Coastal ocean

The /-ratio typically varies from values as low as 0.03 to 0.30 in the open ocean (e.g., McCarthy et al., 1996) to values greater than 0.80 in the coastal ocean (Platt and Harrison, 1985). 

Benitez-Nelson, C. R. and Buesseler, K. O. (1999). Variability of inorganic and organic phosphorus turnover rates in the coastal ocean. Nature 398, 502-505. 

Burnett WC, Kim G, Lane-Smith D (2001a) A continuous radon monitor for assessment of radon in coastal ocean waters. J Radioanal Nucl Chem 249 167-172... 

Th AS A TRACER FOR PARTICLE TRANSPORT AND SEDIMENT PROCESSES IN THE COASTAL OCEAN... 

The short4ived particle reactive radionuclides of the U/Th series also have enormous potential for tracking particle source and transport in ocean margins. Mass balances comparing inventories in sediments with supply can be used to determine import or export of particles to an area. Such approaches are increasingly important in understanding the fates of particle-reactive contaminants whose sources are often enhanced in the coastal ocean. Studies of especially when supplemented by other... 

Gustafsson O, Buesseler KO, Geyer WR, Moran SB, Gschwend PM (1998) An assessment of the relative importance of horizontal and vertical transport of particle-reactive chemicals in the coastal ocean. Cont Shelf Res 18 805-829... 

Guan YF, Wang JZ, Ni HG, Luo XJ, Mai BX, Zeng EY (2007) Riverine inputs of polybrominated diphenyl ethers from the Pearl River Delta (China) to the coastal ocean. Environ Sci Technol 41(17) 6007-6013. doi 10.1021/es070782x... 

The recent Future of Ocean Chemistry in the U.S. (FOCUS) report (NSF, 2000) identified eight key themes for future chemical oceanographic research (Box 1.2). Clearly, oceanographic analyses over the coming decades will involve a wide variety of dissolved and particulate constituents from coastal ocean, open ocean, and seafloor settings, and thus a variety of reference materials will be required to represent these key sample matrices. 

Frank Millero is a Professor of Marine and Physical Chemistry and Associate Dean at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami. Dr. Millero s research interests include the application of physical chemical principles to natural waters to understand how ionic interactions affect the thermodynamics and kinetics of processes occurring in the oceans. He has extensive experience with many aspects of marine chemistry and chemical analysis including the analysis of trace metals and gases in seawater. Dr. Millero is a former member of the NRC s Ocean Studies Board and was a member of the Study Committee on Effects of Human Activities on the Coastal Ocean. 

Groundwater discharges into the coastal ocean are found emanating from sediments that lie on the continental shelves. The flows are very geographically variable as tliey... 

Most cation exchange occurs in estuaries and the coastal ocean due to the large difference in cation concentrations between river and seawater. As riverborne clay minerals enter seawater, exchangeable potassium and calcium are displaced by sodium and magnesium because the Na /K and Mg /Ca ratios are higher in seawater than in river water. Trace metals are similarly displaced. 

The problem with this fixed nitrogen is that its use as a fertilizer requires land application. While some of the nitrogen is retained by the plants, much is carried off the land as stormwater runoff This increases the concentration of DIN in groundwater and river-water. Drainage of these waters into the coastal ocean supplies nutrients that stimulate plankton growth. Remineralization of the plankton biomass can lead to development of hypoxic and anoxic conditions in coastal waters. 

Response of the Coastal Ocean and Estuaries to Future Emissions... 

Based on the results of this modeling effort, the global coastal ocean appears to have acted as a net source of CO2 to the atmosphere over the past 300 y due to the combined production of CO2 from biocalcification and an overall state of net heterotrophy. This role is expected to switch to that of a net CO2 sink in response to rising atmospheric CO2 levels and increasing nutrient runoff from land. The latter is stimulating new production and causing an overall state of net autotrophy. Recent observational... 

Radioactivity is a form of energy emitted by radioactive elements (radioisotopes or radionuclides). Radionuclides can present a health threat to humans and marine organisms because of the ionizing ability of the emitted radiation. The major pathway by which marine organisms and humans are exposed to radionuclides comes from consumption of fish and shellfish due to bioaccumulation of °Po and °Pb. Most of the °Po and Pb in the ocean is natural, but, human activities have increased their inputs to the coastal ocean. 

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