Geographical and temporal variation in levels of organochlorine contaminants in marine mammals

The interpretation of the spatial and temporal patterns of variation in organochlorine concentrations in marine mammal populations is complex because of the lack of wide-scale, long-term surveys. Therefore the results from several surveys must be combined and this causes undesired heterogeneity due to differences in the sampling and analytical techniques used and in the biological characteristics of the individuals sampled. Moreover, information is not homogeneously distributed in either space or in time. Most research is concentrated in western Europe, northern America and certain areas of Asia, while it is extremely limited or non-existent in Africa and most regions of the southern hemisphere. Marine mammals from the temperate fringe of the northern hemisphere, particularly fish-eating species which inhabit the mid-latitudes of Europe and North America, show the greatest organochlorine loads; noteworthy are the extremely high levels found in the Mediterranean Sea and certain locations on the western coasts of the United States. Concentrations in the tropical and equatorial fringe of the northern hemisphere and throughout the southern hemisphere are low or extremely low. The polar regions of both hemispheres showed the lowest concentrations of DDTs and PCBs, although levels of HCHs, chlordanes and HCB were moderate to high in the cold waters of the North Pacific. During recent decades, concentrations have tended to decrease in the regions where pollution was initially high but they have increased in regions located far from the pollution source as a consequence of atmospheric transport and redistribution. It is expected that the Arctic and, to a lesser extent, the Antarctic, will become major sinks for organochlorines in the future; this process may already be significant for some compounds such as HCB and HCHs. Effort should be devoted to both assessment of organochlorine trends in the now highly polluted populations of the temperate fringe of the northern hemisphere and to the implementation of long-term monitoring of marine mammal populations inhabiting polar regions.     

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Recovery of meiofauna communities following mudflat disturbance by trampling associated with crab-tiling

The provision of artificial shelters for the collection of crabs, known as crab-tiling, and the subsequent harvesting of the soft "peeler" crabs for angling bait, are associated with trampling disturbance of intertidal mudflats in the United Kingdom. Recovery of meiofauna communities following crab-tiling activity was investigated on an intertidal mudflat in SW England. Harvesting of experimental plots was reproduced six times over a 2-week period. Meiofauna was collected at low tides 12h, 36 h and 144 h after treatment. Meiofaunal and nematode abundance, and nematode species number, was significantly greater in controls compared to crab-tile stations at 12h. At 36 h and 144 h there were no significant differences between treatments, indicating recovery had occurred in 12-36 h. Multivariate analysis showed nematode assemblage composition from control plots to be significantly different from crab-tile plots at 12h. No significant differences were observed between sediment physical parameters with treatment. Results suggest that the predominant effect of disturbance may be vibration-induced burial, which causes nematodes to bury deeper into the sediment, beyond the depth sampled, and explains the rapid recovery.     

Effects of acoustic alarms, designed to reduce small cetacean bycatch in gillnet fisheries, on the behaviour of North Sea fish species in a large tank

World-wide many cetaceans drown incidentally in fishing nets. To reduce the unwanted bycatch in gillnets, pingers (acoustic alarms) have been developed that are attached to the nets. In the European Union, pingers will be made compulsory in some areas in 2005 and in others in 2007. However, pingers may effect non-target marine fauna such as fish. Therefore in this study, the effects of seven commercially-available pingers on the behaviour of five North Sea fish species in a large tank were quantified. The species tested were: sea bass (Dicentrarchus labrax), pout (Trisopterus luscus), thicklip mullet (Chelon labrosus), herring (Clupea harengus), and cod (Gadus morhua). The fish were housed as single-species schools of 9-13 individuals in a tank. The behaviour of fish in quiet periods was compared with their behaviour during periods with active pingers. The results varied both between pingers and between fish species. Sea bass decreased their speed in response to one pinger and swam closer to the surface in response to another. Thicklip mullet swam closer to the bottom in response to two pingers and increased their swimming speed in response to one pinger. Herring swam faster in response to one pinger, and pout and cod (close relatives) showed no behavioural responses to any of the pingers. Of the seven pingers tested, four elicited responses in at least one fish species, and three elicited no responses. Whether similar responses would be elicited in these fish species in the wild, and if so, whether such responses would influence the catch rate of fisheries, cannot be derived from the results of this study. However, the results indicate the need for field studies with pingers and fish. Based on the small number of fish species tested, the present study suggests that the higher the frequency of a pinger, the less likely it is to affect the behaviour of marine fish.     

Biomarker responses in flounder (Platichthys flesus) and mussel (Mytilus edulis) in the Klaipeda-Būtinge area (Baltic Sea)

During the EU project BEEP a battery of biomarkers was applied in flounder (Platichthys flesus) and the blue mussel (Mytilus edulis) collected at three locations off the Lithuanian coast (Baltic Sea) in June and September 2001 and 2002. The elevated biomarker responses in specimens sampled in September 2001 were apparently related to the extensive dredging activities in the Klaipeda port area and subsequent dumping of contaminated sediments. High concentrations of organic pollutants (organochlorines and PBDEs) were also measured in the tissues of both indicator species. In addition, response levels of genotoxicity, cytotoxicity, immunotoxicity as well as concentrations of PAH metabolites in the bile of flounder showed elevations in 2002 after an oil spill in the Būtinge oil terminal in November 2001. In flounder, biomarker measurements 10 months after the spill indicated recovery processes but in mussels a high level of genotoxicity could still be observed 22 months later. The present study illustrates the usefulness of the multi-biomarker approach in the detection of biological effects of pollution in this region of the Baltic Sea.     

The BEEP project in the Baltic Sea: overview of results and outline for a regional biological effects monitoring strategy

Field studies in the framework of the EU funded BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems, 2001-2004) aimed at validating and intercalibrating a battery of biomarkers of contaminant exposure and effects in selected indicator species in the Mediterranean, the North Atlantic and the Baltic Seas. Major strategic goals of the BEEP project were the development of a sensitive and cost-efficient biological effects monitoring approach, delivery of information and advice to end-user groups, and the implementation of a network of biomarker researchers around Europe. Based on the main results obtained in the Baltic Sea component of the BEEP the present paper summarises and assesses the applicability of biomarkers for different regions and species in this sea area. Moreover, a general strategy and some practical considerations for the monitoring of biological effects in the Baltic Sea are outlined.     

Changes in zooxanthellae density,morphology, and mitotic index in hermatypic corals and anemones exposed to cyanide

Sodium cyanide (NaCN) is widely used for the capture of reef fish throughout Southeast Asia and causes extensive fish mortality, but the effect of NaCN on reef corals remains debated. To document the impact of cyanide exposure on corals, the species Acropora millepora, Goniopora sp., Favites abdita, Trachyphyllia geoffrio, Plerogyra sp., Heliofungia actinformis, Euphyllia divisa, and Scarophyton sp., and the sea anemone Aiptasia pallida were exposed to varying concentrations of cyanide for varying time periods. Corals were exposed to 50, 100, 300, and 600 mg/l of cyanide ion (CN(-)) for 1-2 min (in seawater, the CN(-) forms hydrocyanic acid). These concentrations are much lower than those reportedly used by fish collectors. Exposed corals and anemones immediately retracted their tentacles and mesenterial filaments, and discharged copious amounts of mucus containing zooxanthellae. Gel electrophoreses techniques found changes in protein expression in both zooxanthellae and host tissue. Corals and anemones exposed to cyanide showed an immediate increase in mitotic cell division of their zooxenthellae, and a decrease in zooxanthellae density. In contrast, zooxanthellae cell division and density remained constant in controls. Histopathological changes included gastrodermal disruption, mesogleal degradation, and increased mucus in coral tissues. Zooxanthellae showed pigment loss, swelling, and deformation. Mortality occurred at all exposure levels. Exposed specimens experienced an increase in the ratio of gram-negative to gram-positive bacteria on the coral surface. The results demonstrate that exposure cyanide causes mortality to corals and anemones, even when applied at lower levels than that used by fish collectors. Even brief exposure to cyanide caused slow-acting and long-term damage to corals and their zooxanthellae.     

北京平原地区主要活动断裂带研究进展

本文通过对北京平原地区主要活动断裂的调研、分析,认识到：①北京地区的构造格局是在晚第三纪“二隆夹一凹”(京西隆起、大兴隆起和北京凹陷)的基础上发展起来的,第四纪以来这一总的格局解体。沙河凹陷在第四纪开始发育；整个北京凹陷反向抬升,与大兴隆起结为一体；大兴隆起北部则发育了顺义第四纪凹陷。②黄庄-高丽营断裂、南口-孙河断裂研究的程度相对较深入,新成果较丰富。黄庄-高丽营断裂具有明显的分段活动性质,第四纪期间断裂活动由南向北逐渐加强,最新活动表现在北段的高丽营段,活动时代为全新世,黄庄段最新活动时代为晚更新世。南口-孙河断裂是北京地区规模最大的一条北西向断裂,也是张家口-渤海地震带中一条醒目的地表第四纪活动断裂。