Research Themes

BIOLOGICAL and ECOLOGICAL ASPECTS of CHANGING OCEAN pH

Rising emissions of carbon dioxide (CO2) from worldwide fossil fuel burning are dramatically altering ocean chemistry and threatening marine biodiversity.  The ocean is a sink of CO2 and has absorbed approximately one-third of this excess atmospheric CO2.  The current rates of increase in atmospheric CO2 exceeds the ability of the oceans, through their normal feedback mechanisms, to sequester this additional CO2 with the result that the excess CO2 dissolves in the sea water forming carbonic acid.  The increase in carbonic acid drives the acid/base equilibrium to lower pH and reduces the saturation states of carbonate minerals needed for calcifying organisms, such as corals, crustaceans, and cocolithophores, to form their skeletons and shells.  The result is a disruption of calcification by corals and potentially coral reef accretion, as well as potential impacts on critical elements of the pelagic food web.  In addition, many marine organisms may experience hypercapnia, a build up CO2 with effects on physiology and growth that are independent of the effects caused by decreasing pH. 

The changing pH of the ocean has taken a prominent role in discussions related to ocean carbon cycle programs and is clearly tied to biological and ecological research interests.  A workshop, sponsored by NSF, NOAA and USGS, convened to summarize existing knowledge on the topic, reach a consensus on what the most pressing scientific issues are, and identify future research strategies for addressing these issues. A report, Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifers, was released in June 2006.

The Biological Oceanography Program encourages projects using the research priorities identified in the workshop report as a guide.  Projects should be designed to improve our fundamental understanding of the ecological changes resulting from elevated CO2

LONG-TERM ECOLOGICAL RESEARCH: SUSTAINED OBSERVATION AND EXPERIMENTATION IN A STRONG RESEARCH FRAMEWORK

Time-series research is critical to understanding ecosystem processes and continues to be actively supported by the community (as recommended in the EDOCC, OCTET, OEUVRE, and Millenium reports).   Sustained observations of the biota and their environmental context, coupled to both experimentation and modeling over periods of time are needed to reveal the ecological timescales, and variability, of many important ecosystem processes throughout the oceanic environment.

The Biological Oceanography Program supports time-series research through different mechanisms.  The Long-Term Ecological Research (LTER) program, coordinated with the Division of Environmental Biology, supports several marine ecological programs, including the recently established Moorea Coral Reef LTER and the California Current Ecosystem LTER.  Several investigators have maintained Biological Oceanography funding and produced invaluable time-series data and research, such as Joseph Connell's work on the Great Barrier Reef exceeding 40 years and Peter Glynn’s work in the eastern tropical Pacific ongoing for 35 years.  We also have investigators who have gathered data spanning hundreds of years to answer ecosystem process questions, such as Daniel Schindler's work with Sockeye Salmon in Alaska.  In addition, the program supports the deep-ocean HOT (Hawai'i Ocean Time-series) and BATS (Bermuda Atlantic Time Series) stations (with Chemical Oceanography). 

The Program's involvement with an array of activities is of part of the Division of Ocean Science's commitment to time-series research. This will be increasing in the near future with the development of the Ocean Research Interactive Observatory Networks (ORION).

OCEAN ECOLOGY AND THE CARBON CYCLE

The structure of oceanic food webs influences the quality and amount of carbon exported from ecosystems, as well as the elemental ratios of their biota and the nutrient pools in the water. Food web structure varies in space and in time over seasonal, annual, decadal, and geologic scales. Elemental stoichiometries are often key elements of biogeochemical models. They are emergent properties of marine ecosystems, dictated by the differential partitioning of elements that flow through the food web. We do not fully understand what constrains these ratios, but do know that results of biogeochemical models can be very sensitive to assumptions about stoichiometry.

The EDOCC, OCTET, Millenium and OCCC reports all point strongly to delineating the role of biological processes in the oceanic carbon cycle and the Earth's climate system (past, present and future) and understanding the basic mechanisms of the biological pump. Studies that integrate physical, biogeochemical and biological observation, experimentation and modeling over relevant spatial and temporal scales are needed to understand the ecosystem dynamics and food-web structure in controlling the rates of carbon fixation and fate of organic carbon in the marine environment. Specifically research should continue to 1) determine the probable responses of marine ecosystems to climate shifts, 2) identify feedbacks from these systems to climate and 3) elucidate the factors that contribute most significantly to ecosystem resilience and stability and thereby determine the efficiency of the biological pump and its current and probable future behavior.

The Biological Oceanography Program, in concert with Chemical Oceanography provided the majority of support for the US Joint Global Ocean Flux Study (JGOFS) program over the past decade plus.  We have been actively involved with the Carbon and Water in the Earth Systems crosscutting NSF-initiative in 2006-7, as well as the many other and various solicitations involving carbon cycle research (Biocomplexity’s Coupled Biogeochemical Cycles; GEO’s Biogeosciences, etc.).  We will continue, along with the Chemical Oceanography and Physical Oceanography Programs, to support the research on the fundamentals of the ocean's cycling of carbon as part of an interdisciplinary focused program, and individual investigator science.

POPULATION CONNECTIVITY IN MARINE SYSTEMS

A central goal of marine ecology is to achieve a mechanistic understanding of the factors regulating the abundance, diversity and distribution of marine populations.  The linkages among the populations play a critical role in local and metapopulation dynamics, community structure, genetic diversity, and the resiliency of populations to human exploitation.  The importance of population connectivity to understanding fundamental ecosystems processes was outlined in the OEUVRE, and Millenium reports.  The Population Connectivity in Marine Systems report was released as a result of a NSF sponsored workshop in 2002 that convened specifically to address the scientific issues and needs relevant to resolving marine population connectivity.   A special issue of The Oceanography Society is planned for September 2007 directed at addressing the state of science pertaining to marine population connectivity and highlight future research directions that will be necessary to advance our knowledge and management options.

The Biological Oceanography Program, in partnership with Physical Oceanography, currently supports continued discussions and research concerning priorities in this area.  Specific areas of interest include:

• Population and community ecology: Determine how different kinds and strengths of inter-specific interactions affect the dynamics of open versus closed populations.
• Evolution: Compare degrees of isolation with rates of genetic divergence.
• Biogeography: Evaluate the extent to which range limits are set by barriers to dispersal rather than physical tolerances of adults or biotic interactions.
• Management, conservation and biodiversity: Evaluate the efficacy of extant reserves as determined by regional dispersal patterns

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