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Detection of verotoxin producing Escherichia coli in marine environments of the Caribbean
2013
Walker, Trisha J. | Bachoon, D.S. | Otero, Ernesto | Ramsubhag, Adesh
The goal of this study was to determine the potential for Enterohemorrhagic Escherichia coli O157:H7 (EHEC) contamination in tropical marine waters. Samples were collected from urban, suburban, and rural sites around the islands of Puerto Rico and The Republic of Trinidad and Tobago. Quantification of E. coli and EHEC was evaluated using MI plates and qPCR. EHEC was detected in six sites in Puerto Rico: West of La Parguera Town, Boquilla, Oro Creek, Fishers Association, Joyuda Lagoon, and Boqueron Wetland Creek and in two rural sites in Trinidad: Balandra Bay and Quinam Bay. Plate count enumeration of E. coli was not a reliable indicator for the presence of EHEC. The sites where EHEC was detected on both islands are used for recreational bathing, water sports and recreational/commercial fisheries and therefore pose a public potential health risk.
Show more [+] Less [-]Effects of elevated CO2 on the reproduction of two calanoid copepods
2013
McConville, Kristian | Halsband, Claudia | Fileman, Elaine S. | Somerfield, Paul J. | Findlay, Helen S. | Spicer, John I.
Some planktonic groups suffer negative effects from ocean acidification (OA), although copepods might be less sensitive. We investigated the effect of predicted CO2 levels (range 480–750ppm), on egg production and hatching success of two copepod species, Centropages typicus and Temora longicornis. In these short-term incubations there was no significant effect of high CO2 on these parameters. Additionally a very high CO2 treatment, (CO2=9830ppm), representative of carbon capture and storage scenarios, resulted in a reduction of egg production rate and hatching success of C. typicus, but not T. longicornis. In conclusion, reproduction of C. typicus was more sensitive to acute elevated seawater CO2 than that of T. longicornis, but neither species was affected by exposure to CO2 levels predicted for the year 2100. The duration and seasonal timing of exposures to high pCO2, however, might have a significant effect on the reproduction success of calanoid copepods.
Show more [+] Less [-]Effects of CO2 on benthic biota: An in situ benthic chamber experiment in Storfjorden (Norway)
2013
Ishida, Hiroshi | Golmen, Lars G. | West, Julia | Kruger, Martin | Coombs, Patricia | Berge, John Arthur | Fukuhara, Tastuo | Magi, Michimasa | Kita, Jun
Carbon capture and storage (CCS) methods, either sub-seabed or in ocean depths, introduces risk of CO2 leakage and subsequent interaction with the ecosystem. It is therefore important to obtain information on possible effects of CO2. In situ CO2 exposure experiments were carried out twice for 10days during 2005 using a Benthic Chamber system at 400m depth in Storfjorden, Norway. pCO2 in the water above the sediment in the chambers was controlled at approximately 500, 5000 and 20,000μatm, respectively. This article describes the experiment and the results from measured the biological responses within the chamber sediments. The results show effects of elevated CO2 concentrations on biological processes such as increased nanobenthos density. Methane production and sulphate reduction was enhanced in the approximately 5000μatm chamber.
Show more [+] Less [-]Rhamnolipids enhance marine oil spill bioremediation in laboratory system
2013
Chen, Qingguo | Bao, Mutai | Fan, Xiaoning | Liang, Shengkang | Sun, Peiyan
This paper presents a simulated marine oil spill bioremediation experiment using a bacterial consortium amended with rhamnolipids. The role of rhamnolipids in enhancing hydrocarbon biodegradation was evaluated via GC–FID and GC–MS analysis. Rhamnolipids enhanced total oil biodegradation efficiency by 5.63%, with variation in normal alkanes, polyaromatic hydrocarbons (PAHs) and biomakers biodegradation. The hydrocarbons biodegradation by bacteria consortium overall follows a decreasing order of PAHs>n-alkanes>biomarkers, while in different order of PAHs>biomarkers>n-alkanes when rhamnolipids was used, and the improvement in the removal efficiency by rhamnolipids follows another order of biomarkers>n-alkanes>PAHs. Rhamnolipids played a negative role in degradation of those hydrocarbons with relatively volatile property, such as n-alkanes with short chains, PAHs and sesquiterpenes with simple structure. As to the long chain normal alkanes and PAHs and biomakers with complex structure, the biosurfactant played a positive role in these hydrocarbons biodegradation.
Show more [+] Less [-]Determining trigger values of suspended sediment for behavioral changes in a coral reef fish
2013
Wenger, Amelia S. | McCormick, Mark I.
Sediment from land use increases water turbidity and threatens the health of inshore coral reefs. This study performed experiments with a damselfish, Pomacentrus moluccensis, in four sediment treatments, control (0mgl−1), 10mgl−1(∼1.7NTU), 20mgl−1(∼3.3NTU) and 30mgl−1 (∼5NTU), to determine when sediment triggers a change in habitat use and movement. We reviewed the literature to assess how frequently P. moluccensis would experience sub-optimal sediment conditions on the reef. Preference for live coral declined from 49.4% to 23.3% and movement between habitats declined from 2.1 to 0.4times between 20mgl−1 and 30mgl−1, suggesting a sediment threshold for behavioral changes. Inshore areas of the Great Barrier Reef, P. moluccensis may encounter sub-optimal conditions between 8% and 53% of the time. Changes in these vital processes may have long-term effects on the persistence of populations, particularly as habitat loss on coral reefs increases.
Show more [+] Less [-]The effects of heavy metals on germination and seedling characteristics in two halophyte species in Mediterranean marshes
2013
Márquez-García, B. | Márquez, C. | Sanjosé, I. | Nieva, F.J.J. | Rodríguez-Rubio, P. | Muñoz-Rodríguez, A.F.
The influence of different concentrations (10–2000μM) of heavy metals (Cu, Mn, Ni, Zn) was analysed in Atriplex halimus and Salicornia ramosissima germination pattern and seedling size. They are two halophyte species that grow in the Estuary of Huelva (Southwest Iberian Peninsula, Spain), one of the most heavy metal-polluted environments in the world.All of the metals tested affected the final germination percentage in A. halimus and only Ni reduced germination in S. ramosissima. The germination rate was unaffected in both species.The study of seedling development shows that S. ramosissima, an intertidal annual species, has a higher tolerance of metals than A. halimus, a bush that inhabits the upper part of the marshes.Taking into account the metal concentrations in the estuary and the effects of these on the seedling development of the species analysed, we conclude that metals might limit plant colonisation in some parts of the marshes.
Show more [+] Less [-]Sources and transport of As, Cu, Cd and Pb in the environmental compartments of Deception Island, Antarctica
2013
Mão de Ferro, André | Mota, Ana Maria | Canário, João
Sources and transport processes of As, Cu, Cd and Pb were studied in different environmental compartments of Deception Island, an active volcano in the South Shetland Islands, Antarctica. Element concentrations in fresh water samples are consistent with the lowest values reported elsewhere in Antarctica. Interestingly, higher concentration values of As were found in samples collected in or near spring water courses and its transport may be related with processes of lixiviation in underground waters. While in saline waters Cu and Pb had important punctual sources, concentration values for Cd were consistently high pointing to the existence of a natural and diffuse source possibly related with the hydrothermal activity. The high Si/Al ratio, low carbon content, and a non-significant anthropogenic heavy metal input may explain the surprisingly homogeneous heavy metal content found in sediment samples.
Show more [+] Less [-]Concentration profiles of PCB congeners in the blubber and liver of Steller sea lions (Eumetopias jubatus) from the coast of Hokkaido, Japan
2013
Kubo, Keiko | Yamaguchi, Katsuyuki | Mitsuhashi, Masaki | Hattori, Kaoru | Tanaka, Shunitz
The concentrations of PCB congeners in the blubber and liver of male and female Steller sea lions (Eumetopias jubatus; SSLs) collected from the Shakotan Peninsula and the Nemuro Strait, Hokkaido, Japan in 2008 and 2010 were measured by HRGC–HRMS, in order to express the concentration profiles in SSLs at these regions. #153 predominated in both organs, followed by #138, #99 and #118. In males, #28 and #31 were concentrated particularly in the blubber, while #177 and #199 were accumulated specifically in the liver. The differences in these concentration profiles might be expressed by the differences in the organs and their functions. The concentrations of #99, #118, #138, #153, and #180 in the blubber appeared to correspond significantly with the differences between genders. The details of the surveys on PCB congeners in SSLs could clarify the differences in the residue levels of individual congeners for organs and genders.
Show more [+] Less [-]Occurrence, distribution, and bioaccumulation of antibiotics in coastal environment of Dalian, China
2013
Na, Guangshui | Fang, Xiaodan | Cai, Yaqi | Ge, Linke | Zong, Humin | Yuan, Xiutang | Yao, Ziwei | Zhang, Zhifeng
Seawater, sediment, and aquatic organism samples were collected from 20 sampling sites in coastal environment of Dalian in August, 2011. The occurrence, distribution, and bioaccumulation of 20 antibiotics categorizing into three groups, including 14 sulfonamides (SAs), two chloramphenicols (CAPs) and four tetracyclines (TCs), were investigated. The results suggested that tetracyclines were the predominant antibiotics in the seawater (range: 2.11–9.23ngL−1), while sulfonamides were the dominant antibiotics in both sediments (range: 1.42–71.32μgkg−1) and aquatic organisms (range: 2.18–63.87μgkg−1). The sorption coefficient Kd,s values revealed that sulfameter, sulfadiazine, sulfamethoxypyridazine, sulfamonomethoxine, chloramphenicol, and doxycycline presented higher sorption capacities than the other antibiotics. The average BAFs suggested that sulfamethazine, sulfamethiazole, sulfamonomethoxine, and doxycycline were potentially bioaccumulative, while sulfadiazine, sulfameter, sulfamethoxypyridazine, and chloramphenicol were bioaccumulative.
Show more [+] Less [-]Levels of phenolic compounds in Tibouchina pulchra after fumigation with ozone
2013
da Rosa Santos, Ana Clara | Furlan, Claudia Maria
Tibouchina pulchra (Cham.) Cogn. (Melastomataceae) is a native tree species from the southeast region of Brazil. This early successional species significantly contributes to the characteristic physiognomy and structure of the Atlantic Rain Forest. Saplings were exposed to carbon filtered air (CF), ambient non–filtered air (NF), and ambient non–filtered air +40 ppb ozone (NF+O3), 8 h per day during two months, using open top chambers (OTC). The AOT40 values at the end of the experiment were 48, 910 and 12 895 ppb h–1, respectively for each treatment. After 25 days of exposure, interveinal red stippling appeared in plants in the NF+O3 chamber (AOT40=3 871 ppb h–1). In the NF chamber, symptoms were observed only after 60 days of exposure (AOT40=910 ppb h–1). No changes were observed for total phenolic contents when comparing ozone treatments. However, amounts of tannins and flavonoids were different among treatments. NF+O3 and NF treatment showed enhanced contents of flavonoids, when tannins seem to be reduced after ozone fumigation (p<0.01). Results suggest alteration on phenolic metabolism when saplings are ozone fumigated; those responses, considered T. pulchra, seem to occur before leaf injury appeared, once contents of flavonoids and tannins are also altered by NF treatment (AOT40=910 ppb h–1). This study demonstrates that total phenolic and tannins contents of saplings of T. pulchra also decreased when exposed to ozone. The same alterations were observed for T. pulchra after industrial air pollution, suggesting the reduction on total phenolic and tannins probably is a characteristic response of T. pulchra to presence of any kind of pollutant.
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