Tropical coastal zones receive major part of the annual riverine inputs of freshwater and dissolved and particulate substances. They harbour some of the most productive and diverse ecosystems on earth like coral reefs, seagrasses and mangroves. Besides that they are also among the regions with the strongest human modifications. We investigate the biogeochemical and ecological response of tropical coastal systems to present and past environmental change along three major lines of research.
The delicate ecological balance of either single tropical coastal ecosystems or associations of several of them can be disturbed by a number of indirect and direct effects of human activities. River inputs of land-derived substances can on the one hand nourish, but on the other hand also threaten coastal ecosystems. The most significant processes with respect to human activities are deforestation, agri- and aquaculture, fertilizer and pesticide use, urban and industrial waste discharge, canalization and damming.
Direct effects of human-induced threats to tropical coastal ecosystems are eutrophication, pollution, habitat modification/ destruction and overexploitation and/or selective exploitation of resources. We investigate how direct and indirect effects of land-based human activities alter the water quality and biogeochemistry of tropical coastal systems and hence the living conditions for their flora and fauna.
A major impact of natural processes and human activities is to alter the internal dynamics of coastal ecosystems affecting the cycling of elements. Changes in the physical environment may affect biogeochemical fluxes and their composition in estuaries, mangroves, seagrasses, coral reefs and coastal seas. This may lead to changes in the distribution, abundance and wellbeing of flora and fauna which, in turn, affects the biogeochemical cycling of elements.
The interaction of biota with their abiotic environment is an important control for the internal cycling of elements in coastal ecosystems. We investigate how flora and fauna modify element cycles through feeding and construction activities on the one hand and how changes in the amount and composition of elements beneficial or harmful to life affect the flora and fauna on the other hand.
Predicting future climate and the response of organisms/populations/ecosystems to environmental change requires understanding of the underlying processes. Reconstruction of the paleoenvironment is a suitable tool in this respect. Using proxies from archives which have collected information on the variation of, for example, climate, oceanic circulation or vegetation on land allows to understand the processes responsible for changes in the past.
The knowledge on past variations can then be used in combination with instrumental records which often date back only a couple of decades to model or predict future changes of, for example, climate and ecosystems. We investigate the history of environmental conditions and ecosystem response during times with and without human influence by the use of high-resolution archives in order to distinguish between natural and anthropogenic causes of change.
Group leader
PD Dr. Tim Jennerjahn
Postdocs
Dr. Lucia Herbeck
PhD students
Anne Alpen (Baumgart)
Astrid Contreras
Shilly Elizabeth David
Karin Gesierich
Ingo Jänen
Gabriela Alfaro Espinoza (external, Jacobs University, Bremen)
Hoang Trung Du (external, University of Ho Chi Minh City, Vietnam)
MSc students
Tz-Ching Yeh
Guest scientists
Dr. Claudia Propp
Dr. Regine Moll
Ms. Swati Mohan Sappal (Jawaharlal Nehru University, New Delhi, India)
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SPICE III "TIMES - Terrestrial Influences on Mangrove Ecology and Sustainability of Their Resources", coordination and subproject 10 "Reconstruction of lagoon dynamic stages and mangrove extension in the Segara Anakan Lagoon during the Anthropocene".
SPICE III "CAFINDO - Climate versus anthropogenic forcing of Late Holocene environmental change affecting Indonesian marine, coastal, and terrestrial ecosystems", subproject 2 "Gradients in carbon and nutrient input into the Java Sea related to human activities in river catchments along the transect Java – Kalimantan during the Late Holocene".
BIORESICO – "Reconstructing the biogeochemical response of Indonesian coastal ecosystems to environmental change during the late Quaternary as recorded by marine sediment cores along the Sumatra – Java – Flores transect".
CARIMA – "Natural versus anthropogenic controls of past monsoon variability in Central Asia recorded in marine archives", subproject "Pearl River catchment – human-induced changes".
Kerala – "Interdependencies between Kerala rivers and back¬waters: consequences for water quality, aquatic organisms, economy and environmental governance".
LANCET – "Land-Sea Interactions along Coastal Ecosystems of Tropical China: Hainan", subproject "Land-based activities affecting the fluxes and transformation of nutrients and organic matter from watershed to the coastal sea".
Madura-Monitoring – "Application of water quality control technology in tropical coastal seas: Development and application of an automated water quality measuring system for water quality assessment in Madura Strait, Java, Indonesia", subproject "Impact of seasonally varying nutrient and organic matter inputs of the Brantas River on water quality and biogeochemistry of Madura Strait coastal waters, Java, Indonesia".
Pamba River – "Catchment-scale human interventions in the Pamba River basin (Kerala, India) and their impact on the estuarine ecosystem in the southern Vembanad Lake".
River Inputs – "Impact of river inputs on coral reefs of Nha Trang Bay, Vietnam".