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Spatio-temporal variation of suspended and sedimentary organic matter quality in the Bay of Marseilles (NW Mediterranean) assessed by biochemical and isotopic analyses Full text
2012
Cresson, Pierre | Ruitton, Sandrine | Fontaine, Marie-France | Harmelin-Vivien, M. L. (Mireille L.)
Isotopic and biochemical features of suspended particulate organic matter (POM) in the water column and of sedimentary organic matter (SOM) were investigated seasonally in the Bay of Marseilles. Biochemical compounds (carbohydrates, lipids and proteins) were consistently more concentrated in POM than in SOM, with SOM mainly composed of insoluble carbohydrates. POM displayed lower δ¹³C and higher δ¹⁵N values than SOM. Phytoplanktonic production represented the major contributor of POM year-round with spatial and seasonal variations. Climatic parameters and wind-induced currents created differences in POM contributions, with more important inputs of terrestrial OM at one sampling site. Spatial and seasonal variations were lower for SOM. The composition of this pool appeared to be linked with the permanent inputs of phytoplankton and Posidonia oceanica detritus. The combined use of biochemical and isotopic analyses was a useful tool to characterize OM pools and would help understanding the trophic functioning of this coastal environment.
Show more [+] Less [-]Physical and chemical control of the phytoplankton of Ahe lagoon, French Polynesia Full text
2012
The environmental characteristics of Ahe deep lagoon (Tuamotu Archipelago, French Polynesia) were studied over 3years with the aim of explaining the spatial and temporal variability of the natural food available for pearl oysters with a special focus on phytoplankton biomass and global photosynthesis/respiration ratio of the lagoon. Chlorophyll averaged 0.34±0.01μgL⁻¹ and our findings did not confirm increased phytoplankton biomass in deep lagoonal waters. Phytoplankton production appears to be limited firstly by nitrogen and respiratory processes overpass photosynthetic processes at least in the north-eastern edge of the atoll. Grazing by pearl oysters in culture seems to decrease the POC concentration but not the phytoplankton biomass. Oysters graze mainly on non chlorophyllian particles.
Show more [+] Less [-]Is monitoring for mass spawning events in coral assemblages in north Western Australia likely to detect spawning? Full text
2012
In north Western Australia coral reefs occur near ports being developed to support rapidly expanding resources industries. Dredging for port construction is required to stop during significant mass coral spawning events due to the sensitivity of gametes and larvae to increases in turbidity and sedimentation, but the timing of this event can vary between seasons and years so monitoring is used to predict when spawning is imminent. Here we used simulations to mimick sampling strategies currently used in some coral spawning monitoring programmes in Western Australia, to assess the ability of these programmes to be able to predict multi-specific mass spawning events. We found that current practices may sometimes miss spawning events that are likely to be considered large enough to warrant stopping dredging. Generally, sampling fewer individuals in a large number of species is a better way of monitoring for upcoming spawning than sampling a large number of individuals in a small number of species, but overall, greater sampling efforts than are currently undertaken are needed if moderately sized events are to be detected reliably. Determining exactly how many samples are needed, however, depends on having a clearer definition of what actually constitutes a “significant mass spawning” event in the first place.
Show more [+] Less [-]Persistent organic pollutants and stable isotopes in pinnipeds from King George Island, Antarctica Full text
2012
Cipro, Caio V.Z. | Bustamante, Paco | Taniguchi, Satie | Montone, Rosalinda Carmela
In the present work, fat, skin, liver and muscle samples from Leptonychotes weddellii (Weddell seal, n=2 individuals), Lobodon carcinophagus (crabeater seal, n=2), Arctocephalus gazella (Antarctic fur seal, n=3) and Mirounga leonina (southern elephant seal, n=1) were collected from King George Island, Antarctica, and analysed for POPs (PCBs, organochlorine pesticides and PBDEs) and stable isotopes (δ¹³C and δ¹⁵N in all tissues but fat). PBDEs could be found in only one sample (L. weddellii fat). Generally, PCBs (from 74 to 523ngg⁻¹lw), DDTs (from 14 to 168ngg⁻¹lw) and chlordanes (from 9 to 78ngg⁻¹lw) were the prevailing compounds. Results showed a clear stratification in accordance with ecological data. Nonetheless, stable isotope analyses provide a deeper insight into fluctuations due to migrations and nutritional stress. Correlation between δ¹⁵N and pollutants suggests, to some degree, a considerable ability to metabolize and/or excrete the majority of them.
Show more [+] Less [-]At-sea detection of marine debris: Overview of technologies, processes, issues, and options Full text
2012
Mace, Thomas H.
At-sea detection of marine debris presents a difficult problem, as the debris items are often relatively small and partially submerged. However, they may accumulate in water parcel boundaries or eddy lines. The application of models, satellite radar and multispectral data, and airborne remote sensing (particularly radar) to focus the search on eddies and convergence zones in the open ocean appear to be a productive avenue of investigation. A multistage modeling and remote sensing approach is proposed for the identification of areas of the open ocean where debris items are more likely to congregate. A path forward may best be achieved through the refinement of the Ghost Net procedures with the addition of a final search stage using airborne radar from an UAS simulator aircraft to detect zones of potential accumulation for direct search. Sampling strategies, direct versus indirect measurements, remote sensing resolution, sensor/platform considerations, and future state are addressed.
Show more [+] Less [-]Rapid assessment of the bryozoan, Zoobotryon verticillatum (Delle Chiaje, 1822) in marinas, Canary Islands Full text
2012
Minchin, Dan
A rapid assessment, using the abundance and distribution range method, was used to evaluate the status of a large branching bryozoan, Zoobotryon verticillatum attached to the immersed part of marina pontoons in the Canary Islands. Colonies were also found attached to the hulls of leisure craft berthed alongside pontoons at three marinas in Lanzarote during 2012. Low levels of abundance and distribution of the bryozoan occurred in marinas with a freshwater influence whereas in a sheltered marina lacking direct freshwater inputs colonies occurred at ∼2 per metre of combined pontoon length. While the occurrence of this bryozoan is recent it may be expected to occur elsewhere in Macaronesia most probably spread by leisure craft.
Show more [+] Less [-]Investigating links between polychlorinated biphenyl (PCB) exposure and thymic involution and thymic cysts in harbour porpoises (Phocoena phocoena) Full text
2012
Yap, Xinli | Deaville, Rob | Perkins, Matthew W. | Penrose, Rod | Law, Robin J. | Jepson, Paul D.
The associations between polychlorinated biphenyls (PCBs) exposure and involution of lymphoid tissue and development of epithelial-lined cysts in the thymus of UK-stranded harbour porpoises (Phocoena phocoena) (n=170) were tested. Percentage of thymic lymphoid tissue (%TLT) was histologically quantified. Multiple regression analyses (n=169) demonstrated significant positive correlation between %TLT and nutritional status (p<0.001) and significant negative association between %TLT and onset of sexual maturity (p<0.001). However, in a subgroup of porpoises with total PCB levels above a proposed threshold of toxicity (>17mg/kg lipid weight) (n=109), the negative association between %TLT (as dependent variable) and summed blubber concentrations of 25 chlorobiphenyl congeners (∑25CBs) remained significant (p<0.01) along with nutritional status (p<0.001) and onset of sexual maturity (p<0.001). These results suggest PCB-induced immuno suppression may be occurring in harbour porpoises in UK waters but only at concentrations that exceed proposed toxicity thresholds for marine mammals. In contrast, development of thymic cysts appears predominantly age-related.
Show more [+] Less [-]Evaluation of diffusive gradients in thin-films (DGTs) as a monitoring tool for the assessment of the chemical status of transitional waters within the Water Framework Directive Full text
2012
Montero, N. | Belzunce-Segarra, M.J. | Gonzalez, J.-L. | Larreta, J. | Franco, J.
In this contribution, the potential use of diffusive gradients in thin-films (DGTs) for the chemical evaluation of transitional water bodies within the Water Framework Directive (WFD) has been studied. The water metal concentration has been evaluated in 13 estuaries in the southeastern Bay of Biscay. The DGTs were deployed in triplicate at two stations in each estuary, delimiting the tidal influence. The DGT results were in the ranges of 2–1570ngL⁻¹ for cadmium, 66–515ngL⁻¹ for copper, 30–3650ngL⁻¹ for nickel and 0.8–95.5μgL⁻¹ for zinc. The DGTs provided reliable average labile metal concentrations in highly dynamic systems that were comparable with DGT measurements in coastal and estuarine waters worldwide. In addition, it was possible to discriminate those estuaries more susceptible to environmental impacts, being consistent with the historical contamination of each estuary. Based on the obtained results, a sampling strategy for the monitoring of transitional water bodies using DGTs is proposed.
Show more [+] Less [-]Chemical composition and acute toxicity in the water after in situ burning – A laboratory experiment Full text
2012
Faksness, Liv-Guri | Hansen, Bjørn Henrik | Altin, Dag | Brandvik, Per Johan
The chemical composition and toxicity of a water soluble fraction (WSF) of oil versus the underlying water after in situ burning (ISB), has been studied in a laboratory experiment. A system for allowing water sampling after ISB was developed. Seawater samples and oil were collected prior to and immediately after ISB, and chemical analysis was conducted. The chemical characterization of the water showed that the disappearance of water soluble oil components during ISB was insignificant. Acute toxicity tests with the marine copepod Calanus finmarchicus and Microtox® bioassay was performed to establish LC₅₀/EC₅₀ values of the water. The results were compared with regular WAF systems with unburned weathered oil, and indicated no increase in toxicity in the underlying water after ISB.
Show more [+] Less [-]Distribution and seasonal variation in the partial pressure of CO₂ during autumn and winter in Jiaozhou Bay, a region of high urbanization Full text
2012
Zhang, Longjun | Siuvai, Ming | Liu, Qizhen
We investigated the partial pressure of carbon dioxide (pCO₂) in Jiaozhou Bay (JZB), which is surrounded by the economically developed city of Qingdao, during two cruises undertaken in November, 2007 (autumn) and February, 2008 (winter). Results indicated that sea surface pCO₂ in autumn varied between 315 and 720μatm, with an average level of 418μatm. In winter the sea surface pCO₂ ranged from 145 to 315μatm with an average of 249μatm, which is below atmospheric pCO₂. Despite seasonal temperature variation between autumn and winter, it was noted that biological process (production and respiration) were responsible for both spatial and seasonal variation during these seasons. We found that Jiaozhou Bay served as a net atmospheric CO₂ source in autumn (November) (2.87mmolm⁻²d⁻¹), while in winter (February) it served as a net sink (−16.22mmolm⁻²d⁻¹).
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