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Long-term fluctuations in Cystoseira populations along the west Istrian Coast (Croatia) related to eutrophication patterns in the northern Adriatic Sea
2016
Iveša, Ljiljana | Djakovac, Tamara | Devescovi, Massimo
An exploration of historical data suggested that eutrophication patterns might drive long-term fluctuations in Cystoseira populations along the west Istrian Coast (northern Adriatic Sea, Croatia). The regimes of northern Italian rivers, which flow approximately 100km west of the study area, mainly modulate the eutrophication levels of the northern Adriatic Sea. A regression of Cystoseira populations from the 1970s through the 1990s corresponded to increased levels of eutrophication in the study area. During the late 1990s, the density of sea urchins, which are efficacious macroalgal predators, decreased, likely due to an intense formation of pelagic mucilage aggregates that resulted in mass mortality episodes of macrozoobenthic species. During the 2000–2013 period, an oligotrophication of the northern Adriatic formed the basis for the recovery of Cystoseira taxa, whose abundances from 2009 to 2013 were similar to those characterising the most flourishing Mediterranean Cystoseira assemblages.
Afficher plus [+] Moins [-]Origins and features of oil slicks in the Bohai Sea detected from satellite SAR images
2016
Ding, Yi | Cao, Conghua | Huang, Juan | Song, Yan | Liu, Guiyan | Wu, Lingjuan | Wan, Zhenwen
Oil slicks were detected using satellite Synthetic Aperture Radar (SAR) images in 2011. We investigated potential origins and regional and seasonal features of oil slick in the Bohai Sea. Distance between oil slicks and potential origins (ships, seaports, and oil exploitation platforms) and the angle at which oil slicks move relative to potential driving forces were evaluated. Most oil slicks were detected along main ship routes rather than around seaports and oil exploitation platforms. Few oil slicks were detected within 20km of seaports. Directions of oil slicks movement were much more strongly correlated with directions of ship routes than with directions of winds and currents. These findings support the premise that oil slicks in the Bohai Sea most likely originate from illegal disposal of oil-polluted wastes from ships. Seasonal variation of oil slicks followed an annual cycle, with a peak in August and a trough in December.
Afficher plus [+] Moins [-]On some physical and dynamical properties of microplastic particles in marine environment
2016
Chubarenko, I. | Bagaev, A. | Zobkov, M. | Esiukova, E.
Simplified physical models and geometrical considerations reveal general physical and dynamical properties of microplastic particles (0.5–5mm) of different density, shape and size in marine environment. Windage of extremely light foamed particles, surface area and fouling rate of slightly positively buoyant microplastic spheres, films and fibres and settling velocities of negatively buoyant particles are analysed. For the Baltic Sea dimensions and under the considered idealised external conditions, (i) only one day is required for a foamed polystyrene particle to cross the sea (ca. 250km); (ii) polyethylene fibres should spend about 6–8months in the euphotic zone before sinking due to bio-fouling, whilst spherical particles can be retained on the surface up to 10–15years; (iii) for heavy microplastic particles, the time of settling through the water column in the central Gotland basin (ca. 250m) is less than 18h. Proper physical setting of the problem of microplastics transport and developing of physically-based parameterisations are seen as applications.
Afficher plus [+] Moins [-]Origins of suspended particulate matter based on sterol distribution in low salinity water mass observed in the offshore East China Sea
2016
Kim, Moonkoo | Jung, Jee-hyun | Jin, Yongnu | Han, Gi Myeong | Lee, Taehee | Hong, Sang Hee | Yim, Un Hyuk | Shim, Won Joon | Choi, Dong-Lim | Kannan, Narayanan
The molecular composition and distribution of sterols were investigated in the East China Sea to identify the origins of suspended particulate matter (SPM) in offshore waters influenced by Changjiang River Diluted Water (CRDW). Total sterol concentrations ranged from 3200 to 31,900pgL−1 and 663 to 5690pgL−1 in the particulate and dissolved phases, respectively. Marine sterols dominated representing 71% and 66% in the particulate and dissolved phases, respectively. Typical sewage markers, such as coprostanol, were usually absent at ~250km offshore. However, sterols from allochthonous terrestrial plants were still detected at these sites. A negative relationship was observed between salinity and concentrations of terrestrial sterols in SPM, suggesting that significant amounts of terrestrial particulate matter traveled long distance offshore in the East China Sea, and the Changjiang River Diluted Water (CRDW) was an effective carrier of land-derived particulate organic matter to the offshore East China Sea.
Afficher plus [+] Moins [-]The influence of wastewater discharge on water quality in Hawai'i: A comparative study for Lahaina and Kihei, Maui
2016
Miller-Pierce, Mailea R. | Rhoads, Neil A.
In Maui, Hawai'i, wastewater reclamation facilities (WWRFs) dispose of partially treated effluent into injection wells connected to the nearshore environment. Hawai'i State Department of Health data from 2004–2015 were assessed for qualitative trends in nutrient, turbidity, and Chlorophyll a water quality (WQ) impairments for fourteen marine sites on Maui Island. We introduce a novel method, the Qualitative Impact Percentage (QIP), to facilitate a qualitative comparison of disparate factors contributing to WQ impairment. Sites near the Lahaina WWRF in West Maui, which was found in violation of the Clean Water Act in 2014, had fewer exceedances and lower geometric means compared to sites near the Kihei WWRF. Our results suggest that WQ impairments may be a greater concern in Kihei than previously acknowledged. This paper attempts to raise the awareness of policymakers and the public and to encourage further research assessing the effects of the Kihei WWRF on the marine environment.
Afficher plus [+] Moins [-]Assessing responses of the Hiroshima Bay ecosystem to increasing or decreasing phosphorus and nitrogen inputs
2016
Kittiwanich, Jutarat | Yamamoto, Tamiji | Kawaguchi, Osamu | Madinabeitia, Ione
The Japanese Government is seeking an appropriate level of nutrient load from the land to maintain the highest possible estuarine fishery production and water transparency simultaneously. To provide a scientific basis for the governmental inquiry, we conducted sensitivity analyses using an ecosystem model of Hiroshima Bay in order to assess the ecosystem’s responses to phosphorus and nitrogen inputs. Load levels of phosphorus (Case P), nitrogen (Case N) and both phosphorus and nitrogen (Case NP) that were different from the average loading recorded during 1991–2000 (±25%, ±50%, and ±75%) were applied. The results showed that phosphorus had a significantly greater impact on the primary production of the bay than nitrogen. Case P+25 increased the primary production but led to N-limitation. However, it was found that Case NP at the levels over +25% could bring the Hiroshima Bay ecosystem back to its eutrophic state of 30years ago.
Afficher plus [+] Moins [-]Effect of high sedimentation rates on surface sediment dynamics and mangrove growth in the Porong River, Indonesia
2016
Sidik, Frida | Neil, David H. | Lovelock, Catherine E.
Large quantities of mud from the LUSI (Lumpur Sidoarjo) volcano in northeastern Java have been channeled to the sea causing high rates of sediment delivery to the mouth of the Porong River, which has a cover of natural and planted mangroves. This study investigated how the high rates of sediment delivery affected vertical accretion, surface elevation change and the growth of Avicennia sp., the dominant mangrove species in the region. During our observations in 2010–2011 (4–5years after the initial volcanic eruption), very high rates of sedimentation in the forests at the mouth of the river gave rise to high vertical accretion of over 10cmy−1. The high sedimentation rates not only resulted in reduced growth of Avicennia sp. mangrove trees at the two study sites at the Porong River mouth, but also gave rise to high soil surface elevation gains.
Afficher plus [+] Moins [-]Evaluation of two indoor air pollution abatement techniques in forced-ventilation fattening pig barns
2016
Mostafa, Ehab | Hoelscher, Richard | Diekmann, Bernd | Ghaly, A.E. | Buescher, Wolfgang
Animal agricultural activities can be a significant source of pollutants affecting the health of farmers and neighboring communities. The main objective of this research was to improve the air quality by reducing the interior concentrations of emitting pollutants such as particulate matter (PM) and ammonia (NH3) within forced-ventilated fattening pig barns in order to improve the working conditions for human and the living conditions for animals as well as to have less impact on the surrounding environment. The mitigation techniques were a recirculating air scrubber and spraying of a water-oil mixture. The reduction efficiencies of the two mitigation techniques for PM and NH3 concentrations inside the barns were investigated. Two air scrubbers were mounted in a barn occupied with 515 pigs. A water-oil mixture spraying system with two different nozzles geometries was installed in a barn with 680 pigs. The data obtained from the mitigation system was compared with that obtained from a control barn with the same animal capacity and conditions. The results indicated that the average reduction efficiencies were 63% for total PM, 61% for PM10 and 32% for NH3. The results indicated that the average reduction efficiencies of the spraying system for the whole periods were 74% for total PM, 72% for PM10 and 19.5% for NH3 when using small nozzles and 44% for total PM, 39% for PM10 and 16% for NH3 when using large nozzles. The spraying system reduced the germs and fungal spore concentrations by 14 and 58%, respectively.
Afficher plus [+] Moins [-]Oman's coral reefs: A unique ecosystem challenged by natural and man-related stresses and in need of conservation
2016
Burt, J.A. | Coles, S. | van Lavieren, H. | Taylor, O. | Looker, E. | Samimi-Namin, K.
Oman contains diverse and abundant reef coral communities that extend along a coast that borders three environmentally distinct water bodies, with corals existing under unique and often stressful environmental conditions. In recent years Oman's reefs have undergone considerable change due to recurrent predatory starfish outbreaks, cyclone damage, harmful algal blooms, and other stressors. In this review we summarize current knowledge of the biology and status of corals in Oman, particularly in light of recent stressors and projected future threats, and examine current reef management practices. Oman's coral communities occur in marginal environmental conditions for reefs, and hence are quite vulnerable to anthropogenic effects. We recommend a focus on developing conservation-oriented coral research to guide proactive management and expansion of the number and size of designated protected areas in Oman, particularly those associated with critical coral habitat.
Afficher plus [+] Moins [-]Species-specific accumulation of methyl and total mercury in sharks from offshore and coastal waters of Korea
2016
Kim, Sang-jo | Lee, Hyun Kyung | Badejo, Abimbola C. | Lee, Won-Chan | Moon, Hyo-Bang
Limited information is available on mercury (Hg) levels in various shark species consumed in Korea. The methyl-Hg (Me-Hg) and total Hg concentrations in all shark species ranged from 0.08 to 4.5 (mean: 1.2) mg/kg wet weight and from 0.1 to 7.0 (mean: 1.4) mg/kg wet weight, respectively. Inter-species differences in Hg accumulation were found among the species; however, Hg accumulation was homogenous between dorsal and pectoral fins within species. The highest Hg levels were found in aggressive carnivore shark species. Trophic position was important in determining Hg accumulation for aggressive carnivore sharks. Approximately 80% of shark species exceeded the safety limits for Me-Hg established by domestic and international authorities. The mean estimated daily intake of Me-Hg (1.3μg/kg body weight/day) for Korean populations consuming various sharks was higher than the guidelines proposed by international regulatory authorities, suggesting that excessive shark fin consumption may pose potential health risks for Koreans.
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