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Metal elements in the bottom sediments of the Changjiang Estuary and its adjacent continental shelf of the East China Sea Full text
2015
Cao, Lu | Hong, Gi Hoon | Liu, Sumei
The metal elements (Al, Fe, Mn, Cr, Co, Ni, Cu, Zn, As, Pb and Ca) in the bottom sediment of the Changjiang Estuary and its adjacent continental shelf of the East China Sea were studied to map their spatial distribution and to assess their potential risk to the marine biota. These metal concentrations except Ca were generally higher in the inner shelf and northeastern part, and were found to decrease from the coast to the offshore of the Changjiang Estuary. Sedimentary Ca was most abundant in the outer shelf sediments and decreased in inner shelf. Arsenic (As) appeared to be contaminated due to economic development from 1980s in the inner shelf overall, but the potential ecological risk from the selected metals was low in the coastal sea off the Changjiang.
Show more [+] Less [-]Klebsiella sp. FIRD 2, a TBT-resistant bacterium isolated from contaminated surface sediment along Strait of Johor Malaysia Full text
2015
Abubakar, Abdussamad | Mustafa, Muskhazli B. | Johari, Wan Lutfi Wan | Zulkifli, Syaizwan Zahmir | Ismail, Ahmad | Mohamat-Yusuff, Ferdaus Binti
A possible tributyltin (TBT)-degrading bacterium isolated from contaminated surface sediment was successfully identified as Klebsiella sp. FIRD 2. It was found to be the best isolate capable of resisting TBT at a concentration of 1000μgL−1. This was a concentration above the reported contaminated level at the sampling station, 790μgL−1. Further studies revealed that the isolate was Gram negative and resisted TBT concentrations of up to 1500μgL−1 in a Minimal Salt Broth without the addition of any carbon source within the first 48h of incubation. It is expected that additional work could be conducted to check the degradation activity of this new isolate and possibly improve the degradation capacity in order to contribute to finding a safe and sustainable remediation solution of TBT contamination.
Show more [+] Less [-]Variations in the abundance and structural diversity of microbes forming biofilms in a thermally stressed coral reef system Full text
2015
Mahmoud, Huda
Little information is known about biofilm formation in the thermally stressed coral reef systems north of the Arabian Gulf. The current study investigates the abundance and diversity of marine microbes involved in biofilm formation and their succession over a period of 14weeks (May–August 2007) at temperatures exceeding 32°C. The results showed variations in microbial numbers and the development of more stable biofilm communities as the biofilms aged. The culture-dependent technique and microscopic examination of the developed biofilms showed the dominance of key species known for their role in precipitating CaCO3 such as Vibrio and in facilitating coral larvae settlement and metamorphosis such as Pseudoalteromonas, Bacillariophyceae and Rhodophyceae. The results revealed biofilm formations with microbial diversities that have the potential to support the larval settlement and metamorphism of marine organisms and to consolidate and stabilize biofilms via the process of calcification in the thermally stressed coral reef system considered herein.
Show more [+] Less [-]An assessment of the transport of southern California stormwater ocean discharges Full text
2015
Rogowski, Peter A. | Terrill, Eric | Schiff, Kenneth | Kim, Sŭng-yŏng
The dominant source of coastal pollution adversely affecting the regional coastal water quality is the seasonally variable urban runoff discharged via southern California’s rivers. Here, we use a surface transport model of coastal circulation driven by current maps from high frequency radar to compute two-year hindcasts to assess the temporal and spatial statistics of 20 southern California stormwater discharges. These models provide a quantitative, statistical measure of the spatial extent of the discharge plumes in the coastal receiving waters, defined here as a discharge’s “exposure”. We use these exposure maps from this synthesis effort to (1) assess the probability of stormwater connectivity to nearby Marine Protected Areas, and (2) develop a methodology to estimate the mass transport of stormwater discharges. The results of the spatial and temporal analysis are found to be relevant to the hindcast assessment of coastal discharges and for use in forecasting transport of southern California discharges.
Show more [+] Less [-]JNCC guidelines for minimising the risk of injury and disturbance to marine mammals from seismic surveys: We can do better Full text
2015
Wright, Andrew J. | Cosentino, A Mel
The U.K.’s Joint Nature Conservation Committee 1998 guidelines for minimising acoustic impacts from seismic surveys on marine mammals were the first of their kind. Covering both planning and operations, they included various measures for reducing the potential for damaging hearing – an appropriate focus at the time. Since introduction, the guidelines have been criticised for, among other things: the arbitrarily-sized safety zones; the lack of shut-down provisions; the use of mitigation measures that introduce more noise into the environment (e.g., soft-starts); inadequate observer training; and the lack of standardised data collection protocols. Despite the concerns, the guidelines have remained largely unchanged. Moreover, increasing scientific recognition of the scope and magnitude of non-injurious impacts of sound on marine life has become much more widespread since the last revisions in 2010. Accordingly, here we present feasible and realistic recommendations for such improvements, in light of the current state of knowledge.
Show more [+] Less [-]Mass culture strategy for bacterial yeast co-culture for degradation of petroleum hydrocarbons in marine environment Full text
2015
Priya, Anchal | Mandal, Ajoy K. | Ball, A. S. | Manefield, Mike | Lal, Banwari | Sarma, Priyangshu M.
In the present study a metabolically versatile co-culture with two Bacilli and one yeast strain was developed using enrichment culture techniques. The developed co-culture had affinity to degrade both aliphatic and aromatic fractions of petroleum crude oil. Degradation kinetics was established for designing the fermentation protocol of the co-culture. The developed mass culture strategy led to achieve the reduction in surface tension (26dynescm−1 from 69 dynescm−1) and degradation of 67% in bench scale experiments. The total crude oil degradation of 96% was achieved in 4000l of natural seawater after 28days without adding any nutrients. The survival of the augmented co-culture was maintained (109cellsml−1) in contaminated marine environment. The mass culture protocol devised for the bioaugmentation was a key breakthrough that was subsequently used for pilot scale studies with 100l and 4000l of natural seawater for potential application in marine oil spills.
Show more [+] Less [-]A spatial assessment of baseline nutrient and water quality values in the Ashepoo–Combahee–Edisto (ACE) Basin, South Carolina, USA Full text
2015
Keppler, C.J. | Bergquist, D.C. | Brock, L.M. | Felber, J. | Greenfield, D.I.
The Ashepoo–Combahee–Edisto (ACE) Basin (South Carolina, USA) National Estuarine Research Reserve System (NERRS) encompasses some of the least developed USA coastline. Yet, periodic sampling showed that certain regions have higher nutrient, fecal coliform, and chlorophyll a levels, often with lower dissolved oxygen, than other South Carolina estuaries. To evaluate the spatial extent of these issues, a summer (2008) baseline study was conducted. Physical water quality, total nitrogen and phosphorus, chlorophyll a, dissolved organic carbon, and suspended solids were measured from surface waters of 67 stations (30 tidal creek, 37 open water). Nutrient and chlorophyll a levels were significantly (p<0.01) and negatively correlated with the extent of open water (% land cover), and chlorophyll a and nitrogen levels were, at times, elevated relative to concentrations typical of other estuaries in the state, reinforcing previous findings. This survey also identified several creeks not previously monitored that exhibited elevated nutrients.
Show more [+] Less [-]Distributions, sources and ecological risk assessment of arsenic and mercury in the surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea Full text
2015
Zhuang, Wen | Gao, Xuelu
The spatial distributions of As and Hg in riverine and marine surface sediments of the coastal southwestern Laizhou Bay were obtained, and multiple indices and guidelines were applied to assess their contamination and ecological risks. The As concentrations in riverine sediments were close to those in marine sediments, and on the whole the dominant proportion of As was identified to be from natural sources. The Hg concentrations in riverine sediments were much higher than those in marine sediments, so river transportation was likely the main way of Hg into the southwestern Laizhou Bay. In respect of As, the sediment quality was fine according to the risk assessment methods used; in contrast, Hg presented an extremely contaminated status with a very high ecological risk in some riverine sediments, while most of the marine sediments were relatively much less polluted by Hg and under a lower ecological risk from it.
Show more [+] Less [-]Impaired gamete production and viability in Atlantic croaker collected throughout the 20,000km2 hypoxic region in the northern Gulf of Mexico Full text
2015
Thomas, Peter | Rahman, Md Saydur | Picha, Matthew E. | Tan, Wenxian
The long-term impacts of recent marked increases in the incidence and extent of hypoxia (dissolved oxygen <2mg/L) in coastal regions worldwide on fisheries and ecosystems are unknown. Reproductive impairment was investigated in Atlantic croaker collected in 2010 from the extensive coastal hypoxic region in the northern Gulf of Mexico. Potential fecundity was significantly lower in croaker collected throughout the ~20,000km2 hypoxic region than in croaker from normoxic sites. In vitro bioassays of gamete viability showed reductions in oocyte maturation and sperm motility in croaker collected from the hypoxic sites in response to reproductive hormones which were accompanied by decreases in gonadal levels of membrane progestin receptor alpha, the receptor regulating these processes. The finding that environmental hypoxia exposure reduces oocyte viability in addition to decreasing oocyte production in croaker suggests that fecundity estimates need to be adjusted to account for the decrease in oocyte maturation.
Show more [+] Less [-]Integrated environmental mapping and monitoring, a methodological approach to optimise knowledge gathering and sampling strategy Full text
2015
Nilssen, Ingunn | Ødegård, Øyvind | Sørensen, Asgeir J. | Johnsen, Geir | Moline, Mark A. | Berge, Jørgen
New technology has led to new opportunities for a holistic environmental monitoring approach adjusted to purpose and object of interest. The proposed integrated environmental mapping and monitoring (IEMM) concept, presented in this paper, describes the different steps in such a system from mission of survey to selection of parameters, sensors, sensor platforms, data collection, data storage, analysis and to data interpretation for reliable decision making. The system is generic; it can be used by authorities, industry and academia and is useful for planning- and operational phases. In the planning process the systematic approach is also ideal to identify areas with gap of knowledge. The critical stages of the concept is discussed and exemplified by two case studies, one environmental mapping and one monitoring case. As an operational system, the IEMM concept can contribute to an optimised integrated environmental mapping and monitoring for knowledge generation as basis for decision making.
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