Coral cays form part of the Australian Great Barrier Reef. Coral cays with high densities of seabirds are areas of extreme nitrogen (N) enrichment with deposition rates of up to 1000 kg N ha(-1) y(-1). The ways in which N sources are utilised by coral cay plants, N is distributed within the cay, and whether or not seabird-derived N moves from cay to surrounding marine environments were investigated.

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An assessment of nitrogen sources to the Choptank and Patuxent River (including Island Creek), was conducted during the summer of 2003. Results demonstrated that both rivers were compromised with sewage derived nutrients. An Ecosystem Health Index for defined reporting regions was calculated from a variety of ecosystem heath parameters and then converted to a report card grade from A+ to D- and F for fail (Table 1).

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This newsletter is a summary of the history, mission and accomplishments of the University of Maryland Center for Environmental Science (UMCES). This summary has been prepared to provide a sense of where we have come from, what we are doing and where we are going. It also serves to identify the collaborative role UMCES plays within the University System and the State of Maryland.

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Coral bleaching events have become more frequent and widespread, largely due to elevated sea surface temperatures. Global climate change could lead to increased variability of sea surface temperatures, through influences on climate systems, e.g. El Nino Southern Oscillation (ENSO). Field observations in 1999, following a strong ENSO, revealed that corals bleached in winter after unusually cold weather.

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This poster presents data from the lagoons along the Caribbean coast of the Yucatan Peninsula, Mexico, a region undergoing appreciable growth. The region is characterized by karst limestone without appreciable surface drainage or rivers. However, there are various submarine springs and fissures that deliver runoff to coastal waters. The tropical seagrass Thalassia testudinum was sampled near the developed regions of Cancun as well as in the Puerto Morelos lagoon to the south.

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Direct comparisons between photosynthetic O-2 evolution rate and electron transport rate (ETR) were made in situ over 24 h using the benthic macroalga Ulva lactuca (Chlorophyta), growing and measured at a depth of 1.8 m, where the midday irradiance rose to 400-600 mumol photons m(-2) s(-1). O-2 exchange was measured with a 5-chamber data-logging apparatus and ETR with a submersible pulse amplitude modulated (PAM) fluorometer (Diving-PAM).

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Understanding the ecological role of benthic microalgae, a highly productive component of coral reef ecosystems, requires information on their spatial distribution. The spatial extent of benthic microalgae on Heron Reef (southern Great Barrier Reef, Australia) was mapped using data from the Landsat 5 Thematic Mapper sensor. integrated with field measurements of sediment chlorophyll concentration and reflectance. Field-measured sediment chlorophyll concentrations.

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Current shrimp pond management practices generally result in elevated concentrations of nutrients, suspended solids, bacteria and phytoplankton compared with the influent water. Concerns about adverse environmental impacts caused by discharging pond effluent directly into adjacent waterways have prompted the search for cost-effective methods of effluent treatment.

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Despite evidence linking shrimp farming to several cases of environmental degradation, there remains a lack of ecologically meaningful information about the impacts of effluent on receiving waters. The aim of this study was to determine the biological impact of shrimp farm effluent, and to compare and distinguish its impacts from treated sewage effluent.

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