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  • 1
    Electronic Resource
    Electronic Resource
    Length of larval life in twelve families of fishes at “One Tree Lagoon”, Great Barrier Reef, Australia (1983)
    Springer
    Marine biology 76 (1983), S. 319-324 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The length of larval life in some coral reef fishes was estimated from the number of growth increments in the otoliths of newly settled fishes. We examined 210 individuals comprising 38 species and 5 unidentified taxa, and belonging to 12 families. During 2 successive austral summers (1976–1977 and 1978–1979), specimens were collected from the lagoon at One Tree Reef, Great Barrier Reef, Australia. By assuming that growth increments in otoliths are laid down on a regular daily cycle commencing near the time of hatching, we calculated typical ages ranging from 3 to 6 wk with a minimum of just over 2 wk and a maximum of 12 wk. The otoliths also contain distinctive microstructural features which can serve as approximate temporal markers for the change from the postlarval to juvenile life stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393035
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  • 2
    Electronic Resource
    Electronic Resource
    Amylase, cellulase and protease activities in surface and gut tissues ofDendraster excentricus, Pisaster ochraceus andStrongylocentrotus droebachiensis (Echinodermata) (1991)
    Springer
    Marine biology 109 (1991), S. 53-57 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In general, variance in tissue hydrolase (amylase, cellulase and protease) activity between individuals of a particular species is as great or greater than variance between tissue types or between species, e.g. although the specific activity of amylase in the gut tissue ofDendraster excentricus is significantly lower than that of aboral surface tissue, it is not significantly different than that of the oral surface tissue, or of the aboral surface of eitherPisaster ochraceus orStrongylocentrotus droebachiensis. Cellulase activity of the gut tissue ofS. droebachiensis was significantly higher than that of the gut tissue ofP. ochraceus andD. excentricus, reflecting the omnivorous feeding habit of the sea urchin. Cellulase activity of the gut tissue ofD. excentricus was not significantly higher than inP. ochraceus, an unexpected result, given the highly carnivorous behavior of the latter. Protease activity of the gut tissue ofD. excentricus is significantly higher than that of the oral or aboral surface tissues, but not significantly higher than that of the gut tissues ofP. ochraceus orS. droebachiensis. Amylase and cellulase activities in the guts of detritus- and shrimp-fedD. excentricus showed significant increases over that of field individuals; protease activity displayed no significant increase. Some significant surface (oral and aboral) changes were noted with respect to hydrolase activity, but the direction and lack of consistency of the changes argues that these are incidental to the process of digestion. The lack of significant differences in the surface enzyme activity ofD. excentricus, P. ochraceus andS. droebachiensis suggests that macronutrient digestive events in surface tissues are not uniquely important inD. excentricus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320231
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  • 3
    Electronic Resource
    Electronic Resource
    The production and secreton of digestive enzymes in the purple seastar Pisaster ochraceus (1975)
    Springer
    Marine biology 29 (1975), S. 261-266 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The purple seastar Pisaster ochraceus contains clearly measurable protease and amylase activity. Centrifuged supernatants of pyloric caeca homogenates undergo a spontaneous threefold increase in protease activity when incubated under toluene for 50 h at 25°C. Amylase activity remains nearly constant over this period. Bovine trypsin at a 1 to 100 ratio (trypsin to supernatant protein) induces a twofold increase in protease activity over that of the control supernatant while having virtually no effect on amylase activity over the control. The data indicate a specific interaction of trypsin with a protease zymogen rather than a conspecific hydrolysis of membrane components or vesicles by trypsin. Two percent Triton X-100 used as a diluent in place of distilled, deionized water causes a sevenfold increase in protease activity and a twofold increase in amylase activity in pyloric caeca supernatants. The use of Triton as a diluent in the preparation of a stomach-tissue supernatant allows quantitative measurement of both protease and amylase activity in that tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391852
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  • 4
    Electronic Resource
    Electronic Resource
    Spatial and temporal patterns of recuruitment of juvenile coral reef fishes to coral habitats within “One Tree Lagoon”, great barrier reef (1981)
    Springer
    Marine biology 65 (1981), S. 245-253 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recruitment of juvenile fishes to coral grids, each comprising 4 colonies of 3 species of coral (Acropora formosa, Seriatopora hystrix and Pocillopora damicornis), was examined at 4 widely separated sites within the lagoon of “One Tree Reef” over two successive summers and intervening months (November 1976–January 1978). Recruitment was highly seasonal, with most recruitment occurring during summer. For many species, numbers settling differed greatly from year to year with total numbers (over all sites) differing as much as an order of magnitude between summers. Many fish species demonstrated marked preference among the three coral species as settling sites. The distribution of each of the 20 commonest species across the 4 lagoon sites differed significantly from a random pattern. Differences of an order of magnitude were common in the numbers of a given species recruited to different sites. Each site was preferred by at least one species. In each of 5 cases examined, the pattern of settlement of the species across the 4 sites changed significantly from one summer to the next. The distribution of recruits of a number of species corresponded to the distribution of adults, but for other species there was no correspondence. It is concluded that, at the spatial scale examined, patterns of recruitment of some taxa are consistently more variable than those of other taxa. The implications of spatial variability of recruitment for the distribution of adult fish is discussed and the importance of being able to discriminate such “natural” variability from other kinds of change is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397118
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  • 5
    Electronic Resource
    Electronic Resource
    β-glucanase activity in the seastar Pisaster ochraceus (1995)
    Springer
    Marine biology 123 (1995), S. 735-740 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Specimens of Pisaster ochraceus, an intertidal carnivorous seastar, were collected in northern Puget Sound at Post Point, near Bellingham, Washington, USA, in November 1993, and used in experimentation through September 1994. Ammonium sulfate fractions (60% precipitates) from excised pyloric caeca (digestive glands) possessed β-glucanase activity directed toward such β-linked substrates as carboxymethylcellulose (CMC), partially-digested cellulose (cellodextrins) and the synthetic substrate p-nitrophenyl-β-D-glucoside (PNDG). pH-activity and pH-stability maxima were at pH 6 and 5, respectively. No hydrolytic activity was detectable on native cellulose, native chitin or on cationic-modified celluloses such as DEAE-cellulose. Gel filtration (Sephadex G-100) of this 60% precipitate followed by DEAE-Sephadex column chromatography revealed heterogeneity of β-glucanase activity, with an indication of up to 11 distinct fractions with variable activity directed toward the substrates indicated above (CMC, cellodextrins and PNDG). These fractions displayed differing ratios of hydrolytic activity on these substrates. None of the isolated fractions displayed activity toward either native cellulose or native chitin. Gut extracts from the edible mussel (Mytilus edulis), a common prey species of P. ochraceus, were shown to possess partially digested cellulose (cellodextrins). These cellodextrins were further degraded by seastar β-glucanases in vitro. The digestion of the gut contents of ingested prey provides a possible adaptive explanation for the presence of β-glucanase activity in a carnivore.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349116
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  • 6
    Electronic Resource
    Electronic Resource
    Rates of nitrogen fixation on coral reefs across the continental shelf of the central Great Barrier Reef (1984)
    Springer
    Marine biology 80 (1984), S. 255-262 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study was undertaken in 1981 to determine whether there were major variations in potential rates of nitrogen fixation on apparently bare coralline substrate from reefs across the continental shelf of the central Great Barrier Reef. Nitrogen fixation, measured as rates of ethylene production (nmol cm-2h-1), was significantly lower on substrata from two inner-shelf reefs, (0.46 and 1.07) than on two middle-shelf reefs (2.10 and 2.97) and on two outer-shelf reefs (3.20 and 3.81). By contrast, algal biomass (mg cm-2) on experimental substrate was significantly higher on inner-shelf reefs (80.8 and 59.4) than on middleshelf (27.1 and 23.8) and outer-shelf reefs (26.4 and 22.4). The rate of nitrogen fixation was positively correlated with the proportion of “bare” substratum and significantly higher concentrations of dissolved inorganic nitrogen were found in waters over the reefs than in water flowing onto those reefs. The abundance of algal-grazing fishes was reported previously to be significantly lower on inner-shelf reefs. It is suggested that this cross-shelf variation in the activity of algal-grazing fishes may be a determinant of the observed cross-shelf variations in potential nitrogen fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392820
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of feeding and starvation on proteolytic and tryptic activities in pyloric caecal tissues and duct fluids of the seastar Pisaster ochraceus (1985)
    Springer
    Marine biology 90 (1985), S. 55-59 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pisaster ochraceus were collected at Post Point, Bellingham, Washington, USA, in 1980. Total protease and tryptic specific activities were measured in pyloric caecal tissues and pyloric duct fluids of fed and starved individuals. Feeding resulted in increased levels of total protease and tryptic activities, and led to an increase in the ratio of total protease to tryptic specific activity in pyloric caecal tissue and a decrease in that ratio in pyloric duct fluid, indicating a release of trypsin into the duct with feeding. Trypsin activity showed little variability in fed seastars, but was quite variable in starving individuals. Total proteolytic acitivity, unlike that of tryptic activity, was always present in both fed and starved seastars. This way indicate a much broader role of generalized proteases in the cells of the pyloric caecum (e.g. as lysosomal enzymes of absorptive cells) in comparison to tryptic enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428214
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  • 8
    Electronic Resource
    Electronic Resource
    Stable isotopic investigation of physiological and environmental changes recorded in shell carbonate from the giant clam Tridacna maxima (1987)
    Springer
    Marine biology 94 (1987), S. 385-393 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The aragonitic shell of the photosymbiont-bearing bivalve Tridacna maxima contains a record of the physiological and environmental changes the organism has experienced during its lifetime. This record is preserved as chemical and microstructural variations throughout the shell. Stable isotopic analyses of oxygen (18O/16O) and carbon (13C/12C) in shell carbonate were combined with growth increment studies to interpret the shell record of specimens collected from the Rose Atoll (Lat. 14°31′S; Long. 168°10′W) in April 1982. The seasonal water temperature cycle is recorded in the oxygen isotopic signature of the clams, permitting the recognition of annual cycles in the δ18O profile. The total number of these cycles corresponds to the age of a specimen, while the cycle length is a measure of the yearly growth rate. Large-amplitude cycles, reflecting year-round calcification, characterize the early portion of the growth record. With the onset of sexual maturity and slower growth at an age of approximately ten years, the cycles decrease in amplitude and become more erratic. During this later growth phase calcification is limited to the cooler months of the year, perhaps in response to a re-ordering of energy priorities between growth and gametogenesis. A growth curve developed from the δ18O profile indicates rapid juvenile shell growth followed by slower growth thereafter producing a lifespan of several decades. Carbon isotopic analyses of T. maxima were compared to analyses of the symbiont-barren gastropod Terebra areolata collected from the same locality in April 1984. A 2‰ depletion in the δ13C composition of T. maxima shell carbonate is attributed to a symbiontenhanced metabolic rate and an increased flow of isotopically light, respired CO2 into the carbon pool used in calcification. Such a depletion may prove useful in identifying the presence of photosymbionts in extinct species of fossil mollusks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428244
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  • 9
    Electronic Resource
    Electronic Resource
    Isolation, purification and partial characterization of four digestive proteases from the purple seastar Pisaster ochraceus (1988)
    Springer
    Marine biology 97 (1988), S. 231-236 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An investigation of enzymatic activity in the pyloric caeca of Pisaster ochraceus collected at Post Point, Bellingham, Washington, USA, in 1982, revealed the presence of four distinct proteases. These enzymes have been partially purified and characterized and display tryptic, chymotryptic and carboxypeptidase A-like activity. The two distinctive tryptic enzymes have molecular weights of 88 000 and 25 200 daltons, respectively, as determined by reducting SDS-PAGE electrophoresis. The chymotryptic and carboxypeptidase A proteases have molecular weights of 22 800 and 34 400 daltons, respectively. The tryptic and chymotryptic enzymes are inactivated by phenylmethylsulfonyl fluoride, indicating that all are serine proteases. Both trypsins are inhibited by soybean trypsin inhibitor; however, the high molecular weight trypsin was not inhibited by tosyl-L-lysine chloromethyl ketone. The chymotrypsin was inhibited by tosyl-L-phenylalanine chloromethyl ketone. Both reagents indicate the involvement of histidine in the active site. The low molecular weight trypsin and the chymotrypsin were able to activate bovine trypsinogen to trypsin, as determined in a modified PAGE electrophoresis with trypsinogen and casein copolymerized in the gel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391307
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  • 10
    Electronic Resource
    Electronic Resource
    Response of pioneer soil microalgal colonists to environmental change in Antarctica (1996)
    Springer
    Microbial ecology 31 (1996), S. 177-188 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract There is increasing evidence of climate change in Antarctica, especially elevated temperature and ultraviolet B (UVB) flux within the ozone “hole.” Its origins are debatable, but the effects on ice recession, water availability, and summer growth conditions are demonstrable. Light-dependent, temperature-sensitive, fast-growing organisms respond to these physical and biogeographical changes. Microalgae (cyanobacteria and eukaryotic algae), which are pioneer colonists of Antarctic mineral fellfield soils, are therefore highly suitable biological indicators of such changes. In frost-heaved soil polygons containing naturally sorted fine mineral particles, microalgal growth is restricted to a shallow zone of light penetration. By virtue of this light requirement, microalgae are exposed to extreme seasonal fluctuations in temperature (air and black-body radiation), photosynthetically active radiation, UV radiation, and desiccation. Dominance of conspicuous autofluorescent indicator species with distinctive morphology allowed quantification of responses using epifluorescence microscopy, and image analysis of undisturbed, unstained communities. However, the physical changes in climate, although significant in the long term, are gradual. The changes were therefore amplified experimentally by enclosing the communities at a fellfield site on Signy Island, maritime Antarctica, in cloches (small greenhouses). These were made of polystyrene of either UV transparent or UV opaque acrylic plastic, with or without walls. During a 6-year period, statistically significant changes were observed in microalgal colonization of the soil surface and in the morphology of filamentous populations. Evidence of community succession correlated with measured changes in local environment was found. Results from Signy Island and at continental sites on Alexander Island suggested that rates of microalgal colonization and community development might change significantly during current climate changes in Antarctica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167863
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