خيارات البحث
النتائج 1061 - 1070 من 4,241
The toxic exposure of flamingos to per- and Polyfluoroalkyl substances (PFAS) from firefighting foam applications in Bonaire
2017
de Vries, Pepijn | Slijkerman, Diana M.E. | Kwadijk, Christiaan J.A.F. | Kotterman, Michiel J.J. | Posthuma, Leo | de Zwart, Dick | Murk, Albertinka J. | Foekema, Edwin M.
In 2010 an oil terminal next to nature reservation Saliña Goto (Bonaire) caught fire. Firefighting resulted in elevated per- and polyfluoroalkyl substances (PFAS) concentrations in the salt lake. Within months flamingo abundance in Goto dropped to near complete absence. After statistical analysis, rainfall was deemed an unlikely cause for this decline. Toxicological effects on abundance of prey are likely the main cause for the flamingo absence. This reduced PFAS exposure via food and thus risk towards flamingos during the first years after the fires. Although the sediment is still polluted with persistent PFAS, flamingos returned, and started to feed on organisms with PFAS levels that exceed safety thresholds, placing the birds and other wildlife at risk. Monitoring bird populations is advised to assess potential toxic effects on birds and their offspring. This case suggests that applying persistent chemicals to reduce incident impacts may be more harmful than the incident itself.
اظهر المزيد [+] اقل [-]Exceptionally high abundances of microplastics in the oligotrophic Israeli Mediterranean coastal waters
2017
van der Hal, Noam | Ariel, Asaf | Angel, Dror L.
Seasonal sea surface microplastic distribution was recorded at 17 sites along the Israeli Mediterranean coast. Microplastics (0.3–5mm) were found in all samples, with a mean abundance of 7.68±2.38particles/m3 or 1,518,340particles/km2. Some areas had higher abundances of microplastics than others, although differences were neither consistent nor statistically significant. In some cases microplastic particles were found floating in large patches. One of these patches contained an extraordinary number of plastic particles; 324particles/m3 or 64,812,600particles/km2. Microplastic abundances in Israeli coastal waters are disturbingly high; mean values were 1–2 orders of magnitude higher than abundances reported in other parts of the world. Light-colored (white or transparent) fragments were by far more abundant than all other microplastic colors and types. The results of this study underline the need for action to reduce the flux of plastics to the marine environment.
اظهر المزيد [+] اقل [-]The liver transcriptome of suckermouth armoured catfish (Pterygoplichthys anisitsi, Loricariidae): Identification of expansions in defensome gene families
2017
Parente, Thiago E. | Moreira, Daniel A. | Magalhães, Maithê G.P. | de Andrade, Paula C.C. | Furtado, Carolina | Haas, Brian J. | Stegeman, John J. | Hahn, Mark E.
Pterygoplichthys is a genus of related suckermouth armoured catfishes native to South America, which have invaded tropical and subtropical regions worldwide. Physiological features, including an augmented resistance to organic xenobiotics, may have aided their settlement in foreign habitats. The liver transcriptome of Pterygoplichthys anisitsi was sequenced and used to characterize the diversity of mRNAs potentially involved in the responses to natural and anthropogenic chemicals. In total, 66,642 transcripts were assembled. Among the identified defensome genes, cytochromes P450 (CYP) were the most abundant, followed by sulfotransferases (SULT), nuclear receptors (NR) and ATP binding cassette transporters (ABC). A novel expansion in the CYP2Y subfamily was identified, as well as an independent expansion of the CYP2AAs. Two expansions were also observed among SULT1. Thirty-two transcripts were classified into twelve subfamilies of NR, while 21 encoded ABC transporters. The diversity of defensome transcripts sequenced herein could contribute to this species' resistance to organic xenobiotics.
اظهر المزيد [+] اقل [-]Susceptibility of seagrass to oil spills: A case study with eelgrass, Zostera marina in San Francisco Bay, USA
2017
Fonseca, Mark | Piniak, Gregory A. | Cosentino-Manning, Natalie
Existing literature illustrates inconsistent responses of seagrasses to oil exposure, both in the field and in the laboratory. Here, we add a new study that combined morphometric, demographic and photophysiology assessments to determine the potential oiling impacts to eelgrass (Zostera marina) from the 2007 Cosco Busan event in San Francisco Bay. Shoot densities, reproductive status, and rhizome elongation of Z. marina were examined at sites with pre-spill data, and eelgrass photosynthetic efficiency was measured post-spill. Shoot densities and percent elongation of rhizome internodes formed after the oil spill varied but with no consistent relationship to adjacent shoreline cleanup assessment team (SCAT) oiling categories. Similarly, differences in seagrass photosynthetic efficiency were not consistent with SCAT oiling categories. While thresholds for negative impacts on seagrass in general remain to be defined, conclusive oiling indicators for degree and duration of exposure would be important considerations and need examination under controlled study.
اظهر المزيد [+] اقل [-]Potentially toxic filamentous fungi associated to the economically important Nodipecten nodosus (Linnaeus, 1758) scallop farmed in southeastern Rio de Janeiro, Brazil
2017
Numerous countries have been confronted with infectious diseases in mariculture activities, including fungi infections, although reports in scallops are scarce. Thus, this study aimed to investigate the occurrence of filamentous fungi in Nodipecten nodosus specimens from three marine farms in Southeastern Brazil. Eight fungi genera were observed in the branchial arches, intestine and muscle tissue of the scallop specimens. These include potentially toxin-producing species, such as Aspergillus, Penicillium and Fusarium. Their presence may lead to potential public health concerns, since all sampling sites showed the presence of fungi in all scallop organs, with special concern regarding edible muscle tissue. A significant number of species was observed at one of the study areas, which could indicate a previously unknown source of contamination, since increases in fungi species richness in polluted coastal waters have been reported. This is also, to the best of our knowledge, the first report of Pestalotiopsis in shellfish.
اظهر المزيد [+] اقل [-]Characterization of Enterococcus species isolated from marine recreational waters by MALDI-TOF MS and Rapid ID API® 20 Strep system
2017
Christ, Ana Paula Guarnieri | Ramos, Solange Rodrigues | Cayô, Rodrigo | Gales, Ana Cristina | Hachich, Elayse Maria | Sato, Maria Inês Zanoli
MALDI-TOF Mass Spectrometry Biotyping has proven to be a reliable method for identifying bacteria at the species level based on the analysis of the ribosomal proteins mass fingerprint. We evaluate the usefulness of this method to identify Enterococcus species isolated from marine recreational water at Brazilian beaches. A total of 127 Enterococcus spp. isolates were identified to species level by bioMérieux's API® 20 Strep and MALDI-TOF systems. The biochemical test identified 117/127 isolates (92%), whereas MALDI identified 100% of the isolates, with an agreement of 63% between the methods. The 16S rRNA gene sequencing of isolates with discrepant results showed that MALDI-TOF and API® correctly identified 74% and 11% of these isolates, respectively. This discrepancy probably relies on the bias of the API® has to identify clinical isolates. MALDI-TOF proved to be a feasible approach for identifying Enterococcus from environmental matrices increasing the rapidness and accuracy of results.
اظهر المزيد [+] اقل [-]Life and death of a sewage treatment plant recorded in a coral skeleton δ15N record
2017
Duprey, Nicolas N. | Wang, Xingchen T. | Thompson, Philip D. | Pleadwell, Jeffrey E. | Raymundo, Laurie J. | Kim, Kiho | Sigman, Daniel M. | Baker, David M.
We investigated the potential of coral skeleton δ15N (CS-δ15N) records for tracking anthropogenic-N sources in coral reef ecosystems. We produced a 56yr-long CS-δ15N record (1958–2014) from a reef flat in Guam that has been exposed to varying 1) levels of sewage treatment 2) population density, and 3) land use. Increasing population density (from <30 to 300ind·km−2) and land use changes in the watershed resulted in a ~1‰ enrichment of the CS-δ15N record until a sewage treatment plant (STP) started operation in 1975. Then, CS-δ15N stabilized, despite continued population density and land use changes. Based on population and other considerations, a continued increase in the sewage footprint might have been expected over this time. The stability of CS-δ15N, either contradicts this expectation, or indicates that the impacts on the outer reef at the coring site were buffered by the mixing of reef water with the open ocean.
اظهر المزيد [+] اقل [-]Understanding how physical-biological coupling influences harmful algal blooms, low oxygen and fish kills in the Sea of Oman and the Western Arabian Sea
2017
Harrison, Paul J. | Piontkovski, Sergey | Al-Hashmi, Khalid
In the last decade, green Noctiluca scintillans with its symbiont and other dinoflagellates such as Cochlodinium polykrikoides, Prorocentrum micans and Scrippsiella trochoidea have become the dominant HABs, partially replacing the previously dominant diatoms and red Noctiluca scintillans, especially during the northeast monsoon. Fish kills in the Sea of Oman are linked to a slow seasonal decline in oxygen concentration from January to November, probably due to the decomposition of a series of algal blooms and the deep, low oxygen waters periodically impinging the Omani shelf. In the western Arabian Sea, cyclonic eddies upwell low oxygen, nutrient-rich water and the subsequent algal bloom decays and lowers the oxygen further and leads to fish kills. Warming of the surface waters by 1.2°C over the last 5 decades has increased stratification and resulted in a shoaling of the oxycline. This has increased the probability and frequency of upwelling low oxygen water and subsequent fish kills.
اظهر المزيد [+] اقل [-]Factors influencing organochlorine pesticides distribution in the Brisbane River Estuarine sediment, Australia
2017
Duodu, Godfred Odame | Goonetilleke, Ashantha | Ayoko, G. A. (Godwin A.)
Sediment samples collected from Brisbane River were analysed for organochlorine pesticide residues (OCPs). The factors influencing OCPs distribution in the sediment were investigated using multivariate analytical tools. Thirteen OCPs were detected in the sediment with concentrations ranging between below detection to 83.9ng/g, and detection frequency >90%. With the exception of dieldrin, the OCP inputs appear to be historical and may cause adverse ecological impacts. Multi-criteria ranking of the factors influencing the OCPs (except dieldrin) distribution in the sediment revealed that TOC>silt>intensive urban land use>population>seasons. Dieldrin distribution is significantly influenced by season>TOC>silt>intensive urban land use>population. The study helps to prioritise factors required for managing OCPs contamination in sediments and identification of appropriate mitigation measures.
اظهر المزيد [+] اقل [-]Potential impacts of shipping noise on marine mammals in the western Canadian Arctic
2017
Halliday, William D. | Insley, Stephen J. | Hilliard, R Casey | de Jong, Tyler | Pine, Matthew K.
As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when >100km away, could affect marine mammal behaviour when within 2km for icebreakers vessels, and as far as 52km for tankers. This vessel noise could have substantial impacts on marine mammals during migration and in MPAs. We suggest that locating the corridor farther north, use of marine mammal observers on vessels, and the reduction of vessel speed would help to reduce this impact.
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