A5042168658- Marine and coastal ecosystems
- Marine and fisheries research
- Aquatic Ecosystems and Phytoplankton Dynamics
- Fish Ecology and Management Studies
- Marine Biology and Ecology Research
- Marine Bivalve and Aquaculture Studies
- Ocean Acidification Effects and Responses
- Aquatic Ecosystems and Biodiversity
- Isotope Analysis in Ecology
- Aquaculture Nutrition and Growth
- Microbial Community Ecology and Physiology
- Environmental Toxicology and Ecotoxicology
- Physiological and biochemical adaptations
- Marine and environmental studies
- Aquatic Invertebrate Ecology and Behavior
- Diatoms and Algae Research
- Coral and Marine Ecosystems Studies
- Marine Invertebrate Physiology and Ecology
- Water Quality Monitoring Technologies
- Protist diversity and phylogeny
- Food Industry and Aquatic Biology
- Marine animal studies overview
- Methane Hydrates and Related Phenomena
- Marine and coastal plant biology
- Freshwater macroinvertebrate diversity and ecology
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2016-2025
University of Bremen
2016-2025
Stony Brook University
2020
University of Amsterdam
2013
South Dakota State University
2006-2007
Helmholtz-Zentrum Hereon
2007
Max Planck Institute for Evolutionary Biology
1997-2006
Max Planck Society
1997-2006
Bausch Health (Germany)
2006
NOAA Great Lakes Environmental Research Laboratory
2000
Analyzing one of the most extensive long‐term data series in North Sea, Helgoland Roads time series, we investigated changes factors that potentially drive phytoplankton bloom dynamics German Bight. We compared these with spring phenology. combined zooplankton, nutrient, weather, and to analyze whether there has been a shift trophic interactions Sea affecting timing. The potential influence temperature, mean increase 1.5°C, was investigated. showed Bight around is highly dynamic system...
Rapid and drastic anthropogenic impacts are affecting global biogeochemical processes driving biodiversity loss across Earth's ecosystems. In aquatic ecosystems, species distributions shifting, abundances of many have declined dramatically, threatened with extinction. addition to diversity, the ecosystem functions, services on which humans depend also being heavily impacted. Addressing these challenges not only requires direct action mitigate environmental but innovative approaches identify,...
We studied the way 12 traits responded to fish kairomones in a set of 16 Daphnia magna clones derived from four different habitats—two where daphnids co‐occur with and two without fish. These differed widely their response predator kairomones, none showing significant all for at least one trait. Most showed traits, no evidence an association between traits. Clones habitats were slightly more responsive presence than fishless locations. conclude that most show induced predators (fish) but...
Nutritional imbalances are of great interest in the ecological stoichiometry literature, which researchers have focused almost exclusively on cases where nutrients available low amounts relative to energy (carbon), and animal growth is impaired due insufficient nutrient intake. Little attention has been given situations food elemental content higher than level that satisfies requirements. However, most animals strongly homeostatic with respect composition their body; hence they must excrete...
The objective of this experiment was to measure the digestibilities energy, CP, and AA in 10 samples corn distillers dried grain with solubles (DDGS) fed growing pigs. Twelve barrows (initial BW: 34.0 ± 1.41 kg) were allotted an 8 × 12 Youden square design periods animals. Ten diets based on DDGS (66.7%), 1 diet (97%), last a N-free cornstarch sucrose. Chromic oxide (0.3%) included all as inert marker. Pigs provided their respective at level 3 times estimated energy requirement for...
Nutritional deficiencies are a very common phenomenon, and consumers generally face food that is not optimally suited for their needs. Especially herbivores habitually confronted with of inferior quality, usually result too-low nutrient concentrations in plant material. Waterfleas the genus Daphnia good model organisms to study effect quality food, how animals deal this. We tested algae which we had given different phosphorus contents on both life history feeding parameters magna. Phosphorus...
An experiment was conducted to measure DE and ME the apparent total tract digestibility (ATTD) of energy, N, P in distillers dried grains with solubles (DDGS) fed growing pigs. Ten sources DDGS were obtained from ethanol plants South Dakota Minnesota, 11 diets formulated. One diet based on corn (96.8%), limestone, salt, vitamins, microminerals. additional formulated by mixing each 10 a 1:1 ratio. Eleven pigs (initial BW 29.3 ± 0.42 kg) allotted an × Latin square design, periods Each pig...
We investigated whether nutrient limitations of primary producers act upward through food webs only in terms density effects or if there is a second pathway for limitation signals channelled to higher trophic levels. used tritrophic chains assess the nutrient‐limited phytoplankters (the cryptophyte Rhodomonas salina ) on herbivorous zooplankters calanoid copepod Acartia tonsa and finally zooplanktivores (larval herring Clupea harengus living herbivores. The producers’ quality had significant...
In their seminal paper, Goldman et al. suggested that phytoplankton close to maximum growth rate attains a restricted optimal N : P ratio the Redfield of molar = 16. Recently, presence such global attractor for stoichiometry has been questioned in models and empirical analyses. As chemical composition is major importance our understanding elemental cycles biogeochemical transformations, we assembled 55 data sets biomass ratios meta‐analysis testing (1) whether converges at high rates, (2)...
Herbivores are generally faced with a plethora of resources which differ in quality. Therefore, they should be able to select foods most closely match their metabolic needs. Here, we tested the hypothesis that copepods species Acartia tonsa prey cells based on quality differences within species. We assessed age‐specific variation feeding behaviour and evaluated potential consequences such for nutrient cycles. Nauplii (young) stages characterized by low nitrogen phosphorus (N:P) ratio body...
Herbivory is more prevalent in the tropics than at higher latitudes. If differences ambient temperature are direct cause for this phenomenon, then same pattern should be visible a seasonal gradient, as well experiments manipulating temperature. Using (15)N stable isotope analyses of natural populations copepod Temora longicornis we indeed observed trophic level and decrease with increasing In grazing experiment, mixed diet cryptophyte Rhodomonas salina heterotrophic dinoflagellate Oxyrrhis...
The theories developed in ecological stoichiometry are fundamentally based on traits. On the one hand, traits directly linked to cell/body stoichiometry, such as nutrient uptake and storage traits, well associated trade-offs, have potential shape interactions competition predation within ecosystems. other that indirectly influence influenced by nutritional requirements, size growth rate, tightly organismal stoichiometry. Despite their physiological relevance, seldom explicitly integrated...
The differences in the impact of two major groups herbivorous zooplankton (Cladocera and Copepoda) on summer phytoplankton a mesotrophic lake were studied. Field experiments performed which exposed to different densities types zooplankton, cladocerans copepods. Contrary expectation, neither significantly reduced biomass. However, there strong contrasting impacts size structure individual taxa. Cladocerans suppressed small phytoplankton, while copepods large phytoplankton. unaffected classes...
Ecological stoichiometry is a useful tool for studying how the elemental composition of organisms and their food affects production, nutrient cycling, food- web dynamics. Two analyses are presented here that show use simple element ratios in stoichiometric calculations may certain circumstances prove inadequate because influence animal nutrition biochemical aspects diet. In first, analysis herbivores consuming with varying carbon to nitrogen (C:N) undertaken, which intake C segregated into...
Summary 1. We performed a mesocosm experiment to investigate the structuring and cascading effects of two predominant crustacean mesozooplankton groups on microbial food web components. The natural summer plankton community mesotrophic lake was exposed density gradients Daphnia copepods. Regression analysis used reveal top–down impacts protists bacteria after days 9 15. 2. Selective grazing by copepods caused clear trophic cascade via ciliates nanoplankton. Medium‐sized (20–40 μ m) (mainly...
We investigated the effects of various mineral and biochemical limitations on Daphnia magna. These daphniids have much lower saturation thresholds for growth polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA), arachidonic (ARA) than has been previously described other species. Daphniids take up large amount from food, different are handled differently by D. The saturated (20:0; EPA) was not retained, metabolized, PUFAs were preferably stored. There also differences among PUFAs:...
This essay is the outcome of a colloquium convened in November 2005 at Benthos Laboratory Stazione Zoologica Anton Dohrn Ischia, Italy, on chemical ecology and role secondary metabolites structuring functioning marine biodiversity. The participants workshop are part European Network Excellence MarBEF (Marine Biodiversity Ecosystem Function), consortium 56 institutes to integrate disseminate knowledge expertise Here we review some new trends emerging topics ecology. first section deals with...
There is increasing evidence that the quality of nutrient-limited algae suboptimal for zooplankton production. These effects nutrient limitation are supposed to be important mainly at higher concentrations food because lower quantities overall energetic body growth should hide effect mineral limitations. This has been hypothesized in a variety papers, but experimental still weak. In present study we carried out set experiments investigating very low levels ranging from 30 μg C/L up 150 C/L....
Abstract It is a well accepted fact that nutrient limitation of plants affects the growth and survival herbivores, generally leading to lower performance herbivores feeding on stressed plants. The effect plants' growing conditions predatory organisms, one trophic level up, has been much less studied, there general consensus such effects would be small as often show relatively strong homeostasis with respect their content. Here, we challenge this view, from several examples despite buffer...