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Uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida Full text
2014
The uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida was investigated in both laboratory and field experiments. Under laboratory conditions, total PCBs (tPCBs) uptake was significantly greater in live vs dead plants. The concentration of tPCB taken up in live plants was greatest in the first 24h (1580μgkg−1 dry weight), and then increased at a lower rate from day 2 to 14. Dead plants had a significantly lower tPCB concentration after 24h (609μgkg−1 dry weight) and lower uptake rate through day 14. Lesser chlorinated PCB congeners (below 123) made up the majority of PCBs taken up. Congener composition in both laboratory and field experiments was correlated to congener logKow value and sediment content. Field experiments showed that Ulva plants could concentrate PCBs to 3.9mgkg−1 in 24h. Thus, U. rigida is capable of removing PCBs in sediments at a rapid rate.
Show more [+] Less [-]Ethylene vinyl acetate polymer as a tool for passive sampling monitoring of hydrophobic chemicals in the salmon farm industry Full text
2014
Current monitoring programs are focused on hydrophobic chemicals detection in aquatic systems, which require the collection of high volumes of water samples at a given time. The present study documents the preliminary use of the polymer ethylene vinyl acetate (EVA) as a passive sampler for the detection of a hydrophobic chemical used by salmon industries such as cypermethrin. Initially, an experimental calibration in laboratory was performed to determine the cypermethrin equilibrium between sampler and aquatic medium, which was reached after seven days of exposure. A logarithm of partitioning coefficient EVA–water (logKEVA–W) of 5.6 was reported. Field deployment of EVA samplers demonstrated average concentrations of cypermethrin in water to be 2.07±0.7ngL−1 close to salmon cages, while near-shore was 4.39±0.8ngL−1. This was a first approach for assessing EVA samplers design as a tool of monitoring in water for areas with salmon farming activity.
Show more [+] Less [-]Heavy metal concentrations in sediment cores from the northern Baltic Sea: Declines over the last two decades Full text
2014
Vallius, Henry
The Baltic Sea has received considerable loads of pollutants due to industrialization in Eastern Europe. Concern for the Baltic’s ecological health eventually led to legislation and voluntary measures to limit pollution during the last decades of the 20th century. Heavy metal concentrations in open sea surface sediments reflected these steps to limit contaminant loads almost immediately, suggesting the possibility that the trend would continue in the ensuing years. Recent seafloor samples reveal that the declines have persisted over the past two decades. Currently, almost all heavy metal species have declined in surface sediments to levels approaching the safe limits for humans and the environment. Cadmium and mercury however remain at relatively high concentrations in many areas. Arsenic concentrations, which occur at safe levels within the Gulf of Finland persist at unacceptably high levels in surface sediments of the Bothnian Bay, and thus pose a potential threat to marine life in the area.
Show more [+] Less [-]Community change and evidence for variable warm-water temperature adaptation of corals in Northern Male Atoll, Maldives Full text
2014
McClanahan, T.R. | Muthiga, N.A.
This study provides a descriptive analysis of the North Male, Maldives seven years after the 1998 bleaching disturbance to determine the state of the coral community composition, the recruitment community, evidence for recovery, and adaptation to thermal stress. Overall, hard coral cover recovered at a rate commonly reported in the literature but with high spatial variability and shifts in taxonomic composition. Massive Porites, Pavona, Synarea, and Goniopora were unusually common in both the recruit and adult communities. Coral recruitment was low and some coral taxa, namely Tubipora, Seriatopora, and Stylophora, were rarer than expected. A study of the bleaching response to a thermal anomaly in 2005 indicated that some taxa, including Leptoria, Platygyra, Favites, Fungia, Hydnophora, and Galaxea astreata, bleached as predicted while others, including Acropora, Pocillopora, branching Porites, Montipora, Stylophora, and Alveopora, bleached less than predicted. This indicates variable-adaptation potentials among the taxa and considerable potential for ecological reorganization of the coral community.
Show more [+] Less [-]Identification of the toxic constituents of sediments in a Brazilian subtropical estuary Full text
2014
Poleza, Fernanda | Souza, Rafael C. | Resgalla, Charrid
Phase 1 of the TIE method was applied to samples of elutriates from sediments of the Itajaí-Açu estuary and adjacent coastal region in southern Brazil. Embryo-larval toxicity assays were used with the sea urchin Arbacia lixula in samples of raw elutriate, and treated with Ulva fasciata, EDTA and sodium thiosulfate. Inside the estuary, ammonia was responsible for more than 40% of the toxicity in both the dredged and undredged regions. A toxicity gradient was observed, between the estuary and the coastal region, with an increase in the importance of metals for the latter. Temporally, there is strong evidence of the influence of dredging and disposal of sediments in the contamination of the coastal dumping site. The results indicating that this area presents limitations in its saturation capacity. Chemical analysis indicated the metal Cu is probably responsible for the toxicity of the sediments observed, without the interference of ammonia.
Show more [+] Less [-]Marine mammals and ocean noise: Future directions and information needs with respect to science, policy and law in Canada Full text
2014
Williams, Rob | Ashe, Erin | Blight, Louise | Jasny, Michael | Nowlan, Linda
Marine mammals are ecologically and culturally important species, and various countries have specific legislation to protect the welfare of individual marine mammals and the conservation of their populations. Anthropogenic noise represents a particular challenge for conservation and management. There is a large and growing body of research to support the conclusion that anthropogenic noise can affect marine mammal behavior, energetics, and physiology. The legal, policy, and management issues surrounding marine mammals and noise are similarly complex. Our objective is twofold. First, we discuss how policy and legal frameworks in Canada have some important differences from other jurisdictions covered in previous reviews, and provide a useful general case study. Secondly, we highlight some priority research areas that will improve marine mammal conservation and management. Our examples focus on the research needed to meet stated conservation objectives for marine mammal species in waters under Canadian jurisdiction.
Show more [+] Less [-]Marine litter ensemble transport simulations in the southern North Sea Full text
2014
Neumann, Daniel | Callies, Ulrich | Matthies, Michael
The drift of marine litter in the southern North Sea was simulated with the offline Lagrangian transport model PELETS-2D. Assuming different source regions, passive tracer particles were released every 28h within a nine-year period. Based on pre-calculated hourly wind and ocean current data, drift simulations were carried out forward and backward in time with and without the assumption of extra wind forces influencing particle movement. Due to strong variability of currents, backward simulations did not allow for the identification of particular source regions influencing given monitoring sites. Neither accumulation regions at open sea could be identified by forward simulations. A seasonal signal, however, could be identified in the number of tracer particles that reached the coastal areas. Both particle drift velocity and variability of drift paths further increased when an extra wind drift was assumed.
Show more [+] Less [-]Characterization of fish hold effluent discharged from commercial fishing vessels into harbor waters Full text
2014
Albert, Ryan J. | McLaughlin, Christine | Falatko, Debra
Fish hold effluent and the effluent produced from the cleaning of fish holds may contain organic material resulting from the degradation of seafood and cleaning products (e.g., soaps and detergents). This effluent is often discharged by vessels into near shore waters and, therefore, could have the potential to contribute to water pollution in bays and estuaries. We characterized effluent from commercial fishing vessels with holds containing refrigerated seawater, ice slurry, or chipped ice. Concentrations of trace heavy metals, wet chemistry parameters, and nutrients in effluent were compared to screening benchmarks to determine if there is a reasonable potential for effluent discharge to contribute to nonattainment of water quality standards. Most analytes (67%) exceeded their benchmark concentration and, therefore, may have the potential to pose risk to human health or the environment if discharges are in significant quantities or there are many vessels discharging in the same areas.
Show more [+] Less [-]Deepwater marine litter densities and composition from submersible video-transects around the ABC-islands, Dutch Caribbean Full text
2014
Debrot, A.O. | Vinke, E. | van der Wende, G. | Hylkema, A. | Reed, J.K.
Baseline data on anthropogenic seafloor debris contamination in the year 2000 is provided for 24 submersible video transects at depths of 80–900m, off the Dutch ABC-islands (Aruba, Bonaire, Curaçao), in the southeastern Caribbean Sea. In total, 202 objects were documented from a combined 21,184m of transect, ranging from sandy lower island-slope to rocky upper island-slope habitat. Debris densities differed significantly with depth. Highest debris accumulation (0.459 items 100m−2 or 4590 items per km2) occurred at depths of 300–600m on more shallow-sloping (20–30°) sand and silt bottoms. The overall average debris density was 0.27 objects per 100m2 (or 2700 items per km2), which is an order of magnitude higher than most other deepwater debris studies. What we describe may be representative for other small, populated, steep volcanic Caribbean islands. Food and beverage-related items were the single largest usage category identified (44% of objects; mostly glass beverage bottles).
Show more [+] Less [-]Cover versus recovery: Contrasting responses of two indicators in seagrass beds Full text
2014
Soissons, Laura M. | Han, Qiuying | Li, Baoquan | van Katwijk, Marieke M. | Ysebaert, Tom | Herman, Peter M.J. | Bouma, Tjeerd J.
Despite being a highly valuable key-stone ecosystem, seagrass meadows are threatened and declining worldwide, creating urgent need for indicators of their health status. We compared two indicators for seagrass health: standing leaf area index versus relative recovery from local disturbance. Disturbance was created by removing aboveground biomass and recording the rate of regrowth for Zostera marina meadows exposed to contrasting wave regimes and nutrient stress levels.Within the experimental period, relative regrowth in gaps was around 50% in most plots, except for the ambient nutrient treatment at the sheltered site, where it exceeded 100%. The two indicators showed an opposite response to disturbance: the higher the standing leaf area index, the lower the relative recovery from disturbance. This conflicting response raises the question on the proper interpretation of such indicators to estimate seagrass health and resilience, and how to ideally monitor seagrass ecosystems in order to predict collapse.
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