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Evaluation of physical, chemical and microbiological parameters of water quality in the Harris Neck estuarine marshes along the Georgia coast
2011
Markand, Shanu | Bachoon, Dave S. | Gentit, Lisa | Sherchan, Samendra | Gates, Keith
Analysis of the physical, chemical and biological parameters assessing water quality in Harris Neck estuary indicated that the average dissolved oxygen level was 8.6mg/L, it maintained moderate levels of total dissolved nitrogen (2.7–4.6mg/L) and total dissolved phosphorous (<0.05mg/L), chlorophyll a was above 5.0μg/L and it is contaminated with low levels of fecal bacteria. Bifidobacterium adolescentis, a putative marker of human fecal pollution, was detected once at stations 3 and 5. Overall the Harris Neck water quality analyses indicated a relatively pristine and a healthy functioning marine environment.
Show more [+] Less [-]ANN application for prediction of atmospheric nitrogen deposition to aquatic ecosystems
2011
Palani, Sundarambal | Tkalich, Pavel | Balasubramanian, Rajasekhar | Palanichamy, Jegathambal
The occurrences of increased atmospheric nitrogen deposition (ADN) in Southeast Asia during smoke haze episodes have undesired consequences on receiving aquatic ecosystems. A successful prediction of episodic ADN will allow a quantitative understanding of its possible impacts. In this study, an artificial neural network (ANN) model is used to estimate atmospheric deposition of total nitrogen (TN) and organic nitrogen (ON) concentrations to coastal aquatic ecosystems. The selected model input variables were nitrogen species from atmospheric deposition, Total Suspended Particulates, Pollutant Standards Index and meteorological parameters. ANN models predictions were also compared with multiple linear regression model having the same inputs and output. ANN model performance was found relatively more accurate in its predictions and adequate even for high-concentration events with acceptable minimum error. The developed ANN model can be used as a forecasting tool to complement the current TN and ON analysis within the atmospheric deposition-monitoring program in the region.
Show more [+] Less [-]PBDEs in the blubber of marine mammals from coastal areas of São Paulo, Brazil, southwestern Atlantic
2011
Yogui, G.T. | Santos, M.C.O. | Bertozzi, C.P. | Sericano, J.L. | Montone, R.C.
Limited information is available in the literature on the levels of brominated flame retardants in the southern hemisphere. This study presents concentrations of polybrominated diphenyl ethers (PBDEs) in the blubber of small cetaceans from the coast of São Paulo (Brazil), southwestern Atlantic. PBDE levels were highest in Stenellafrontalis (770ngg⁻¹ lipid) followed by Stenobredanensis (475ngg⁻¹ lipid), Sotaliaguianensis (65.6ngg⁻¹ lipid), Tursiopstruncatus (64.2ngg⁻¹ lipid) and Pontoporiablainvillei (60.3ngg⁻¹ lipid). In general, continental shelf individuals exhibited higher contamination than inshore animals. This might be related to larger prey items consumed by continental shelf dolphins. The pattern of contamination indicates that Penta-BDE commercial mixtures are a major source of PBDEs to top predators in the southwestern Atlantic. Congeners found in Octa-BDE formulations were not detected in the investigated animals.
Show more [+] Less [-]Occurrence of the toxic dinoflagellate Ostreopsis cf. ovata in relation with environmental factors in Monaco (NW Mediterranean)
2011
Cohu, Stéphanie | Thibaut, Thierry | Mangialajo, Luisa | Labat, Jean-Philippe | Passafiume, Ornella | Blanfuné, Aurélie | Simon, Nathalie | Cottalorda, Jean-Michel | Lemée, Rodolphe
To study environment characteristics favoring the toxic benthic dinoflagellate Ostreopsis cf. ovata, a survey was conducted in Monaco (NW Mediterranean Sea), in summers 2007 and 2008. Epiphytic and planktonic blooms occurred almost simultaneously and a high variation of abundances at low spatial scales was observed. An early and very marked bloom occurred in 2007, compared to a later and less abundant development in 2008. These distinct patterns in bloom timing corresponded with very different hydroclimatic scenarios in 2007 (hot spring and relatively cold summer) and 2008 (standard year compared to the median year profile estimated with data from 1995 to 2008). No clear impacts of summer seawater temperature, rainfall or nutrient concentrations were evident. Strong wind may favor the dispersal of benthic and planktonic cells. Our study suggests that further investigations are needed to examine the potential role of Ostreopsis nutritional mode (i.e. autotrophy vs. mixotrophy).
Show more [+] Less [-]Sampling epifauna, a necessity for a better assessment of benthic ecosystem functioning: An example of the epibenthic aggregated species Ophiothrix fragilis from the Bay of Seine
2011
Lozach, Sophie | Dauvin, Jean-Claude | Méar, Yann | Murat, Anne | Davoult, Dominique | Migné, Aline
Sampling the sea bottom surface remains difficult because of the surface hydraulic shock due to water flowing through the gear (i.e., the bow wave effect) and the loss of epifauna organisms due to the gear’s closing mechanism. Slow-moving mobile epifauna, such as the ophiuroid Ophiothrix fragilis, form high-density patches in the English Channel, not only on pebbles like in the Dover Strait or offshore Brittany but also on gravel in the Bay of Seine (>5000indm⁻²). Such populations form high biomasses and control the water transfer from the water column to the sediment. Estimating their real density and biomass is essential for the assessment of benthic ecosystem functioning using trophic web modelling. In this paper, we present and discuss the patch patterns and sampling efficiency of the different methods for collecting in the dense beds of O. fragilis in the Bay of Seine. The large Hamon grab (0.25m⁻²) highly under-estimated the ophiuroid density, while the Smith McIntyre appeared adequate among the tested sampling grabs. Nowadays, diving sampling, underwater photography and videos with remote operated vehicle appear to be the recommended alternatives to estimate the real density of such dense slow-moving mobile epifauna.
Show more [+] Less [-]Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp
2011
Stoner, Elizabeth W. | Layman, Craig A. | Yeager, Lauren A. | Hassett, Heather M.
Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study.
Show more [+] Less [-]Growth anomalies on Acropora cytherea corals
2011
Irikawa, Akiyuki | Casareto, Beatriz E. | Suzuki, Yoshimi | Agostini, Sylvain | Hidaka, Michio | van Woesik, Robert
This ten-year study examined the morphological, physiological, and ecological characteristics of coral growth anomalies on Acropora cytherea on Amuro Island, Okinawa, Japan. The objectives of the study were to assess whether the growth anomalies, identified as diffuse disruptions on the skeleton: (i) were more prevalent on large colonies than on small colonies, (ii) were more common near the center of the colonies than peripherally, (iii) affected colony growth and mortality, and (iv) affected coral-colony fecundity and photosynthetic capacity. We hypothesized that the growth anomalies were signs of the onset of aging. The growth anomalies were more prevalent on colonies >2m diameter, and were concentrated near the central (older) portions of the colonies. The growth anomalies were also associated with reduced productivity and dysfunctional gametogenesis. Still, the growth anomalies did not appear to affect colony survival. The contact experiments showed that the growth anomalies were not contagious, and were most likely a sign of aging that was exacerbated by thermal stress.
Show more [+] Less [-]Development of the sediment and water quality management strategies for the Salt-water River, Taiwan
2011
Lin, C.E. | Chen, C.T. | Kao, C.M. | Hong, A. | Wu, C.Y.
The Salt-water River watershed is one of the major river watersheds in the Kaohsiung City, Taiwan. Water quality and sediment investigation results show that the river water contained high concentrations of organics and ammonia–nitrogen, and sediments contained high concentrations of heavy metals and organic contaminants. The main pollution sources were municipal and industrial wastewaters. Results from the enrichment factor (EF) and geo-accumulation index (Igₑₒ) analyses imply that the sediments can be characterized as heavily polluted in regard to Cd, Cr, Pb, Zn, and Cu. The water quality analysis simulation program (WASP) model was applied for water quality evaluation and carrying capacity calculation. Modeling results show that the daily pollutant inputs were much higher than the calculated carrying capacity (1050kgday⁻¹ for biochemical oxygen demand and 420kgday⁻¹ for ammonia–nitrogen). The proposed watershed management strategies included river water dilution, intercepting sewer system construction and sediment dredging.
Show more [+] Less [-]Seasonal nitrogen and phosphorus dynamics during benthic clam and suspended mussel cultivation
2011
Nizzoli, Daniele | Welsh, David Thomas | Viaroli, Pierluigi
Effects of suspended mussel and infaunal clam cultivation on sediment characteristics, and benthic organic and inorganic nitrogen and phosphorus fluxes were compared in a shallow coastal lagoon. The two species had different impacts on sediment features, but both created “hotspots” of nutrient fluxes with annual N and P regeneration rates being 4.9 and 13.5 (mussel) and 4.5 and 14.9 (clams) fold greater than those of unfarmed control sediments. Mussel farming also caused considerable nutrient regeneration within the water column with the mussel ropes contributing ∼25% of total inorganic N and P production and at times dominating the sediments (e.g. 95% of SRP production in summer and 45% of DIN production in winter). Such nutrient regeneration rates seriously question the proposal that suspension-feeding bivalves act as a eutrophication buffer, especially during summer when nutrient regeneration rates are maximal, but other nutrient sources (freshwater run-off and unfarmed sediments) are at their lowest.
Show more [+] Less [-]Temporal changes of polyphenols and enzyme activities in seedlings of Kandelia obovata under lead and manganese stresses
2011
Yan, Zhong Zheng | Tam, Nora Fung Yee
The temporal responses of peroxidase (POD), superoxide dismutase (SOD), total polyphenols (TP), extractable condensed tannins (ECT) to different levels of lead (Pb) or manganese (Mn) stress, as well as the metal accumulation, in seedlings of Kandelia obovata were investigated. Both stress time and stress intensity had significant effects with significant accumulation of Pb and Mn in roots at Day 1. Pb and Mn showed no significant effects on root or leaf TP and ECT at Day 1. Prolonged exposure to metals caused significant drops of root TP and ECT but increased in leaves at Days 7 and 49. POD activities decreased in both roots and leaves at Day 1, while POD and SOD both increased under moderate levels of Pb and Mn at Day 7. The present study showed that antioxidative enzyme activities were more sensitive indicators to Pb or Mn stresses than phenolic compounds.
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