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Public awareness and attitudes towards naval sonar mitigation for cetacean conservation: A preliminary case study in Fairfax County, Virginia (the DC Metro area) Full text
2011
Zirbel, K. | Balint, P. | Parsons, E.C.M.
The potential impacts of naval sonar on cetaceans has led to a series of court cases and statements of concern by international organizations. However, there has been no research conducted on attitudes of the general public with respect to this issue. To investigate this, a preliminary public survey was conducted in Fairfax, Virginia (the Washington, DC Metro region). The majority of the public sampled believed that naval sonar impacted marine mammals (51.3%), that the US Navy should not be exempt from environmental regulations in time of peace (75.2%), and that sonar use should be moderated if it impacts cetaceans (75.8%). Individuals who were conservative, Republican, and have served in the military were more likely to believe the Navy should be exempt from marine mammal protection regulations. In addition, expert interviews were conducted to gain opinions on the potential ramifications of the recent US Supreme Court case on naval sonar mitigation.
Show more [+] Less [-]The destructive date-mussel fishery and the persistence of barrens in Mediterranean rocky reefs Full text
2011
Guidetti, Paolo
The illegal and destructive fishery of date mussels (i.e. the endolithic mollusc Lithophaga lithophaga) reduces the bio-physical complexity of Mediterranean rocky reefs and dramatically impacts biodiversity. Although date-mussel fishermen do not directly impact sea urchins, these echinoids dramatically increase in abundance on rocky reefs impacted by date-mussel fishery (DMF). The recovery of rocky reefs affected by DMF is hampered by the intense unselective grazing of sea urchins on benthic organisms. No evidence is available, however, about the mechanisms that cause the increase in the population density of sea urchins. I demonstrated here that DMF creates a new microhabitat, i.e. the holes left empty after date mussels are extracted, where small-sized sea urchins take refuge and escape predation. This study thus sheds light on a mechanism through which DMF may locally increase sea urchin population density, contributing to maintain the rocks bare on the long term.
Show more [+] Less [-]Bacterioplankton dynamics along the gradient from highly eutrophic Pearl River Estuary to oligotrophic northern South China Sea in wet season: Implication for anthropogenic inputs Full text
2011
Zhou, Weihua | Long, Aimin | Jiang, Tao | Chen, Shaoyong | Huang, Liangmin | Huang, Hui | Cai, Chuanghua | Yan, Yan
Bacterioplankton abundance (BA) and biomass (BB) from the eutrophic Pearl River Estuary (PRE) to the oligotrophic northern South China Sea (NSCS) were studied in the wet season. BA was significantly higher (p<0.05) in PRE (12.51±3.52×10⁸cellsL⁻¹), than in the continental shelf neritic province (CSNP, 4.95±2.21×10⁸cellsL⁻¹) and in the deep oceanic province (OP, 3.16±1.56×10⁸cellsL⁻¹). Nutrient-replete PRE waters (DIN>100μM and PO₄>1μM) resulted in high chl a and BB, whereas nutrient-depleted offshore waters (DIN <5μM and PO₄<0.5μM) had low biomass. Temperature (>26°C) was not the controlling factor of BA. BB was significantly correlated with chl a biomass both in PRE and NSCS. The bacteria to phytoplankton biomass (BB/PB) ratio increased clearly along the gradient from near-shore PRE (0.15) to offshore CSNP (0.93) and deep OP (2.75), indicating the important role of small cells in the open ocean compared to estuarine and coastal zones.
Show more [+] Less [-]Environmental magnetic and petroleum hydrocarbons records in sediment cores from the north east coast of Tamilnadu, Bay of Bengal, India Full text
2011
Venkatachalapathy, R. | Veerasingam, S. | Basavaiah, N. | Ramkumar, T. | Deenadayalan, K.
In this study, mineral magnetic properties and petroleum hydrocarbons were statistically analysed in four sediment cores (C1, A1, T1 and K1) from the north east coast of Tamilnadu, India to examine the feasibility of PHC concentrations assessment using magnetic susceptibility. The C1 and A1 cores reveal a clear horizon of increase in PHC above 35 and 50cm respectively suggesting the excess anthropogenic loading occurred in the recent past. Magnetic properties which were enhanced in the upper part of the sediment cores were the result of ferrimagnetic minerals from anthropogenic sources. Factor analysis confirmed that the input of magnetic minerals and petroleum hydrocarbons in Chennai coastal sediments are derived from the same sources. The present study shows that instead of expensive and destructive PHC chemical methods, magnetic susceptibility is found to be a suitable, cheap and rapid method for detailed study of petroleum hydrocarbon contamination in marine sediments.
Show more [+] Less [-]Relationship of photosynthetic carbon fixation with environmental changes in the Jiulong River estuary of the South China Sea, with special reference to the effects of solar UV radiation Full text
2011
Li, Gang | Gao, Kunshan | Yuan, Dongxing | Zheng, Ying | Yang, Guiyuan
Phytoplankton cells in estuary waters usually experience drastic changes in chemical and physical environments due to mixing of fresh and seawaters. In order to see their photosynthetic performance in such dynamic waters, we measured the photosynthetic carbon fixation by natural phytoplankton assemblages in the Jiulong River estuary of the South China Sea during April 24–26 and July 24–26 of 2008, and investigated its relationship with environmental changes in the presence or the absence of UV radiation. Phytoplankton biomass (Chl a) decreased sharply from the river-mouth to seawards (17.3–2.1μgL⁻¹), with the dominant species changed from chlorophytes to diatoms. The photosynthetic rate based on Chl a at noon time under PAR-alone increased from 1.9μgC (μg Chl a)⁻¹L⁻¹ in low salinity zone (SSS<10) to 12.4μgC (μg Chl a)⁻¹L⁻¹ in turbidity front (SSS within 10–20), and then decreased to 2.1μgC (μg Chl a)⁻¹L⁻¹ in mixohaline zone (SSS>20); accordingly, the carbon fixation per volume of seawater increased from 12.8 to 149μgCL⁻¹h⁻¹, and decreased to 14.3μgCL⁻¹h⁻¹. Solar UVR caused the inhibition of carbon fixation in surface water of all the investigated zones, by 39% in turbidity area and 7–10% in freshwater or mixohaline zones. In the turbidity zone, higher availability of CO₂ could have enhanced the photosynthetic performance; while osmotic stress might be responsible for the higher sensitivity of phytoplankton assemblages to solar UV radiation.
Show more [+] Less [-]The use of Lagrangian trajectories for the identification of the environmentally safe fairways Full text
2011
Soomere, Tarmo | Andrejev, Oleg | Myrberg, Kai | Sokolov, Alexander
We propose and test a method for the optimisation of marine fairways to minimise the risk to high-value areas, based on statistical analysis of Lagrangian trajectories of current-driven pollution transport. The offshore areas are quantified according to the probability of pollution released in these areas to reach vulnerable regions. The method contains an eddy-resolving circulation model, a scheme for tracking of Lagrangian trajectories, a technique for the calculation of quantities characterising the potential of different sea areas to supply adverse impacts, and routines to construct the optimum fairway. The gain is expressed in terms of the probability of pollution transport to the nearshore and the associated time (particle age). The use of the optimum fairway would decrease the probability of coastal pollution by 40% or increase the average time of reaching the pollution to the coast from 5.3 to about 9days in the Gulf of Finland, the Baltic Sea.
Show more [+] Less [-]Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence Full text
2011
Azevedo, Juliana S. | Braga, Elisabete S. | Favaro, Deborah T. | Perretti, Adriana R. | Rezende, Carlos Eduardo | Souza, Cristina Maria M.
Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary. For comparison, samples were also collected in a non-polluted system with similar hydrochemistry characteristics, the Cananeia estuary. The water characteristics and THg levels in sediment and fish samples confirmed a high human influence in the Santos-São Vicente estuary. The lowest THg values, observed in Cananeia, were evidence of low anthropogenic influence. High values observed in Santos-São Vicente show the necessity for a monitoring program.
Show more [+] Less [-]Marine mammals and debris in coastal waters of British Columbia, Canada Full text
2011
Williams, Rob | Ashe, Erin | O’Hara, Patrick D.
Entanglement in and ingestion of synthetic marine debris is increasingly recognized worldwide as an important stressor for marine wildlife, including marine mammals. Studying its impact on wildlife populations is complicated by the inherently cryptic nature of the problem. The coastal waters of British Columbia (BC), Canada provide important habitat for marine mammal species, many of which have unfavorable conservation status in the US and Canada. As a priority-setting exercise, we used data from systematic line-transect surveys and spatial modeling methods to map at-sea distribution of debris and 11 marine mammal species in BC waters, and to identify areas of overlap. We estimated abundance of 36,000 (CIs: 23,000–56,600) pieces of marine debris in the region. Areas of overlap were often far removed from urban centers, suggesting that the extent of marine mammal–debris interactions would be underestimated from opportunistic sightings and stranding records, and that high-overlap areas should be prioritized by stranding response networks.
Show more [+] Less [-]Phytoplankton pigments and epifluorescence microscopy as tools for ecological status assessment in coastal and estuarine waters, within the Water Framework Directive Full text
2011
Seoane, Sergio | Garmendia, Maialen | Revilla, Marta | Borja, Angel | Franco, Javier | Orive, Emma | Valencia Rincón, Victoriano
Inverted microscopy is widespread employed for the analysis of phytoplankton composition within water quality monitoring networks. However, the analysis at the lowest taxonomical level is not always required for ecological status assessment. In addition, inverted microscopy can underestimate the small phytoplankton, and not always distinguish photoautotrophic from heterotrophic cells. In this study, as alternative tools, epifluorescence microscopy and High Performance Liquid Chromatography (HPLC) were employed to characterize phytoplankton communities within waters of different trophic condition. Epifluorescence microscopy confirmed its effectiveness to count the small phytoplankton. Furthermore, significant correlations between nutrients of anthropogenic origin and nanoplankton abundances were found. However, this technique resulted very time-consuming. HPLC together with the CHEMTAX program was more appropriate than inverted microscopy, in terms of cost-effectiveness. Also, the main variability patterns observed in the phytoplankton community structure by HPLC coincided with previous findings in the study area. Nevertheless, a rapid screening at the inverted microscope is recommended.
Show more [+] Less [-]Effects of chronic exposure to dispersed oil on selected reproductive processes in adult blue mussels (Mytilus edulis) and the consequences for the early life stages of their larvae Full text
2011
Baussant, Thierry | Ortiz-Zarragoitia, Maren | Cajaraville, Miren P. | Bechmann, Renée Katrin | Taban, Ingrid Christina | Sanni, Steinar
Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015–0.25mg/l) for 7months covering the whole gamete development cycle. After 1month exposure to 0.25mgoil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25mgoil/l. Parental exposure to 0.25mgoil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2days post-fertilization; reduced growth 7days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25mgoil/l. Similar studies are warranted for risk assessment prognosis.
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