Publications by authors named "Kevin Sellner"

3 Publications

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Temporal Stability of Escherichia coli Concentrations in Waters of Two Irrigation Ponds in Maryland.

Appl Environ Microbiol 2018 02 17;84(3). Epub 2018 Jan 17.

USDA-ARS Environmental Microbial and Food Safety Laboratory, Beltsville, Maryland, USA.

Fecal contamination of water sources is an important water quality issue for agricultural irrigation ponds. concentrations are commonly used to evaluate recreational and irrigation water quality. We hypothesized that there may exist temporally stable spatial patterns of concentrations across ponds, meaning that some areas mostly have higher and other areas mostly lower than average concentrations of To test this hypothesis, we sampled two irrigation ponds in Maryland at nodes of spatial grids biweekly during the summer of 2016. Environmental covariates-temperature, turbidity, conductivity, pH, dissolved oxygen, chlorophyll , and nutrients-were measured in conjunction with concentrations. Temporal stability was assessed using mean relative differences between measurements in each location and averaged measurements across ponds. Temporally stable spatial patterns of concentrations and the majority of environmental covariates were expressed for both ponds. In the pond interior, larger relative mean differences in chlorophyll corresponded to smaller mean relative differences in concentrations, with a Spearman's rank correlation coefficient of 0.819. Turbidity and ammonium concentrations were the two other environmental covariates with the largest positive correlations between their location ranks and the concentration location ranks. Tenfold differences were found between geometric mean concentrations in locations that were consistently high or consistently low. The existence of temporally stable patterns of concentrations can affect the results of microbial water quality assessment in ponds and should be accounted for in microbial water quality monitoring design. The microbial quality of water in irrigation water sources must be assessed to prevent the spread of microbes that can cause disease in humans because of produce consumption. The microbial quality of irrigation water is evaluated based on concentrations of as the indicator organism. Given the high spatial and temporal variability of concentrations in irrigation water sources, recommendations are needed on where and when samples of water have to be taken for microbial analysis. This work demonstrates the presence of a temporally stable spatial pattern in the distributions of concentrations across irrigation ponds. The ponds studied had zones where concentrations were mostly higher than average and zones where the concentrations were mostly lower than average over the entire observation period, covering the season when water was used for irrigation. Accounting for the existence of such zones will improve the design and implementation of microbial water quality monitoring.
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http://dx.doi.org/10.1128/AEM.01876-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772220PMC
February 2018

Employing a socio-ecological systems approach to engage harmful algal bloom stakeholders.

Aquat Ecol 2016 Sep 11;50(3):577-594. Epub 2015 Dec 11.

Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences, 701 E. Pratt Street, Baltimore, MD 21202, USA.

Harmful algal blooms (HABs) pose substantial health risks to seafood consumers, drinking water supplies, and recreationalists with apparent increases associated with anthropogenic eutrophication of freshwaters and coastal areas. Attempts to intervene in these blooms can be met with reticence by citizens, non-governmental organizations, and officials, often due to local perceptions and beliefs. Hence, the social sciences have an important role to play in HAB research and mitigation. Much of the social science HAB research to date has focused on how best to communicate associated risks and appropriate behavioral responses to affected local communities. The emphasis has been on the direct human impacts, particularly in the areas of health outcomes and identification of any sociocultural and economic barriers to proposed mitigation. While this focus is warranted and valuable, there is also a need to understand HABs as part of a larger human-environmental coupled system, where blooms trigger a wide range of cultural and behavioral responses that are driven by how blooms impact other social and ecosystem dynamics. The research presented here describes a case study of a bloom in a lake in the Chesapeake Bay watershed where anthropologists worked with HAB researchers. The results of this interdisciplinary collaboration show that approaching the bloom and mitigation within a 'socio-ecological systems' framework provides stakeholders with a range of rationales and approaches for addressing HAB mitigation, enhancing both short-term successes and longer-term opportunities, even if is still present in the lake.
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http://dx.doi.org/10.1007/s10452-015-9562-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777728PMC
September 2016

Harmful algal blooms: causes, impacts and detection.

J Ind Microbiol Biotechnol 2003 Jul 30;30(7):383-406. Epub 2003 Jul 30.

Chesapeake Research Consortium, 645 Contees Wharf Road, Edgewater, MD 21037, USA.

Blooms of autotrophic algae and some heterotrophic protists are increasingly frequent in coastal waters around the world and are collectively grouped as harmful algal blooms (HABs). Blooms of these organisms are attributed to two primary factors: natural processes such as circulation, upwelling relaxation, and river flow; and, anthropogenic loadings leading to eutrophication. Unfortunately, the latter is commonly assumed to be the primary cause of all blooms, which is not the case in many instances. Moreover, although it is generally acknowledged that occurrences of these phenomena are increasing throughout the world's oceans, the reasons for this apparent increase remain debated and include not only eutrophication but increased observation efforts in coastal zones of the world. There is a rapidly advancing monitoring effort resulting from the perception of increased impacts from these HABs, manifested as expanding routine coastal monitoring programs, rapid development and deployment of new detection methods for individual species, toxins, and toxicities, and expansion of coastal modeling activities towards observational forecasts of bloom landfall and eventually bloom prediction. Together, these many efforts will provide resource managers with the tools needed to develop effective strategies for the management and mitigation of HABs and their frequently devastating impacts on the coastal environment.
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http://dx.doi.org/10.1007/s10295-003-0074-9DOI Listing
July 2003