Refine search
Results 501-510 of 1,310
Small plastic debris changes water movement and heat transfer through beach sediments Full text
2011
Carson, Henry S. | Colbert, Steven L. | Kaylor, Matthew J. | McDermid, Karla J.
We investigated the physical properties of beaches contaminated with plastic fragments. We compared sediment cores from Hawai‘i Island’s Kamilo Beach, notable for plastic accumulation, to cores from a nearby beach. Compared to the nearby beach, Kamilo sediments contained more plastics (up to 30.2% by weight), were coarser-grained, and were more permeable (t-test, p<0.0001). 85% of the fragments were polyethylene, and 95% were concentrated in the top 15cm of the cores. We constructed artificial cores of standardized grain size and varying plastic-to-sediment ratios. Adding plastic significantly increased the permeability (ANOVA, p=0.002), which was partially attributed to the fragments increasing the mean grain size. Sediments with plastic warmed more slowly (16% maximum decrease in thermal diffusivity), and reached lower maximum temperatures (21% maximum increase in heat capacity). These changes have a variety of potential effects on beach organisms, including those with temperature-dependent sex-determination such as sea turtle eggs.
Show more [+] Less [-]Heavy oil exposure induces high moralities in virus carrier Japanese flounder Paralichthys olivaceus Full text
2011
Song, Jun-Young | Nakayama, Kei | Murakami, Yasunori | Kitamura, Shin-Ichi
The relationship between chemical exposure and disease outbreak in fish has not been fully defined due to the limitations of experimental systems (model fish and pathogens). Therefore, we constructed a system using the Japanese flounder, Paralichthys olivaceus, and viral haemorrhagic septicemia virus (VHSV), and evaluated it by heavy oil (HO) exposure. The fish were exposed to HO at 0.3, 0.03, 0.003, and 0g/L following VHSV infection at doses of 10².⁵ or 10³.⁵ tissue culture infectious dose (TCID)₅₀/fish. As a result, groups given the dual stressors showed more than 90% mortality. Although VHSV infection at 10².⁵ and 10³.⁵ TCID₅₀/fish without HO exposure also induced high mortality, at 68.8% and 81.3%, respectively, HO exposure induced faster and higher mortality in the virus carrier fish, indicating that chemical stressors raise the risk of disease outbreak in fish. The experimental system established in this study could be useful for chemical risk assessment.
Show more [+] Less [-]Can patterns in benthic communities be explained by an environmental pressure index? Full text
2011
Oigman-Pszczol, Simone S. | Creed, Joel. C.
Many studies have assessed in unison specific biological attributes and certain environmental impacts but few studies have analyzed multiple biological variables and pressures from multiple sites at the same time. Our study’s goal was to quantify the major potential human pressures in the shallow subtidal rocky reefs along a tropical Atlantic coast; propose a relative environmental pressure index and investigate the relationships between environmental pressures, the benthic community and coral population attributes. The analysis of human pressures suggests that one-third of sites were under high or very high proportional stress. Sites with high human pressure had lower live cover, higher percent of recent mortality and density of Siderastrea stellata. These relations were species specific. The coral species S.stellata seemed to be the best indicator of present environmental stress. These findings demonstrate the need to include multiple species and stressors in monitoring programs designed to contribute to coastal management initiatives.
Show more [+] Less [-]Seasonal nitrogen and phosphorus dynamics during benthic clam and suspended mussel cultivation Full text
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 [-]Development of the sediment and water quality management strategies for the Salt-water River, Taiwan Full text
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 [-]Implementation of the European Marine Strategy Framework Directive: A methodological approach for the assessment of environmental status, from the Basque Country (Bay of Biscay) Full text
2011
Borja, Angel | Galparsoro, Ibon | Irigoien, Xabier | Iriondo, Ane | Menchaca, Iratxe | Muxika, Iñigo | Pascual, Marta | Quincoces, Iñaki | Revilla, Marta | Germán Rodríguez, J. | Santurtún, Marina | Solaun, Oihana | Uriarte, Ainhize | Valencia Rincón, Victoriano | Zorita, Izaskun
The implementation of the Marine Strategy Framework Directive (MSFD) is directing European marine research towards the coordinated and integrated assessment of sea environmental status, following the ecosystem-based approach. The MSFD uses a set of 11 descriptors which, together, summarise the way in which the whole system functions. As such, the European Commission has proposed an extensive set of indicators, to assess environmental status. Hence, taking account of the large amount of data available for the Basque coast (southern Bay of Biscay), together with a recent proposal for assessment within the MSFD, an integrated environmental status assessment approach is developed (for the first time) in this contribution. The strengths and weaknesses of the method, combined with proposals from the MSFD, are discussed.
Show more [+] Less [-]Occurrence of perfluorinated compounds in water, sediment and mussels from the Cantabrian Sea (North Spain) Full text
2011
Gómez, Cristian | Vicente, Joana | Echavarri-Erasun, Beatriz | Porte, Cinta | Lacorte, Silvia
Perfluorinated compounds (PFCs) have emerged as significant global environmental pollutants with persistent, bioaccumulative and toxic properties. The aim of this study was to determine the occurrence of PFCs in water (wastewater, submarine emissaries and port-waters), sediment and transplanted mussels in estuarine areas of high urban and industrial impact from Northern Spain. Five PFCs of industrial use were studied: perfluorooctanesulfonate, perfluorohexanesulfonate, perfluorobutanesulfonate, perfluorooctanoate acid and perfluorononanoate acid. After selective extraction, samples were analyzed by Ultra Performance Liquid Chromatography coupled to tandem mass spectrometry. ΣPFCs ranged from 0.06 to 10.9ng/L in water, with higher levels in wastewater treatment plants effluents and port waters than in submarine emissaries. Little accumulation was observed in sediments and mussels with ΣPFCs ranging from 0.01–0.13ng/g dw and 0.01–0.06ng/g ww, respectively. Most ubiquitous compounds were PFOS and PFOA. Mass fluxes of PFCs to the Cantabrian Sea are estimated and the impact to the coastal ecosystem is discussed.
Show more [+] Less [-]Distribution and accumulation of organotin species in seawater, sediments and organisms collected from a Taiwan mariculture area Full text
2011
Liu, Li-Lian | Wang, Jih-Terng | Chung, Kuo-Nan | Leu, Ming-Yih | Meng, Pei-Jie
The present study was undertaken to evaluate the distribution and accumulation of tributyltin (TBT) and triphenyltin (TPhT) in seawater, sediments and selected organisms from a cage mariculture area in southern Taiwan, Hsiao Liouchiou Island. Our results show that ΣOTs were found in concentrations as high as 196ng/L in seawater collected from the sites in Pai-Sa harbor, and up 1040ng/g dry wt. in sediments dredged from sites within Da-Fu harbor. Also, ΣOTs concentrations of 859ng/g dry wt. were observed in the liver of cobia (Rachycentron canadum) from mariculture cages. As most published studies have focused on the acute toxicity and bioaccumulation of organotins in mussels, the effects of organotins on cobia and other marine fauna are still poorly understood. This study highlights the significance of ΣBTs accumulation in cobia, as well as in the sediments and seawater surrounding their culture facilities.
Show more [+] Less [-]Occurrence of endocrine-disrupting chemicals in riverine sediments from the Pearl River Delta, China Full text
2011
Gong, Jian | Ran, Yong | Chen, Di-Yun | Yang, Yu
The endocrine-disrupting chemicals (EDCs) was investigated in 28 riverine sediments from the Pearl River system, China and analyzed by an ultrasonication extraction and GC–MS method. The concentrations of 4-tert-octylphenol (OP), 4-nonylphenol (NP), and bisphenol A (BPA) in the sediments were in the ranges of <2.0–210, 107–16198 and <1.7–430ng/g dw, respectively. The steroid estrogens estrone (E1) and 17β-estradiol (E2) in the sediments ranged from <1.3 to 10.9ng/gdw and from <0.9 to 2.6ng/gdw, respectively. The spatial distribution of these chemicals was related to the discharge of domestic and industrial wastewater along the rivers. The positive correlation between EDCs and total organic carbon indicates that sedimentary organic carbon is an important factor in controlling the distributions of EDCs. Compared with other previous studies, the ZR and DR rivers from the PRD were heavily contaminated by APs and BPA.
Show more [+] Less [-]Polybrominated diphenyl ethers (PBDEs) in marine foodstuffs in Australia: Residue levels and contamination status of PBDEs Full text
2011
Shanmuganathan, Devarajan | Megharaj, Mallavarapu | Chen, Zuliang | Naidu, R.
Edible marine products (n=24) collected from the fish markets in Adelaide, Australia, were analysed for the presence of polybrominated diphenyl ethers (PBDEs). The total concentration of 11 PBDE congeners found in the marine products ranged from 1.01 to 45ng/g fresh weight. Among the samples analysed, imported silver fish and prawns from Vietnam and Thailand respectively, recorded the highest ∑PBDEs concentrations (45.10 and 43.29ng/g fresh weight) as against 13.08 and 12.57ng/g fresh weight in Australian king prawns and Gar fish. BDE-209 was the most dominant congener in the marine products followed by BDE-47, 99 and 100. The calculated average daily intakes of ∑PBDEs per day for an adult male and female (19 or more years old) were 1026.8 and 1188.4ng/kg per day, respectively. This study clearly shows that the dietary exposure to marine foods can contribute to PBDEs accumulation in human body.
Show more [+] Less [-]