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  • 1
    Electronic Resource
    Electronic Resource
    Population and species diversity fluctuations in a rocky intertidal community relative to severe aerial exposure and sediment burial (1982)
    Springer
    Marine biology 71 (1982), S. 87-96 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From a series of 10 quarterly assessment between October 1975 and May 1978 (inclusive), fluctuations in abundance were determined for macroinvertebrates and macrophytes of a rocky intertidal community on Santa Cruz Island, California, USA. During afternoon low tides in late fall and winter of the first 2 yr of study, organisms of the upper and middle intertidal zones were subjected to prolonged aerial exposure. Many species there tolerated this exposure, but die-backs occurred for a barnacle (Chthamalus fissus/C. dalli) and several algae (Endocladia muricata, Pelvetia fastigiata f. gracilis, Corallina officinalis var. chilensis, Corallina vancouveriensis, Cylindrocarpus rugosus and Codium fragile). These die-backs were succeeded by blooms of Ulva californica and Porphyra perforata. In the upper and middle intertidal zones, the major cover organisms that could tolerate prolonged aerial exposure were disproportionately prevalent and appeared to be maintained by the periodic repression of species intolerant to such exposure. In February 1978, heavy rainfall caused sediment inundation of the middle and lower intertidal zones. This event was followed by declines in abundance of a barnacle (Tetraclita rubescens) and several algae (Pelvetia fastigiata f. gracilis and corallina spp.). Shannon-Wiener H′ species diversity fluctuated from a high in October to a low the following May during both 1975–1976 and 1976–1977 in conjunction with the period of increased daytime aerial exposure in late fall and winter. A further decline in diversity following sediment inundation in February 1978 contributed to a long-term trend of declining H′ species diversity (3.06 in October 1975 to 1.87 in May 1978). We hypothesize that predictable late fall to winter aerial exposure stresses, in combination with a random physical disturbance (sediment burial), exceeded an “optimal” intermediate level of disturbance predicted for maximal species diversity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396995
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Spatial structure of an intertidal molluscan assemblage on a sheltered sandy beach (1978)
    Springer
    Marine biology 46 (1978), S. 137-145 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intertidal molluscan fauna on a sandy-mud beach in Newport Bay, California, USA, is divisible into two vertically distinct species assemblages which correspond to the midlittoral zone and sublittoral fringe observed on rocky coastlines and exposed sandy beaches. The species assemblage comprising the midlittoral zone is unusual, however, in that the numerically dominant species are not confined to this zone but range downward through the sublittoral fringe. The two species assemblages are vertically separated at +0.5 to +1.0 ft (+0.15 to +0.30 m; relative to 0.0 tidal datum at mean lower low water), which is higher than previously observed for the separation between the midlittoral zone and sublittoral fringe on rocky shores and exposed sandy beaches. The species composition of some of the samples at +0.5 and +1.0 ft (+0.15 and +0.30 m) was intermediate between samples higher and lower on the beach, while several samples were devoid of molluscs altogether. Additionally, the surface sedimentary environment changes in terms of an increased percent silt-clay fraction and higher sorting coefficients below +0.5 ft (+0.15 m). Since infaunal zonation is correlated with tidal height at the substrate surface, environmental factors operative at the surface are probably most important in influencing the zonation on this beach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391529
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Predation by the epipelagic heteropod mollusk Carinaria cristata forma japonica (1980)
    Springer
    Marine biology 60 (1980), S. 137-146 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In surface waters off Southern California (USA), Carinaria cristata forma japonica van der Spoel, 1972 feeds on a variety of zooplankton, although thaliaceans, chaetognaths, and copepods predominate numerically in the diet. Feeding intensity is greatest on the most abundant of two species of thaliaceans, depending on which one dominates in the plankton at the time. Some cannibalism occurs, with the prey being about one half the size of the predator. Feeding intensity is greatest during the day, possibly because heteropods depend on vision to locate prey and because prey species are more available by day. Comparisons of the proportion of each prey species in the diet and in the plankton indicate preferential feeding on thaliaceans, chaetognaths, and mollusks; in contrast, crustaceans and especially the copepods are non-preferred prey. These preference patterns may reflect differences among prey species in the ability to escape capture. Predator and prey size are positively correlated for Doliolum denticulatum gonozoids and oozoids, Thalia democratica aggregates, and Sagitta spp. Smaller individuals of D. denticulatum gonozoids and Sagitta spp. are selectively preyed on, resulting in size refuges for larger individuals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389157
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Distribution and abundance of the epipelagic mollusk Carinaria japonica in waters off Southern California (1974)
    Springer
    Marine biology 24 (1974), S. 243-250 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and abundance of the heteropod mollusk Carinaria japonica Okutani is described from midwater trawl records off Southern California (USA) and northern Baja California (Mexico). Maximal numbers of individuals were recorded during August in oceanic waters off Southern California. In oceanic waters near Guadalupe Island, Baja California, low population levels were recorded irrespective of season. In neritic waters over the continental shelf off Southern California, C. japonica were present in low numbers, mainly between July and December when conditions seemed most favorable for their entry into the Southern California Eddy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391899
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Luminescent flashing in the midwater squids Pterygioteuthis microlampas and P. giardi (1982)
    Springer
    Marine biology 69 (1982), S. 299-308 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The luminescent flashing capabilities and swimming behavior were examined for two species of small midwater squids (Pterygioteuthis microlampas and P. giardi). Recently captured squid were placed in a small aquarium, where their movements and luminescent flashes could be recorded with an image intensifier, a photomultiplier tube and associated equipment. Flashing behavior was initiated by disturbing the squid with an eletrical shock. The following 4 behaviors were observed: (1) a short flash and a rapid departure from the electrode; (2) a short flash and a delayed, slow departure from the electrode; (3) a longer flash persisting after a rapid departure from the electrode; (4) a longer flash when departure was prevented by continuing the shock. Luminescent flashes probably have a general defensive function, discouraging or disrupting an attack by potential predators, and within this context there may exist numerous strategies involving flashes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397495
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    Paper (German National Licenses)
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