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Researchers:
Dr. J. Brandes, Dr. R. Jahnke, Dr. A. Peck, Dr. S. Wakeham, Dr. H. Windom
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The chemistry of ocean waters and underlying sediments play a fundamental role in controlling the ecology, species composition and overall health of the marine environment and determine the role of the oceans in larger-scale societal issues such as global climate change. Chemical research at SkIO addresses a broad set of science topics that span the breadth of these research areas. Because carbon plays a central role in the biogeochemical functioning of all ecosystems, it is the focus of numerous research efforts.
The organic biogeochemistry group (Wakeham) investigates the characteristics and reactivity of organic matter in aquatic environments by examining its molecular and isotopic composition. Studies extend to lipid and other compounds that have the potential to provide information about the organisms responsible for synthesizing them. Tracked through time in marine sediments this information can provide insight into how ecosystems have evolved in the past and how present ecosystems may be altered in the future in response to natural cycles and human-induced changes.
Work in the area of global ecology (Brandes) focuses on determining the mechanisms controlling the flow of C, N, and P in ecosystems, from extremely large basin-wide scales to nanoscales. Tackling problems over such wide spatial scales provides a different view of diagenesis. Dr. Brandes is a biogeochemist with expertise in stable isotopes, x-ray microscopy, nutrient cycling and organic geochemistry.
Exotic, human synthesized compounds are also making their way to marine environments and their influences on coastal ecosystems are still largely unknown but are an active focus of research (Peck).
The cycling of inorganic carbon (Jahnke; Benthic Geochemistry) in the oceans is also a major research focus as it plays a dominant role in the mitigation of greenhouse warming by carbon dioxide. Uptake of anthropogenic carbon dioxide by the oceans also leads to ocean acidification which may alter marine ecosystems and specifically impact organisms that make shells and structures from calcium carbonate such as foraminifera and corals.
Trace metals also play a major role in structuring the composition of marine ecosystems (Mann) and determining the health of coastal environments (Windom). By examining the variations of specific metals captured in coastal sediments, the history of metal pollution and the effectiveness of regulations and policies can be assessed (Alexander, Windom).
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| Organic Biogeochemistry |
The organic biogeochemistry group at the Skidaway Institute of Oceanography (SkIO) investigates the reactivity of organic matter in aquatic environments by examining the molecular and isotopic composition of lipids in rivers, lakes and oceans.
Dynamic cycles link the distributions of the major elements between living and non-living organic matter and various inorganic reservoirs. The term "biogeochemistry" highlights the close coupling between biology, geology and chemistry in the multidisciplinary science that strives to understand the relationship between the biosphere and the geosphere.
Lipids are important biochemicals in organisms where they play roles in energy storage and mobilization, membrane structure, and hormonal regulation of metabolic processes. Due to their wide assortment of organic functional groups, the diverse molecular structures of lipids make them useful for tracing organic matter sources, alterations and transport. Additionally, stable- and radio-carbon isotopic compositions of individual lipid compounds provide a powerful tool for identifying lipid sources and for following carbon flow through ecosystems. |
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| Benthic Geochemistry |
| The benthic geochemistry group investigates sediment chemical, biological and physical processes that control the chemistry of benthic and marine systems. |
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| Specific examples of recent research interests and projects include:
1. development of ocean observatory infrastructure via the ORION Program and coastal observatory research via the CoOP Program, including the Coastal Benthic Exchange Dynamics (CBED) project BOTTOMS-UP.
2. biogeochemistry of permeable sediments including advective porewater transport and groundwater inputs (Jahnke et al. (2005) CSR 25:1433-1452; Niencheski and Jahnke (2002) Aquat. Geochem. 8:135-152; Jahnke et al. (2003) ECSS 56:641-653.)
3. continental shelf biogeochemistry including benthic primary production (Jahnke et al. (2000) CSR 20:109-127)
4. denitrification pathways in sediments, in collaboration with former graduate student Alex Rao, now at Woods Hole Oceanographic Institution.
5. the metabolic and chemical processes controlling the dissolution and preservation of calcium carbonate on the deep sea floor (Jahnke and Jahnke (2004) GCA 68:47-59)
6. the magnitude and distribution of the global flux of organic carbon to the deep ocean and sediments (Jahnke (1996) GBC 10:71-88) |
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| Global Ecology |
Research on Global ecology at the Skidaway Institute focuses on determining the mechanisms controlling the flow of C, N, and P in ecosystems, from extremely large basin-wide scales to nanoscales. Tackling problems over such wide spatial scales provides a different view of diagenesis. |
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Examining Marine Phosphate Sources and Sinks using Advanced Spectromicroscopy and NMR Techniques - New Project with Ellery Ingall, GT, and Claudia Benitez-Nelson, USC
Dr. J. Brandes is currently working on a 3-year NSF- funded project to examine the phosphorus cycling in marine environments. He just completed his main cruises for this investigation in 2007 and is working up the data.
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