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Eutrophication of Cape Cod estuaries: Effect of decadal changes in global-driven atmospheric and local-scale wastewater nutrient loads Texte intégral
2016
Valiela, Ivan | Owens, Caroline | Elmstrom, Elizabeth | Lloret, Javier
Nitrogen (N) supply by atmospheric deposition, wastewater, and fertilizers controls estuarine eutrophication. In New England, atmospheric N loads recently decreased by 50% and land-derived contributions rose about 80%, owing to national-scale emission controls and local urban development. The decrease in atmospheric deposition was large enough to balance increases in land-derived N loads, so total N loads to Waquoit Bay estuaries in Cape Cod did not change significantly between 1990 and 2014. Unchanged N regimes were corroborated by finding no differences in estuarine nutrient concentrations and macrophyte biomass between pre-2005 and in 2015. Coastal zones, subject to reasonably rapid changes in global and local driver variables, will require that assessment and management of eutrophication include adaptive strategies that capture effects of changing baselines. Management initiatives will be constrained by spatial scale of driver variables: local efforts may address wastewater and fertilizer N sources, but atmospheric sources require national or international attention.
Afficher plus [+] Moins [-]Prickly business: abundance of sea urchins on breakwaters and coral reefs in Dubai Texte intégral
2016
Bauman, Andrew G. | Dunshea, Glenn | Feary, David A. | Hoey, Andrew S.
Echinometra mathaei is a common echinoid on tropical reefs and where abundant plays an important role in the control of algal communities. Despite high prevalence of E. mathaei on southern Persian/Arabian Gulf reefs, their abundance and distribution is poorly known. Spatial and temporal patterns in population abundance were examined at 12 sites between breakwater and natural reef habitats in Dubai (UAE) every 3months from 2008 to 2010. Within the breakwater habitat, densities were greatest at shallow wave-exposed sites, and reduced with both decreasing wave-exposure and increasing depth. Interestingly, E. mathaei were significantly more abundant on exposed breakwaters than natural reef sites, presumably due to differences in habitat structure and benthic cover. Population abundances differed seasonally, with peak abundances during summer (July–September) and lower abundances in winter (December–February). Seasonal fluctuations are likely the result of peak annual recruitment pulses coupled with increased fish predation from summer to winter.
Afficher plus [+] Moins [-]Regional variation in the structure and function of parrotfishes on Arabian reefs Texte intégral
2016
Hoey, Andrew S. | Feary, David A. | Burt, John A. | Vaughan, Grace | Pratchett, Morgan S. | Berumen, Michael L.
Parrotfishes (f. Labridae) are a unique and ubiquitous group of herbivorous reef fishes. We compared the distribution and ecosystem function (grazing and erosion) of parrotfishes across 75 reefs in Arabia. Our results revealed marked regional differences in the abundance, and taxonomic and functional composition of parrotfishes between the Red Sea, Arabian Sea, and Arabian Gulf. High densities and diversity of parrotfishes, and high rates of grazing (210%year−1) and erosion (1.57kgm−2year−1) characterised Red Sea reefs. Despite Arabian Sea and Red Sea reefs having broadly comparable abundances of parrotfishes, estimates of grazing (150%year−1) and erosion (0.43kgm−2year−1) were markedly lower in the Arabian Sea. Parrotfishes were extremely rare within the southern Arabian Gulf, and as such rates of grazing and erosion were negligible. This regional variation in abundance and functional composition of parrotfishes appears to be related to local environmental conditions.
Afficher plus [+] Moins [-]Monitoring of trace metals in coastal sediments around Korean Peninsula Texte intégral
2016
Hwang, Dong-Woon | Kim, Seong-Gil | Choi, Minkyu | Lee, In-Seok | Kim, Seong-Soo | Choi, Hee-Gu
Spatial distributions and temporal variations of trace metals in Korean coastal sediments were investigated by determining seven metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) in sediment collected from 71 stations between 2004 and 2010 (n=491). High metal concentrations were found in the southeastern coast, where there are many cities and industrial complexes, indicating that metal concentrations in Korean coastal sediment are significantly influenced by human activities associated with urbanization and industrialization. However, metal concentrations in sediment did not markedly vary temporally, which was because the coast is managed sustainably and because of the characteristics of the sediment environments. Based on the sediment quality guidelines and geoaccumulation index, Korean coastal sediments are practically unpolluted with Cd, Cr, Cu, Hg, Pb and Zn but moderately polluted with As. More intensive monitoring is required to determine the potential As sources and to understand the As geochemical cycles in Korean coastal sediments.
Afficher plus [+] Moins [-]Isolation, identification, and crude oil degradation characteristics of a high-temperature, hydrocarbon-degrading strain Texte intégral
2016
Liu, Boqun | Ju, Meiting | Liu, Jinpeng | Wu, Wentao | Li, Xiaojing
In this work, a hydrocarbon-degrading bacterium Y-1 isolated from petroleum contaminated soil in the Dagang Oilfield was investigated for its potential effect in biodegradation of crude oil. According to the analysis of 16S rRNA sequences, strain Y-1 was identified as Bacillus licheniformis. The growth parameters such as pH, temperature, and salinity were optimised and 60.2% degradation of crude oil removal was observed in 5days. The strain Y-1 showed strong tolerance to high salinity, alkalinity, and temperature. Emplastic produced by strain Y-1 at high temperatures could be applied as biosurfactant. Gas chromatography analysis demonstrated that the strain Y-1 efficiently degraded different alkanes from crude oil, and the emplastic produced by strain Y-1 promoted the degradation rates of long-chain alkanes when the temperature increased to 55°C. Therefore, strain Y-1 would play an important role in the area of crude oil contaminant bioremediation even in some extreme conditions.
Afficher plus [+] Moins [-]Plastic debris in great skua (Stercorarius skua) pellets corresponds to seabird prey species Texte intégral
2016
Hammer, S. | Nager, R.G. | Johnson, P.C.D. | Furness, R.W. | Provencher, J.F.
Plastic is a common item in marine environments. Studies assessing seabird ingestion of plastics have focused on species that ingest plastics mistaken for prey items. Few studies have examined a scavenger and predatory species that are likely to ingest plastics indirectly through their prey items, such as the great skua (Stercorarius skua). We examined 1034 regurgitated pellets from a great skua colony in the Faroe Islands for plastics and found approximately 6% contained plastics. Pellets containing remains of Northern fulmars (Fulmarus glacialis) had the highest prevalence of plastic. Our findings support previous work showing that Northern fulmars have higher loads of plastics than other sympatric species. This study demonstrates that marine plastic debris is transferred from surface feeding seabird species to predatory great skuas. Examination of plastic ingestion in species that do not ingest plastics directly can provide insights into how plastic particles transfer vertically within the food web.
Afficher plus [+] Moins [-]Application of novel image base estimation of invisible leaf injuries in relation to morphological and photosynthetic changes of Phaseolus vulgaris L. exposed to tropospheric ozone Texte intégral
2016
Drapikowska, M. | Drapikowski, P. | Borowiak, K. | Hayes, F. | Harmens, H. | Dziewiątka, T. | Byczkowska, K.
This study aimed to evaluate the degree of Phaseolus vulgaris L. (bean) leaf tissue injury caused by tropospheric ozone. To validate O3 symptoms at the microscopic level, Evans blue staining together with an image processing method for the removal of distortions and calculation of dead leaf areas was applied. Net photosynthetic rate (PN), stomatal conductance (gs) and intercellular CO2 concentration (Ci) were determined to evaluate leaf physiological responses to ozone. It was found that both resistant and sensitive varieties of bean were damaged by ozone; however, the size of necrotic and partially destroyed leaf area in the sensitive genotype (S156) was bigger (1.18%, 2.18%) than in the resistant genotype (R123), i.e. 0.02% and 0.50%. Values of net photosynthetic rates were lower in the sensitive genotype in ambient air conditions, than in the resistant genotype in ambient air conditions. We further found that there was a correlation between physiological and anatomical injuries; net photosynthetic rate (PN) was negatively correlated with percentage of necrotic area of both genotypes, while stomatal conductance (gs), intercellular CO2 concentration (Ci) were positively correlated with percentage of necrotic tissue of both genotypes. Moreover, visible injures in both genotypes were positively correlated with percentage of anatomical injures. In conclusion, the presented combinations of morphological, anatomical and physiological markers allowed differential diagnosis of ozone injury.
Afficher plus [+] Moins [-]Assessment of vertical element distribution in street canyons using the moss Sphagnum girgensohnii: A case study in Belgrade and Moscow cities Texte intégral
2016
Goryainova, Zoya | Vuković, Gordana | Uros̆ević, Mira Aničić | Vergel, Konstantin | Ostrovnaya, Tatyana | Frontasyeva, Marina | Zechmeister, Harald
Sphagnum girgensohnii moss bags were used to study the small-scale vertical distribution of some major and trace elements in different types of street canyons (regular, deep and avenue types) in Belgrade and Moscow urban area. The exposure time was 10 weeks during the summer of 2011. The exposure of moss bags was at three different levels to test differences in deposition patterns according to height. The differences between the street and off-street side in the vertical element distribution in Moscow were tested too. The concentration of 25 major and trace elements in moss was determined by instrumental neutron activation analysis. The results showed that the accumulation of elements in the exposed moss bags were higher in deep and regular street canyons in comparison to that of the avenue type, the latter even with a higher traffic flow. The element concentrations were the highest at the lowest heights compared to those of the upper floors. For most determined elements the concentrations were lower on the off-street avenue side compared to the on-street side for all heights of moss exposure. The results obtained indicate that S. girgensohnii is sensitive to small-scale variations of the total concentrations of elements.
Afficher plus [+] Moins [-]Factors controlling the origin of Cochlodinium polykrikoides blooms along the Goheung coast, South Korea Texte intégral
2016
Lee, Moon Ock | Kim, Jong Kyu | Kim, Byeong Kuk
We investigated the factors influencing the origin of Cochlodinium polykrikoides blooms along the Goheung coast (GH), and compared them to those along the Geoje (GJ) coast and in the East China Sea (ECS) which were used as reference sites. Stratification did not develop in GH during C. polykrikoides blooms, unlike that in GJ. The surface salinity during summer in ECS was equivalent to that of GH, whereas surface temperature and concentration of nutrients in ECS were markedly higher than those in GH or GJ. Thermohaline (or thermal) fronts appeared between the Korea Southern Coastal Water (KSCW) and the outer seawater during C. polykrikoides blooms. The result of numerical simulation models indicated that freshwater from the Yangtze River clearly affected KSCW. As a result, the origin of C. polykrikoides blooms in GH during summer could be attributed to the inflow of seawater from ECS with high water temperature and abundant nutrients.
Afficher plus [+] Moins [-]Assessment of perfluorooctanoic acid and perfluorooctane sulfonate in surface water - Tamil Nadu, India Texte intégral
2016
Sunantha, Ganesan | Vasudevan, Namasivayam
As an emerging class of environmentally persistent organic pollutants, perfluorinated compounds (PFCs), particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS); have been universally found in the environment. Wastewater and untreated effluents are likely the major causes for the accumulation of PFCs in surface water. There are very few reports on the contamination of PFCs in the developing countries, particularly in India. This study reports the quantitative analysis of PFOA and PFOS in Noyyal, Cauvery, and also lakes in and around Chennai, using Ultra-Fast liquid chromatograph. The concentration of PFOA and PFOS ranged from 4 to 93ng/L and 3 to 29ng/L, respectively. The concentration of PFOS was below detectable limit in Cauvery River. A reliable concentration of PFOA was recorded at all sites of River Cauvery (5ng/L). The present study could be useful for the assessment of future monitoring programs of PFOA and PFOS in the surface water.
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