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  • 1
    Electronic Resource
    Electronic Resource
    Abundance and arm loss of the infaunal brittlestar Ophiophragmus filograneus (Echinodermata: Ophiuroidea), with an experimental determination of regeneration rates in natural and planted seagrass beds (1994)
    Springer
    Marine biology 121 (1994), S. 97-104 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The regeneration rate of arms of the infaunal brittlestar Ophiophragmus filograneus was determined in natural and planted beds of the seagrass (Halodule wrighttii) in Tampa Bay, Florida, USA in 1990. Annually, brittlestar densities did not differ on average between the two beds, but they did show marked differences on individual dates. Rates of arm loss could not be determined for the two sites separately, but were estimated for the entire area. Between 52 and 94% of the brittlestars collected showed evidence of arm regeneration. Approximately one-third of those collected were regenerating one arm, with smaller proportions regenerating two or more arms. Regeneration rate was greater overall for individuals that had lost more tissue; however, the rate of soft-tissue regeneration per arm regenerated was significantly greater for those that had lost one arm compared to those that had lost three arms. The rate of soft-tissue regeneration did not differe between individuals from the two seagrass beds, and regeneration rate was lower than reported for other infaunal brittlestars. Skeletal regeneration per arm was similar in both arm-removal treatments. This result supports the hypothesis that echinoderm skeleton is energetically inexpensive and may help to lengthen arms during early regeneration. The rate of skeletal production was three-fold greater in individuals from the planted seagrass than in those from the natural. bed. As increased skeletal regeneration requires some additional energy, this indicates a greater energy expenditure and differential allocation by brittlestars regenerating in the planted seagrass areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349478
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  • 2
    Electronic Resource
    Electronic Resource
    Meiofauna on the seagrass Thalassia testudinum: population characteristics of harpacticoid copepods and associations with algal epiphytes (1993)
    Springer
    Marine biology 116 (1993), S. 137-146 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The composition and abundance of bladedwelling meiofauna was determined over a 15 mo period (1983–1984) from a Thalassia testudinum Banks ex König meadow near Egmont Key, Florida, USA. Harpacticoid copepods, copepod nauplii, and nematodes were the most abundant meiofaunal taxa on T. testudinum blades. Temporal patterns in species composition and population life-history stages were determined for harpacticoid copepods, the numerically predominant taxon. Sixteen species or species complexes of harpacticoid copepods were identified. Harpacticus sp., the most abundant harpacticoid, comprised 47.8% of the total copepods collected, and was present throughout the study. Copepodites dominated the population structures of the blade-dwelling harpacticoid species on most collection dates. Ovigerous females and/or copepodites were always present, indicating continuous reproductive activity. Results suggest that epiphytic algae influence meiofaunal abundance on seagrass blades, as densities of most meiofaunal taxa at Egmont Key were positively associated with percent cover of epiphytic algae throughout the study. The majority of significant correlations between meiofaunal density and cover of epiphytic algae involved filamentous algae, although encrusting algae dominated the epiphytic community. It appears that resources provided by epiphytic algae to seagrass meiofauna (additional food, habitat, and/or shelter from predation) may be associated with algal morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350741
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  • 3
    Electronic Resource
    Electronic Resource
    Investigations on epibenthic meiofauna I. Abundances on and repopulation of the tube-caps of Diopatra cuprea (Polychaeta: Onuphidae) in a subtropical system (1982)
    Springer
    Marine biology 67 (1982), S. 303-309 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cryptic meiofauna populated the imbricate, shell-sediment matrix of the tube-caps produced by the polychaete Diopatra cuprea (Bose) in Tampa Bay, Florida, USA. Nematodes, copepods (adults and nauplii), polychaetes (adults and juveniles) and amphipods (adults and juveniles) were the most abundant taxa found on tube-caps. Meiofaunal densities on tube-caps were 4 to 19 times higher than equivalent volumes of sediment in cores taken adjacent to D. cuprea tubes. Recruitment onto tube structure occurred within 1 to 2 d after defaunated tube-caps were replanted into sediments in the field (February–November 1980). Repopulation of copepods (adults and nauplii) attained levels equal to or exceeding natural abundances on tube caps within 1 to 5 d; nematode recovery rates were inconsistent. Short-term experiments using a variety of defaunated tube treatments indicated that immigration onto above-sediment tube-caps proceeds via both water column and sediment pathways. Based on data on tube-cap longevity and construction as well as meiofaunal recruitment rates, we conclude that the generation of new tube-cap structure is exploited rapidly by meiofauna.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397671
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    An experimental study of the relationship between below-ground structure and meiofaunal taxa (1983)
    Springer
    Marine biology 76 (1983), S. 33-39 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An experimental study was conducted in a South Carolina, USA salt marsh to examine relationships between meiofaunal-sized tube structure and densities of burrowing meiofauna. Abundance of the tube-building polychaete Manayunkia aestuarina Bourne was increased by erecting exciosure areas from June–August 1979. Non-manipulated areas of identical dimensions were staked out in adjacent locales. Densities of burrowing meiofauna and nematode trophic groups, and volumes of Spartina alterniflora root mat and tube-builders were monitored approximately every 2 wk from each experimental treatment. Volumes of tube-builders were significantly higher inside exclosure sites on all dates in July and August. Root-mat volume and total number of nematodes were not different between treatments at any time. The dominant copepod species, Stenhelia (D.) bifidia, and the nematode species, Spirinia sp., first increased in number inside manipulated sites and then decreased in abundance as tube volume increased. No general trend was apparent for nematode trophic groups when areas with increased volumes of tubebuilders were compared to unmanipulated sites. The fact that densities of S (D.) bifidia and Spirina sp. decreased only when tube-builders attained highest abundance suggests that negative interactions between tube-builders and these meiofaunal taxa may be effective only at elevated abundances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393052
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Short-term temporal variation in population structure of two harpacticoid copepods, Zausodes arenicolus and Paradactylopodia brevicornis (1984)
    Springer
    Marine biology 84 (1984), S. 53-63 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aspects of the population biology of two harpacticoid copepod species [Zausodes arenicolus Wilson and Paradactylopodia brevicornis (Claus)] living in Tampa Bay, Florida, USA, were studied on time scales of hours to days during November 1983. Fluctuations in population agestructure, adult sex-ratio, and proportion of ovigerous females were determined for these two species in a control plot and in an experimental plot defaunated by raking. For both species, immigrants into the defaunated plot differed significantly from conspecifics in the control plot in all characteristics examined. The disturbed plot contained a larger proportion of young juveniles of both species compared to the unmanipulated site after 4 h but not after 8 h. In Z. arenicolus, adult males returned to the experimental plot more quickly than adult females. For both species, rapid and significant changes in population age-structure, adult sex-ratio, and the proportion of adult females with eggs occurred within the control plot. It is suggested that this variation was too large and occurred too rapidly to be accounted for solely by in situ processes in the absence of large-scale immigration and/or emigration of individuals. Potential implications of these results for population studies of harpacticoid copepods and other benthic invertebrates are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394527
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  • 6
    Electronic Resource
    Electronic Resource
    Active swimming in meiobenthic copepods of seagrass beds: geographic comparisons of abundances and reproductive characteristics (1988)
    Springer
    Marine biology 98 (1988), S. 351-358 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The entry of meiobenthic copepods from sediments or seagrass blades into the water column and reproductive characteristics of actively migrating fauna were investigated from 1981–1986 in a temperate intertidal Zostera capricorni seagrass bed in Pautahanui Inlet, New Zealand and in a subtidal Thalassia testudinum bed in Tampa Bay, Florida, USA. Emergence of copepods in New Zealand varied over a tidalcycle, while in Florida a distinct diel periodicity was displayed. Selected copepod species in New Zealand had similar numbers emerging from sediments and/or blades over a 6 h period as the common copepods actively migrating from sediments in Florida. Daily abundances of emerging copepods (24 h) in Tampa Bay, Florida, were substantially greater than those in New Zealand, where migration is linked to tidal cover. In Z. capricorni meadows in New Zealand, sex ratios of copepods in sediments and on blades were dominated by females; males dominated water-column samples. In T. testudinum meadows in Tampa Bay, sex ratios of males to females, although of a lowermagnitude than in Z. capricorni beds, were higher in trap than in sediment samples. Differences in sex ratios, the availability in emergence traps of females of appropriate stage for mating, and observations on clasping in live samples from traps suggest that swimming behavior in copepods may be partly linked to prenuptial courtship. Meiobenthic copepods may use the water column as an important habitat for reproductive behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391111
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