Search results | Digital Commons of Moss Landing Marine Laboratories

Title: Effect of sample area and sieve size on benthic macrofaunal community condition assessments in california enclosed bays and estuaries,
Description: Benthic macrofauna are used extensively for environmental assessment, but the area sampled and sieve sizes used to capture animals often differ among studies. Here, we sampled 80 sites using 3 different sized sampling areas (0.1, 0.05, 0.0071m2) and sieved those sediments through each of 2 screen sizes (0.5, 1mm) to evaluate their effect on number of individuals, number of species, dominance, nonmetric multidimensional scaling (MDS) ordination, and benthic community condition indices that are used to assess sediment quality in California. Sample area had little effect on abundance but substantially affected numbers of species, which are not easily scaled to a standard area. Sieve size had a substantial effect on both measures, with the 1-mm screen capturing only 74% of the species and 68% of the individuals collected in the 0.5-mm screen. These differences, though, had little effect on the ability to differentiate samples along gradients in ordination space. Benthic indices generally ranked sample condition in the same order regardless of gear, although the absolute scoring of condition was affected by gear type. The largest differences in condition assessment were observed for the 0.0071-m2 gear. Benthic indices based on numbers of species were more affected than those based on relative abundance, primarily because we were unable to scale species number to a common area as we did for abundance. © 2010 SETAC., Cited By (since 1996):3, Invertebrates, ,
Author: Hammerstrom, Ranasinghe, Weisberg, Oliver, Fairey, Slattery, Oakdeny
Date: 2012-01-01T00:00:00Z

Title: Scavenging and other feeding habits of lysianassid amphipods (Orchomene spp.) from McMurdo Sound, Antarctica,
Description: The distribution and scavenging habits of the two most abundant lysianassid amphipods in McMurdo Sound differ markedly. Orchomene plebs lives primarily in deep water (>100 m), where planktonic and benthic food is sparser and scavenging events are less common and predictable than in shallower water. Orchomene plebs is common in shallow areas (<100 m) only under the Ross Ice Shelf and along the western McMurdo Sound. Here Weddell seals frequent tidal cracks in which they discard carrion and defecate; otherwise food is scarce. Orchomene pinguides lives on shallow (<10 m) wave-cut benches that are rich in food along the eastern McMurdo Sound. They, along with other omnivorous invertebrates which scavenge the food-rich eastern sound benches, are rare from shallow water along the western sound. The eastern benches are bathed by dense plankton blooms and harbor a high biomass of benthic diatoms and invertebrates. Scavenging events there were observed throughout the year. Orchomene plebs is larger and more motile, and came to laboratory carrion and baited field traps more rapidly and in greater numbers than O. pinguides. The crop contents of O. plebs contained only amorphous organic matter that suggested a scavenging habit. Crops of O. pinguides contained not only amorphous organic matter but also invertebrate prey, especially planktonic copepods that impact the bottom during winter. © 1986 Springer-Verlag., Cited By (since 1996):33, CODEN: POBID, ,
Author: Slattery, Oliver
Date: 1986-01-01T00:00:00Z

Title: High species density patterns in macrofaunal invertebrate communities in the marine benthos,
Description: Species density of macrofaunal invertebrates living in marine soft sediments was highest at the shelf-slope break (100-150m) in Monterey Bay (449 m-2). There were 337 species m-2 in the mid-shelf mud zone (80 m). There were fewer species along the slope: 205 m-2 from the lower slope (950-2000 m) and 335 m-2 on the upper slope (250-750 m). Species density was highest inside the bay (328-446 m-2) compared to outside (336-339 m-2), when examining samples at selected water depths (60-1000 m). There was little difference in local species density from 1 km of shoreline compared to regional species density along 1000 km of shoreline at both shelf and slope depths. The highest species densities worldwide in the literature are recorded along the Carolina slope in the Atlantic Ocean, where peak species density (436/0.81 m2) at 800 m and values at the largest sample areas are similar to those on the Monterey Bay shelf. We speculate that the highest species densities occur where ocean water exchanges energy with shoaling topography at the continental margin, bringing more food to the benthos -- areas such as the very productive waters in the upwelling system of Monterey Bay., Cited By (since 1996):1, ,
Author: Oliver, Hammerstrom, McPhee-Shaw, Slattery, Oakden, Kim, Hartwell
Date: 2011-01-01T00:00:00Z

Title: Destruction and opportunity on the sea floor: effects of gray whale feeding,
Description: Eschrichtius robustus are highly disruptive bottom feeders that remove infaunal invertebrate prey and sediments by suction. The response of the benthos to gray whale feeding was examined in the primary feeding grounds of the Bering Sea and in an ecological analog of these prey communities along the W coast of Vancouver Island. Large feeding excavations (often 2-20m2) were rapidly colonized by scavenging lysianassid amphipods, especially Anonyx spp. that attacked injured and dislodged infauna. Many of the attacked animals were small crustaceans (<1cm long) and polychaete worms. Anonyx spp. was 20-30 times more abundant inside fresh excavations than in the surrounding tube mat, where they dispersed within hours after the initial feeding disturbance. A smaller species of lysianassid, Orchomene minuta, invaded less rapidly and remained much longer in excavations than the larger, Anonyx spp. Within days and weeks, gray whale feeding excavations trapped organic debris. Most invading species were much more abundant in debris patches compared to debris-free areas of the same excavations. The numbers of some colonists remained elevated in disturbed areas for 2 mo., Cited By (since 1996):68, ,
Author: Oliver, Slattery
Date: 1985-01-01T00:00:00Z

Title: Walrus feeding disturbance: Scavenging habits and recolonization of the Bering Sea benthos,
Description: Walruses (Odobenus rosmarus Illiger) influenced the structure of macrobenthic assemblages in a variety of ways as they excavated their major bivalve prey from soft sediments. Benthic animals were attracted to discarded bivalve shells and they colonized pits and furrows made during prey excavation. Discarded shells contained soft tissues that were eaten by several invertebrate scavengers. The most abundant and widespread scavenger was the sea star, Asterias amurensis Lutken. Sea stars out-competed brittle stars (Amphiodia craterodmeta Clark) for fresh scavenging events. They also attacked brittle stars under shells in the laboratory, and thus may have obtained two meals from discarded shells by eating remnant tissue and by consuming animals that used the shell as a habitat. In nature, brittle stars were abundant under discarded shells. In experiments, brittle stars invaded shells with soft tissue in the absence of sea stars, but not in their presence. In other experiments, brittle stars were most abundant under shells with soft tissue, but were also attracted to shells without organic matter. Large brittle stars were more abundant under shells than in the surrounding bottom, and the reverse was true of small individuals. Bottom communities recovered gradually inside experimental feeding excavations, which were not invaded by large numbers of opportunistic infaunal or epifaunal invertebrates. This is in contrast to gray whale feeding excavations, which are colonized by a large number of opportunistic peracarid crustaceans. © 1985., Cited By (since 1996):32, CODEN: JEMBA, ,
Author: Oliver, Kvitek, Slattery
Date: 1985-01-01T00:00:00Z