Project Details
Projekt
Harvestable Secondary Production in the Amazon River Plume and tropical North Atlantic (HSP-Amazon)
Applicant
Dr. Natalie Loick-Wilde
Subject Area
Oceanography
Term
since 2026
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 572105417
The amount of zooplankton biomass that supports fish stock productivity and carbon sequestration is referred to as harvestable secondary production (HSP). HSP is an important aspect of the marine nitrogen (N) cycle and concerns the growth of zooplankton on the basis of primary production fertilized by N sources from outside the euphotic zone (e.g. upwelling, riverine inputs or N2 fixation), also called new production. Currently, there is no approach to directly quantify zooplankton growth that can be applied to the entire zooplankton community, as is the case for ocean primary production. For this reason, HSP is the least understood process in biogeochemical models. More than 50 years after the first method to quantify New Production in the ocean, recent results from isotope ecology now allow for the first empirical quantification of HSP at the community level using the trophodynamic approach. For this purpose, three types of nitrogen isotope analysis must be combined: a) natural abundances and b) artificially enriched abundances of N isotopes in the total nitrogen of zooplankton and phytoplankton, and c) natural abundances of N isotopes in proteinogenic amino acids of zooplankton. In the HSP-Amazon project, this new approach is being systematically pursued for the first time in order to gain fundamental insights into secondary production in the sea. For this purpose, the Amazon plume with its habitat-specific changes in the new nitrogen sources and in the N cycle is used as a natural laboratory.
DFG Programme
Research Grants
