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Gill D.A.,The University of the West Indies, Cave Hill Campus | Schuhmann P.W.,University of North Carolina Wilmington | Oxenford H.A.,The University of the West Indies, Cave Hill Campus
Ecological Economics

This study sought to quantify the potential effects of changes in Caribbean reef fish populations on recreational divers' consumer surplus. Over five hundred tourist SCUBA divers were interviewed at seven sites across three Caribbean countries representing a diversity of individuals within the Caribbean dive market. A choice experiment was used to assess willingness to pay as a function of the abundance and size of reef fishes, the presence of fishing activity/gear, and dive price. Despite some preference heterogeneity both between and within sites, the results indicate that future declines in the abundance of reef fishes, and particularly in the number of large fishes observed on recreational dives, will result in significant reductions in diver consumer surplus. On the other hand, improvements in fish populations and reduced fishing gear encounters are likely to result in significant economic gains. These results can be used to justify investment in pre-emptive management strategies targeted at improving reef fish stocks (namely reducing unsustainable fishing activities and land-based reef impacts), managing conflicting uses, as well as to indicate a possible source of financing for such conservation activities. © 2015 Elsevier B.V. Source

Brownlee C.,Marine Biological Association of The United Kingdom | Wheeler G.L.,Marine Biological Association of The United Kingdom | Taylor A.R.,University of North Carolina Wilmington
Seminars in Cell and Developmental Biology

Coccolithophores are unicellular phytoplankton that are characterized by the presence intricately formed calcite scales (coccoliths) on their surfaces. In most cases coccolith formation is an entirely intracellular process - crystal growth is confined within a Golgi-derived vesicle. A wide range of coccolith morphologies can be found amongst the different coccolithophore groups. This review discusses the cellular factors that regulate coccolith production, from the roles of organic components, endomembrane organization and cytoskeleton to the mechanisms of delivery of substrates to the calcifying compartment. New findings are also providing important information on how the delivery of substrates to the calcification site is co-ordinated with the removal of H+ that are a bi-product of the calcification reaction. While there appear to be a number of species-specific features of the structural and biochemical components underlying coccolith formation, the fluxes of Ca2+ and a HCO3 - required to support coccolith formation appear to involve spatially organized recruitment of conserved transport processes. © 2015. Source

Hopwood M.J.,UK National Oceanography Center | Statham P.J.,UK National Oceanography Center | Skrabal S.A.,University of North Carolina Wilmington | Willey J.D.,University of North Carolina Wilmington
Marine Chemistry

We present the first evidence of Fe(II) complexation by natural organic ligands in estuarine waters. Across five diverse river/estuary systems we find evidence of terrestrially derived ligands with binding constants (log KFe(II)L) mainly in the range 6-8. These Fe(II) ligands were stable over short time periods (1-2days), generally equivalent to, or in excess of, ambient freshwater Fe(II) concentrations (which ranged from 12 to 3600nM) and had similar binding constants to ligands that were leached by water from vegetation and detritus (log KFe(II)L 7-8). A class of terrestrially derived ligands may therefore be important in stabilising Fe(II) concentrations in freshwater systems. However, in coastal seawater the impact of these ligands upon Fe(II) speciation is likely to be diminished due to a combination of dilution, loss of humic material during flocculation and increased ionic strength. The temperate and sub-tropical river systems studied included the Beaulieu (England), Itchen (England), Cape Fear (North Carolina, USA), Winyah Bay (South Carolina, USA) and Loch Etive (Scotland). Freshwaters in each system possessed a broad range of dissolved organic carbon (DOC, 200-1300μM), labile dissolved Fe (LDFe, Fe<0.2μm available to ferrozine after reduction with ascorbic acid, 100nM-20μM) and pH (5.5-8.5). In the Itchen estuary, where anthropogenic discharge constitutes >10% of freshwater input, ligand binding constants were elevated (up to log KFe(II)L 11) and the expected decrease in LDFe with increasing salinity along the estuary was not observed (LDFe and DOC both peaked at a salinity of 7) due to effluent inputs. © 2014 Elsevier B.V. Source

Arfken A.M.,University of North Carolina Wilmington | Arfken A.M.,Virginia Institute of Marine Science | Song B.,University of North Carolina Wilmington | Song B.,Virginia Institute of Marine Science | And 2 more authors.
Journal of Microbiology and Biotechnology

Airborne bacteria from hog farms may have detrimental impacts on human health, particularly in terms of antibiotic resistance and pathogen zoonosis. Despite human health risks, very little is known about the composition and diversity of airborne bacteria from hog farms and hog-related spray fields. We used pyrosequencing analysis of 16S rRNA genes to compare airborne bacterial communities in a North Carolina hog farm and lagoon spray field. In addition, we isolated and identified antibiotic-resistant bacteria from both air samples. Based on 16S rRNA gene pyrosequence analysis, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla in airborne bacterial communities from both hog farm and spray field sites. Within the Firmicutes genera, Clostridium spp. were more abundant in the hog farm, whereas Staphylococcus spp. were higher in the spray field. The presence of opportunitic pathogens, including several Staphylococcus species and Propionibacterium acnes, was detected in both bioaerosol communities based on phylogenetic analysis. The isolation and identification of antibiotic-resistant bacteria from air samples also showed similar results with dominance of Actinobacteria and Proteobacteria in both hog farm and spray field air. Thus, the existence of opportunistic pathogens and antibiotic resistant bacteria in airborne communities evidences potential health risks to farmers and other residents from swine bioaerosol exposure. © 2015 by The Korean Society for Microbiology and Biotechnology. Source

Lisa J.A.,University of North Carolina Wilmington | Lisa J.A.,Virginia Institute of Marine Science | Song B.,University of North Carolina Wilmington | Song B.,Virginia Institute of Marine Science | And 2 more authors.
Estuarine, Coastal and Shelf Science

Tidal and seasonal fluctuations in the oligohaline reaches of estuaries may alter geochemical features that influence structure and function of microbial communities involved in sedimentary nitrogen (N) cycling. In order to evaluate sediment community responses to short-term (tidal) and long-term (seasonal) changes in different tidal regimes, nitrogen cycling rates and genes were quantified in three sites that span a range of tidal influence in the upper portion of the Cape Fear River Estuary. Environmental parameters were monitored during low and high tides in winter and spring. 15N tracer incubation experiments were conducted to measure nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonia (DNRA). Abundances of functional genes including bacterial and archaeal ammonia monooxygenase (amoA), nitrite reductases (nirS and nrfA), nitrous oxide reductase (nosZ), and hydrazine oxidoreductase (hzo) were measured using quantitative PCR assays. Denitrification rates were highest among the measured N cycling processes while bacteria carrying nrfA genes were most abundant. A discernable pattern in the short-term variation of N cycling rates and gene abundance was not apparent under the different tidal regimes. Significant seasonal variation in nitrification, denitrification, and anammox rates as well as bacterial amoA, nirS and nosZ gene abundance was observed, largely explained by increases in substrate availability during winter, with sediment ammonium playing a central role. These results suggest that the coupling of nitrification to N removal pathways is primarily driven by organic carbon mineralization and independent of tidal or salinity changes. Finally, changes in denitrification and nitrification activities were strongly reflected by the abundance of the respective functional genes, supporting a linkage between the structure and function of microbial communities. © 2015 Elsevier Ltd. Source

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