Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
On polar seafloors (benthos), large corals and sponges (macrofauna) provide the habitat for a species-rich community that is largely unexplored. To date, the roles of physical disturbance, ecological interactions and climate change on the structure and dynamics of polar animal communities in their natural environment are still unknown.
Our scientific focus is to investigate the role of environmental changes (bottom-up processes) versus natural processes such as feeding pressure from fish and seals (top-down processes) in structuring communities. We combine traditional sampling methods with novel instrumentation to observe the macrofauna and resident animal communities. With a regional focus on the Weddell Sea, we contrast the rapid climate-induced changes in the Antarctic Peninsula region with the more gradual changes along the eastern Weddell Sea shelf in response to warming. Furthermore, we do research in the Patagonian fjords of Chile, since the origin of many organisms, such as cold-water corals in the deep sea, allows us to find these animals both in the Antarctic and north of the Drake Passage. Studies on organisms in the Patagonian fjords therefore allow conclusions to be drawn about their relatives in Antarctica.
- The section BPP’s long term goal is to quantify the structure and function of polar macrobenthic organisms, their interaction with the pelagic system, and susceptibility to natural disturbances and climate change. A mechanistic understanding of the bentho-pelagic processes can serve as an important baseline to model the biological responses to polar climate change.
- Although retreating ice-shelves, increased iceberg calving and changing seasonal pack-ice cover are expected to have important repercussions on the Antarctic benthos, reliable data on benthic productivity and material cycling are still lacking. We aim at filling this gap to better understand the dynamics of Antarctic benthic communities and ecological functions by carrying out the first direct measurements to date on important process variables in situ, using advanced underwater technologies. While the focus is on sponges and corals, large skeletal filter-feeders providing important habitat for other organisms, we also study mobile sentinel species for climate change such as pinnipeds and fish, which play an important role in the Antarctic ecosystem as apex predators.
- The midterm goal is to combine results from investigations in structure and processes to better understand the biotic and environmental factors governing the distribution of biodiversity and biomass as well as their feedbacks to Antarctic climate change.
Most of what we know from ocean life derives from extractive sampling using nets, bottles, grabs, cores, or trawls. While providing valuable material, e.g. for biodiversity or experimental studies, these destructive methods fail to preserve the spatial structure and function characterizing living communities, where bottom trawls reduce underwater seascapes to piles of unsorted creatures on deck. Over the last decades, technological advancements have begun to shed a new and fascinating light on marine biology. Cabled instruments and observatories now allow to explore living communities in their natural environment in a non-destructive manner:
- Remotely operated vehicles (ROVs) equipped with cameras and sensor packages provide high-resolution images from the plankton and seabed communities in their dynamic surroundings,
- Eddy Covariance measurements allow the continuous and non-invasive determination of benthic fluxes of oxygen, particles, and heat in the benthic boundary layer,
- sampling the seabed and the water column above with Multi Corers and Carousel Water Samplers is essential for the scientific work of the BPP section,
- Microsensor measurements offer insights into instantaneous physiological processes and help to understand possible mechanisms to cope with future climate conditions,
- Scientific diving allows for undisturbed observation, environmentally friendly sampling, targeted collection of measurement data, and the performance of underwater experiments.
- Biologging units and satellite transmitters allow to study the marine environment from the perspective of marine mammals.
These tools are used and refined by BPP scientists engineers and technicians to understand the factors governing Antarctic communities in an era of climate change and to assess the role of Antarctic communities in geochemical cycling.
Prof. Dr. Claudio Richter, Bentho-Pelagic Processes, Alfred Wegener Institute, Center for Polar and Marine Research, Bremerhaven, Germany
Projects within Bentho-Pelagic Processes you find here