John D. Christensen

Nocturnal fish movement and trophic flow across habitat boundaries in a coral reef ecosystem (SW Puerto Rico)

Abstract. Few studies have quantified the extent of nocturnal cross-habitat movements for fish, or the influence of habitat adjacencies on nutrient flows and trophodynamics. To investigate the patterns of nocturnal cross-boundary movements of fish and quantify trophic connectivity, fish were sampled at night with gillnets set along the boundaries between dominant habitat types (coral reef/seagrass and mangrove/ seagrass) in southwestern Puerto Rico. Fish movement across adjacent boundary patches were equivalent at both coral reefs and mangroves. Prey biomass transfer was greater from seagrass to coral reefs (0.016 kg/km) and from mangroves to seagrass (0.006 kg/km) but not statistically significant, indicating a balance of flow between adjacent habitats. Pelagic species (jacks, sharks, rays) accounted for 37% of prey biomass transport at coral reef/seagrass and 46% at mangrove/seagrass while grunts and snappers accounted for 7% and 15%, respectively. This study indicated that coral reefs and mangroves serve as a feeding area for a wide range of multi-habitat fish species. Crabs were the most frequent prey item in fish leaving coral reefs while molluscs were observed slightly more frequently than crabs in fish entering coral reefs. For most prey types, biomass exported from mangroves was greater than biomass imported. The information on direction of fish movement together with analysis of prey data provided strong evidence of ecological linkages between distinct adjacent habitat types and highlighted the need for greater inclusion of a mosaic of multiple habitats when attempting to understand ecosystem function including the spatial transfer of energy across the seascape.

Chemical contamination assessment of Gulf of Mexico oysters in response to hurricanes Katrina and Rita

Hurricane Katrina made landfall on August 29, 2005 and caused widespread devastation along the central Gulf Coast states. Less than a month later Hurricane Rita followed a similar track slightly west of Katrina’s. A coordinated multi-agency response followed to collect water, sediment and tissue samples for a variety of chemical, biological and toxicological indicators. The National Oceanic and Atmospheric Administration’s National Status and Trends Program (NS&T) participated in this effort by measuring chemical contamination in sediment and oyster tissue as part of the Mussel Watch Program, a long-term monitoring program to assess spatial and temporal trends in a wide range of coastal pollutants. This paper describes results for contaminants measured in oyster tissue collected between September 29 and October 10, 2005 and discusses the results in the context of Mussel Watch and its 20-year record of chemical contamination in the region and the nation. In general, levels of metals in oyster tissue were higher then pre- hurricane levels while organic contaminants were at or near record lows. No contaminant reported here exceeded the FDA action level for food safety.

A historical assessment of coastal contamination in Birch Harbor, Maine based on the analysis of mussels collected in the 1940s and the Mussel Watch Program.

Coastal contamination in the 1940s was assessed based on analysis of canned blue mussels presumably collected from Birch Harbor, Maine, USA. Analytical results on legacy organic contaminants were compared to long-term National Oceanic and Atmospheric Administration (NOAA) Mussel Watch (MW) monitoring data to estimate the degree of coastal contamination before World War II (WWII) when many synthetic organic compounds were first introduced into the environment. While dieldrin and chlordane were not detected in the canned mussels, dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexanes (HCHs) were present at lower concentrations relative to the more recent MW data. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were detected, and the later were significantly higher in canned mussels relative to the MW data (p<0.05). Furthermore, moving average analysis applied to the MW data depicted three-phased temporal trend patterns (increase-decrease-steady state) for virtually all contaminants indicating an overall increased coastal contamination in post WWII era.

Refocusing Mussel Watch on contaminants of emerging concern (CECs): The California pilot study (2009–10)

To expand the utility of the Mussel Watch Program, local, regional and state agencies in California partnered with NOAA to design a pilot study that targeted contaminants of emerging concern (CECs). Native mussels (Mytilus spp.) from 68 stations, stratified by land use and discharge scenario, were collected in 2009-10 and analyzed for 167 individual pharmaceuticals, industrial and commercial chemicals and current use pesticides. Passive sampling devices (PSDs) and caged Mytilus were co-deployed to expand the list of CECs, and to assess the ability of PSDs to mimic bioaccumulation by Mytilus. A performance-based quality assurance/quality control (QA/QC) approach was developed to ensure a high degree of data quality, consistency and comparability. Data management and analysis were streamlined and standardized using automated software tools. This pioneering study will help shape future monitoring efforts in Californias coastal ecosystems, while serving as a model for monitoring CECs within the region and across the nation.

Assessment of coastal storm impacts on contaminant body burdens of oysters collected from the Gulf of Mexico.

This study evaluated changes in oyster tissue contaminant levels following North Atlantic tropical cyclones to determine if changes in contaminant concentrations were predictable. The basis for this study was analysis of coastal chemical contaminant data from the National Oceanic and Atmospheric Administration’s (NOAA) National Status and Trends Mussel Watch Program and NOAA’s National Weather Service storm track data. The tendency for contaminant (metals and organic compounds) body burdens to increase or decrease in oyster tissue after a storm was assessed using contingency and correspondence analyses. Post-storm contaminant levels in oysters revealed a consistent pattern of distribution, which could be described as follows: (1) most of the organic contaminants stay within their long-term concentration ranges, (2) very few organic contaminants decreased, and (3) metals overwhelmingly tend to increase.

Characterization of organic chemical contaminants in sediments from Jobos Bay, Puerto Rico.

Jobos Bay, located on the southeastern coast of Puerto Rico, contains a variety of habitats including mangroves, seagrass meadows, and coral reefs. The watershed surrounding the bay includes a number of towns, agricultural areas, and the Jobos Bay National Estuarine Research Reserve (NERR). Jobos Bay and the surrounding watershed are part of a Conservation Effects Assessment Project (CEAP), involving the Jobos Bay NERR, the US Department of Agriculture, and the National Oceanic and Atmospheric Administration (NOAA) to assess the benefits of agricultural best management practices (BMPs) on the terrestrial and marine environments. As part of the Jobos Bay CEAP, NOAA collected sediment samples in May 2008 to characterize over 130 organic chemical contaminants. This paper presents the results of the organic contaminant analysis. The organic contaminants detected in the sediments included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and the pesticide DDT. PAHs at one site in the inner bay near a boat yard were significantly elevated; however, all organic contaminant classes measured were below NOAA sediment quality guidelines that would have indicated that impacts were likely. The results of this work provide an important baseline assessment of the marine environment that will assist in understanding the benefits of implementing BMPs on water quality in Jobos Bay.

Chemical contamination in southwest Puerto Rico: A survey of contaminants in the coral Porites astreoides

Abstract. Coral (Porites astreoides) from eight sites in southwest Puerto Rico were analyzed for approximately 150 chemical contaminants, to provide a preliminary characterization of environmental contamination in the corals, and assess the relationships between chemical contamination in corals and adjacent sediments. Overall, the concentration of PAHs (polycyclic aromatic hydrocarbons) and PCBs (polychlorinated biphenyls) detected in the limited number of coral samples collected were comparable to concentrations found in sediments. However, the concentration of a chemical contaminant (e.g., PAHs) in the corals at a site was often different from what was found in adjacent sediments. The level of PCBs and DDT (dichlorodiphenyltrichloroethane) in the corals appeared higher just outside of Guanica Bay, and there was some evidence of a downstream concentration gradient for these two contaminant classes. The trace elements copper and zinc were frequently detected in Porites astreoides, and the concentrations were usually comparable to those found in adjacent sediments. Chromium was an exception in that it was not detected in any of the coral samples analyzed, although it was detected in all of the sediment samples.