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Introduction
Current institution
Additional affiliations
October 2011 - present
October 2011 - present
Position
- Managing Director
Description
- & Professor of Earth System Sciences at Rostock University
October 2002 - October 2011
Publications
Publications (170)
Worldwide, many aquatic systems are under anthropogenic induced pressure by elevated nutrient inputs. In particular, increased nitrogen and phosphorus usage have led to human-induced eutrophication (including cyanobacterial blooms and hypoxia) of all kinds of water bodies. Associated pressures need to be described, and diminished, in order to reach...
Tiergemeinschaften am Meeresboden sind auf komplexe Weise von Vorgängen in der Wassersäule abhängig. Prozesse am Meeresboden beeinflussen andererseits die pelagischen Lebensgemeinschaften. Änderungen an der Meeresoberfläche (Erwärmung, pH-Erniedrigung, Planktonumschichtung, Verschiebung von Hochproduktionsgebieten etc.) können sich bis in Meerestie...
This special issue of Ambio compiles a series of contributions made at the 8th International Phosphorus Workshop (IPW8), held in September 2016 in Rostock, Germany. The introducing overview article summarizes major published scientific findings in the time period from IPW7 (2015) until recently, including presentations from IPW8. The P issue was su...
(English abstract below)
Kurzfassung
Optische Technologien und Verfahren sind sowohl in der limnischen als auch marinen Forschung Deutschlands über alle Bereiche und Skalen etabliert und entwickeln sich rasant weiter. Die Arbeitsgruppe „Aquatische Optische Technologien“ (AOT) will Forschern und Anwendern eine Plattform bieten, die Wissenstransfer...
Trophic dynamics of 2 abundant macrozooplankton species Salpa thompsoni and Themisto gaudichaudii were studied during the austral summer at 2 locations near the Antarctic Polar Front with contrasting low and high chlorophyll a (chl a) concentrations. Compound-specific stable isotope analysis, complemented by gut content and bulk isotope analyses, w...
Distribution, density, and feeding dynamics of the pelagic tunicate Salpa thompsoni have been investigated during the expedition ANTARKTIS XVIII/5b to the Eastern Bellingshausen Sea on board RV Polarstern in April 2001. This expedition was the German contribution to the field campaign of the Southern Ocean Global Ocean Ecosystems Dynamics Study (SO...
Optische Technologien und Verfahren sind sowohl in der limnischen als auch marinen Forschung Deutschlands über alle Bereiche und Skalen etabliert und entwickeln sich rasant weiter. Die Arbeitsgruppe „Aquatische Optische Technologien“ (AOT) will Forschern und Anwendern eine Plattform bieten, die Wissenstransfer fördert, der nationalen Entwicklergeme...
The diet of Antarctic salps was elucidated by investigating their gut content using automated ribosomal intergenic spacer analysis (ARISA) and 454-pyrosequencing. Salp samples were collected during the Lazarev Sea Krill Study in the western Weddell Sea (summer 2005-06 and 2007-08, autumn 2004 and winter 2006). Two salp species, Salpa thompsoni and...
The macrozooplankton and micronekton community of the Lazarev Sea (Southern Ocean) was investigated at 3 depth layers during austral summer, autumn and winter: (1) the surface layer (0–2 m); (2) the epipelagic layer (0–200 m); and (3) the deep layer (0–3000 m). Altogether, 132 species were identified. Species composition changed with depth from a e...
Pelagic zooplankton were monitored from 2000 to 2012 at a permanent location near the Svalbard archipelago, at the boundary between the central Arctic Ocean and the Greenland Sea in the eastern Fram Strait. The temporal results reveal the first evidence of successful reproduction in Arctic waters by an Atlantic pelagic crustacean from temperate wat...
Significance
Silica-shelled diatoms dominate marine phytoplankton blooms and play a key role in ocean ecology and the global carbon cycle. We show how differences in ecological traits of dominant Southern Ocean diatom species, observed during the in situ European Iron Fertilization Experiment (EIFEX), can influence ocean carbon and silicon cycles....
Life-cycle characteristics of the free-swimming lysianassoid amphipod Cyclocaris guilelmi were investigated and compared to those of other regularly appearing amphipods in the Arctic deep-sea community. In this context we analysed time-series data of meso- and bathypelagic amphipods collected as swimmers in moored sediment traps from 2004 to 2008 a...
Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncerta...
Time series length-frequency data are presented for . Themisto amphipods collected as swimmers by moored sediment traps since 2000 at the AWI deep-sea observatory HAUSGARTEN (79°N/4°E) in the eastern Fram Strait. Amphipod occurrences increased significantly from 2000 to 2009 at 200-300. m depth, and the North Atlantic species . Themisto compressa w...
The association of Antarctic krill Euphausia superba with the under-ice habitat was investigated in the Lazarev Sea (Southern Ocean) during austral summer, autumn and winter. Data were obtained using novel Surface and Under Ice Trawls (SUIT), which sampled the 0-2 m surface layer both under sea ice and in open water. Average surface layer densities...
Jan Andries van Franeker, Hauke Flores, Michiel van Dorssen: The Surface and Under-Ice Trawl (SUIT). Detailed description of the novel sampling device used in this study.
(PDF)
Two species of salps, Salpa thompsoni and Ihlea racovitzai, were sampled during three cruises to the Lazarev Sea, Southern Ocean, in summer (December–January) 2005/2006, Autumn (April–May)
2004 and Winter (July–August) 2006. Dry weight, carbon, nitrogen, protein, lipid and carbohydrate contents were measured to
characterize the potential value of s...
Time series length-frequency data are presented for Themisto amphipods collected as swimmers by moored sediment traps since 2000 at the AWI deep-sea observatory HAUSGARTEN (79°N/4°E) in the eastern Fram Strait. Amphipod occurrences increased significantly from 2000 to 2009 at 200-300 m depth, and the North Atlantic species Themisto compressa was co...
Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both
species were positively correlated with ambient surface chlorophyll a (chl a). No evidence was found for salp clogging even at dense surface concentra...
We have studied the seasonal dynamics of abundance and feeding characteristics of three species of calanoid copepods (Acartia spp., Centropages hamatus and Temora longicornis) in the White Sea from the surface water layer (0–10m), in order to assess their role in the pelagic food web and to determine
the major factors governing their population dyn...
The benthic fauna was investigated during the expedition ANT-XXIV/2 (2007/08) in relation to
oceanographic features, biogeochemical properties and sediment characteristics, as well as the benthic,
pelagic and air-breathing fauna. The results document that Maud Rise (MR) differs distinctly from
surrounding deep-sea basins investigated during previou...
We estimate the energy flow through meso-and bathypelagic chaetognaths in the Atlantic sector of the Southern Ocean from (1) depth-structured chaetognath abundance and body mass data, (2) a general chaetognath respiration model driven by body mass, temperature, water depth and taxon, and (3) published relationships between respiration, production a...
Ecological and physiological studies focused on dietary preferences, lipid biochemistry and energetics within the three Antarctic
chaetognaths Eukrohnia hamata, E. bathypelagica and E. bathyantarctica from meso- and bathypelagic depths. Eukrohnia hamata and E. bathypelagica respired 0.15 μL O2 mg dry mass (DM)−1 h−1, which translates to an average...
Dieser Artikel thematisiert, wie mikroskopisch kleine Meeresalgen und -tiere das Klima beeinflussen und wie die ansteigende Konzentration des klimarelevanten Gases Kohlenstoffdioxid (CO2) den Säuregrad (pH) und das Carbonatsystem des Meerwassers verändert. Drei Transportprozesse verfrachten Kohlenstoff aus den Oberflächenschichten der Ozeane in der...
There is a need to characterise the physical environment associated with Antarctic minke whale density in order to understand long-term changes in minke whale distribution and density in open waters of the Southern Ocean during austral summer months. To investigate environmental drivers of Antarctic minke whale density, generalised additive models...
Copepod grazing impact on planktonic communities has commonly been underestimated due to the lack of information on naupliar
feeding behaviour and ingestion rates. That is particularly true for small cyclopoid copepods, whose nauplii are mainly in
the microzooplankton size range (<200μm). The trophic role of Oithona spp. nauplii was investigated of...
Plankton are the main food source in the majority of marine ecosystems and have a crucial role in climate change through primary production and the export of carbon to the deep ocean. Understanding how ocean biology and biogeochemical cycles contribute and respond to climate and other global change is a major challenge of high significance for the...
The oceans play a key role in climate regulation especially in part buffering (neutralising) the effects of increasing levels of greenhouse gases in the atmosphere and rising global temperatures. This chapter examines how the regulatory processes performed by the oceans alter as a response to climate change and assesses the extent to which positive...
We conducted multinet sampling during winter and summer in the Southern Ocean (Atlantic sector) to investigate the effect
of water mass, season and water depth on abundance and species composition of meso- and bathypelagic chaetognaths. Eukrohnia hamata (mean 115ind.1,000m−3) and Sagitta marri (mean 51 ind. 1,000m−3) were dominant, complemented by...
Abstract The physiological,condition of larval Antarctic krill was investigated during austral autumn,2004 and winter 2006 in the Lazarev Sea. The condition of larvae was quantified in both seasons by determining,their body length (BL), dry weight (DW), elemental and biochemical composition, stomach content analysis, and rates of metabolism and gro...
The diet of three Antarctic copepods, Calanus simillimus, Rhincalanus gigas and Pleuromamma robusta, was studied from samples collected during the European iron fertilization experiment (EIFEX) in austral fall 2004. The diet was investigated using microscopical gut content analysis. The food spectra of the three copepod species showed a clear overl...
Chaetognaths are among the most abundant predators in the Southern Ocean and are potentially important components in the biological
carbon pump due to the production of large, fast-sinking fecal pellets. In situ S. gazellae abundance, fecal pellet production, sinking rates, carbon content, and vertical carbon fluxes were measured at the Lazarev Sea...
Seasonal dynamics of major biochemical features were studied for three abundant egg-diapausing copepods Acartia
bifilosa, Centropages hamatus and Temora longicornis, in the White Sea (66°N), between June 2002 and September 2002. Dry weight (DW) and prosome length varied from 0.54μgind−1 and 0.163±0.012mm (A. bifilosa, CI) to 9.58±0.72μgind−1 and 1....
We investigated the causes of a large increase in abundance of small copepods, in particular Oithona similis, that was observed during the iron fertilisation experiment EisenEx in the Southern Ocean. Oithona spp. individuals showed a pronounced migratory response and shifted their vertical distribution towards the progressively phytoplankton-enrich...
lankton are the main food source in the majority of marine ecosystems and have a crucial role in climate change through primary production and the export of carbon to the deep ocean. Understanding how ocean biology and biogeochemical cycles contribute and respond to climate and other global change is a major challenge of high significance for the f...
The physiological condition of larval Antarctic krill was investigated during austral autumn 2004 and winter 2006 in the Lazarev Sea, to provide better understanding of a critical period of their life cycle. The condition of larvae was quantified in both seasons by determining their body length (BL), dry mass (DM), elemental- and biochemical compos...
Zooplankton stock as well as faecal pellet numbers were monitored over 2 weeks during May in the central Baltic. Considerable changes in concentrations of chlorophyll and its derivates in copepod faecal pellets as well as in surface sediments were found during this period. The maximum concentration of 1.05 ngchl. a faecal pellet-1, measured on 12 M...
A biochemical model of Antarctic krill Euphausia superba was developed to investigate the physiological mechanisms which enable krill to survive winter, when food is scarce. In this mod- eling approach data sets on the biochemical composition of krill and its food sources are combined into a model that takes food quality into account rather than ju...
Pronounced changes in temperature, salinity (density) and upwelling have occurred in surface and deeper waters of the oceans, contributing with changing patterns and strength of winds to an alteration in ocean circulation. Together these changes have a potentially large impact through feedbacks on climate change.
The viability of different phytoplankton species within copepod faecal pellets was tested. Monocultures of the dinoflagellate Scrippsiella trochoidea and the diatoms Fragilariopsis kerguelensis, Proboscia alata and Chaetoceros dichaeta were fed to Calanus helgolandicus, Temora longicornis and Centropages typicus. Microscopic observations of faecal...
The reproductive response of Rhincalanus gigas to the build up of a phytoplankton bloom in the Southern Ocean was studied during the European iron fertilization experiment (EIFEX). Egg production experiments were conducted over a period of approximately 5weeks during development of a diatom dominated bloom. R. gigas showed a clear response to incre...
Feeding activity, selective grazing and the potential grazing impact of two dominant grazers of the Polar Frontal Zone, Calanus simillimus and Rhincalanus gigas, and of copepods < 2 mm were investigated with incubation experiments in the course of an iron fertilized diatom bloom in November 2000. All grazers were already actively feeding in the low...
Distribution, density, and feeding dynamics of the pelagic tunicate Salpa thompsoni have been investigated during the expedition ANTARKTIS XVIII/5b to the Eastern Bellingshausen Sea on board RV Polarstern in April 2001. This expedition was the German contribution to the field campaign of the Southern Ocean Global Ocean Ecosystems Dynamics Study (SO...
Detailed determination of Salpa thompsoni elemental composition has been carried out on specimens collected in the Eastern Bellingshausen Sea and at the northern edge of the Weddell Gyre during austral autumn (April and May) of 1996 and 2001. More than 170 Antarctic tunicates S. thompsoni were analysed to determine wet weight (WW), dry weight (DW),...
Feeding strategies of copepods were studied during a dinoflagellate-dominated bloom in the North Sea in August 2001. The aim of this study was to evaluate the importance of mesozooplankton grazing as a biological loss factor of harmful algal blooms under natural conditions. Therefore, ingestion, egestion and egg production experiments were performe...
A 17 month record of vertical particle flux of dry weight, carbonate and organic carbon were 25.8, 9.4 and 2.4g/m**2/y, respectively. Parallel to trap deployments, pelagic system structure was recorded with high vertical and temporal resolution.Within a distinct seasonal cycle of vertical particle flux, zooplankton faecal pellets of various sizes,...
Feeding activity, selective grazing and the potential grazing impact of two dominant grazers of the Polar Frontal Zone, Calanus simillimus and Rhincalanus gigas, and of copepods
The European Iron Fertilization Experiment EIFEX studied the growth and decline of a phytoplankton bloom stimulated by fertilising 10 km2 in the core of a mesoscale (80 × 120 km) cyclonic eddy south of the Antarctic Polar Front with about 2 times 7 tonnes of iron sulphate. The phytoplankton accumulation induced by iron fertilization did not exceed...
As the German contribution to the Southern Ocean Global Ocean Ecosystems Dynamics Study (SO GLOBEC), RV Polarstern visited the Eastern Bellingshausen Sea between 18 April and 1 May 2001. This paper examines in situ feeding cycles, ingestion rates and growth of larval krill Euphausia superba. Larval krill were exceptionally numerous, especially over...
The physiological condition and feeding activity of the dominant larval stages of Euphausia superba (calyptopis stage III, furcilia stages I and II) were investigated from February to March 2000 at the Rothera Time Series monitoring station (67degrees34'S, 68degrees07'W, Adelaide Island, Western Antarctic Peninsula). A dense phytoplankton bloom (5...
Toxic dinoflagellate blooms are a common phe- nomenon in the North Sea, but the fate of the toxins in the food web is largely unknown. Herbivorous copepods may play a key role in the transport of toxins through the food web, but it is still uncertain to what extent toxic algae are grazed. The present experiment was carried out during an autumn bloo...
Within the high nutrient–low chlorophyll regime of the Antarctic Circumpolar Current (ACC), high phytoplankton concentrations are frequently observed in the vicinity of the Antarctic Polar Front (APF). As is typical for frontal systems, hydrography in this region is characterized by meanders and eddies as well as up- and downwelling cells which red...
To investigate regional and interannual variability of the ecosystem in the Southern Ocean, a coupled circumpolar ice–ocean–plankton
model has been developed. The ice–ocean component (known as BRIOS-2) is based on a modified version of the s-coordinate primitive
equation model (SPEM) coupled to a dynamic–thermodynamic sea-ice model. The biological...
The chlorophyll a (chl a) biomass and primary production of three phytoplankton size fractions were estimated in the Atlantic sector of the Southern Ocean from 12 December 1995 to 20 January 1996. Elevated concentrations of chl a, primary production, and contribution of microplankton (>20 μm) coincided with dominance by large or long-chained diatom...
