Hydrocarbon uptake and loss by the mussel Mytilus edulis

The dynamics of accumulation and elimination of hydrocarbons by the blue mussel Mytilus edulis were studied in a continuous-flow system. Mussels were exposed for as long as 41 days to 200 – 400 g/l of diesel fuel adsorbed on kaolin particles. Hydrocarbons were accumulated in the tissues in excess of 1000 times the exposure levels. Upon termination of dosing, the mussels exhibited a rather rapid loss of hydrocarbons for the first 15 to 20 days (biological half-life=2.7 to 3.5 days). Subsequently, however, elimination was reduced to a minimum and a considerable fraction of the hydrocarbons could be recovered from the tissues after as long as 32 days of depuration. The mussels exhibited definite signs of physiological stress due to chronic exposure to diesel fuel, although recovery was rapid upon termination of dosing. It is concluded that mussels could be utilized as a test organism for monitoring long-term hydrocarbon pollution in marine waters. The implications for the mussel culture industry are discussed.     

Grazing rates of the copepods Calanus glacialis and C. finmarchicus in arctic waters of the Barents Sea

Natural feeding rates of Copepodite Stages IV and V, and adult female Calanus glacialis (Jaschnov) and Copepodite Stage V and adult female C. finmarchicus (Gunnerus) were estimated using fluorescence analysis of gut contents. Measurements were made on copepods sampled from arctic waters east of Svalbard (Barents Sea) during the spring phytoplankton increase, in the period from 27 May to 13 June, 1983. Observations on Copepodite Stages IV and V and adult female C. glacialis suggest that the gastric evacuation rate is independent of developmental stage, whereas C. finmarchicus Copepodite Stage V showed a lower gastric evacuation rate than adult females. Gut fullness displayed a low correlation with the ambient chlorophyll concentrations. Ingestion rates calculated for C. glacialis were 0.3, 2.3, and 11.0 g C h^-1 for Copepodite Stages IV and V and adult females, respectively. Copepodite Stage V and adult female C. finmarchicus ingested 0.9 and 1.1 g C h^-1 at a temperature of ca.-1.0°C. The maximum ingestion rate in terms of percent body carbon d^-1 was higher for adult female C. glacialis and C. finmarchicus than for the respective Copepodite Stage V's. The results are discussed both in relation to the physiological state of the species and to the environmental conditions.     

Growth and grazing loss rates in single-celledPhaeocystis sp. (Prymnesiophyceae)

Growth and grazing loss rates of naturalPhaeocystis sp. single cells were measured using a seawater dilution technique. Measurements were performed during an intensePhaeocystis sp. bloom in the North Sea between 19 April and 5 May 1988. Experimental results yielded rapid carbon turnover rates. Population growth rates varied from 0.033 to 0.098 h^–1, grazing loss rates from 0.037 to 0.174 h^–1. From measured growth rates, average doubling rages of 1.3 doublings d^–1 were calculated. The growth rates would have resulted in maximum carbon production rates of 146 mg C m^–3 d^–1. Grazing rates increased in the course of the bloom and exceeded growth rates at the end. Grazing loss was caused primarily by microzooplankton feeding. Ciliates and heterotrophic dinoflagellates were identified as the major potential consumers of single cells ofPhaeocystis sp. at the beginning of the bloom. The grazing impact of larger microzooplankton species appeared to increase during the progressing bloom.     

Rhythmic release of dissolved free amino acids from partly synchronized Thalassiosira rotula under nearly natural conditions

In outdoor tanks enclosed monocultures of Thalassiosira rotula showed partly synchronized cell divisions during exponential growth. The changes in division activity showed a characteristic frequency, which also could be found for cell length (pervalvar axis) and assimilation rate as well as for concentration changes of dissolved free amino acids (DFAA) and ammonia. Excretion of DFAA occurred preferentially during periods of reduced cell division activity, when assimilation was at a higher level. The concentration of ammonia decreased during these periods. The rates per hour of these parameters showed significant multiple correlations. The release of six individual amino acids (ala, -ala, gly, lys, orn and ser) seemed to be controlled by the physiological status of the diatoms. These amino acids amounted to a portion of about 70–80% of the total DFAA. Uptake and release rates of DFAA nitrogen and ammonia were in the same range with maxima of about 350 ng at nitrogen dm^-3 h^-1 and litre. These dynamics pointed to strong fluxes of organic bound nitrogen in marine micro-heterotrophs.     

Changes in the biochemical composition ofOstrea edulis larvae fed on different food regimes

Ostrea edulis larvae from an adult stock maintained in a raft in the Ría of Arousa (Galicia, Spain), were cultured in 1988 under four different food regimes:Pavlova lutheri, Isochrysis galbana, Phaeodactylum tricornutum andSkeletonema costatum. Growth, mortality, percentage of eyed larvae in each tank, as well as the biochemical composition of larvae at different stages of development were also studied. Protein and carbohydrate levels increase during larval development. Total lipids also increase from liberation to Day 8, and increase slightly or decrease from Day 8 to the beginning of metamorphosis. Since lipids are the main energy reserve in larvae, it is very plausible that they are being consumed during development, especially when metamorphosis begins. Data on growth, survival and biochemical composition of these larvae, which spawned 4 d after transfer of parental stock to the conditioning circuit, are compared with unpublished data on larvae from a laboratory conditioned broodstock.     

The “Tsesis” oil spill: Acute and long-term impact on the benthos

The “Tsesis” oil spill in October 1977 resulted in the release of over 1 000 tons of medium grade fuel oil in an archipelago in the brackish Baltic Sea. Considerable oil quantities reached the benthos by sedimentation. Within 16 d benthic amphipods of the genus Pontoporeia, as well as the polychaete Harmothoe sarsi Kinberg, showed reduction to less than 5% of pre-spill biomasses at the most impacted station. The clam Macoma balthica (L.) was more resistant, and showed little or no mortality, but was heavily contaminated by oil (about 2 000 μg g^-1 dry wt total hydrocarbons). The meiofauna was strongly affected, with ostracods, harpacticoids, Turbellaria and kinorhynchs showing clear reductions in abundance, while nematodes, as a group, were more resistant. In the winter following the spill gravid Pontoporeia affinis Lindström females showed a statistically significant increase in the frequency of abnormal or undifferentiated eggs. Food-chain transfer of oil to flounder [Platichthys flesus (L.)] was indicated. Not until the second summer after the spill were the first signs of recovery noted at the most heavily impacted station: Amphipods, H. sarsi and harpacticoids increased and the oil concentrations in M. balthica decreased (to about 1 000 μg g^-1). In the area where amphipods had been virtually eliminated, there was an unusually heavy recruitment of M. balthica, reaching 4 000 juveniles, of 1.5–2 mm length, per square metre, probably from settling in summer 1978. Three years after the spill Pontoporeia spp. biomass was still depressed in the most affected area, while H. sarsi showed normal biomass, and M. balthica abundance was inflated. Oil concentrations in M. balthica (about 250 μg g^-1) and flounder were only slightly elevated and the oil could no longer be confidently ascribed to “Tsesis” origin, even using GC/MS-analysis. Recovery was thus underway, but the long lifespan of M. balthica implies that the disturbed community composition may persist for many years at this station. Full recovery is likely to require more than 5 yr and may take a decade or more. An effort to evaluate the accumulated monetary loss to fishery from the accident indicates that direct costs of shoreline cleanup and vessel damage were considerably greater.     

Fine-scale distribution of juvenile cephalopods in the Scotia Sea and adaptive allometry of the brachial crown

The pelagic nekton community was sampled with the RMT 25 opening/closing net and a neuston net at two stations in the Scotia Sea south of the Antarctic Polar Front in the open ocean (Station 1) and on the South Georgia northwestern slope (Station 2). Downward oblique tows were made with the RMT 25 through discrete 200 m layers to 1000 m in daylight and darkness. A total of 119 cephalopods representing nine species were removed from the samples, and mantle and arm lengths were measured to the nearest 0.1 mm. The most abundant species at each station was an undescribed Brachioteuthis sp. (B. ?picta). Galiteuthis glacialis and Alluroteuthis antarcticus were caught at both stations. Histioteuthis eltaninae, Bathyteuthis abyssicola and Psychroteuthis glacialis were caught at Station 1. Mastigoteuthis psychrophila and a Chiroteuthis sp. were caught at Station 2. B. ?picta was present throughout the water column to 1000 m at both stations, with little evidence of ontogenetic descent. There was evidence for ontogenetic descent in G. glacialis. This species was absent from the Antarctic Surface Water (ASW) at Station 1, where it was concentrated in the Circumpolar Deep Water (CDW). At Station 2 it was present throughout the water column to 1000 m. The other species were all caught in the core of the CDW (>400 m). In juvenile B. ?picta, G. glacialis and A. antarcticus, growth of the brachial crown is positively allometric with respect to mantle length. Recent data on biomass spectra in high-latitude pelagic systems show that they are characterised by the presence of peaks of biomass separated by biomass minima. Positive allometric growth in the brachial crown of these antarctic oceanic squid is suggested to have evolved as an adaptation to the peaked, or domed, structure of the pelagic biomass spectrum which must be spanned by these predators as their optimum prey size increases with growth. Interspecific differences in the allometry of tentacle growth are probably related to differences in strategies for stalking and capture of prey.     

PCDD/F emissions from heavy duty vehicle diesel engines

The currently available information on PCDD/F emissions from diesel vehicles is briefly surveyed. Considerable uncertainty is identified concerning the emissions from heavy duty diesel trucks which have been measured only twice so far. These measurements led to emission factors differing by a factor of 200; similar discrepancy was also revealed by measurements of ambient air in traffic tunnels. New PCDD/F emission measurement results are presented which have been carried out at the exhaust systems of a stationary engine and of a modern heavy duty vehicle engine at transient operation conditions simulated on a test bench. PCDD/F concentrations in the exhaust gases were found to be in the range of control blank samples. Based on the highest concentration observed in the truck engine exhaust (9.7 pg I-TEQ/dry standard m3) a worst case estimate of the annual PCDD/F emission freight from diesel fuel combustion in the European countries of about 30 g I-TEQ/year is calculated. This emission appears to be irrelevant compared to the overall emission rate of more than 6,000 g I-TEQ/year being inventoried recently. Finally the possibilities to link congener/homologue profiles of diesel emission to profiles found in food or human samples are discussed.     

Mandibular bone fluoride levels and occurrence of fluoride induced dental lesions in populations of wild red deer (Cervus elaphus) from Central Europe

Analysis of chlordane contamination in selected finfish and shellfish species from estuarine and coastal marine waters of New Jersey, USA, indicates consistently highest organochlorine pesticide levels in samples from the north and northeast regions of the state. Gas chromatographic analysis of tissue samples from four finfish species (American eel, Anguilla rostrata; bluefish, Pomatomus saltatrix; striped bass, Morone saxatilis; and weakfish, Cynoscion regalis) and one shellfish species (blue crab, Callinectes sapidus) collected at 28 stations throughout the state during the 1986-1987 sampling period and 42 stations during the 1988-1991 sampling period revealed chlordane concentrations ranging from 5 to 2150 ppb wet weight (wet wt). Highest mean concentrations of chlordane (300 ppb wet wt) occurred in American eel from the Camden region, with secondary maxima (100 ppb wet wt) observed in the northeast region. Lower mean concentrations of chlordane (< 100 ppb wet wt) were recorded in tissue samples of other species collected elsewhere in the state. In general, the lowest levels of chlordane contamination (mean < 50 ppb wet wt) were found in samples from the south coast and Delaware regions. A major conclusion of this study is that some commercially and recreationally important finfish and shellfish species in New Jersey waters, especially those which are lipid-rich, have continued to accumulate chlordane from the environment long after restrictive regulations were first placed on its use in the US. The greatest impact of chlordane contamination is nearby metropolitan centers of the state (i.e., New York, Newark, Camden), although the total concentrations of chlordane in tissue samples from these areas are currently far less than the US Food and Drug Administration action level of 300 ppb wet wt.     

Organochlorines in polar bears (Ursus maritimus) at Svalbard

A comprehensive survey on organochlorine (OC) contaminants in polar bears at Svalbard has been undertaken. Subcutaneous tissue, blood and milk have been sampled from anesthetized free-ranging bears of both sexes and different ages in the period from 1990 to 1994. A number of sexually mature females have been fitted with satellite transmitters which make it possible to follow their reproductive behaviour pattern. We report on contamination levels and pattern of PCB congeners, chlordanes, DDT-compounds, HCB and HCH-isomers in the various tissues. The relation of age, sex and reproductive status to OC contamination has been described, and the capacity of polar bears in metabolising OCs has been discussed from the isomer/metabolite composition of residues. Finally, the possible association between OC contamination and reproduction success has been assessed. The PCB levels present in polar bears at Svalbard are extremely high. Especially high levels of higher chlorinated PCBs are found, and they accumulate with age, particularly in males. With females, considerable amounts of OCs are transferred to the offspring via milk. However, more efficient OC transfer between subcutaneous depot lipid and circulatory lipids than from the circulatory system to milk is found particularly for the most lipophilic compounds. The OC pattern in suckling yearlings reflects the low transfer of the highest chlorinated PCBs into maternal milk. The levels of most other OCs, however, are higher in depot lipid of yearlings than in that of their mothers. The polar bears have high capacity to metabolise several OCs. This may protect them against toxic action of the contaminants. No relation between OC levels in females and their ability to get pregnant is found in this preliminary investigation on OC effects on the polar bears at Svalbard.