Marleen Stuhr PhD.

The Leibniz Centre for Tropical Marine Research (ZMT)


The production of reef structure by coral communities and the generation, transport and accumulation of carbonate sediments by other calcifying and bioeroding organisms are essential drivers of tropical beach and island formation and maintenance.

Coral reefs are increasingly impacted by climate change and local human pressures, which may lead to alterations in reef communities and thus diminish the important geo-ecological functions they provide.

In collaboration with Dr. Ines Lange and Prof. Chris Perry I aim to quantify the contribution of different sediment producers to reef and island sediments to examine spatial and temporal differences in sedimentary carbonate production states. We look at patterns in sediment composition and production across reef zones and aim to explore the impacts of (micro-)benthic community structures at sites with distinct trends of reef recovery since the 2015/2016 bleaching event, as well as differences in seabird derived nutrient input.

I am particularly interested in the contribution of large benthic foraminifera to local sediment budgets. These photosymbiotic protists may locally dominate carbonate production and are commonly used as bioindicators for recent and past environmental conditions. They therefore provide valuable proxies that can be easily integrated in coral reef monitoring efforts.

The geo-ecological indicators provided by carbonate sediments can be used to characterize the biotic composition of ecosystems. I am also working with Joanna Harris in the Reef Manta Rays in the Chagos Archipelagos, aiming to contribute to a better understanding of the natural biological and oceanographic processes influencing the archipelago’s reef manta ray habitats.

The increasing impacts of human pressures alter coral reef communities and diminish their crucial geo-ecological functions. It is amazing to have the rare opportunity to study these fascinating ecosystems in the remote atolls of Chagos Archipelago to understand important geo-ecological processes of natural reefs under minimal direct human impacts.

Marleen Stuhr


2021 Present
Leader (interim) of Geoecology and Carbonate Sedimentology workgroup at the Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
2019 2021
Postdoctoral research fellow, Coral Ecophysiology workgroup at the Interuniversity-Institute for Marine Sciences (IUI) in Eilat, and Bar-Ilan University, Ramat Gan, Israel
2018 2019
Postdoctoral researcher at ZMT, Bremen, Germany
2014 2017
Ph.D. candidate and researcher at ZMT, Bremen, Germany
2011 2013
M.Sc. Geoökologie, University of Tübingen, Germany

Other Interests

I am broadly interested in the anthropogenic impacts of on calcifying organisms and carbonate sediment systems and aim to support efforts focusing on the resilience, biodiversity and conservation of coral reefs and associated ecosystems.

Adaptation and acclimatization to environmental changes are vital under future ocean conditions. To investigate the effects of climate change on coral reef organisms I conduct laboratory and field experiments simulating future ocean acidification and warming scenarios. I apply innovative proteomic approaches to marine photosymbionts such as coral or large benthic foraminifera and link these to eco-physiological methods to unravel underlying mechanisms of stress responses and recovery processes.

Using foraminifera and carbonate sediments as bioindicators to characterise marine habitats, I am also involved in field-based surveys and experiments focusing on spatial and temporal variations of biological communities in coral reef and seagrass ecosystems. Moreover, I am interested in how human pressures affect the calcification of marine skeletons and shells, how we can better reconstruct environmental conditions using modern biogeochemical proxies, as well as in practical approaches to support the conservation of their biodiversity but also the geo-ecological processes and functions of coral reefs.