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Early warning indicators for river nutrient and sediment loads in tropical seagrass beds: A benchmark from a near-pristine archipelago in Indonesia Full text
2011
van Katwijk, M.M. | van der Welle, M.E.W. | Lucassen, E.C.H.E.T. | Vonk, J.A. | Christianen, M.J.A. | Kiswara, W. | Inayat al Hakim, I. | Arifin, A. | Bouma, T.J. | Roelofs, J.G.M. | Lamers, L.P.M.
In remote, tropical areas human influences increase, potentially threatening pristine seagrass systems. We aim (i) to provide a bench-mark for a near-pristine seagrass system in an archipelago in East Kalimantan, by quantifying a large spectrum of abiotic and biotic properties in seagrass meadows and (ii) to identify early warning indicators for river sediment and nutrient loading, by comparing the seagrass meadow properties over a gradient with varying river influence. Abiotic properties of water column, pore water and sediment were less suitable indicators for increased sediment and nutrient loading than seagrass properties. Seagrass meadows strongly responded to higher sediment and nutrient loads and proximity to the coast by decreasing seagrass cover, standing stock, number of seagrass species, changing species composition and shifts in tissue contents. Our study confirms that nutrient loads are more important than water nutrient concentrations. We identify seagrass system variables that are suitable indicators for sediment and nutrient loading, also in rapid survey scenarios with once-only measurements.
Show more [+] Less [-]Distribution and characteristics of PAHs in sediments from the Mediterranean coastal environment of Egypt Full text
2011
Barakat, Assem O. | Mostafa, Alaa | Wade, Terry L. | Sweet, Stephen T. | El Sayed, Nadia B.
To assess the contamination of polycyclic aromatic hydrocarbons (PAHs) in the Mediterranean coastal environment of Egypt, 26 sediment samples from the coastline, harbours, estuaries and coastal lakes were collected and analyzed. The sediment PAH concentrations of thirty-nine 2–6 ring PAHs ranged from 13.5 to 22,600ng/g. PAH profiles varied according to the nature of the site and its proximity to sources. Industrialized and urbanized region showed high level of PAHs contamination. In general, the contamination levels of PAHs were similar to those observed in contaminated and slightly contaminated sediments of the Mediterranean Sea. Molecular indices based on ratios of selected PAH concentrations were used to differentiate PAHs from pyrogenic and petrogenic and mixed origins. Good correlations were observed between the petrogenic index, MP/P, A-PAHs/P-PAHs and HMW/LMW. Finally, PAH levels in sediments were compared with Sediments Quality Guidelines (ERM–ERL) for evaluation of probable toxic effects on organism.
Show more [+] Less [-]Application of entropy analysis of in situ droplet-size spectra in evaluation of oil chemical dispersion efficacy Full text
2011
Li, Zhengkai | Lee, Kenneth | King, Thomas | Niu, Haibo | Boufadel, Michel C. | Venosa, Albert D.
In situ droplet-size distributions were measured using a laser in situ scattering and transmissiometry (LISST-100X) particle size analyzer during the evaluation of natural and chemical dispersion efficiency of crude oils under different wave and current conditions. An entropy grouping of the in situ dispersed oil droplet-size spectra has classified the multi-modal droplet-size distributions into different groups based on similar droplet-size spectra characteristics within groups and distinction between groups. A generalized linear logistic regression model was fitted to analyze the effects of a number of factors and their interactions on the grouping of oil droplet-size spectra. The grouped results corresponded to the oil dispersion efficiency at different levels. This new method for droplet-size distribution data analysis can have significant implication in field evaluation of natural and chemical dispersion efficiency of oil.
Show more [+] Less [-]The new potential invader Linopherus canariensis (Polychaeta: Amphinomidae) in a Mediterranean coastal lake: Colonization dynamics and morphological remarks Full text
2011
Cosentino, A. | Giacobbe, S.
The newly introduced polychaete Linopherus canariensis Langerhans, 1881 was found in the Lake of Faro (NE Sicily), during a study comparing the macrobenthos in artificial modules with a neighboring sandy bottom assemblage. Of a total of 4465 specimens, almost 6% showed morphological variation related to branchial turfs and mean body size. The sandy bottom exhibited an average density of 41.86indL⁻¹ and a wet biomass of 30.35mgL⁻¹, whereas the artificial substratum reached levels of 205.29indL⁻¹ and 318.44mgL⁻¹. The highest estimated immigration rate was 3.7indL⁻¹d⁻¹ (5.8mgL⁻¹d⁻¹). In the artificial microhabitat, 0.4% of the population showed mid-anterior fragmentation, with anterior- (2%), mid- (<1%) and posterior- (1%) regenerating lineages, which contributed significantly to the dispersion ability of this species. L. canariensis was a selective micro-deposit feeder, even under conditions of reduced sediments. Linopherus was found to be a new potential invader of stressed environments that is probably tied to the import of oysters.
Show more [+] Less [-]Large-scale oil-in-ice experiment in the Barents Sea: Monitoring of oil in water and MetOcean interactions Full text
2011
Faksness, Liv-Guri | Brandvik, Per Johan | Daae, Ragnhild L. | Leirvik, Frode | Børseth, Jan Fredrik
A large-scale field experiment took place in the marginal ice zone in the Barents Sea in May 2009. Fresh oil (7000L) was released uncontained between the ice floes to study oil weathering and spreading in ice and surface water. A detailed monitoring of oil-in-water and ice interactions was performed throughout the six-day experiment. In addition, meteorological and oceanographic data were recorded for monitoring of the wind speed and direction, air temperature, currents and ice floe movements. The monitoring showed low concentrations of dissolved hydrocarbons and the predicted acute toxicity indicated that the acute toxicity was low. The ice field drifted nearly 80km during the experimental period, and although the oil drifted with the ice, it remained contained between the ice floes.
Show more [+] Less [-]Using existing data and focused surveys to highlight Cuvier’s beaked whales favourable areas: A case study in the central Tyrrhenian Sea Full text
2011
Gannier, Alexandre
This study focuses on the necessary elements to implement strategic mitigation in order to avoid Cuvier’s beaked whale (CBW) strandings linked to intense sound sources, such as military active sonars, in the Mediterranean Sea. A careful review of stranding data and the analysis of existing survey results are required to highlight the main characters of the species regional distribution. Focused and repeated surveys are needed to confirm that possible favourable areas, such as the Balearic, Tyrrhenian or Aegean Seas, are really favourable CBW habitats. These surveys should be carried out with sea states 0 to 1 in order to minimize the risk of false absence data. Among the regions of interest, the central Tyrrhenian Sea was surveyed with a 12m sailboat in 2007 and 2008. With 907km of effective effort, a mean sighting rate of 1.9 CBW school/100km was obtained, which is amongst the highest densities recorded in the Mediterranean.
Show more [+] Less [-]Proximate environmental drivers of coral communities at Palmyra Atoll: Establishing baselines prior to removing a WWII military causeway Full text
2011
Williams, Gareth J. | Knapp, Ingrid S. | Maragos, James E. | Davy, Simon K.
A management proposal aims to partly remove a WWII military causeway at Palmyra Atoll to improve lagoon water circulation and alleviate sedimentation stress on the southeast backreef, an area of high coral cover and diversity. This action could result in a shift in sedimentation across reef sites. To provide management advice, we quantified the proximate environmental factors driving scleractinian coral cover and community patterns at Palmyra. The proportion of fine sedimentation was the optimal predictor of coral cover and changes in community structure, explaining 23.7% and 24.7% of the variation between sites, respectively. Scleractinian coral cover was negatively correlated with increases in fine sedimentation. Removing the causeway could negatively affect the Montipora corals that dominate the western reef terrace, as this genus was negatively correlated with levels of fine sedimentation. The tolerance limits of corals, and sediment re-distribution patterns, should be determined prior to complete removal of the causeway.
Show more [+] Less [-]Risk acceptance criterion for tanker oil spill risk reduction measures Full text
2011
Psarros, George | Skjong, Rolf | Vanem, Erik
This paper is aimed at investigating whether there is ample support for the view that the acceptance criterion for evaluating measures for prevention of oil spills from tankers should be based on cost-effectiveness considerations. One such criterion can be reflected by the Cost of Averting a Tonne of oil Spilt (CATS) whereas its target value is updated by elaborating the inherent uncertainties of oil spill costs and establishing a value for the criterion’s assurance factor. To this end, a value of $80,000/t is proposed as a sensible CATS criterion and the proposed value for the assurance factor F=1.5 is supported by the retrieved Protection and Indemnity (P&I) Clubs’ Annual Reports. It is envisaged that this criterion would allow the conversion of direct and indirect costs into a non-market value for the optimal allocation of resources between the various parties investing in shipping. A review of previous cost estimation models on oil spills is presented and a probability distribution (log-normal) is fitted on the available oil spill cost data, where it should be made abundantly clear that the mean value of the distribution is used for deriving the updated CATS criterion value. However, the difference between the initial and the updated CATS criterion in the percentiles of the distribution is small. It is found through the current analysis that results are partly lower than the predicted values from the published estimation models. The costs are also found to depend on the type of accident, which is in agreement with the results of previous studies. Other proposals on acceptance criteria are reviewed and it is asserted that the CATS criterion can be considered as the best candidate. Evidence is provided that the CATS approach is practical and meaningful by including examples of successful applications in actual risk assessments. Finally, it is suggested that the criterion may be refined subject to more readily available cost data and experience gained from future decisions.
Show more [+] Less [-]Diet of bream Abramis brama (Linnaeus, 1758) in Belgrade section of the Danube River [Serbia] | Ishrana deverike Abramis brama (Linnaeus, 1758) beogradskog sektora reke Dunav [Srbija]
2011
Đikanović, V., Institut za biološka istraživanja Siniša Stanković, Beograd (Serbia) | Jakovčev-Todorović, D., Institut za biološka istraživanja Siniša Stanković, Beograd (Serbia) | Tubić, B., Institut za biološka istraživanja Siniša Stanković, Beograd (Serbia) | Zorić, K., Institut za biološka istraživanja Siniša Stanković, Beograd (Serbia) | Cakić, P., Institut za biološka istraživanja Siniša Stanković, Beograd (Serbia)
The paper presents the results of preliminary study of the intestinal content in bream (Abramis brama L. 1758) of the Danube River through the Belgrade Region. The fishes were collected in May and October during the period 2007-2009 at two sampling sites along the course. A total of 42 fish specimens of different age (2+ to 6+) were examined. By examination of compositing of intestine of bream have been found members from macrozoobentho-groups – Oligochaeta, Gastropoda (Lithoglyphus naticoides), Bivalvia, Amphipoda (Gamaridae). Our investigation showed that the diet of bream is dependent of bottom fauna composition and structure.
Show more [+] Less [-]Dynamics microbiological and physical-chemical feature [of] source [part of] river Brvenice [Serbia] | Динамика микробиолошких и физичко-хемијских одлика изворишног дела реке Брвенице [Србија]
2011
Живић, Н., Природно-математички факултет, Косовска Митровица (Serbia) | Томић, С., ЈКП Рашка, Рашка (Serbia) | Лабус, Н., Природно-математички факултет, Косовска Митровица (Serbia)
Physico-chemical and microbiological analysis of Brvenica River water was conducted in period 2006-2010 and showed seasonal variations of water quality. The results of correspondence analysis indicated that the year 2006 regarding the physical and chemical characteristics of water, was different from the rest of the examined period. This year was characterized by the absence of ammonia, low contents of nitrite, iron and chlorine, and increased concentrations of KMnO4 consumption. In 2007 and 2008 presence of manganese in water, low concentration of KMnO4 consumption was detected as well increased turbidity and electrical conductivity. And the third distinguish period are years 2009 and 2010 when water was characterized by low concentration of NO3, and the presence of ammonia, NO2, and iron in the water, while turbidity was low and conductivity was average. In Brvenica River water Escherichia coli, Citrobacter sp., Enterococcus sp., Klebsiella sp. are detected. In year 2006 number of aerobic bacteria and total coliforms were rather low, while their number in 2008 is relatively high. Over the whole period, only in 2008 fecal streptococci were not detected. Other years are characterized by growth of aerobic bacteria and total coliforms and the occasional presence of fecal streptococci. Throughout the whole examination period fecal coliform bacteria were present in the water.
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