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Aquatic Food Webs

We are interested in consumer driven nutrient cycling and chemical networks in planktonic food webs especially in oligotrophic environments.  Our research focusses on essential elements and compounds for primary and secondary production like nitrogen, carbon, and amino acids as well as on zooplankton associated waste products like DOM (in cooperation with Prof. Dr. Thorsten Dittmar, ICBM Oldenburg) and methane (in cooperation with Dr. Oliver Schmale, Trace Gases).

A second focus of our group is the development and implementation of interdisciplinary analytical approaches using GC-C-IRMS, GC-MS, NanoSIMS, and FT-ICRMS technology to develop a mechanistic understanding of consumer driven nutrient cycling.

Projects

  • Collaborative Research: Impact of the Amazon River Plume on nitrogen availability and planktonic food web dynamics in the Western Tropical North Atlantic
  • ZET Change - Zooplankton energy turnover in a changing environment
  • ZooM - Zooplankton assoziierte Methanproduktion

Team

Dr. Natalie Loick-Wilde

Elvita Eglite, PhD

Melvin Bach, Masterstudent

Igor Urruzola Fernandez, PostDoc

Research fields

Zooplankton and diazotrophs

Fast incorporation of nitrogen from nitrogen fixation (diazotroph N) is a critical trait in phytoplankton and zooplankton like copepods, which allows for biological production when diazotrophs increasingly dominate the phytoplankton due to global change.  The unambiguous identification and quantification of diazotroph nitrogen in amino acid nitrogen of zooplankton is realized via GC-C-IRMS analysis, which only recently has been established in our working group.

Zooplankton exudation

Evidence is growing that mesozooplankton have to adjust their feeding behavior in response to changes in food quality and quantity in order to maintain constant nitrogen specific net growth efficiencies and elemental (C:N) ratios in their tissues (Loick-Wilde et al. 2015).  What are the ecosystem consequences of biochemical mismatches between diet and consumer, e.g. when cellulose-rich dinoflagellates are consumed by copepods?

Development of new isotope indicators

Kinetic isotope fractionation in biological samples is mainly driven by enzyme activity.  The identification of amino acid specific fractionation factors associated with the rapid turnover of amino acid pools may help to unravel physiological and biochemical factors regulating secondary production in natural environments without experimental manipulations.