Metabolically active bacteria detected with click chemistry in low organic matter rainwater.

Rain contains encapsulated bacteria that can be transported over vast distances during relatively short periods of time. However, the ecological significance of bacteria in "precontact" rainwater-rainwater prior to contact with non-atmospheric surfaces-remains relatively undefined given the methodological challenges of studying low-abundance microbes in a natural assemblage. Here, we implement single-cell "click" chemistry in a novel application to detect the protein synthesis of bacteria in precontact rainwater samples as a measure of metabolic activity. Using epifluorescence microscopy, we find approximately 103-104 bacteria cells mL-1 with up to 7.2% of the observed cells actively synthesizing protein. Additionally, our measurement of less than 30 µM total organic carbon in the samples show that some rainwater bacteria can metabolize substrates in very low organic matter conditions, comparable to extremophiles in the deep ocean. Overall, our results raise new questions for the field of rainwater microbiology and may help inform efforts to develop quantitative microbial risk assessments for the appropriate use of harvested rainwater.

Carbon limitation in response to nutrient loading in an eelgrass mesocosm: influence of water residence time.

Altered primary productivity associated with eutrophication impacts not only ecosystem structure but also the biogeochemical cycling of oxygen and carbon. We conducted laboratory experiments to empirically determine how residence time (1, 3, 10 d) influences eutrophication responses in a simplified Pacific Northwest Zostera marina-green macroalgal community. We expected long-residence time (RT) systems to exhibit eutrophication impairments. Instead, we observed an accumulation of nutrients at all RTs and a shift in the dissolved inorganic carbon speciation away from CO2 (aq) with unexpected consequences for eel grass plant condition, including shoot mortality. Most metrics responded more strongly to temperature treatments than to RT treatments. No dramatic shifts in the relative abundance of Z. marina and green macro algae were detected. Z. marina shoot density proliferated in cool temperatures (12°C) with a modest decline at 20°C. Eelgrass loss was associated with high total scale pH (pHT) and CO2 (aq) concentrations of <10 µmol kg-1 CO2 (aq), but not with high nutrients. Z. marina δ13C values support the hypo thesis that carbon availability was greater at short RT. Further, very low leaf sugar concentrations are consistent with extreme photosynthetic CO2 (aq) limitation. We suggest that the effects of extremely low environ mental car bon concentrations (CO2 (aq)) and increased respiration at warm temperatures (20°C) and other physiological processes can lead to internal carbon limitation and shoot mortality. Eutrophication responses to nutrient loading are more nuanced than just light limitation of eelgrass and require additional research on the interaction of the biogeochemical environment and plant physiology to better understand estuarine ecosystem disruption.

Integrating High-Resolution Coastal Acidification Monitoring Data Across Seven United States Estuaries.

Beginning in 2015, the United States Environmental Protection Agency's (EPA's) National Estuary Program (NEP) started a collaboration with partners in seven estuaries along the East Coast (Barnegat Bay; Casco Bay), West Coast (Santa Monica Bay; San Francisco Bay; Tillamook Bay), and the Gulf of Mexico (GOM) Coast (Tampa Bay; Mission-Aransas Estuary) of the United States to expand the use of autonomous monitoring of partial pressure of carbon dioxide (pCO2) and pH. Analysis of high-frequency (hourly to sub-hourly) coastal acidification data including pCO2, pH, temperature, salinity, and dissolved oxygen (DO) indicate that the sensors effectively captured key parameter measurements under challenging environmental conditions, allowing for an initial characterization of daily to seasonal trends in carbonate chemistry across a range of estuarine settings. Multi-year monitoring showed that across all water bodies temperature and pCO2 covaried, suggesting that pCO2 variability was governed, in part, by seasonal temperature changes with average pCO2 being lower in cooler, winter months and higher in warmer, summer months. Furthermore, the timing of seasonal shifts towards increasing (or decreasing) pCO2 varied by location and appears to be related to regional climate conditions. Specifically, pCO2 increases began earlier in the year in warmer water, lower latitude water bodies in the GOM (Tampa Bay; Mission-Aransas Estuary) as compared with cooler water, higher latitude water bodies in the northeast (Barnegat Bay; Casco Bay), and upwelling-influenced West Coast water bodies (Tillamook Bay; Santa Monica Bay; San Francisco Bay). Results suggest that both thermal and non-thermal influences are important drivers of pCO2 in Tampa Bay oxygen, National Estuary Program and Mission-Aransas Estuary. Conversely, non-thermal processes, most notably the biogeochemical structure of coastal upwelling, appear to be largely responsible for the observed pCO2 values in West Coast water bodies. The co-occurrence of high salinity, high pCO2, low DO, and low temperature water in Santa Monica Bay and San Francisco Bay characterize the coastal upwelling paradigm that is also evident in Tillamook Bay when upwelling dominates freshwater runoff and local processes. These data demonstrate that high-quality carbonate chemistry observations can be recorded from estuarine environments using autonomous sensors originally designed for open-ocean settings.

Statistical models of fecal coliform levels in Pacific Northwest estuaries for improved shellfish harvest area closure decision making.

There is a substantial need for tools that effectively predict spatial and temporal fecal pollution patterns in estuarine waters. In this study, statistical models of exceedances of shellfish fecal coliform (FC) water quality criteria were developed using a 10-year dataset of FC levels and environmental data. Performance (sensitivity, specificity, and predictive capacity) of five different types of models was tested (MLR regression, Tobit (censored) regression, Firth's binary logistic regression (BLR), classification trees, and mixed-effects regression) for each of three conditionally managed shellfish-harvesting areas in Tillamook Bay, Oregon (USA). The most influential variables were related to precipitation and river stage height in the wet season and wind and tidal-stage in the dry season. Classification tree and Firth's BLR approaches better explained exceedances of shellfish water quality standards than the current closure thresholds. Findings demonstrate the utility of statistical modeling approaches for improved management of shellfish harvesting waters.

Seagrass habitat metabolism increases short-term extremes and long-term offset of CO2 under future ocean acidification.

The role of rising atmospheric CO2 in modulating estuarine carbonate system dynamics remains poorly characterized, likely due to myriad processes driving the complex chemistry in these habitats. We reconstructed the full carbonate system of an estuarine seagrass habitat for a summer period of 2.5 months utilizing a combination of time-series observations and mechanistic modeling, and quantified the roles of aerobic metabolism, mixing, and gas exchange in the observed dynamics. The anthropogenic CO2 burden in the habitat was estimated for the years 1765-2100 to quantify changes in observed high-frequency carbonate chemistry dynamics. The addition of anthropogenic CO2 alters the thermodynamic buffer factors (e.g., the Revelle factor) of the carbonate system, decreasing the seagrass habitat's ability to buffer natural carbonate system fluctuations. As a result, the most harmful carbonate system indices for many estuarine organisms [minimum pHT, minimum Ωarag, and maximum pCO2(s.w.)] change up to 1.8×, 2.3×, and 1.5× more rapidly than the medians for each parameter, respectively. In this system, the relative benefits of the seagrass habitat in locally mitigating ocean acidification increase with the higher atmospheric CO2 levels predicted toward 2100. Presently, however, these mitigating effects are mixed due to intense diel cycling of CO2 driven by aerobic metabolism. This study provides estimates of how high-frequency pHT, Ωarag, and pCO2(s.w.) dynamics are altered by rising atmospheric CO2 in an estuarine habitat, and highlights nonlinear responses of coastal carbonate parameters to ocean acidification relevant for water quality management.

Macrophyte Community Response to Nitrogen Loading and Thermal Stressors in Rapidly Flushed Mesocosm Systems.

A mesocosm system was developed to simulate estuarine conditions characteristic of short water-residence time ecosystems of the Pacific Coast of North America, and used to evaluate the response of multiple macrophyte metrics to gradients of NO3 loading and temperature. Replicated experiments found that few responses could be directly attributed to NO3 loading up to 6 x ambient. Some response metrics exhibited weak relationships with nutrient loading but could not be resolved with available statistical power. While direct nutrient responses were found for some species-specific metrics (e.g. green macroalgal growth and biomass, tissue N%, etc.), many patterns were confounded with temperature. Temperature generally had a larger effect on response metrics than did nutrient load. Experimental macrophyte communities exhibited community shifts consistent with the predicted effects of nutrient loading at 20 °C, but there was no evidence of other eutrophication symptoms (phytoplankton blooms or hypoxia) due to the short system-residence time. The Z. marina Nutrient Pollution Index (NPI) tracked the NO3 gradient at 10 °C, but exhibited no response at 20 °C, which may limit the utility of this metric in areas with marked thermal seasonality. Results suggest that teasing apart the influence of temperature and nutrients on the expression of eutrophication symptoms will require complex multi-stressor experiments and the use of indicators that are sensitive across a broad range of conditions.

A method to identify estuarine water quality exceedances associated with ocean conditions.

Wind-driven coastal upwelling along the Pacific Northwest Coast of the USA results in oceanic water that may be periodically entrained into adjacent estuaries and which possesses high nutrients and low dissolved oxygen (DO). Measurement of water quality indicators during these upwelling water entrainment events would represent extreme values for water quality thresholds derived from typical estuarine conditions. Tools are therefore needed to distinguish upwelled waters from other causes of exceedances of water quality thresholds within estuaries of the region. We present an example application of logistic regression models to predict the probability of exceedance of a water quality threshold, using DO data from the Yaquina estuary, Oregon, USA. Models including water temperature and salinity correctly classified exceedances of DO about 80 % of the time. Inclusion of in situ fluorescence in the logistic regression model for DO improved the model performance and reduced the rate of false positives.

Ecoregional analysis of nearshore sea-surface temperature in the North Pacific.

The quantification and description of sea surface temperature (SST) is critically important because it can influence the distribution, migration, and invasion of marine species; furthermore, SSTs are expected to be affected by climate change. To better understand present temperature regimes, we assembled a 29-year nearshore time series of mean monthly SSTs along the North Pacific coastline using remotely-sensed satellite data collected with the Advanced Very High Resolution Radiometer (AVHRR) instrument. We then used the dataset to describe nearshore (<20 km offshore) SST patterns of 16 North Pacific ecoregions delineated by the Marine Ecoregions of the World (MEOW) hierarchical schema. Annual mean temperature varied from 3.8°C along the Kamchatka ecoregion to 24.8°C in the Cortezian ecoregion. There are smaller annual ranges and less variability in SST in the Northeast Pacific relative to the Northwest Pacific. Within the 16 ecoregions, 31-94% of the variance in SST is explained by the annual cycle, with the annual cycle explaining the least variation in the Northern California ecoregion and the most variation in the Yellow Sea ecoregion. Clustering on mean monthly SSTs of each ecoregion showed a clear break between the ecoregions within the Warm and Cold Temperate provinces of the MEOW schema, though several of the ecoregions contained within the provinces did not show a significant difference in mean seasonal temperature patterns. Comparison of these temperature patterns shared some similarities and differences with previous biogeographic classifications and the Large Marine Ecosystems (LMEs). Finally, we provide a web link to the processed data for use by other researchers.

Incidence of health crises in tourists visiting Jamaica, west indies, 1998 to 2000.

BACKGROUND: Tourism is important to the Jamaican economy accounting for approximately 25% of the gross domestic product. Health problems in tourists could have significant impact on the health of the local population, the scarce health service resources, and the tourist industry. This study was conducted to identify health problems most commonly occurring in tourists visiting Jamaica and examine how these problems are managed. METHODS: Records of health problems occurring in tourists who visited principal tourist areas on the north coast from June 1998 to June 2002 were reviewed for the type of illness and how the problem was handled. The data were analyzed using Epi-Info software (Centers for Disease Control and Prevention, Atlanta, GA) and Statistical Analysis System software (SAS Institute, Cary, NC). RESULTS: Accidents were the most common health crises reported by tourists. Gastrointestinal, respiratory, and cardiovascular problems occurred less frequently. Those less than 40 years of age more frequently reported accidents or injury, gastrointestinal problems, and drug abuse, whereas respiratory and cardiovascular problems were more common among those above 40 years of age. Cardiovascular problems, drug abuse, and death were more common in men than in women. Hotel nurses handled most of the cases and were more likely to refer patients to private physicians or hospitals than to public hospitals (p <.05). Factors influencing the way the crisis was handled were age (p =.0441); who handled the crisis (p <.0001); and the method of payment (p =.0072). The factors that influenced hospitalization were gender (p =.0615); who handled the crisis at the onset (p =.0497); how the crisis was dealt with (p =.0336); and previous health problems (p =.0056). Men were more likely to be hospitalized and to be referred to a public hospital than women. Medical insurance covered the costs for 11% of tourists, and 75% paid out of pocket. CONCLUSION: The information provided by this study can be used to implement changes to reduce health problems in tourists and improve emergency health services in tourist areas.