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Intersex in the clam Scrobicularia plana (Da Costa): Widespread occurrence in English Channel estuaries and surrounding areas 全文
2015
Pope, N.D. | Childs, K. | Dang, C. | Davey, M.S. | O’Hara, S.C.M. | Langston, K. | Minier, C. | Pascoe, P.L. | Shortridge, E. | Langston, W.J.
Estuarine clams Scrobicularia plana were sampled from 108 intertidal locations around the English Channel and adjacent areas. Although S. plana is believed to be a strict gonochorist, 58% of the populations sampled included intersexed individuals (described as male clams exhibiting ovotestis). Over the entire region, on average, 8.6% of male clams exhibited intersex, although proportions of affected males ranged from 0% to 53% depending on location. The severity of intersex was assessed using a simple classification scale, with the majority of individuals showing low levels of impact. Sex ratios were significantly skewed at some sites. There were no significant relationships between incidence or severity of intersex; or with size or parasitism of individual clams. Intersex in S. plana is a useful tool to assess endocrine disruptive effects in estuaries, although mechanisms of impact and causative agents remain uncertain.
显示更多 [+] 显示较少 [-]Spatial and vertical distributions of heavy metals and their potential toxicity levels in various beach sediments from high-background-radiation area, Kerala, India 全文
2015
Suresh, G. | Ramasamy, V. | Sundarrajan, M. | Paramasivam, K.
The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area.
显示更多 [+] 显示较少 [-]Three decadal inputs of total organic carbon from four major coastal river basins to the summer hypoxic zone of the Northern Gulf of Mexico 全文
2015
He, Songjie | Xu, YJun
This study investigated long-term (1980–2009) yields and variability of total organic carbon (TOC) from four major coastal rivers in Louisiana entering the Northern Gulf of Mexico where a large-area summer hypoxic zone has been occurring since the middle 1980s. Two of these rivers drain agriculture-intensive (>40%) watersheds, while the other two rivers drain forest-pasture dominated (>50%) watersheds. The study found that these rivers discharged a total of 13.0×104t TOC annually, fluctuating from 5.9×104 to 22.8×104t. Seasonally, the rivers showed high TOC yield during the winter and early spring months, corresponding to the seasonal trend of river discharge. While river hydrology controlled TOC yields, land use has played an important role in fluxes, seasonal variations, and characteristics of TOC. The findings fill in a critical information gap of quantity and quality of organic carbon transport from coastal watersheds to one of the world’s largest summer hypoxic zones.
显示更多 [+] 显示较少 [-]Debris ingestion by the Antillean Manatee (Trichechus manatus manatus) 全文
2015
Attademo, Fernanda Loffler Niemeyer | Balensiefer, Deisi Cristiane | Freire, Augusto Carlos da Bôaviagem | de Sousa, Glaucia Pereira | da Cunha, Fábio Adonis Gouveia Carneiro | Luna, Fábia de Oliveira
The Antillean manatee inhabits coastal regions of North and Northeastern Brazil and currently is considered an endangered species in the country. Aiming to gather information for the development of public policies focusing on the conservation of manatees, the National Center for Research and Conservation of Aquatic Mammals of the Chico Mendes Institute for Biodiversity has been rescuing, rehabilitating and releasing these mammals since the 1980s. Over the last 36years, 40 manatees were released by the CMA/ICMBio and four of them were rescued again due to debris ingestion. Two of these manatees died and the other two were taken back into captivity for a new rehabilitation process. The four mammals had confirmed diagnosis of plastic debris ingestion. These findings demonstrate that the environment where the manatees live after being released had a significant amount of garbage which may hinder the success of the species conservation in Brazil.
显示更多 [+] 显示较少 [-]Accumulation and distribution of trace metals within soils and the austral cordgrass Spartina densiflora in a Patagonian salt marsh 全文
2015
Idaszkin, Yanina L. | Lancelotti, Julio L. | Bouza, Pablo J. | Marcovecchio, Jorge E.
Concentrations of Cd, Cu, Fe, Pb, and Zn were determined in soils and in below- and above-ground structures of Spartina densiflora in a Patagonian salt marsh (San Antonio, Río Negro, Argentina). Also, the relationship between trace metal concentrations in soils and plants was investigated to improve our knowledge regarding the ability of this plant species to take up and accumulate trace metals from the soil. Our results indicate that, within the studied salt marsh, soil trace metal concentrations follow a decreasing concentration gradient toward the sea. They show moderate pollution and a potentially negative biological effect in one site of the salt marsh. While below-ground structures reflect the soil metal concentration pattern, this is not so evident in above-ground concentrations. Also, S. densiflora is able to absorb a limited amount of metals present in the soil, the soil bioaccumulation factor being lower in sites where soil metal concentration is higher.
显示更多 [+] 显示较少 [-]Polycyclic aromatic hydrocarbons alter the structure of oceanic and oligotrophic microbial food webs 全文
2015
Cerezo, Maria Isabel | Agusti, Susana
One way organic pollutants reach remote oceanic regions is by atmospheric transport. During the Malaspina-2010 expedition, across the Atlantic, Indian, and Pacific Oceans, we analyzed the polycyclic aromatic hydrocarbon (PAH) effects on oceanic microbial food webs. We performed perturbation experiments adding PAHs to classic dilution experiments. The phytoplankton growth rates were reduced by more than 5 times, being Prochlorococcus spp. the most affected. 62% of the experiments showed a reduction in the grazing rates due to the presence of PAHs. For the remaining experiments, grazing usually increased likely due to cascading effects. We identified changes in the slope of the relation between the growth rate and the dilution fraction induced by the pollutants, moving from no grazing to V-shape, or to negative slope, indicative of grazing increase by cascade effects and alterations of the grazers' activity structure. Our perturbation experiments indicate that PAHs could influence the structure oceanic food-webs structure.
显示更多 [+] 显示较少 [-]Baseline monitoring of organic sunscreen compounds along South Carolina's coastal marine environment 全文
2015
Bratkovics, Stephanie | Wirth, Edward | Sapozhnikova, Yelena | Pennington, Paul | Sanger, Denise
Organic ultraviolet filters (UV-F) are increasingly being used in personal care products to protect skin and other products from the damaging effects of UV radiation. In this study, marine water was collected monthly for approximately one year from six coastal South Carolina, USA sites and analyzed for the occurrence of seven organic chemicals used as UV filters (avobenzone, dioxybenzone, octocrylene, octinoxate, oxybenzone, padimate-o and sulisobenzone). The results were used to examine the relationship between beach use and the distribution of UV-F compounds along coastal South Carolina, USA. Five of the seven target analytes were detected in seawater along coastal South Carolina during this study. Dioxybenzone and sulisobenzone were not detected. The highest concentrations measured were >3700ng octocrylene/L and ~2200ng oxybenzone/L and beach use was greatest at this site; a local beach front park. Patterns in concentrations were assessed based on season and a measure of beach use.
显示更多 [+] 显示较少 [-]Depositional record of trace metals and degree of contamination in core sediments from the Mandovi estuarine mangrove ecosystem, west coast of India 全文
2015
Veerasingam, S. | Vethamony, P. | Mani Murali, R. | Fernandes, B.
The concentrations of seven trace metals (Fe, Mn, Cu, Cr, Co, Pb and Zn) in three sediment cores were analysed to assess the depositional trends of metals and their contamination level in the Mandovi estuary, west coast of India. All sediment cores showed enrichment of trace metals in the upper part of core sediments and decrease in concentration with depth, suggesting excess of anthropogenic loading (including mining activities) occurred during the recent past. Scanning electron microscope (SEM) images distinguished the shape, size and structure of particles derived from lithogenic and anthropogenic sources in core sediments. The geo-accumulation index (Igeo) values indicate that Mandovi estuary is ‘moderately polluted’ with Pb, whereas ‘unpolluted to moderately polluted’ with Fe, Mn, Cu, Cr, Co and Zn. The comparative analysis of trace metals revealed that Fe and Mn were highly enriched in the Mandovi estuary compared to all other Indian estuaries.
显示更多 [+] 显示较少 [-]Seasonal variation of bacterial communities in shellfish harvesting waters: Preliminary study before applying phage therapy 全文
2015
Pereira, C. | Santos, L. | Silva, A.P. | Silva, Y.J. | Cunha, A. | Romalde, J.L. | Nunes, M.L. | Almeida, A.
Seasonal variation of bacterial communities in shellfish harvesting waters: Preliminary study before applying phage therapy 全文
2015
Pereira, C. | Santos, L. | Silva, A.P. | Silva, Y.J. | Cunha, A. | Romalde, J.L. | Nunes, M.L. | Almeida, A.
The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro.During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/summer season is a critical period during which phage therapy should be applied.
显示更多 [+] 显示较少 [-]Seasonal variation of bacterial communities in shellfish harvesting waters: preliminary study before applying phage therapy 全文
2015 | 1000
Pereira, C. | Santos, L. | Silva, A. P. | Silva, Y. J. | Cunha, A. | Romalde, J. L. | Nunes, M. L. | Almeida, A.
The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro. During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/ summer season is a critical period during which phage therapy should be applied.
显示更多 [+] 显示较少 [-]Levels of arsenic, cadmium, lead and mercury in the branchial plate and muscle tissue of mobulid rays 全文
2015
Ooi, Michelle S.M. | Townsend, Kathy A. | Bennett, Michael B. | Richardson, Anthony J. | Fernando, Daniel | Villa, Cesar A. | Gaus, Caroline
Mobulid rays are targeted in fisheries for their branchial plates, for use in Chinese medicine. Branchial plate and muscle tissue from Mobula japanica were collected from fish markets in Sri Lanka, and muscle tissue biopsies from Manta alfredi in Australia. These were analysed for arsenic, cadmium, lead and mercury and compared to maximum levels (MLs) set by Food Standards Australia and New Zealand (FSANZ), European Commission (EC) and Codex Alimentarius Commission. The estimated intake for a vulnerable human age group was compared to minimal risk levels set by the Agency for Toxic Substances and Disease Registry. The mean inorganic arsenic concentration in M. japanica muscle was equivalent to the FSANZ ML while cadmium exceeded the EC ML. The mean concentration of lead in M. alfredi muscle tissue exceeded EC and Codex MLs. There were significant positive linear correlations between branchial plate and muscle tissue concentrations for arsenic, cadmium and lead.
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