Suprabenthic Peracarida (Crustacea, Malacostraca) sampled at 75°N off East Greenland

During an expedition with RV Polarstern in 1994 samples were taken at 75°N off Greenland, by means of an epibenthic sledge, which was equipped with an epi- and an additional suprabenthic net with an opening 1–1.33 m above the seafloor. Within the Peracarida (Crustacea, Malacostraca) sampled, 12 species were more frequent in the suprabenthic net, while 8 species were only sampled in this upper net. Received: 9 August 1996 / Accepted: 1 October 1996     

Terrestrial soil diatom assemblages from different vegetation types in Zackenberg (Northeast Greenland)

A total of 81 taxa were observed from 30 soil samples taken from 5 different vegetation types in Northeast Greenland. Most of the dominant diatoms are well-known cosmopolitan aerophilic taxa; only Caloneis aerophila and Pinnularia lagerstedtii are less widespread species. The valve lengths of P. borealis and Hantzschia amphioxys are correlated with the moisture content of the soils. Average cell number/g dry weight of soil amounts to 1,120,000 ± 740,000. In a TWINSPAN classification, the soils of the different vegetation types are separated, with the exception of the Vaccinium soils, which are grouped partly with the Cassiope samples and partly with the Salix soils. In a CCA ordination diagram, the Navicula atomus–Fragilaria elliptica assemblage shows a positive correlation with organic content and pH and a negative one with permafrost depth. The Pinnularia divergentissima var. martinii–P. obscura assemblage is positively correlated with moisture. The Pinnularia lagerstedtii–Caloneis aerophila assemblage is positively correlated with permafrost depth and negatively with pH and moisture. Accepted: 27 November 1999     

Use of skin biopsies for assessing levels of organochlorines in walruses (Odobenus rosmarus)

Skin and blubber samples of ten adult male Pacific walruses (Odobenus rosmarus divergens) from Alaska were used to investigate the relationship between organochlorine (OC) levels in skin and blubber of individuals. For analyses we selected 11 components that were quantified in the blubber of all individuals: hexachlorocyclohexanes (αHCH and βHCH), the DDT (dichlorodiphenyltrichloroethane) metabolite p,p′DDE, oxychlordane, and 7 individual PCB congeners, 28, 99, 105, 118, 138, 153 and 180. The correlation between the levels in the two types of tissues was significant and the relation was isometric for all components. The regression coefficient between levels in blubber (dependent variable) and levels in skin (independent variable) was different from 1 for only four of the components. The mean levels in the two types of tissues were significantly different for 3 of the 11 chemical components (βHCH, oxychlordane, and PCB28). Although this analysis is based on only ten individuals, we propose that skin samples taken by biopsy darts can be used to monitor OC levels in walruses. In August 1993 skin biopsies were collected from 25 adult male Atlantic walruses (O. r. rosmarus) at haul-out sites in southeastern Svalbard in the Norwegian Arctic and from 28 walruses of different sex and age at haul-out sites at Franz Josef Land in the Russian Arctic. The mean levels of OCs were 2–10 times higher at Svalbard than at Franz Josef Land. The dominant OC component was PCB153 in both areas. A principal component analysis detected differences between areas in OC levels but not in patterns. Since the Franz Josef Land samples were mainly taken from females and young individuals and the Svalbard samples were taken largely from adult males, we believe the differences in tissue OC levels observed from these areas can be explained by differences in sex and age of the walrus sampled. Comparable organochlorine levels in skin samples from walruses from other areas are not available. However, compared to the corresponding OC levels found in walrus blubber in other areas, the OC levels from Svalbard and Franz Josef Land are higher. The high levels of OCs in walruses from Svalbard and Franz Josef Land may be a combined effect of high pollution level in the environment and seal-eating habits. In the present study we show that it is possible to use skin biopsies taken by a non-destructive method to assess OC levels in walruses. Accepted: 24 October 1999     

Variation of Microcystin Content of Cyanobacterial Blooms and Isolated Strains in Lake Grand-Lieu (France)

Abstract Cyanobacterial blooms were sampled at five locations in Lake Grand-Lieu on seven different occasions during May–October 1994. Strains of Microcystis aeruginosa and Anabaena circinalis were isolated from the samples. Microcystins were detected in freeze-dried field samples and the isolated strains by HPLC. The toxins were present in the blooms sampled between June and October. The microcystin content in the blooms varied with site and time, from undetectable concentrations to 0.23 mg g⁻¹. The highest concentrations of microcystin were found in blooms sampled in September. Microcystin-LR and microcystins with retention times close to the retention time of [Dha⁷]microcystin-RR (probably varieties of microcystin-RR) were found in the field samples. Sixteen of the 98 isolated M. aeruginosa strains and 2 of the 24 A. circinalis strains produced microcystins. The total amount of microcystins varied from undetectable concentrations to 5.06 mg g⁻¹ in the M. aeruginosa isolates, and from undetectable concentrations to 1.86 mg g⁻¹ in the A. circinalis strains. Microcystin-LR was the main toxin found in strains of M. aeruginosa, but was not present in strains of A. circinalis. Both microcystin-producing strains and strains that did not produce microcystin coexisted in the bloom samples. Received: 23 January 1997; Accepted: 25 March 1997     

Distribution of zooplankton in the estuary of Keretskaya Guba (White Sea)

The horizontal heterogeneity of common zooplankton species in the Keretskaya Guba tidal estuary in the White Sea was studied. Based on an analysis of a series of simultaneously taken samples and the dispersion index, I _w = σ²/[`(m)]\bar{m} (where σ<sup>2</sup> is dispersion and [`(m)]\bar{m} is average population number), the existence of two and more levels of aggregation in most of the studied zooplankton species was found. The formation of patches of 1–20 m was most likely determined by biological causes, while patches some hundreds of meters long were formed due to the hydrodynamic conditions of the area.     

Fatty acid composition of the blubber in white whales (Delphinapterus leucas)

Fatty acid (FA) composition of the blubber in free-ranging white whales (Delphinapterus leucas) from Svalbard's waters was determined and compared with the fatty acid composition of potential prey species in an attempt to assess diet. This methodology is based on the common assumption that unique arrays of FAs found within groups of organisms are transferred, largely unaltered, up marine food chains and thus may be useful for assessment of diet composition. Complete-column blubber biopsies were sampled from white whales (n=7) during the summers of 1996 and 1997. All captured animals were adult males. FAs were extracted from 2–4 replicates taken from an area about 10 cm in front of the mid-dorsal ridge. FA data from a total of 12 potential prey species from the Svalbard area were compared to the white-whale blubber samples. Twenty-two FAs were consistently found in relative amounts >0.5% of the total FA composition in white whales. These FAs accounted for 94–96% of the total FAs present. The blubber was composed almost entirely of triacylglycerols. The major saturated FAs were 14:0 and 16:0; 16:1(n-7), 18:1(n-9) and 20:1(n-9) were the major monounsaturated FAs and 20:5(n-3) and 22:6(n-3) were the major polyunsaturated FAs. Sixteen of the 22 FAs consistently found in the white-whale blubber were also found in considerable amounts (>0.5% of total FAs) in most of the potential species. Principal Component Analysis run on these 16 FAs suggests that polar cod (Boreogadus saida) had the most similar FA composition to the white-whale blubber, followed by capelin (Mallotus villosus), the copepod Calanus hyperboreus and the shrimp Pandalus borealis. Accepted: 27 November 1999     

Experimental evidence of seawater drinking in juvenile hooded (Cystophora cristata) and harp seals (Phoca groenlandica)

This study was undertaken to measure whether young harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) drink seawater and, if so, to investigate how the excess salt load is handled. Blood and urine samples were collected from hooded seal pups (n=3) and harp seal pups (n=3) after 2 weeks of freshwater exposure, at intervals during 3 weeks of seawater exposure and, finally, after 2 weeks of re-exposure to fresh water. Total water turnover, as measured by injection of tritiated water, was 2200 ml · day⁻¹ and 3300 ml · day⁻¹ in hooded seals and harp seals, respectively. The extent of mariposia was taken as the difference between total water turnover and influx of water through food (free and metabolic water) and respiratory water exchange. Seawater drinking amounted to 14% and 27% of total water turnover (r_H2O) for the hooded seals and harp seals, respectively. Further evidence of mariposia was obtained from an increase in the excretion rate of the urine osmolytes Na⁺, Cl⁻ and Mg²⁺, during the period of seawater exposure. It is concluded that water influx due to seawater drinking can not be excluded as a source of error when estimating food consumption of free-ranging harp seals and hooded seals, by use of labeled water techniques. Accepted: 11 May 2000     

A year round comparative study on the population structures of pelagic Ostracoda in Admiralty Bay (Southern Ocean)

The population structures of the three dominant planktonic halocyprid Ostracoda species in Admiralty Bay (King George Island, Antarctic Peninsula) were followed throughout the course of a year in zooplankton samples collected once every three weeks from February 1993 to January 1994. The sampling was conducted at two stations: A in the central part of Admiralty Bay (400–0 m) and B in the entrance to the Bay from the Bransfield Strait (400–0 m). The samples were taken using a WP-2 net (square mouth opening of 0.196 m² and 200 μm mesh) hauled vertically from the bottom to the surface. Changes in the age structures of the populations of three species Alacia belgicae, Alacia hettacra and Metaconchoecia isocheira were tracked. Their population structures differed. The changes in A. belgicae suggested that it reproduces year-round, whereas both A. hettacra and M. isocheira probably complete their life cycles within a year. The cycle in A. hettacra probably starts earlier in the year than that of M. isocheira. Populations of A. belgicae and M. isocheira were more advanced in their development at station A, than at station B, but A. hettacra was more advanced at the latter. Advection appears to play a role in maintaining the populations in the shelf waters. Comparisons between populations in the shelf area (Admiralty Bay) and in open ocean waters (Croker Passage) show that the M. isocheira population is older in shelf water whereas the age structure of A. belgicae population is not influenced by the locality.     

Microbial communities of the stratified soda Lake Doroninskoe (Transbaikal region)

The physicochemical properties, species composition, and vertical distribution of microorganisms in the water column, shoreline microbial mat, and small shoreline mud volcanoes of the stratified soda Lake Doroninskoe were investigated in September 2007. The lake is located in the Transbaikal region, in the permafrost zone (51°25′N; 112°28′E). The maximal depth of the contemporary lake is about 6 m, the pH value of the water is 9.72, and the water mineralization in the near-bottom horizon is 32.3 g l⁻¹. In summer, the surface oxygen-containing horizon of the water column becomes demineralized to 26.5 g l⁻¹; at a depth of 3.5–4.0 m, an abrupt transition occurs to the aerobic zone containing hydrosulfide (up to 12.56 g l⁻¹). Hydrosulfide was also detected in trace quantities in the upper water horizons. The density stratification of the water column usually ensures stable anaerobic conditions until the freezing period (November and December). The primary production of oxygenic phototrophs reached 176–230 μg l⁻¹. High rates of dark CO₂ assimilation (61–240 μg l⁻¹) were detected in the chemocline. Within this zone, an alkaliphilic species of sulfur-oxidizing bacteria of the genus Thioalkalivibrio was detected (10⁴ cells ml⁻¹). Lithoheterotrophic bacteria Halomonas spp., as well as bacteriochlorophyll a-containing aerobic anoxygenic phototrophic bacteria (AAP) Roseinatronobacter sp. capable of thiosulfate oxidation, were isolated from samples collected from the aerobic zone (0–3 m). The water transparency in September was extremely low; therefore, no visible clusters of anoxygenic phototrophic bacteria (APBs) were detected at the boundary of the hydrosulfide layer. However, purple sulfur bacteria which, according to the results of the 16S rRNA gene analysis, belong to the species Thioalkalicoccus limnaeus, Ectothiorhodospira variabilis, “Ect. magna,” and Ect. shaposhnikovii, were isolated from samples of deep silt sediments. Ect. variabilis and Ect. shaposhnikovii were the major APB species in the shoreline algo-bacterial mat. The halotolerant bacterium Ect. shaposhnikovii, purple nonsulfur bacteria of the genus Rhodobacter, and AAP of Roseococcus sp. were isolated from the samples collected from mud volcanoes. All these species are alkaliphiles, moderate halophiles, or halotolerant microorganisms.     

Faunal trophic interaction in an oligotrophic-dystrophic lake (Shirakoma-ike, Japan)

 The trophic interaction in the pelagic food web of oligotrophic-dystrophic Lake Shirakoma-ike was investigated by a stable isotope technique. Carbon and nitrogen isotope analyses revealed the trophic interaction among Piona carnea (a water mite), Chaoborus sp. (a phantom midge), Daphnia longispina (a cladoceran), and Acanthodiaptomus pacificus (a calanoida copepoda). The δ¹³C values for estimating the relative contributions of D. longispina and A. pacificus to carnivores were used, and they were also used for the constraint of the trophic enrichment factor of δ¹⁵N. Both Chaoborus sp. and P. carnea were suggested to consume D. longispina and A. pacificus at almost the same ratio (1 : 1). However, both carnivores preferred A. pacificus to D. longispina, because D. longispina was much more abundant in the lake than A. pacificus. Omnivory of P. carnea was also analyzed by the mixing model. Received: February 28, 2002 / Accepted: July 10, 2002 Present address: Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Tel. +81-52-789-3434; Fax +81-52-789-3436 e-mail: lee@ihas.nagoya-u.ac.jp Present address: Research Institute for Humanity and Nauture, Kyoto, Japan Acknowledgments We would like to thank Professor Kikuo Kato for providing useful comments and colleagues in the Laboratory of Biogeochemical Data Analysis, Nagoya University, for their support with the sample collection. We are in debt to Dr. R. Coucett for the kind suggestion on the trophic enrichment factors for blood-sucking insects. We also thank the members of the Suwa Hydrobiological Station, Shinshu University, who kindly allowed us to use facilities for sampling in Lake Shirakoma-ike. The zooplankton samples were partly provided by Mr. Masataka Yoshida. Correspondence to:J.-Y. Lee     

Comparative analysis of the digestive efficiency and nitrogen and energy requirements of the phyllostomid fruit-bat (Artibeus jamaicensis) and the pteropodid fruit-bat (Rousettus aegyptiacus)

Nitrogen (N) and energy (E) requirements of the phyllostomid fruit bat, Artibeus jamaicensis, and the pteropodid fruit bat Rousettus aegyptiacus, were measured in adults that were fed on four experimental diets. Mean daily food intake by A. jamaicensis and R. aegyptiacus ranged from 1.1–1.6 times body mass and 0.8–1.0 times body mass, respectively. Dry matter digestibility and metabolizable E coefficient were high (81.1% and 82.4%, respectively) for A. jamaicensis and (77.5% and 78.0%, respectively) for R. aegyptiacus. Across the four diets, bats maintained constant body mass with mean metabolizable E intakes ranging from 1357.3 kJ · kg^−0.75 · day⁻¹ to 1767.3 kJ · kg^−0.75 · day⁻¹ for A. jamaicensis and 1282.6–1545.2 kJ · kg^−0.75 · day⁻¹ for R. aegyptiacus. Maintenance E costs were high, in the order of 3.6–5.4 times the basal metabolic rate (BMR). It is unlikely that the E intakes that we observed represent a true measure of maintenance E requirements. All evidence seems to indicate that fruit bats are E maximizers, ingesting more E than required and regulating storage by adjusting metabolic output. We suggest that true maintenance E requirements are substantially lower than what we observed. If it follows the eutherian norm of two times the BMR, fruit bats must necessarily over-ingest E on low-N fruit diet. Dietary E content did affect N metabolism of A. jamaicensis. On respective low- and high-E diets, metabolic fecal N were 0.492 mg N · g⁻¹ and 0.756 mg N · g⁻¹ dry matter intake and endogenous urinary N losses were 163.31 mg N · kg^−0.75 · day⁻¹ and 71.54 mg N · kg^−0.75 · day⁻¹. A. jamaicensis required 332.3 mg · kg^−0.75 · day⁻¹ and 885.3 mg · kg^−0.75 · day⁻¹ of total N on high- and low-E diets, respectively, and 213.7 mg · kg^−0.75 · day⁻¹ of truly digestible N to achieve N balance. True N digestibilities were low (29% and 49%) for low- and high-E diets, respectively. For R. aegyptiacus, metabolic fecal N and endogenous urinary N losses were 1.27 mg N · g⁻¹ dry matter intake and 96.0 mg N · kg^−0.75 · day⁻¹, respectively, and bats required 529.8 mg · kg^−0.75 · day⁻¹ (total N) or 284.0 mg · kg^−0.75 · day⁻¹ (truly digestible N). True N digestibility was relatively low (50%). Based on direct comparison, we found no evidence that R. aegyptiacus exhibits a greater degree of specialization in digestive function and N retention than A. jamaicensis. When combined with results from previous studies, our results indicate that all fruit bats appear to be specialized in their ability to retain N when faced with low N diet. Accepted: 24 November 1998     

Overstreetia olsoni n. sp. (Digenea: Zoogonidae) from the Capricorn silverside Atherinomorus capricornensis (Woodland) (Atherinidae) off Heron Island, southern Great Barrier Reef

A new species, Overstreetia olsoni, is described from Atherinomorus capricornensis off Heron Island on the Great Barrier Reef off Queensland, Australia. It differs from its only known congener in that the enlarged spines of the circum-oral rows are smaller ( ≤ 4.5 × 3.5 vs ≤ 21.5 × 10.5μm), the sucker-ratio is smaller (1: 0.97–1.01 vs 1:1.8) and the eggs are larger (40–45 × 22–28 vs 34–37 × 17–22μm).     

Ethidium bromide binding to native and denatured poly(dA)poly(dT)

Isotherms of the EtBr adsorption on native and denatured poly(dA)poly(dT) in the temperature interval 20–70°C were obtained. The EtBr binding constants and the number of binding sites were determined. The thermodynamic parameters of the EtBr intercalation complex upon changes of solution temperature 20–48°C were calculated: 1.0·10⁶ M⁻¹≤K≤1.4·10⁶ M⁻¹, free energy ΔG ^o=−8.7±0.3 kcal/mol, enthalpy ΔH ^o≅0, and entropy ΔS ^o=28±0.5 cal/(mol deg). UV melting has shown that the melting temperature (T _m) of EtBr-poly(dA)poly(dT) complexes (μ=0.022,4.16·10⁻⁵ M EtBr) increased by 17°C as compared with the ΔT _m of free homopolymer, whereas the half-width of the transition (T _m) is not changed. It was shown for the first time that EtBr forms complexes of two types on single-stranded regions of poly(dA)poly(dT) denatured at 70°C: strong (K ₁=1.7·10⁵ M⁻¹; ΔG ^o=−8.10±0.03 kcal/mol) and weak (K ₂=2.9·10³ M⁻¹; ΔG ^o=−6.0±0.3 kcal/mol).The ΔG ^o of the strong and weak complexes was independent of the solution ionic strength, 0.0022≤μ≤0.022. A model of EtBr binding with single-stranded regions of poly(dA)poly(dT) is discussed.     

Phylogenetic Analysis of Three Lipocalin-Like Proteins Present in the Milk of Trichosurus vulpecula (Phalangeridae, Marsupialia)

Three proteins have been identified in the milk of the common brush tail possum, Trichosurus vulpecula that from sequence analysis are members of the lipocalin family. They include β-lactoglobulin, which appears to have two forms; a homologue to the late-lactation protein found in tammar, Macropus eugenii; milk; and a novel protein termed trichosurin. Whereas β-lactoglobulin and trichosurin are both expressed throughout lactation, the late-lactation protein is not detected in samples taken before days 100–110 of lactation. The cDNAs encoding each of these proteins have been isolated from cDNA libraries prepared using possum mammary mRNA and sequenced. Phylogenetic analysis showed that the T. vulpeculaβ-lactoglobulin, along with two other macropod β-lactoglobulins, forms a subclass of β-lactoglobulins distinct from those for eutherian mammals; both marsupial late-lactation proteins appear to have similarities to a family of odorant-binding proteins, whereas trichosurin has similarities to the major urinary proteins of rodents. Received: 28 October 1996 / Accepted: 19 May 1997     

Distribution and abundance of postlarval and juvenile Pleuragramma antarcticum (Pisces, Nototheniidae) off Terra Nova Bay (Ross Sea, Antarctica)

During the Italian Antarctic Expedition of 1987–1988 zooplankton was collected in Terra Nova Bay (Ross Sea) by a multinet BIONESS (250-μm or 500-μm net mesh size). The early life history of Pleuragramma antarcticum was described from 268 samples. More than 98% of a total of 34,436 fish larvae belonged to P. antarcticum. The mean relative abundance in the whole area for positive 0 to 150-m hauls was 434 ind./100 m³ (±720 SD). Postlarvae were most abundant and frequent in the samples (99.8%) while low concentrations of juveniles were found (n=67). Length of age group 0 ranged from 8 to 20 mm and age group 1+ were from 36 to 53 mm. Average growth rate over a period of 1 year was 0.08 mm per day. Based on modal values, the mean daily increment of P. antarcticum postlarvae in the period 5 January to 2 February (29 days) was about 0.21 mm. Highest abundances occurred near Cape Washington (mean: 2,108 ind./100 m³) while lower densities were recorded in the northern basin of the self (31 ind./100 m³). Horizontal and vertical distribution patterns in Terra Nova Bay seem to be strictly correlated to hydrographic features and different water masses with highest densities associated with the westward flowing current of the limb of the Antarctic coastal current and southern limb of the Ross Sea Gyre. These currents become part of the clockwise gyre in Terra Nova Bay. More than 62% of the postlarvae were collected in well-stratified warm surface water (0–50 m) near the summertime thermocline (20–70 m). The northern part of Terra Nova Bay seems to represent nursery ground of early stages of P. antarcticum and the presence of permanent polynya could provide favourable food conditions for development of the first stages of life. Differing distribution patterns probably reflect an interaction of various parameters including bathymetry, floating ice shelf, hydrographic features such as currents, local eddies and frontal systems, with P. antarcticum postlarval biology (spawning) and ecology (feeding, horizontal and vertical distribution patterns). Received: 10 June 1996 / Accepted: 19 July 1997     

Boron Contents of Some Wild-Growing Mushrooms Collected from the Vicinity of Boron Mines in Balikesir,Turkey

The aim of the study was to determine the boron contents of some wild-growing mushrooms collected from the vicinity of several boron mines located in Balikesir, Turkey and compare the boron contents of some mushroom and soil samples. The locations of the mushroom samples collected were within the distance of 0–100, 100–500, and 500–1,000 m to the mines. Soil samples were taken from beneath randomly selected fungal fruit bodies. A total of 40 mushroom samples were found in the study area and 37 different species were identified. Among the 40 samples analyzed, the highest boron content was detected to be 273 mg kg⁻¹ in Suillus collinitus. Also, Tricholoma terreum (69.52 mg kg⁻¹), Myxomphalia maura (36.52 mg kg⁻¹), Otidea concinna (30.70 mg kg⁻¹), Sepultaria arenosa (28.94 mg kg⁻¹), Melanoleuca paedida (28.33 mg kg⁻¹), and Lycoperdon lividum (28.31 mg kg⁻¹) relatively have high levels of boron and these species are proposed as candidates for boron accumulation. The boron contents of the other mushrooms varied and a pattern was observed where the boron content was found to be decreased as the distance from the mines increased.     

Seasonal photosynthetic performance of the endemic antarctic red algaPalmaria decipiens (Reinsch) Ricker

 A male gametophyte of the endemic Antarctic red macroalga Palmaria decipiens (Reinsch) Ricker was cultivated under fluctuating daylengths, simulating the seasonal changes at the site of collection (King George Island, Antarctica). The plant was maintained at 0±1°C, an irradiance of 25 μmol m^-2 s^-1 and under growth-saturating nutrient conditions. Samples were taken at intervals of 3–6 weeks to measure growth, photosynthesis, dark respiration and pigment content. The growth optimum in spring coincided with a higher photosynthetic activity. Whereas dark respiration was constantly low over the year, there was a rapid increase in maximum photosynthetic rate (P_max) in conditions corresponding to September and October. This was correlated with a change in the initial slope (α) of the photosynthesis versus irradiance (P vs I) curve. Higher activity in photosynthesis mainly resulted from higher Chl a and phycobilin concentrations during Antarctic spring, an indication of an increase in absorption cross-section areas of photosynthetic reaction centres. These changes in physiology are discussed in relation to the seasonal growth “strategy” of the species, which is controlled by seasonal variation in daylength. Received: 27 February 1995/Accepted 3 October 1995     

Microbial activity in the sediment of the Sognefjord (Norway)

The activity of microorganisms was investigated in sediment samples of the Norwegian Sognefjord at a 1260 m depth. The enzymatic potential (measured, using the cleavage of fluoresceindiacetate FDA) ranged between 11 and 29 nmol FDA cm⁻³ h⁻¹. LabeledAnacystis sp. (Cyanobacteria) were degraded (measured as liberation of¹⁴C-labeled CO₂) at a rate of 0.67–1.24% day⁻¹. The assays were run at 1 atm and at 126 atm pressure. In both cases, activity was higher when samples were incubated under 1 atm than under simulated in-situ conditions. This indicates that the sediment community of the fjord is adapted only to a limited extent to the elevated pressure at the bottom. The results are compared and discussed with data from other deep marine environments.     

Migratory histories of three types of Cottus pollux (small-egg, middle-egg, and large-egg types) as revealed by otolith microchemistry

 Migratory histories of three types of Cottus pollux, the small-egg type (SE type), middle-egg type (ME type), and large-egg type (LE type), were studied by examining strontium (Sr) and calcium (Ca) in their otoliths with wavelength dispersive X-ray spectrometry on an electron microprobe. The Sr : Ca ratios in the otoliths changed both with ontogenetic development and with salinity of the habitat. Otolith Sr : Ca ratios of LE-type samples and the ME-type samples from the Honmyo River, Kyushu Island, showed consistently low ratios, averaging 1.8 × 10⁻³ and 2.4 × 10⁻³ from the core to the edge, respectively. In contrast, otolith Sr : Ca ratios of SE-type samples and the other four ME-type samples from Hokkaido and Honshu Islands fluctuated strongly along the life history transects in accordance with migration patterns from freshwater to the sea and vice versa. The otolith Sr : Ca ratios of SE-type samples showed low ratios from the core to a point around 15 μm, averaging 1.5 × 10⁻³, and subsequently increased sharply with a high Sr : Ca ratio phase to a point around 400 μm, averaging 5.5 × 10⁻³, and followed again a low ratio phase to the edge with averages of 3.1 × 10⁻³. Similar fluctuation patterns in otolith Sr : Ca ratios were found for the four ME-type samples. These findings clearly demonstrated that otolith Sr : Ca ratios reflected the sculpin's life histories, as being fluvial for the LE type and the Honmyo River ME type and amphidromous for the SE type and the other four populations of ME type. Received: August 1, 2002 / Revised: October 15, 2002 / Accepted: October 28, 2002 Acknowledgments We thank Dr. N. Miyazaki, University of Tokyo, for his kind guidance of our joint research. Thanks are also offered to Drs. H. Sakai, National Fisheries University, Y. Yamazaki, Toyama University, and R. Yokoyama, Hokkaido University, and Mrs. N. Okabe and Y. Suzuki of Yamagata Prefecture for their help in sample collection. This work was partly supported by a Grant-in-Aid (No. 13660171) from the Japan Ministry of Education, Science, Sports and Culture to A. Goto. Correspondence to:Akira Goto