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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 73 (1983), S. 269-283 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Special hydrodynamic-chemical conditions at the East Flower Garden brine seep have provided the opportunity to examine the community structure of the thiobios and the oxybiotic-thiobiotic boundary. The boundary between the thiobios, whose population maxima occur in sulfidedependent chemoclines and which presumably have an ecologic requirement for sulfide, and the oxybios, which occur in oxidized zones above the chemocline, is controlled by sulfide, not oxygen. The boundary, which may not be at zero sulfide, is determined by a time-concentration phenomenon based on a dynamic interplay of sulfide and oxygen supply rates and the biota's sulfide detoxification capabilities. In Gollum's Canyon, where oxygen is plentiful, the boundary is at 10–40 μg-atoms·l-1 sulfide. Total abundances of organisms at thiobiotic stations were comparable to total abundances at oxybiotic stations. Highest thiobiotic abundance was 202 051 organisms per m2; highest oxybiotic abundance was 240 572 organisms per m2. The thiobios is dominated by representatives of the lower Bilateria (viz. Gnathostomulida, Platyhelminthes and Aschelminthes). These groups accounted for 50–80% of all the organisms present in the thiobiotic stations but less than 20% of all organisms in the oxybiotic stations. At two thiobiotic stations, over 50% of all organisms were gnathostomulids. Thiobios included macrofaunal as well as meiofaunal components. Peak abundances of amphipods were associated with the thiobiotic environment.
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  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calcification rate in the coral Acropora cervicornis was reduced significantly when exposed for 24 h to 100-ppm kaolin, but was unchanged in corals exposed to 50-ppm kaolin. Calcification rate returned to control levels during a 48-h recovery period. Most free amino acids (FAA) in the FAA pool decreased significantly in corals exposed to 100-ppm kaolin, but were unchanged in corals exposed to 50-ppm kaolin. After a 48-h recovery period, the FAA pool remained considerably below control levels in the 100-ppm exposed corals and dropped below control levels in the 50-ppm exposed corals. Calcification rate dropped less and later during the exposure period in the growing tip than in sections further down the stalk. The reduction in FAA pool size was considerably larger in the growing tip than further down the stalk. Soluble protein concentration remained unchanged during both exposure and recovery. The data are consistent with the interpretation that turbidity not only causes a decrease in photosynthetic rate and the synthesis of small molecules, but also causes a large increase in the utilization of stored organic molecules for such metabolically costly processes as mucus production and sediment removal.
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  • 3
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. A quantitative gonadal index was developed for oysters, Crassostrea virginica (Gmelin. 1791), using polyclonal antibodies from eggs and sperm. Percoll used in the purification of oyster eggs and sperm greatly improved the purity of antigens compared to filtering the egg or sperm through a fine mesh only. The antigen-antibody reaction was tested with indirect sandwich ELISA using alkaline phosphatase-conjugated goat anti-rabbit igG as a secondary antibody. Rabbit anti-oyster egg IgG and anti-oyster sperm IgG initially exhibited a weak cross-reactivity over somatic tissue. Absoring with acetone-dried oyster tissue powder removed this cross-reactivity. Both antisera exhibited strong specific immunological reactions to oyster eggs or sperm respectively. The quantity of eggs or sperm was measured using ELISA and a quantitative gonadosomatic index (dry wt of egg or sperm/dry wt oyster) (GSI) calculated. GSI from ELISA correlated with gonadal stage measured histologically. Monthly mean GSI of female oysters was highest during late spring to early summer (0·157–0·201) and lowest during early winter to early spring (0·002-0·000). Maximum GSI observed during the study was 0·422 for female oysters and 0·446 for male oysters. Female oysters produce 3·7–65·4 million eggs, with an average of 21·1 million during each spawning. A positive correlation was observed between the number of eggs produced and oyster size; the number of eggs in the gonad increased as oyster size (i.e. total dry wt) increased (r= 0·67); however, the relationship was non-linear. Large oysters contained proportionally fewer eggs. Prevalence of Perkinsus marinus parasitism was high, 90–100%, during the study, as was weighted incidence, 1·33 to 2·67, No statistically significant correlation was observed between infection intensity and the per cent weight of oyster eggs or egg number.
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  • 4
    Electronic Resource
    Electronic Resource
    Berlin, Germany : Blackwell Verlag GmbH
    Journal of applied ichthyology 21 (2005), S. 0 
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The Illex illecebrosus fishery in the northwestern Atlantic Ocean is a trawl-based fishery. Illex illecebrosus normally lives 〈1 year, thus managing the fishery using a standard stock assessment approach is difficult. Real-time management is an attractive option. The purpose of this study was to investigate the utility of data on size composition reported by commercial vessels for application in real-time management in the I. illecebrosus fishery. Observations were collected from fish processors for 1996–98 and from fishing vessels directly reporting in 1999–2001. Mean size of I. illecebrosus increased more or less steadily through the fishing season in each year. Apparent growth rates, determined by evaluating the change in mean size in the catch, varied considerably between years. Apparent growth rates appear to be reasonable expressions of true growth rates because either the bulk of the squid entered the fishery at the beginning of the fishery and remained with the fishery for the duration of the season, or the squid on the outer shelf, available to the fishery, represented an emigrated portion of a larger coherent offshore population. Depth exerted only a minor influence on the size of squid caught, whereas the size–frequency varied significantly with latitude. Largest squid were caught at the southern and northern extremes of the study domain. Refrigerated seawater (RSW) trawlers consistently caught smaller squid than did freezer trawlers. The complexity of I. illecebrosus size structure revealed by this study indicates the necessity of obtaining a dispersed data set, in space, with a degree of temporal detail to elucidate trends. Such a data set is conceivably obtainable from fishing vessels reporting information as they fish providing that the sampling design addresses issues concerning the dispersion of vessels across latitude, the appropriate composition of the reporting fleet, and the collection of sufficient observations per tow to adequately resolve the range in size as well as the mean.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International journal of earth sciences 88 (1999), S. 377-391 
    ISSN: 1437-3262
    Keywords: Key words Cold seep ; Petroleum seep ; Continental shelf distribution ; Continental slope ; Hydrothermal vent ; Chemosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Cold-seep communities have relatively low diversity, are dominated by one or two taxa present in high density and high biomass in comparison with the surrounding fauna, and are restricted to aphotic habitats. Their associated heterotrophic fauna are usually distinctive from the fauna of their surroundings. In contrast, a more commonplace chemoautotrophically based community occurs in shallow photic habitats. The associated heterotrophic fauna includes many of the species typical of the surrounding communities and typically dominates abundance, whereas the species with chemoautotrophic symbionts dominate biomass. All modern seep assemblages are deeper than 550 m. Many fossil seep assemblages occurred in water as shallow as the mid-shelf (〈200 m). In contrast, communities where species with chemoautotrophic symbionts are biomass dominants, but not numerical dominants, are common in shallow waters at present but rarely reported in the geological record. We suggest that the absence of cold-seep communities on the continental shelf presently is due to a combination of predation and competitive exclusion by primary consumers limiting the presence of species dependent on chemoautotrophic symbionts. We suggest that cold-seep assemblages are more common at shelf depths in the fossil record for two reasons: (a) The biases of preservation have accentuated their distribution by transforming communities where species with chemoautotrophic symbionts dominate by biomass, but not numerically, into cold-seep-appearing assemblages. (b) The importance of predation pressure and oligotrophy has varied, with decreased predation pressure accompanying increased oligotrophy favoring cold-seep communities. We suggest that the paucity of shallow-water assemblages with species harboring chemoautotrophic symbionts as biomass dominants in the fossil record is based on the reliance of paleoecological analysis on numerical abundance data when energy flow analyses are required to identify these assemblages. The distinctiveness of the fossil seep assemblage is intensified by taphonomic processes that bias the assemblage against small individuals and epifaunal species, so that diversity declines, the small heterotrophic component of the assemblage is significantly reduced, and the epifaunal component is minimized. The final assemblage is usually dominated by the better-preserved large infaunal clams which perchance are also the species with chemoautotrophic symbionts. In contrast, preservation does not enhance the distinctiveness of these chemoautotroph-harboring species in shallow water.
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  • 6
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The effect of used drilling muds on coral health was examined by monitoring changes in calcification rate and soluble tissue protein concentration in the coral Acropora cervicornis. Exposure to 25 ppm (v/v) of one mud for 24 h reduced calcification rate in the growing tips by as much as 62%. In recovery experiments, corals were exposed to drilling muds for 24 h; some of them were allowed to recover in clean seawater for 48 h. After the 24-hour exposure, calcification rates were significantly less than those of the controls. After a 48-hour recovery period, calcification rates returned to control levels for one mud but were still significantly below control levels for another. The results indicate that the capacity for recovery after exposure cannot be predicted from the results of experiments on exposure only. Recovery capacity must be independently verified for all studies on the effects of short-term exposure to drilling muds.
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  • 7
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of changes in vertical and horizontal microscale gradients of oxygen and sulfide on meiofaunal distributions were examined in laboratory microcosms. Specifically, the effect of tube abandonment and reestablishment by macro-infauna on the distribution of subsurface turbellarians, gnathostomulids and gastrotrichs was studied. Meiofauna responded rapidly (within 6 h) to changing sediment chemistry, consistently trying to reoccupy optimal habitat. Every subsurface taxon had a preferred suboptimal habitat which it occupied primarily during transit from deteriorating to newly established optimal habitat. Only during this time did the distribution of ecologically similar taxa overlap substantially. Changes in oxygen and sulfide gradients could explain most but not all of the response; food availability might also be important. Oxybios consistently chose oxic suboptimal microhabitat. Thus behaviorally, as well as biochemically and ecologically, thiobios represent a distinct group among the meiofauna.
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  • 8
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 13 (1984), S. 243-258 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Corals were exposed to drilling mud for 24 hr and then allowed to recover for 48 hr in clean seawater. Depending on the concentration and the mud used, exposure produced either an increase or decrease in free amino acid (FAA) pool size. Aspartate was affected to a greater degree than other amino acids. No clear instance of recovery could be ascertained after 48 hr in clean seawater. In several cases, corals, apparently unaffected by a 24 hr exposure, nevertheless suffered significant changes in the FAA pool during the 48 hr recovery period. Thus, the degree of toxicity of the drilling mud could not be accurately predicted from the 24 hr exposure data. In many cases, the choice of a normalizing parameter determined whether two sets of data were significantly different or not. Accurate effects assessment depends on a comparison of several methods of normalization to confirm statistical results.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 45 (1989), S. 198-200 
    ISSN: 1420-9071
    Keywords: Catalase ; sulfide ; methane ; oxygen ; petroleum seep ; bivalve ; vestimentiferan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vesicomyid and lucinid clams and tubeworms from Gulf of Mexico petroleum seeps, all of which bear symbiotic sulfide-oxidizing bacteria, have much lower catalase activities than shallow-water species lacking symbionts. A petroleum seep mussel bearing methane-oxidizing bacteria is unusual in having catalase activities as high as shallow-water bivalves. Unlike sulfide-dependent meiofauna from shallow-water marine sands, catalase from all petroleum seep species was inhibited by 3-amino-1,2,4-triazole.
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