017 and 2018 large blooms of the appendicularian Fritillaria sp. were found, especially at the northern station. These might be an indicator of warmer temperatures and an increasing borealization of the Arctic. The LOKI and MultiNet hauls compared at station S3 in 2017 showed differences regarding species abundances, with the LOKI often recording only a fraction of what was found in the MultiNet data. This disparity was mostly accounted for by copepods of the genus Oithona, whose translucent bodies were not well captured by the LOKI. On the other hand, the high vertical resolution of the LOKI allowed to detect a close correlation of Metridia longa to Atlantic Water and a niche separation of developmental stages of M. longa with only females and CV performing a diel vertical migration. These results, while not finding a statistically significant difference between the northern stations N4/5 and the southern station S3, illustrate the importance of time series stations in indicator regions such as the Fram Strait in order to monitor climate change processes.

Description: In this master thesis, Raman Lidar data from Ny-Å?lesund, Spitsbergen have beenanalysed for January to April 2019. Optical parameters (the aerosol backscatter at532 nm, the depolarisation ratio at 532 nm, the color ratio and the Lidar ratio at 355nm) and their typical values have been presented per height interval and per month,as well as the differences between those. Also, the links between the different opticalparameters have been investigated and those values were compared with values ofMarch 2018. March 2019 showed lower backscatter and higher depolarisation ratios,indicating fewer and more spherical particles as in March 2018. For January the 28thand February the 06th, hygroscopic growth has been determined. Relative humiditydata measured by radiosondes have been investigated for strong gradients andbackscatter data has been plotted against the relative humidity. The parametrizationof the scattering enhancement factor (f(RH) = (1??RH)????) has been used to plotgrowth curves through the backscatter data and optimal values for??have beenfound. For the 28th of January, the calculated??-values ranged from 0.3 to 1.4 andthe most likely value appeared to be 0.64. Growth factors (g(RH)) and??-valueshave been calculated as well based onin situ(PM10-filter) data using the Zdanovskii-Stokes-Robinson relation. The resulting??-values for January the 28th and Februarythe 6th were respectively 0.98 and 0.73. For the 19th of January, a general overviewof the aerosol situation on that day has been presented using different results fromdifferent techniques. Mostly small sized aerosol particles (14〈D〈300 nm) havebeen found for that day and low depolarisation values were measured, indicating thepresence of small, spherical ammonium sulfate species. Further research combiningLidar andin situdata is needed for making more precise and accurate conclusions considering Arctic aerosols.

Description: 〈jats:title〉Abstract〈/jats:title〉〈jats:p〉Natural history collections are leading successful large-scale projects of specimen digitization (images, metadata, DNA barcodes), thereby transforming taxonomy into a big data science. Yet, little effort has been directed towards safeguarding and subsequently mobilizing the considerable amount of original data generated during the process of naming 15,000–20,000 species every year. From the perspective of alpha-taxonomists, we provide a review of the properties and diversity of taxonomic data, assess their volume and use, and establish criteria for optimizing data repositories. We surveyed 4113 alpha-taxonomic studies in representative journals for 2002, 2010, and 2018, and found an increasing yet comparatively limited use of molecular data in species diagnosis and description. In 2018, of the 2661 papers published in specialized taxonomic journals, molecular data were widely used in mycology (94%), regularly in vertebrates (53%), but rarely in botany (15%) and entomology (10%). Images play an important role in taxonomic research on all taxa, with photographs used in >80% and drawings in 58% of the surveyed papers. The use of omics (high-throughput) approaches or 3D documentation is still rare. Improved archiving strategies for metabarcoding consensus reads, genome and transcriptome assemblies, and chemical and metabolomic data could help to mobilize the wealth of high-throughput data for alpha-taxonomy. Because long-term—ideally perpetual—data storage is of particular importance for taxonomy, energy footprint reduction via less storage-demanding formats is a priority if their information content suffices for the purpose of taxonomic studies. Whereas taxonomic assignments are quasifacts for most biological disciplines, they remain hypotheses pertaining to evolutionary relatedness of individuals for alpha-taxonomy. For this reason, an improved reuse of taxonomic data, including machine-learning-based species identification and delimitation pipelines, requires a cyberspecimen approach—linking data via unique specimen identifiers, and thereby making them findable, accessible, interoperable, and reusable for taxonomic research. This poses both qualitative challenges to adapt the existing infrastructure of data centers to a specimen-centered concept and quantitative challenges to host and connect an estimated $ \le $2 million images produced per year by alpha-taxonomic studies, plus many millions of images from digitization campaigns. Of the 30,000–40,000 taxonomists globally, many are thought to be nonprofessionals, and capturing the data for online storage and reuse therefore requires low-complexity submission workflows and cost-free repository use. Expert taxonomists are the main stakeholders able to identify and formalize the needs of the discipline; their expertise is needed to implement the envisioned virtual collections of cyberspecimens. [Big data; cyberspecimen; new species; omics; repositories; specimen identifier; taxonomy; taxonomic data.]〈/jats:p〉

Description: TESTThe aim of this study was to contribute to a general understanding of the response of the Antarctic macrobenthos to environmental variability and climate-induced changes. The change in population size of selected macrobenthic organisms was investigated in the Larsen A area east of the Antarctic Peninsula in 2007 and 2011 using ROV-based imaging methods. The results were complemented by data from the Larsen B collected in 2007 to allow a conceptual reconstruction of the environment-driven changes before the period of investigation. Both Larsen areas are characterised by ice-shelf disintegration in 1995 and 2002, respectively, as well as high inter-annual variability in sea-ice cover and oceanographic conditions. In 2007 one ascidian species, Molgula pedunculata, was abundant north and south of the stripe of remaining ice shelf between Larsen A and B. Population densities decreased drastically in the Larsen A between 2007 and 2011, coincident with the decrease in Corella eumyota, another ascidian. Among the ophiuroids, the population of deposit feeders increased, while suspension feeders halved their abundance. Current measurements indicated a northward flow between the Larsen B and Larsen A, suggesting that a major physical forcing on benthic population development comes from the South. The results demonstrate that Antarctic macrobenthic populations can exhibit dramatic population dynamics. Analyses of sea-ice dynamics, salinity, temperature and surprisingly ice-shelf disintegration history, however, did not provide any clear evidence for environmental drivers underlying the apparent changes. © 2013 Springer-Verlag Berlin Heidelberg.

Description: The present study examines the effects of experimentally generated disturbance on bathyal nematode communities at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN, situated in the Fram Strait, between Greenland and Svalbard. In order to understand the complex interactions between the biota and environmental perturbations we deployed a free-falling device (bottom lander) equipped with three rotating fork-like disturber units, able to perturbate the upper sediment layers with different disturbance frequencies at chosen time intervals. During a one-year deployment at 2493 m water depth, disturber unit DI was programmed to rotate every 14 days, DII every 28 days, and DIII every 72 days, resulting in 28, 14, and 7 perturbations, respectively. Sediment sampling following this experimental period was conducted with push-coring devices deployed by the Remotely Operated Vehicle “QUEST 4000” (MARUM, Bremen). These sediment cores were sub-sampled to determine the effect of the sediment perturbations on various sediment parameters (i.e., grain size distribution, chloroplastic pigment concentrations) as well as on benthic nematode communities. A total of 4773 nematodes from 27 families and 81 genera were identified. Nematode densities in the disturbed areas ranged from 617 ind. / 10 cm2 to 1566 ind. / 10 cm2, with a mean density of 1193 ind. / 10 cm2 observed overall in the disturbed sediments. Control sediments contained on average 20% more nematode specimens than were found within the disturbed sediments, with an average density of 1477 ind. / 10 cm2 observed. Nematode evenness (J'), genera richness (EG(51)) and heterogeneity (H′) were not significantly different between the treatments and controls (undisturbed vs disturbance). We found a significant effect of the interaction of disturbance frequency and sediment depth (interaction term Fr x De) on heterogeneity and genera richness, while evenness significantly differed between different sediment depths (De) and within the disturbed sediments between different disturbance frequencies (Fr). Although surface sediments in the three disturbed areas were effectively perturbated, sediment depth still has the most pronounced influence on nematode community attributes, while the experimentally induced disturbance had only a limited impact on nematode diversity and community structure. Although we found the density of some nematode genera was negatively affected by the disturbances, the deep-sea nematode community at HAUSGARTEN was generally characterized by a relatively high diversity and seemed to be largely resilient to the experimental disturbances.

Description: The aim of our study is to analyse physical properties of internal layers of deep ice cores in Greenland (NGRIP and NEEM) and a new ice core record from the East GReenland Ice-core Project (EGRIP) on the North East Greenland Ice Stream (NEGIS). For this purpose, in the first part of this study, we have established the initial chronology for the EGRIP ice core over the Holocene and the late last glacial period. We rely on conductivity patterns and volcanic events determined by means of dielectric profiling (DEP), electrical conductivity measurements (ECM) and tephra records for the synchronization between the EGRIP, NEEM and NGRIP ice cores in Greenland. We have transferred the annual-layer-counted Greenland ice Core Chronology 2005 (GICC05) timescale from the NGRIP core to the EGRIP ice core by means of 373 match points. The second part of this study compares numerically modelled radargrams and the airborne radar measurements (radio-echo sounding) to understand the recorded physical properties of internal layers towards reflection mechanisms. Synthetic modelling of electromagnetic wave propagation has been applied to the EGRIP, NEEM and NGRIP2 ice cores based on the conductivity and permittivity, as measured at 250 kHz by DEP. For the comparison between synthetic and observed data, we have used radio-echo sounding data from AWI’s multichannel ultra-wideband radar around the EGRIP drill site, that were recorded during the 2018 field season, and the CReSIS data from the University of Kansas around the NEEM and NGRIP2 drill sites. The timescales (depth-age relation from first part of our study) have been transferred to the synthetic and observed radargrams by means of sensitivity studies. We have found that conductivity only explains a fraction of the radar signals in Greenland ice sheet and the orientated fabric is widespread and influences the radar data.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.