Clearance and retention efficiency of natural suspended particles by the rock-pool bivalve Venerupis corrugatus in relation to tidal availability
1992; Inter-Research; Volume: 82; Linguagem: Inglês
10.3354/meps082175
ISSN1616-1599
Autores Tópico(s)Aquatic Invertebrate Ecology and Behavior
ResumoThe natural spectrum of food particles available to and used by the burrowing clam Venerupls corrugatus (Gm ) was studled u n d e ~ contrasting weather conditions prevailing SE wind in summer and a NE wlnd in wlnter Sealvater samples collected hourly during a 13 h spring tldal cycle from a rock/sand pool were analysed for particle slze range ( ~n c l u d l n g b a c t e r ~a ) partlculate q u a n t ~t y (counts total and organlc dry wt) and quality ( o ~g a n ~c content) Particle numbels Increased on the flood tide, especially those < 4 pm In diameter w h ~c h rose 15-fold Furthermore maxlmum particle slze increased from 12 pm at low tide to 23 pm at h ~g h t ~d e rvh~le total particulate dry w e ~g h t ~n c l e a s e d 3to 4-fold to a maxlmum of 23 mg I-' However total pa~tlculate dry weight nevei d i f f e ~e d by more than 15-fold between s a m p l ~n g occasions At low tide V corrugatus flltered out part~cles of 5 to 9 pm at maxlinum rates of 2 3 to 3 1 1 h-' g-l, partlcle retention efflc~encles weie 70 to 100 'X, At high tide part~cles of 8 to 13 pin were cleared at the fastest rates ( 3 2 to 4 4 I h g l ) a n d retalned with eff~ciencies between 75 and 100 Yu Possible mechanisms for these reponses are discussed Such feeding behavlour enabled V corrugatus to Increase gross lngest~on of organlc materlal by 65 ' %" at high tide even when pseudofaeces production was considered net organlc Intake at high tide was stlll 39 ' % above that at low tlde V corrugatus appears to make maxlmum use of a natural resoulce whose supply is pred~ctable with respect to tidal cycles, but highly variable in terms of partlcle size spectra, quantity and quallty
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