Ecological drivers of the ocean carbonate pump and carbon export: linking biodiversity, trophic interactions, and carbonate biogeochemistry

Rational and motivation:

The ocean plays a pivotal role in the global carbon cycle, absorbing atmospheric CO₂ and sequestering it in the deep ocean and sediments via physical and biological processes. The ocean carbonate pump influences atmospheric CO₂ storage and sequestration by modulating surface alkalinity (through calcification and shallow dissolution) and by exporting inorganic carbon in the form of hard tissues and alkalinity, while the biological pump transports organic carbon to the deep ocean. While current Earth system models represent carbonate pump processes only implicitly, evidence shows organismal diversity, physiology and trophic interactions strongly shape carbonate production, dissolution, and carbon export. This PhD project will investigate how ecological processes influence the magnitude and efficiency of the carbonate pump and how these dynamics affect (organic and inorganic) carbon sequestration in the deep ocean.  

Research objectives:  

1. Quantify the contribution of key calcifying plankton (e.g., coccolithophores, foraminifera, pteropods) to pelagic carbonate stock, production and export under varying ecological and environmental conditions and the role of shallow biological dissolution.
2. Determine how diversity, trophic interactions and ecological traits regulate carbonate production, dissolution, and export throughout the water column.
3. Assess how the carbonate pump modulates organic carbon transfer to the deep ocean.

Methodology:

The project will benefit from a large collection of samples available at the host institution, as well as opportunities to collect new samples during forthcoming oceanographic expeditions. Methods will combine field studies, diverse laboratory techniques, and exploration of time-series datasets.  

High research impact:

This project strengthens understanding of how marine life regulates carbon storage in the ocean, with direct relevance for predicting and mitigating climate change.”

We are looking for a highly motivated candidate with a BSc and/or MSc degree in Oceanography, Earth or Life Sciences, or a related field relevant to the position. The ideal candidate will have a solid academic background in marine biogeochemistry and the oceanic carbon cycle.

The position involves sampling processes, laboratory and analytical work, as well as data analysis and interpretation. Previous experience in fieldwork, laboratory techniques (chemical analyses and microscopy), and advanced data analysis will be highly valued. Programming skills in R or Matlab are particularly desirable.

The successful candidate should be able to work independently while also collaborating effectively within interdisciplinary research teams. Strong written and oral English skills are essential for successfully conducting the research and communicating the results.

The MERS research group investigates biogeochemical processes in marine and freshwater systems, which support life and human wellbeing but are highly sensitive to climate change. The MERS strategic research areas include: the interaction of marine organisms with global change (biodiversity, ecological shifts, restoration), anthropogenic impacts on coastal and oceanic ecosystems, land-ocean and wetland-atmosphere interaction processes, dynamics of oceanic biogeochemical cycles (carbon/carbonate), paleoceanography, and marine social sciences.

MERS is committed to open science and knowledge transfer, contributing to assessment reports and policy briefings, and organizing international workshops, conference sessions, and scientific cruises. Members serve on prestigious scientific advisory panels, editorial boards, and thesis committees, with achievements reflected in numerous publications, funded projects and research activities.