Nutrient deficiencies and the restriction of compensatory mechanisms in copepods
Burian, A.; Grosse, J.; Winder, M.; Boschker, H.T.S. (2018). Nutrient deficiencies and the restriction of compensatory mechanisms in copepods. Funct. Ecol. 32(3): 636-647. https://doi.org/10.1111/1365-2435.13016
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In: Functional Ecology. Blackwell Publishers: Oxford. ISSN 0269-8463; e-ISSN 1365-2435, more
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| Author keywords |
amino acid; co-limitation; compound-specific stable isotopes; elemental stoichiometry; fatty acid; food quality; predator–prey interaction; zooplankton |
| Authors | | Top |
- Burian, A.
- Grosse, J., more
- Winder, M.
- Boschker, H.T.S., more
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| Abstract |
The flexible regulation of feeding behaviour and nutrient metabolism is a prerequisitefor consumers to grow and survive under variable food conditions. Thus, it isessential to understand the ecological trade-offs that restrict regulatory mechanismsin consumers to evaluate the consequences of nutrient limitations for trophicinteractions. Here, we assessed behavioural and physiological adjustments to nutrient deficienciesin copepods and examined whether energy limitation, food digestibility orco-limitation with a second nutrient restricted compensatory mechanisms. A combination of 13C-labelling and compound-specific stable isotope measurementsrevealed that copepods compensated nitrogen deficiencies by raising retentionefficiencies of amino acids (AA). The costs of higher retention efficiencies werereflected in the doubling of structural fatty acids (FA), probably required for morphologicaladaptations of the gut. A depletion of highly unsaturated FA in storagelipids and their selective retention suggested that these FA became co-limiting andrestricted a further increase in AA retention efficiencies.4. Copepods feeding on phosphorus-limited algae showed a marked increase in ingestionrates but were not fully able to compensate dietary deficiencies. The increasein ingestion rates was thereby not restricted by higher foraging costs because energystorage in copepods increased. Instead, thicker cell walls of nutrient-limitedalgae indicated that algal digestion resistance restricted the extent of surplusfeeding.The strongly nutrient-specific response of copepods had large implications for recyclingrates, growth efficiencies and the potential top-down control at the plant–animal interface. Compensatory mechanisms to mitigate nutrient deficiencies aretherefore an essential aspect of trophic interactions and have the potential to alterthe structure of food web. |
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