Benthic biology and ecology
Project Manager/Lead Scientist: Jim Barry
This continuing project focuses on three principal research areas described under the headings below. Together, these studies investigate patterns of animal distribution and relate them to sources or food, nutritional pathways, and also to potentially harmful human activities. Results from these studies broaden our understanding of processes regulating deep-sea communities throughout the world ocean.
Seafloor community dynamics and benthic-pelagic coupling
Studies of seafloor community dynamics and benthic-pelagic coupling focus on the role of carbon transport and cycling in the structure and energy flow of benthic faunal communities, with a particular focus on Monterey Canyon. We are comparing these processes at a site 1300 meters deep in Monterey Canyon with a site on Smooth Ridge (non-canyon) at the same depth. Community patterns are determined from video transects and sediment samples, and carbon cycling is measured by sediment traps (measuring carbon flux), benthic respiration chambers (measuring oxygen / carbon uptake), and sediment samples (oxygen profiles and carbon content). Moored instruments measure currents, turbidity, and chlorophyll at both sites. Together, these data sets will help determine the role of submarine canyons in the transport of organic material and sediment from continental shelves to the deep-sea and will help identify processes that influence patterns of faunal distribution in the deep-sea.
Chemosynthetic Biological Community Studies
Studies continue on the biology of chemosynthetic organisms inhabiting methane- and sulfide-rich habitats in Monterey Bay. Unlike most deep-sea communities, chemosynthetic clams and tubeworms that inhabit chemosynthetic biological communities do not depend nutritionally on surface water production and instead rely on reduced inorganic compounds like methane and sulfide to support life through symbiotic relationships with chemosynthetic bacteria.. Manipulative experiments are underway to measure the level of inter-species competition that may affect the abilities of some clam species to exploit these sulfide-rich sites. Competition experiments will determine the potential interference by Calyptogena kilmeri (a large clam species) on access to sulfide-rich sediments by Calyptogena pacifica, a smaller species inhabiting marginal sulfide habitats. Measurements of clam mobility in relation to shell shape may shed light on processes that have influenced the evolution of shell morphology in this group.
Biological consequences of deep-sea CO2 disposal
Studies of the biology of deep-sea carbon dioxide (CO2) disposal center on the expected magnitude of biological impacts from a large-scale, deep-sea CO2 sequestration program. Ocean sequestration–directly injecting CO2 from power plants into the deep sea–is one of several options under consideration to mitigate the accelerating rise in atmospheric CO2 emissions. Our experiments will measure the tolerance of deep-sea animals to changes in carbon dioxide and pH. Investigators from several other institutions are involved in these studies, which are funded by MBARI and DOE.