Particle capture and deposition by deep-sea sponges from the Norwegian-Greenland Sea

Abstract

Particle uptake and deposition by the 2 most abundant deep-sea demosponge species from the Nolwegian and Greenland Sea (Thenea abyssorum) and the deep fjords of western Norway (Thenea muncata) were studied In flume expenments Fluorescent part~cles of 1, 2, 3 6 10 a n d 16 p m diameter (miclospheres, Duke S c i e n t~f~c Corporat1ono) with a density of 1 0 5 g cm were used at 2 curlent velocities, 1 5 and 5 cm s ' Both species ingested small particles exclusively ( < 6 pm and < l 0 pm, respectively) w~t h a preference for the smallest fiaction at both current speeds The results suggest that the size spectrum actually ingested depends on the s u p p l~e d particle s u e s rather than on current velocity Culrent velocity fields aiound dead speclinens were recorded and turbulence intens~t y calculated in older to determine the influence of the sponge actlng as a biogemc structure on the neai-bottom current leginle Disruption of flow conditions was detected as far as 14 cm downstream and several cm laterallv from the blogenic obstacles Bulk biodeposition rates calculated from sponge biomass and volume of Ingested particles iange between 7 and 10 mg d ' g ' ash-free dry weight K E Y WORDS Deep sea Sponge Suspension feeding Biodeposition Blogenic structure Flow regime

Natural diet and grazing rate of the temperate sponge Dysidea avara (Demospongiae, Dendroceratida) throughout an annual cycle

“…cellulose and siliceous walls), with these cells requiring longer exposure to digestive enzymes (Reiswig 197 1). Several previous studies have reported the ability of sponges to capture diatoms (Reiswig 1971, Frost 1981, Simpson 1984, Witte et al 1997). However, knowledge of their importance as a food source is still Limited.…”

Spatial dynamics of virus-like particles and heterotrophic bacteria within a shallow coral reef system

“…3C). A potential mechanism for this pattern may be the selective consumption of the larger HDNA bacteria (Gasol et al 1999) by benthic filter-feeding organisms on the reef (Reiswig 1971, Sorokin 1973, Wilkinson et al 1984, Witte et al 1997.…”

In situ feeding and metabolism of glass sponges (Hexactinellida, Porifera) studied in a deep temperate fjord with a remotely operated submersible

“…Whereas the nutritional ecology of shallow suspension feeders has been well studied, equivalent studies of the nutritional ecology of deep-dwelling suspension feeders (below scuba depth) are scarce (Roberts and Hirshfield 2004) and rely largely on descriptive anatomy and in vitro experiments (e.g., Fiala-Medioni et al 1986;Witte et al 1997; Pile and Young 1999 …”

“…The feeding activity of these animals can control the water column properties in shallow bays (Cloern 1982), rivers (Strayer et al 1999), and fjords (Riisgå rd 1998), either directly (through grazing on the plankton community) or indirectly (by intensifying nutrient recycling or by selective removal of a specific planktonic component) (Thorp and Casper 2003). These activities are tightly coupled with hydrodynamic processes.Whereas the nutritional ecology of shallow suspension feeders has been well studied, equivalent studies of the nutritional ecology of deep-dwelling suspension feeders (below scuba depth) are scarce (Roberts and Hirshfield 2004) and rely largely on descriptive anatomy and in vitro experiments (e.g., Fiala-Medioni et al 1986;Witte et al 1997; Pile and Young 1999 …”