Aggregations and temporal changes in the activity and bioturbation contribution of the sea cucumber Holothuria whitmaei (Echinodermata: Holothuroidea)
MetadataShow full item record
The population density, activity and bioturbation contribution of the sea cucumber Holothuria whitmaei was investigated on Ningaloo Reef, Western Australia. Two methods, stratified manta tows and blanket manta tows, recorded population densities between 11.4 and > 100 individuals (ind.) ha -1. Further analysis revealed a heterogeneous pattern of distribution, with individuals tending to aggregate (Moran's I; 0.039; p < 0.05) on the outer reef lagoon and particularly in areas of high flow. Densities within aggregations were up to 7.2 times greater than those obtained after blanket manta tows (17.1 ind. ha-1), and 4.5 to 6.3 times greater than those obtained after traditional stratified manta tows (19.3 to 27.1 ind. ha-1). Behavioural studies, including investigations of activity and bioturbation, were conducted over a 2 yr time frame (2002-2003) incorporating 3 monitoring periods within each year: January, April and August. Rates of activity varied diurnally, increasing between morning and afternoon, and seasonally, increasing in April, relative to January and August. Temporal patterns of feeding were more difficult to characterise; although rates of sediment egestion were in many cases higher in the morning, no conclusive diurnal or seasonal patterns could be established. Subsequent regression analysis, however, did find a significant positive correlation between the distance travelled and the volume of sediment egested. The volume of sediment bioturbated by H. whitmaei at a population level was found to represent only a small fraction of the sediments available (ca. 2 to 14% per annum), even though the contribution per individual was greater than that of smaller sea cucumber species. However, at maximum densities and typical rates of activity, H. whitmeai makes physical contact with approximately 2 times the available coral reef sediments per annum per hectare, simply by crawling. This may represent an important ecological contribution, particularly in light of previously documented links between sea cucumber activity, nutrient recycling and the enhancement of benthic microalgal communities. © Inter-Research 2010.
Showing items related by title, author, creator and subject.
Lintern, Melvyn John (2011)Calcrete has been shown to contain significant Au, derived from nearby mineralisation, and this has led to its current use as an exploration sampling medium. Calcretes are secondary carbonates, principally consisting of ...
Introducing an improved multi-proxy approach for paleoenvironmental reconstruction of loess-paleosol archives applied on the Late Pleistocene Nussloch sequence (SW Germany)Gocke, M.; Hambach, U.; Eckmeier, E.; Schwark, Lorenz; Zo ller, L.; Fuchs, M.; Lo scher, M.; Wiesenberg, G. (2014)© 2014 Elsevier B.V.To study paleoenvironmental and paleoclimatic changes in loess-paleosol sequences (LPS), most proxies except for screening parameters have often been applied at low sampling density, typically 1-2 per ...
Effect of Bioturbation on Reservoir Rock Quality of Reservoir Sandstones in the Baram Delta, Offshore Sarawak, MalaysiaBen-Awuah, Joel; Padmanabhan, E. (2015)With the Baram Delta in Malaysia as research subject, the effect of bioturbation on porosity and permeability of reservoir sandstones is evaluated and analyzed based on core and thin section analysis, EDX (energy-dispersive ...