| In order to evaluate effect of the infaunal Manila clam Ruditapes philippinarum onbenthic-pelagic coupling in a coastal ecosystem, biodeposit production rate bybottom-cultured clam in Jiaozhou Bay (446 km2) in northern China was determined in situusing sediment traps. Oxygen consumption rate (RO), ammonia excretion rate (RN), andphosphorus excretion rate (RP) were in situ measured. In this study, contents of the particulatecarbon, nitrogen and phosphorus nutrients in the sediment were investigates in Jiaozhou Bay.The main results are as follows.1. Effects of bivalve bottom-cultured on environment were reviewed in detail. Throughthe function of filtration, biodeposition and excretion, bivalves play the important role inmaterial and nutrient circulation of coastal culture ecosystem.2. Biodeposit rates by bottom-cultured clam in Jiaozhou Bay was determined in situ usingsediment traps from October 2003 to July 2004 and from August to December 2005. Resultsshowed that biodeposition rates were relatively high, indicating remarkable seasonal variation.The results of different size large, middle and small clams were 121.6～1527.4mg,49.5～902.1mg and 14.2～653.9mg, respectively. The contents of OM in the biodeposits of large,middle and small clams were 6.0±1.3%,5.9±1.3% and 6.0±1.2%, respectively. For thecontents of TP 399±26ppm, 372±16ppm and 345±15ppm, respectively;and for the contentsof OP 80±17,92±12 and 102±10ppm, respectively. The allometric relationship betweenbiodeposition rate (BDR;g ind-1·d-1) and dry tissue weight (W;g ind-1) of the clam wasmodeled using the formula BDR=aWb, with the value of a ranging from 0.85 to4.50.Chemical composition of clams' dry tissue in Jiaozhou Bay was determined. In theRuditapes philippinarum, the C and N contents account for 42.21±2.26% and 9.78±1.14%.The OM, C, N, TP and OP contents of shells of clams were 3.28±0.47%, 109.2±16.6ppm,64±22.9ppm, 12.21±0.30% and 0.19±0.05%, respectively.3. Oxygen consumption rate (RO), ammonia excretion rate (RN), and phosphorus excretionrate (RP) were in situ measured. The allometric functions between RO or RN or RP and drytissue weight of the clam were determined using the formula Y=aXb, respectively. There wereseasonal variation of RO, RN and RP of clams in Jiaozhou Bay. RO of clams was highest in Julyin summer, it was 1.72 g/ind.h;RN and RP of clams were highest in August in summer, thosewere 2.44 and 0.58μmol/ ind·h. The value of O:N ranged from 10.7 to 31.9. There weresignificant seasonal variations of O:N and N:P, general arrived at peak high in August insummer.4. Contents of OM,OC,ON,TP and OP in the sediment in were aquacultural and naturalarea, investigated in Jiaozhou Bay from May 2003 to December 2005. Results showed thatthe contents of OM,OC,ON,TP and OP in the sediment of the clam-cultured area wererelatively high. The seasonal variation of the contents of OM,OC,ON,TP and OP was notremarkable, 3.5%,0.7%,0.06%, 285ppm and 50ppm, respectively.As an important bottom cultured species in Jiaozhou Bay, R. philippinarum in large-scaleaquaculture may play an important role in benthic-pelagic coupling in Jiaozhou Bayecosystem.
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