Growth rate of the bathypelagic crustacean Gnathophausia ingens (Mysidacea: Lophogastridae)

The content of water, ash, carbohydrate, lipid, protein, chitin, carbon, hydrogen, nitrogen and energy was measured for all life stages of the bathypelagic mysid Gnathophausia ingens collected in San Clemente Basin off Southern California, USA between January 1969 and February 1982. These data are used to examine the life history, growth rates, growth pattern and partitioning of material and energy over the life of this species. Females reproduce only once and brood their young for about 1.5 yr, during which time the females do not feed. This species has a very high reproductive effort: of the energy accumulated over its life, 61.3% is used in egg production, 13.4% in parental care of young, 5.6% in cast exoskeletons and only 19.6% remains in the females after brooding. The relative rate of growth (percentage of energy d^?1) is about 1% immediately after leaving the mother and declines to about 0.2% as maturity is approached. Such growth rates appear to be typical for an animal of this size living at low temperatures. The evolutionary context of this mysid's life history is discussed.     

Evaluation of chlorophyll fluorescence, in vivo spectrophotometric pigment absorption and ion leakage as biomarkers of UV-B exposure in marine macroalgae

The photosynthetic fluorescence ratio F_v:F_m, in vivo absorption spectra and ion leakage were evaluated as biomarkers of ambient and elevated UV-B (280 to 320 nm) exposure of the intertidal alga Enteromorpha intestinalis (Chlorophyta) and the sublittoral alga Palmaria palmata (Rhodophyta). Measurements of thallus growth were also used to assess adverse biological effects. Ambient and elevated UV-B significantly inhibited photosynthesis in both species. It was shown that the F_v:F_m ratio is a sensitive, non-specific general biomarker of UV-B exposure in both species. Moreover, the in vivo absorption of what was tentatively identified as chlorophylls a and b as well as phycoerythrin and/or carotenoids, phycoerythrobilin and phycocyanin decreased in a dose-response dependent manner and was associated with a decrease in growth rate in P. palmata. The intertidal alga E. intestinalis showed a greater degree of tolerance to UV-B exposure. These results indicate that changes in the F_v:F_m ratio together with reductions in in vivo pigment absorption could provide an early quantitative warning of the detrimental effects of UV-B in marine macroalgae. Received: 16 May 1997 / Accepted: 16 July 1997     

The Rossby Centre Regional Atmospheric Climate Model part II: application to the Arctic climate

The Rossby Centre regional climate model (RCA2) has been integrated over the Arctic Ocean as part of the international ARCMIP project. Results have been compared to observations derived from the SHEBA data set. The standard RCA2 model overpredicts cloud cover and downwelling longwave radiation, during the Arctic winter. This error was improved by introducing a new cloud parameterization, which significantly improves the annual cycle of cloud cover. Compensating biases between clear sky downwelling longwave radiation and longwave radiation emitted from cloud base were identified. Modifications have been introduced to the model radiation scheme that more accurately treat solar radiation interaction with ice crystals. This leads to a more realistic representation of cloud-solar radiation interaction. The clear sky portion of the model radiation code transmits too much solar radiation through the atmosphere, producing a positive bias at the top of the frequent boundary layer clouds. A realistic treatment of the temporally evolving albedo, of both sea-ice and snow, appears crucial for an accurate simulation of the net surface energy budget. Likewise, inclusion of a prognostic snow-surface temperature seems necessary, to accurately simulate near-surface thermodynamic processes in the Arctic.     

Influence of kinetic sorption and diffusion on pesticide movement through aggregated soils

Laboratory studies were carried out to investigate solute leaching at different times from application in relation to temperature and initial soil moisture. Aggregates of a heavy clay soil were treated with a non-interactive solute (bromide) and the herbicides chlorotoluron, isoproturon and triasulfuron. The soil was incubated at 90% field capacity and either 5 or 15 degrees C. The influence of application to initially dry and initially wet aggregates on the behaviour of isoproturon was also investigated. At intervals, samples were either leached in small columns, centrifuged to characterise the fraction of chemical available in pore water under natural moisture conditions or extracted with organic solvents to assess total residues in soil. Bromide concentrations in leachate and in pore water extracted by centrifugation were constant with time. In contrast, availability for leaching and concentration in pore water of the herbicides decreased with increasing time from application in soil incubated at 15 degrees C. The effect of residence time was much smaller at 5 than at 15 degrees C. At the higher temperature, pesticide concentrations in leachate and pore water declined faster than would be expected from degradation alone, probably due to slow diffusion of the pesticides into soil aggregates where they are less available for leaching and/or slow sorption-desorption. The faster decline in availability for leaching at 15 than at 5 degrees C was attributed to faster degradation of the readily available fraction. There was no significant influence of initial soil moisture on either the leaching behaviour of isoproturon or its availability in soil water.     

PCB and PAH releases from power stations and waste incineration processes in the UK

This study focused on emissions of polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) from incineration and power generation processes. Increased concern over human exposure to both classes of compounds has meant that environmental regulators need to assess the contribution made by emissions from regulated processes to human exposure. In the first part of an assessment in the UK we reviewed literature data on emissions of PCB, focusing on the dioxin-like PCB assigned toxic equivalency factors by the World Health Organization, and PAH. The literature study was supplemented by a series of plant tests to gather initial real plant data. Literature data were limited and the lack of standard protocols for measurement and reporting of both PCB and PAH meant that few data sets were comparable. Levels of dioxin-like PCB reported in the literature and measured in UK plant tests showed that well-controlled modem combustion plants with comprehensive pollution controls gave low emissions, typically about 5-10% of the toxic equivalent of the emissions of polychlorinated dibenzodioxins and dibenzofurans at the same plants and below the widely used standard of 0.1 ng TEQ/N m3.     

Comparative toxicity of a zinc salt, zinc powder and zinc oxide to Eisenia fetida, Enchytraeus albidus and Folsomia candida

The pore water zinc concentration and the calcium chloride extracted zinc fraction are higher in the soils spiked with a zinc salt (ZnCl2) compared to soils spiked with zinc oxide or zinc powder. Based on total zinc concentrations in the soil, the acute toxicity of zinc salt to the compost worm Eisenia fetida, the potworm Enchytraeus albidus and the springtail Folsomia candida was lower compared to zinc oxide and zinc powder. However, when expressed on the basis of pore water concentrations or calcium chloride extracted fractions, acute toxicity was higher for zinc salt, which indicated that dermal uptake via the pore water is not the only route of uptake. Chronic toxicity of zinc salt, zinc oxide and zinc powder was similar when based on total concentrations in the soil which again indicates that the pore water route of uptake is not the only route of exposure but that oral uptake is also important.     

Tolerance and acclimation to zinc of Ceriodaphnia dubia

Zinc is an essential metal for all living organisms. However, so far, little or no attention has been paid to the consequences of zinc deficiency or acclimation to this metal during culturing and testing on toxicity test results. In this study, the cladoceran Ceriodaphnia dubia was acclimated for 10 generations to four zinc concentrations ranging from 0 to 100 microg Zn/l and changes in zinc tolerance were monitored using acute (48 h) and chronic (9 days) assays. C. dubia deprived of zinc and acclimated to 13 microg Zn/l had a lower fitness in comparison with organisms acclimated to 50 and 100 microg Zn/l. In the two lowest versus the two highest acclimation concentrations the 9dEC50 values (on immobility) were 358-387 microg Zn/l versus 486-489 microg Zn/l; the mean number of young per female was 11-18 versus 25-32; and the time to first brood was 4.7-5.0 days versus 4.0-4.3 days. Moreover, the coefficient of variation of all parameters tested was highest in the two lowest acclimation concentrations. The results indicate that culturing test animals in media lacking trace metals such as zinc could give rise to animals that are unnaturally sensitive to those same metals daring toxicity tests.     

The contribution from shipping emissions to air quality and acid deposition in Europe

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO2, NOx, VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m(-2) yr(-1) over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met.     

Flame retardants, surfactants and organotins in sediment and mysid shrimp of the Scheldt estuary (The Netherlands)

Sediment and mysids from the Scheldt estuary, one of the largest and most polluted estuaries in Western Europe, were analyzed for a number of contaminants that have been shown to possess endocrine-disrupting activity, i.e. organotins, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), nonylphenol ethoxylates (NPE) and transformation products, nonylphenol (NP) and nonylphenol ether carboxylates (NPEC). In addition, in vitro estrogenic and androgenic potencies of water and sediment extracts were determined. Total organotin concentrations ranged from 84 to 348 ng/g dw in sediment and 1110 to 1370 ng/g dw in mysid. Total PBDE (excluding BDE-209) concentrations ranged from 14 to 22 ng/g dw in sediment and from 1765 to 2962 ng/g lipid in mysid. High concentrations of BDE-209 (240-1650 ng/g dw) were detected in sediment and mysid (269-600 ng/g lipid). Total HBCD concentrations in sediment and mysid were 14-71 ng/g dw and 562-727 ng/g lipid, respectively. Total NPE concentrations in sediment were 1422 ng/g dw, 1222 ng/g dw for NP and 80 ng/g dw for NPEC and ranged from 430 to 1119 ng/g dw for total NPE and from 206 to 435 ng/g dw for NP in mysid. Significant estrogenic potency, as analyzed using the yeast estrogen assay, was detected in sediment and water samples from the Scheldt estuary, but no androgenic activity was found. This study is the first to report high levels of endocrine disruptors in estuarine mysids.     

Patterns of growth,energy utilization and reproduction in some meso- and bathypelagic fishes off Southern California

We have studied growth, energy use and reproduction in 4 mesopelagic fishes and 5 bathypelagic fishes living off Southern California (USA). All of the mesopelagic species underwent diurnal vertical migrations, while none of the bathypelagic species did so. The life histories of these pelagic fishes were compared among themselves and with epipelagic sardines and anchovies studied by others. The epipelagic species had the highest growth rates (estimated from otoliths, expressed in standard length or kilocalories), the mesopelagic species had the lowest growth rates and the bathypelagic species had intermediate growth rates. The relatively rapid growth rates of the bathypelagic fishes were achieved by high relative growth efficiencies made possible by low metabolic rates. Of the species studied, the lifespans of the epipelagic and bathypelagic species ranged from 4 to 8 yr and the lifespans of mesopelagic species from 5 to 8 yr. Data on egg diameters suggest that the mesopelagic species first reproduce in their 3rd yr, while the bathypelagic species do so in their last year. Epipelagic fishes generally have a large size, rapid growth, long life and early, repeated reproduction. Mesopelagic fishes are characterized by small size, slow growth, long life and early, repeated reproduction. Bathypelagic fishes generally have large size, rapid growth, somewhat shorter lives and late reproduction, which is possible a single event. The latter pattern is evidently feasible only in a rather stable environment where juvenile survivorship would always display relatively low variability. Many unusual characteristics of deep-living animals have possibly been selected by factors peculiar to the environment; however, such characteristics are just as likely to have been selected by factors equally present in many other environments, but not expressed there due to masking selective forces. In particular, we have in mind the darkness, stability and homogeneity of the bathypelagic realm as phenomena which represent the effective absence of many selective forces.The first two authors contributed equally and their names are listed in alphabetical order