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A century of introductions by coastal sessile marine invertebrates in Angola, South East Atlantic Ocean Полный текст
2017
South Atlantic studies referring to non-native taxa are mostly restricted to Argentinean, Brazilian, and South African coasts. In this study we examined the literature to provide a list of sessile marine invertebrates along the Angolan coast, to infer its introduction status according to their biogeographical distribution and natural history. We reported 29 non-native and 7 cryptogenic species, a small number when compared to other South Atlantic regions of similar extension. Half of the non-native species were reported for Luanda. The majority of the introduced species had a northern hemisphere origin, a consequence of the main introduction route being from the North Atlantic/Mediterranean Sea during the Portuguese colonization. This is the first comprehensive assessment of this kind for the Angolan coast and the diversity of introduced species is certainly underestimated. Regular and rigorous assessments and monitoring of introduced marine species will help to understand the vectors, routes and time of introductions.
Показать больше [+] Меньше [-]Marine debris boost in juvenile Magellanic penguins stranded in south-eastern Brazil in less than a decade: Insights into feeding habits and habitat use Полный текст
2017
Di Beneditto, Ana Paula Madeira | Siciliano, Salvatore
The Magellanic penguin (Spheniscus magellanicus) is a marine sentinel for the southern Atlantic Ocean that is a proxy of environmental quality. The presence of marine debris (macro-debris) in the stomach contents of emaciated juvenile penguins stranded from 21°S to 23°S was compared at different times (2000 and 2008), and the debris ingestion pathway was determined. The frequency of marine debris in the stomachs doubled in less than a decade, and flexible plastics remained the main ingested item over time (68–70%). The pelagic octopus, Argonauta nodosa, which inhabits the sea surface, was the most important prey species recovered in the stomach contents. The poor physical condition of the penguins that reach the northern migration limit (study area) reduces the diving capacity of the animals and increases their vulnerability to debris ingestion. Considering their preferred prey and physical condition, we conclude that the penguins likely ingested the marine debris in surface waters.
Показать больше [+] Меньше [-]Ingestion of microplastics by natural zooplankton groups in the northern South China Sea Полный текст
2017
Sun, Xiaoxia | Li, Qingjie | Zhu, Mingliang | Liang, Junhua | Zheng, Shan | Zhao, Yongfang
The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505μm and 160μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125μm and 167μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1pieces/m3 for Net I and 131.5pieces/m3 for Net II.
Показать больше [+] Меньше [-]Long-term perspective on the relationship between phytoplankton and nutrient concentrations in a southeastern Australian estuary Полный текст
2017
Larsson, Michaela E. | Ajani, Penelope A. | Rubio, Ana M. | Guise, Kristy | McPherson, Ross G. | Brett, Steven J. | Davies, Kevin P. | Doblin, Martina A.
Sixteen years (1997–2013) of physicochemical, nutrient and phytoplankton biomass (Chlorophyll-a (Chl-a)) data and a decade (2003-2013) of phytoplankton composition and abundance data were analyzed to assess how the algal community in a temperate southeastern Australian estuary has responded to decreased chronic point source nitrogen loading following effluent treatment upgrade works in 2003. Nitrogen concentrations were significantly lower (P<0.05) following enhanced effluent treatment and Chl-a levels decreased (P<0.05) during the warmer months. Temperature and nutrient concentrations significantly influenced temporal changes of Chl-a (explaining 55% of variability), while salinity, temperature, pH and nutrient concentrations influenced phytoplankton abundance and composition (25% explained). Harmful Algal Bloom (HAB) dynamics differed between sites likely influenced by physical attributes of the estuary. This study demonstrates that enhanced effluent treatment can significantly decrease chronic point source nitrogen loading and that Chl-a concentrations can be lowered during the warmer months when the risk of blooms and HABs is greatest.
Показать больше [+] Меньше [-]Relative influence of sediment variables on mangrove community assembly in Leizhou Peninsula, China Полный текст
2017
Liu, Jing | Ma, Keming | Qu, Laiye
Effective conservation of mangroves requires a complete understanding of vegetation structure and identification of the variables most important to their assembly. Using canonical correspondence analysis (CCA) combined with variation partition, we determined the independent and joint effects of sediment variables, including physicochemical characteristics and heavy metals, on mangrove community assemblies in the overstory and understory in Leizhou Peninsula, China. The results indicated that the contributions of sediment physicochemical variables to community assembly were greater than were those of heavy metals, particularly in overstory vegetation. However, the independent contributions of heavy metals were higher in understory mangrove vegetation than in the overstory. The TOC, TP, and salinity of the sediment, distance from the coastline, and concentration of As were limiting factors for mangrove assembly in overstory vegetation, while understory vegetation may be affected to a greater degree by the distance from the coastline, electrical conductivity, and concentration of As and Pb in the sediment.
Показать больше [+] Меньше [-]Kinetic and equilibrium based fractionation study of Pb in continental shelf sediment of India Полный текст
2017
Chakraborty, Sucharita | Chakraborty, Parthasarathi | Sarkar, Arindam | Nagender Nath, B.
Two independent analytical methods (kinetic and sequential extraction protocols) were used to understand the distribution, stability, and lability of Pb-sediment complexes in Indian continental shelf. The concentrations of sedimentary Pb varied from 12.0±0.6 to 30.4±0.1mg·kg−1 and 15.9±0.3 to 36.7±0.4mg·kg−1 in the western and eastern shelf of India respectively. The kinetic extraction study showed that higher proportion of labile Pb-complexes were present in the eastern shelf sediments (~24% of total Pb) than the western shelf sediments (~14% of total Pb). The sedimentary organic matter was found to regulate lability of sedimentary Pb complexes. The sequential extraction study suggested that Fe/Mn oxyhydroxide were the primary hosting phase for labile Pb complexes. This study showed that water soluble, exchangeable, carbonate/bicarbonate-Pb complexes in the sediments was labile. This study provides a better physicochemical description of stability or lability of Pb complexes in the coastal sediment of India.
Показать больше [+] Меньше [-]Light-stick: A problem of marine pollution in Brazil Полный текст
2017
Cesar-Ribeiro, Caio | Rosa, Helena Costi | Rocha, Daniele Oliveira | dos Reis, Camila Galli Baldini | Prado, Tabata Sarti | Muniz, Daniela Hernandes Coimbra | Carrasco, Raquel | Silva, Flávia Milão | Martinelli-Filho, José Eduardo | Palanch-Hans, Maria Fernanda
Light-sticks are used as bait in surface long-line fishing, to capture swordfish and other large pelagic predators. When discharged in the ocean, it may reach the beaches. The traditional Brazilian community of Costa dos Coqueiros, Bahia, use light-sticks as a medicine for rheumatism, vitiligo and mycoses. It may affect the marine life when its content leak in the open ocean. This work evaluated and identified the acute and chronic toxicity of the light-stick. A high acute toxicity was observed in the mobility/mortality of Artemia sp.; in the fertilization of sea urchin eggs, and a high chronic toxicity in the development of the pluteus larvae of the same sea urchin. The main compounds that probably caused toxicity were the volatiles such as the fluorescent PAH and oxidants such as the hydrogen peroxide. Its disposal in the open ocean is a potential threat for marine life.
Показать больше [+] Меньше [-]Indication of spatial variations in annual cycles of functional groups of planktonic ciliates to environmental change in marine ecosystems Полный текст
2017
Xu, Henglong | Jiang, Yong | Xu, Guangjian | Warren, Alan
The indication of spatial variations in annual cycles of functional groups of planktonic ciliates to environmental changes was studied in a bay, northern Yellow Sea. Samples were biweekly collected at five stations with different hydrographic conditions during a 1-year cycle. The second-stage-matrix-based multivariate approach was used to summarize the internal interactions of the ciliate functional groups among five stations during a 1-year period. The functional groups of the ciliates represented a clear spatial variation in annual cycle among five stations. Mantel analysis demonstrated that the spatial variation in annual cycles of the ciliate functional groups were significantly correlated with the changes nutrients (mainly soluble reactive phosphates and nitrates), alone or in combination with salinity among five stations. Based the results, it is suggested that the spatial variation in annual cycles of functional groups of planktonic ciliates may indicated the changes of hydrographic conditions.
Показать больше [+] Меньше [-]A coastal three-dimensional water quality model of nitrogen in Jiaozhou Bay linking field experiments with modelling Полный текст
2017
Lü, Dongliang | Li, Keqiang | Liang, Shengkang | Lin, Guohong | Wang, Xiulin
With anthropogenic changes, the structure and quantity of nitrogen nutrients have changed in coastal ocean, which has dramatically influenced the water quality. Water quality modeling can contribute to the necessary scientific grounding of coastal management. In this paper, some of the dynamic functions and parameters of nitrogen were calibrated based on coastal field experiments covering the dynamic nitrogen processes in Jiaozhou Bay (JZB), including phytoplankton growth, respiration, and mortality; particulate nitrogen degradation; and dissolved organic nitrogen remineralization. The results of the field experiments and box model simulations showed good agreement (RSD=20%±2% and SI=0.77±0.04). A three-dimensional water quality model of nitrogen (3DWQMN) in JZB was improved and the dynamic parameters were updated according to field experiments. The 3DWQMN was validated based on observed data from 2012 to 2013, with good agreement (RSD=27±4%, SI=0.68±0.06, and K=0.48±0.04), which testifies to the model's credibility.
Показать больше [+] Меньше [-]Tree bark as bioindicator of metal accumulation from road traffic and air quality map: A case study of Chiang Mai, Thailand Полный текст
2017
Janta, Rungruang | Chantara, Somporn
Trees have been recognized as air quality bioindicators, but they have still not been fully implemented in tropical areas. In this study, bark of Cassia fistula was used to inspect accumulation of air pollutants (metals) emitted from road traffic in the city of Chiang Mai, Thailand. The mean concentrations of metal accumulated on tree bark (ng/cm2) in descending order were Al (1,238) > Fe (707) > Zn (162) » Cu (21.1) » Pb (6.37) > Cr (2.14). Correlations of Enrichment Factors: EFTS (metal concentrations on bark compared to those in soil) among metals were relatively strong (r > 0.6) meaning that they were probably generated from the same sources. Moreover, principal component analysis and cluster analysis of EFTS values revealed that Al and Fe were generated from soil resuspension that were attached on vehicle wheels and on road surfaces, while Cr, Cu, Pb and Zn resulted directly from vehicle emissions. The results lead to the conclusion that tree bark is a good bioindicator for air pollutant accumulation in this area. In addition, pollution indices, including total geoaccumulation index (IGEO-tot) and pollution load index (PLI), were applied to generate air quality maps of the city. The maps illustrated that the most polluted areas in the city are the areas that have high traffic volume and building density, in which hospitals and schools are located. The degree of pollution presented in each area was influenced by both road traffic volume and density of buildings in relation to air ventilation capacity.
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