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17-year change in species composition of mixed seagrass beds around Santiago Island, Bolinao, the northwestern Philippines
2014
Tanaka, Yoshiyuki | Go, Gay Amabelle | Watanabe, Atsushi | Miyajima, Toshihiro | Nakaoka, Masahiro | Uy, Wilfredo H. | Nadaoka, Kazuo | Watanabe, Shuichi | Fortes, Miguel D.
Effects of fish culture can alter the adjacent ecosystems. This study compared seagrass species compositions in 2012 with those in 1995, when fish culture was less intensive compared to 2012 in the region. Observations were conducted at the same four sites around Santiago Island, Bolinao: (1) Silaqui Island, (2) Binaballian Loob, (3) Pislatan and (4) Santa Barbara, and by using the same methods as those of Bach et al. (1998). These sites were originally selected along a siltation gradient, ranging from Site 1, the most pristine, to Site 4, a heavily silted site. By 2012, fish culture had expanded around Sites 2, 3 and 4, where chlorophyll a (Chl a) was greater in 2012 than in 1995 by one order of magnitude. Enhalus acoroides and Cymodocea serrulata, which were recorded in 1995, were no longer present at Site 4, where both siltation and nutrient load are heavy.
Afficher plus [+] Moins [-]Interactions between finfish aquaculture and lobster catches in a sheltered bay
2014
Loucks, Ronald H. | Smith, Ruth E. | Fisher, E Brian
Interactions between open-net pen finfish aquaculture and lobster catches in a sheltered bay in Nova Scotia, Canada, were investigated using fishermen’s participatory research in annual lobster trap surveys over seven years.Fishermen recorded lobster catches during the last two weeks of May from 2007 to 2013. Catches for each trap haul were recorded separately for ovigerous and market-sized lobsters. Catch trends within the bay were compared to regional trends. Results of correlation analyses indicated that ovigerous catch trends were strongly affected by the fish farm’s feeding/fallow periods. There was no significant correlation between trends for bay and LFA lobster landings.Patterns of lobster catch per unit effort extending over considerable distance in Port Mouton Bay appear to be influenced by proximity to the fish farm regardless of year-to-year variation in water temperatures and weather conditions. Odours and habitat changes surrounding open-net pen finfish operations are potential factors affecting lobster displacement.
Afficher plus [+] Moins [-]Analysis of daily average PM10 predictions by generalized linear models in Brno, Czech Republic
2014
Huebnerova, Zuzana | Michalek, Jaroslav
Ambient air quality assessment and management plays an important role in the current European Union policy. Among others, air pollution by PM10 is being monitored. A previous analysis of PM10 aimed at identifying factors affecting air pollution in stations in the City of Brno using available observed meteorological variables. However, the studied model cannot be used for predicting the level of PM10 pollution because the included meteorological variables are not available exactly at the time when the prediction is requested. In that case, we should base the predictions on available predicted variables, namely on temperature, wind direction, wind speed, and cloud cover. A comparison of obtained predictions with the observed values of PM10 during a testing period allows us to evaluate a loss of prediction quality when the predicted covariates are used instead of the observed ones. The presented analysis based on test of symmetry and test of homogeneity of the marginal distribution of two–way contingency tables shows that the loss of prediction quality by employing the predicted meteorological variables is non–significant in the studied case. This observation suggests that the model with predicted meteorological variables can be employed in environmental management processes.
Afficher plus [+] Moins [-]Downscaling of monthly PM10 indices at different sites in Bavaria (Germany) based on circulation type classifications
2014
Beck, Christoph | Weitnauer, Claudia | Jacobeit, Jucundus
Atmospheric circulation affects local concentrations of particulate matter with an aerodynamic diameter of 10μm or less (PM10) in different ways: Via the determination of local meteorological conditions favoring or suppressing the formation and the accumulation of PM10, and through its control on short–and long–range transport of particles and precursors. The quantitative assessment of the connections between the large–scale atmospheric circulation and local PM10 is relevant not only for the understanding of observed variations in PM10 concentrations. It is even more important for estimating the potential effects of projected future changes in large–scale atmospheric circulation on PM10. In this contribution, daily atmospheric circulation types (CTs), resulting from variants of three different classification methods, and their monthly occurrence frequencies have been utilized in three different downscaling approaches for estimating monthly indices of PM10 for the period 1980–2010 at 16 locations in Bavaria (Germany). All variants of approaches have been evaluated via a leave–one–out cross validation procedure in order to attain reliable performance ratings to detect the most suitable downscaling approaches. Results indicate that the highest performance of downscaling approaches is achieved in winter when the best performing models explain on average roughly 50% of the observed PM10 variance. From this it can be concluded that classification–based approaches are generally suitable for the downscaling of PM10, particularly during winter when PM10 concentrations in Bavaria reach maximum values. As preferable settings of the downscaling approaches, the usage of rather small spatial domains and a relatively high number of classes for circulation type classification and furthermore the utilization of multiple linear regression analyses or random forest analyses for relating CTs to PM10 have been ascertained. These findings provide the basis for further enhancements of the classification–based downscaling of monthly PM10 that will be realized in successive investigations.
Afficher plus [+] Moins [-]Acetylcholinesterase activity in the host–parasite system of the cod Gadus morhua and acanthocephalan Echinorhynchus gadi from the southern Baltic Sea
2014
Podolska, M. | Nadolna, K. | Szostakowska, B.
Acetylcholinesterase (AChE) activity measurement is widely used as a specific biomarker of neurotoxic effects. The aim of this study was to evaluate AChE activity in a host fish (the cod) and its acanthocephalan parasite Echinorhynchus gadi from the southern Baltic. AChE activity in hosts and parasites was inversely related: the highest cod AChE activity corresponded to the lowest E. gadi enzymatic activity and vice versa (“mirror effect”). This is the first report on the simultaneous application of this biomarker in cod and its acanthocephalan parasites. Results obtained for the host–parasite system are complementary and provide comprehensive information about the response of this biomarker. Analysis of the system allows for detection of a greater number of factors influencing AChE activity in the marine environment than separate analysis of the host and parasites. Thus, AChE activity measurement in a host–parasite system may be considered to be a promising tool for biomonitoring.
Afficher plus [+] Moins [-]Physiological responses of the seagrass Thalassia hemprichii (Ehrenb.) Aschers as indicators of nutrient loading
2014
Zhang, Jingping | Huang, Xiaoping | Jiang, Zhijian
To select appropriate bioindicators for the evaluation of the influence of nutrients from human activities in a Thalassia hemprichii meadow, environmental variables and plant performance parameters were measured in Xincun Bay, Hainan Island, South China. Nutrient concentrations in the bay decreased along a gradient from west to southeast. Moreover, the nutrients decreased with an increase in the distance from the shore on the southern side of the bay. Among the candidate indicators, the P content of the tissues closely mirrored the two nutrient loading gradients. The epiphytic algae biomass and the N content in the tissues mirrored one of the two nutrient loading trends. The leaf length, however, exhibited a significant negative correlation with the nutrient gradients. We propose that changes in the P content of T. hemprichii, followed by epiphytic algae biomass and N content of the tissues, may be the useful indicators of nutrient loading to coastal ecosystems.
Afficher plus [+] Moins [-]Levels of endocrine disrupting compounds in South China Sea
2014
Zhang, Li-Peng | Wang, Xin-Hong | Ya, Miao-Lei | Wu, Yu-Ling | Li, Yong-Yu | Zhang, Zu-lin
The occurrence of estrogens in the aquatic environment has become a major concern worldwide because of their strong endocrine disrupting potency. In this study, concentrations of four estrogenic compounds, estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), estriol (E3) were determined with liquid chromatography-tandem mass spectrometry analyses in surface water from South China Sea, and distributions and potential risks of their estrogenic activity were assessed. The estrogenic compounds E1, E2 and E3 were detected in most of the samples, with their concentrations up to 11.16, 3.71 and 21.63ngL−1. However, EE2 was only detected in 3 samples. Causality analysis, EEQ values from chemical analysis identified E2 as the main responsible compounds. Based on the EEQ values in the surface water, high estrogenic risks were in the coastal water, and low estrogenic risks in the open sea.
Afficher plus [+] Moins [-]Predictable pollution: An assessment of weather balloons and associated impacts on the marine environment – An example for the Great Barrier Reef, Australia
2014
O’Shea, Owen R. | Hamann, Mark | Smith, Walter | Taylor, Heidi
Efforts to curb pollution in the marine environment are covered by national and international legislation, yet weather balloons are released into the environment with no salvage agenda. Here, we assess impacts associated with weather balloons in the Great Barrier Reef World Heritage Area (GBRWHA). We use modeling to assess the probability of ocean endpoints for released weather balloons and predict pathways post-release. In addition, we use 21months of data from beach cleanup events to validate our results and assess the abundance and frequency of weather balloon fragments in the GBRWHA. We found between 65% and 70% of balloons land in the ocean and ocean currents largely determine final endpoints. Beach cleanup data revealed 2460 weather balloon fragments were recovered from 24 sites within the GBRWHA. This is the first attempt to quantify this problem and these data will add support to a much-needed mitigation strategy for weather balloon waste.
Afficher plus [+] Moins [-]Occurrence and fate of triclosan and triclocarban in a subtropical river and its estuary
2014
Lv, Min | Sun, Qian | Xu, Haili | Lin, Lifeng | Chen, Meng | Yu, Chang-Ping
The occurrence of triclosan (TCS) and triclocarban (TCC) in a subtropical river (Jiulong River) and its estuary was investigated for two years. TCS and TCC were ubiquitously detected in the Jiulong River and its estuary. The levels of TCS and TCC ranged from less than the method detection limit to 64ng/L and from 0.05 to 14.1ng/L in the river, respectively. The levels of TCS and TCC in the estuary ranged from 2.56 to 27.25ng/L and 0.38 to 5.76ng/L, respectively. Temporal and spatial variations of TCS and TCC in the Jiulong River and its estuary were observed during the investigation. The weather conditions did not show significant correlations with TCS and TCC, whereas several water quality parameters showed high correlations with TCS and TCC. The microcosm studies showed that both direct photolysis and biodegradation contributed to TCS removal, whereas indirect photolysis was important for TCC removal in the surface water.
Afficher plus [+] Moins [-]Bioaccumulation of heavy metals in commercially important marine fishes from Mumbai Harbor, India
2014
Velusamy, A. | Satheesh Kumar, P. | Ram, Anirudh | Chinnadurai, S.
Seventeen commercially important marine fish species were caught in Mumbai Harbor using a trawl net and evaluated using Atomic Absorption Spectroscopy and ICP-OES. It was found that certain species of fish contained lower levels of all metals tested. J. elongatus and C. dussumieri had the highest levels of all 8 metals tested. The heavy metal concentrations were significantly varied within and between the studied fishes (p<0.05). However, a significant correlation among heavy metals was observed. This investigation indicated that various levels of heavy metals exist in the fish species sampled, but those concentrations are within the maximum residual levels recommended by the European Union and FAO/WHO. Therefore, fish caught in Mumbai Harbor can be considered safe for human consumption.
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