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Habitat association of larval fish assemblages in the northern Persian Gulf Full text
2015
Rabbaniha, Mahnaz | Molinero, Juan Carlos | López-López, Lucia | Javidpour, Jamileh | Primo, Ana Ligia | Owfi, Feryadoon | Sommer, Ulrich
We examined the habitat use of fish larvae in the northern Persian Gulf from July 2006 to June 2007. Correspondence Analysis showed significant differences between hydrological seasons in habitat use and structure of larval fish assemblages, while no differences were found regarding abundance among coralline and non-coralline habitats. The observed configuration resulted in part from seasonal reproductive patterns of dominant fish influencing the ratio pelagic:demersal spawned larvae. The ratio increased along with temperature and chlorophyll-a concentration, which likely fostered the reproduction of pelagic spawner fish. The close covariation with temperature throughout hydrographic seasons suggests a leading role of temperature in the seasonal structure of larvae assemblages. Our results provide new insights on fish larval ecology in a traditionally sub-sampled and highly exposed zone to anthropogenic pollution, the northern Persian Gulf, and highlight the potential role of Khark and Kharko Islands in conservation and fishery management in the area.
Show more [+] Less [-]A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement Full text
2015
Lenz, Robin | Enders, Kristina | Stedmon, Colin A. | Mackenzie, David M.A. | Nielsen, Torkel Gissel
Identification and characterisation of microplastic (MP) is a necessary step to evaluate their concentrations, chemical composition and interactions with biota. MP ≥10μm diameter filtered from below the sea surface in the European and subtropical North Atlantic were simultaneously identified by visual microscopy and Raman micro-spectroscopy. Visually identified particles below 100μm had a significantly lower percentage confirmed by Raman than larger ones indicating that visual identification alone is inappropriate for studies on small microplastics. Sixty-eight percent of visually counted MP (n=1279) were spectroscopically confirmed being plastic. The percentage varied with type, colour and size of the MP. Fibres had a higher success rate (75%) than particles (64%). We tested Raman micro-spectroscopy applicability for MP identification with respect to varying chemical composition (additives), degradation state and organic matter coating. Partially UV-degraded post-consumer plastics provided identifiable Raman spectra for polymers most common among marine MP, i.e. polyethylene and polypropylene.
Show more [+] Less [-]Persistent organic pesticide residues in sediments of Vasai Creek near Mumbai: Assessment of sources and potential ecological risk Full text
2015
Singare, Pravin U.
Thirteen persistent organic pesticides were investigated in the sediments of Vasai Creek near Mumbai to evaluate their pollution levels and potential risks. It was observed that ΣOCPs level was in the range of 597–1538ng/g dw, with an average value of 1115.25ng/g dw. The level of ΣOPPs was in the range of 492–1034ng/g dw, with an average value of 798.15ng/g dw. The values o,p′-DDT/p,p′-DDT ratio gives an indication of use of technical DDT as the prime source of DDT, while the α/γ-BHC ratio indicate that BHCs in study area might have been received from fresh lindane. The results of an ecological risk assessment showed that sediment bound organic pesticides are of more ecotoxicological concern as they might create adverse ecological risk to the marine breeding habitats. These pesticides residues may get remobilize and released to overlying waters creating adverse effects on terrestrial and aquatic organisms.
Show more [+] Less [-]Oil spill experiment using airborne DLR ESAR off the coast of Diu, India Full text
2015
Sasamal, S.K. | Rao, M.V.
Oil spill experiment results in the coastal waters of Diu, India, with an airborne DLR ESAR sensor are discussed with reference to the SAR frequency, polarization and viewing angle. The SAR data acquired in the quad polarization of the L band and dual polarization of the C band over two spills are studied. A higher oil and water contrast is observed in the L-VV polarization than in the C-HH mode. Oil spill discrimination is possible over a wider view angle of the airborne SAR sensor data in L band than in C band. This study has also analyzed the spread and drift of oil in coastal waters.
Show more [+] Less [-]Passive sampling reversed: Coupling passive field sampling with passive lab dosing to assess the ecotoxicity of mixtures present in the marine environment Full text
2015
Claessens, Michiel | Monteyne, Els | Wille, Klaas | Vanhaecke, Lynn | Roose, Patrick | Janssen, Colin R.
This study presents a new approach in aquatic toxicity testing combining passive sampling and passive dosing. Polydimethylsiloxane sheets were used to sample contaminant mixtures in the marine environment. These sheets were subsequently transferred to ecotoxicological test medium in which the sampled contaminant mixtures were released through passive dosing. 4 out of 17 of these mixtures caused severe effects in a growth inhibition assay with a marine diatom. These effects could not be explained by the presence of compounds detected in the sampling area and were most likely attributable to unmeasured compounds absorbed to the passive samplers during field deployment.The findings of this study indicate that linking passive sampling in the field to passive dosing in laboratory ecotoxicity tests provides a practical and complimentary approach for assessing the toxicity of hydrophobic contaminant mixtures that mimics realistic environmental exposures. Limitations and opportunities for future improvements are presented.
Show more [+] Less [-]Number of bacteria decomposing organic phosphorus compounds and phosphatase activity in the sand of two marine beaches differing in the level of anthropopressure Full text
2015
Mudryk, Z.J. | Perliński, P. | Antonowicz, J. | Robak, D.
Number of heterotrophic bacteria ability to decompose organic phosphorus compounds and the level of phosphatase activity in the sand of two marine beaches (southern coast of the Baltic Sea) differing in the level of anthropopressure were studied. The study showed that the number of bacteria and level phosphatase activity were higher in the sand of the beach subjected to stronger anthropopressure. In both studied beaches bacteria hydrolysing DNA were the most numerous (92.7–302.8CFU·g−1 d.w.). The least numerous were phytin (26.0·103CFU·g−1 d.w.) and phenolphthalein diphosphate (11.1·103CFU·g−1 d.w.) decomposing bacteria. Number of bacteria able to attack tested organic phosphorus compounds were the most numerous in dry zones (10.77–739.92CFU·g−1 d.w.) then wet zones (3.34–218.15CFU·g−1 d.w.). In both studied beaches bacteria hydrolysing organic phosphorus compounds and phosphatase activity generally were more numerous in surface sand layer. Seasonal variation in the occurrence of bacteria in both studied beaches was observed.
Show more [+] Less [-]Efficacy of single and multi-metric fish-based indices in tracking anthropogenic pressures in estuaries: An 8-year case study Full text
2015
Martinho, Filipe | Nyitrai, Daniel | Crespo, Daniel | Pardal, Miguel A.
Facing a generalized increase in water degradation, several programmes have been implemented for protecting and enhancing the water quality and associated wildlife, which rely on ecological indicators to assess the degree of deviation from a pristine state. Here, single (species number, Shannon–Wiener H’, Pielou J’) and multi-metric (Estuarine Fish Assessment Index, EFAI) community-based ecological quality measures were evaluated in a temperate estuary over an 8-year period (2005–2012), and established their relationships with an anthropogenic pressure index (API). Single metric indices were highly variable and neither concordant amongst themselves nor with the EFAI. The EFAI was the only index significantly correlated with the API, indicating that higher ecological quality was associated with lower anthropogenic pressure. Pressure scenarios were related with specific fish community composition, as a result of distinct food web complexity and nursery functioning of the estuary. Results were discussed in the scope of the implementation of water protection programmes.
Show more [+] Less [-]Preliminary assessment of contaminants in the sediment and organisms of the Swartkops Estuary, South Africa Full text
2015
Nel, L. | Strydom, N.A. | Bouwman, H.
Preliminary assessment of contaminants in the sediment and organisms of the Swartkops Estuary, South Africa Full text
2015
Nel, L. | Strydom, N.A. | Bouwman, H.
Urban estuaries are susceptible to metal and organic pollution, yet most remain understudied in South Africa with respect to the presence, concentrations and distribution of contaminants. Metal and organic chemical concentrations were assessed in sediment and organisms from different trophic levels in the lower reaches of the Swartkops Estuary. Species sampled included Upogebia africana (Malacostraca: Upogebiidae), Gilchristella aestuaria (Clupeidae), Psammogobius knysnaensis (Gobiidae), Mugil cephalus (Mugilidae), Lichia amia (Carangidae), Argyrosomus japonicus (Sciaenidae), Pomadasys commersonnii (Haemulidae) and Larus dominicanus (Avis: Laridae). This study is one of the most comprehensive studies to date assessing pollution levels in a food web in estuaries in South Africa. Due to biomagnification, higher concentrations of Arsenic, Lead, Mercury and Cadmium were found in the juveniles stages of popular angling fishes. High concentrations of Cadmium and Arsenic were recorded in the liver of L. amia, A. japonicus and P. commersonnii which exceed international quality food guidelines. Eggs from the gull, L. dominicanus, showed detectable concentrations of PCBs.
Show more [+] Less [-]Preliminary assessment of contaminants in the sediment and organisms of the Swartkops Estuary, South Africa
Methods for Treatment of Animal Manures to Reduce Nutrient Pollution Prior to Soil Application Full text
2015
Szogi, Ariel A. | Vanotti, Matias B. | Ro, Kyoung S.
For centuries, animal manures have been a traditional source of nutrients in agriculture. However, disposal of animal manure has become an environmental problem in recent times as a result of increased concentration of animal production within small geographic areas. Manure nitrogen (N) and phosphorus (P) applied in excess of the assimilative soil capacity have the potential to reach and pollute water resources through soil leaching or runoff. Yet, conservation and recovery of N and P is a concern in modern agriculture because of the high cost and future limited supply of commercial fertilizers, particularly P which is extracted from mineral deposits. Therefore, N and P recovery methods are necessary to reduce their excess prior to manure soil application and recover them as valuable products. This article is a review of existing technologies for animal waste treatment and additional new methods for recycling manure N and P and possible recovery as valuable byproducts.
Show more [+] Less [-]Concentrations of viable oil-degrading microorganisms are increased in feces from Calanus finmarchicus feeding in petroleum oil dispersions Full text
2015
Størdal, Ingvild Fladvad | Olsen, Anders Johny | Jenssen, Bjørn Munro | Netzer, Roman | Hansen, Bjørn Henrik | Altin, Dag | Brakstad, Odd Gunnar
Zooplankton are suggested to be biotic contributors to the transport and weathering of oil in marine environments due to their ingestion of oil. In the present experiment, feeding activity and microbial communities in feces from Calanus finmarchicus feeding in oil dispersions were characterized. Feeding activity was significantly reduced in oil dispersions. The microbial communities in clean and oil-containing copepod feces were dominated by Rhodobacteraceae family bacteria (Lesingera, Phaeobacter, Rugeria, and Sulfitobacter), which were suggested to be indigenous to copepod feces. The results also indicated that these bacteria were metabolizing oil compounds, as a significant increase in the concentrations of viable oil degrading microorganisms was observed in oil-containing feces. This study shows that bacteria in feces from copepods feeding in dilute oil dispersions have capacity for degradation of oil. Zooplankton may therefore contribute to weathering of oil by excreting feces with microbial communities already adapted to degradation of oil.
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