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cje ›› 2012, Vol. 31 ›› Issue (02): 374-380.

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Bio-scavenging of self-pollutants with different carbon and nitrogen loads from a raft bivalve and macroalgae culture system by deposit-feeding sea cucumber Apostichopus japonicus Selenka.

YUAN Xiu-tang1,2, WANG Li-li1, YANG Hong-sheng2**, YANG Da-zuo3   

  1. 1 National Marine Environmental Monitoring Center, Dalian 116023, Liaoning, China; 2 Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, Shandong, China; 3 Key Laboratory of Mariculture and Biotechnology, Dalian Ocean University, Dalian 116023, Liaoning, China
  • Online:2012-02-08 Published:2012-02-08

Abstract: Self-pollutant loading of bivalve biodeposits and macroalgae detritus from the raft culture system in the shallow sea of North China may negatively affect the aquaculture environment, while deposit-feeders may effectively utilize these particulate wastes and act as the scavenger. In this study, a laboratory experiment was designed to estimate the carbon and nitrogen budgets of the deposit-feeding sea cucumber Apostichopus japonicus fed with five simulative particulate wastes (biodeposits and/or powder algae) from the raft bivalve and macroalgae culture system, and evaluate the bio-scavenging efficiency (SE) of the wastes carbon and nitrogen. A. japonicus could effectively ingest the particulate wastes, with the feeding rates of carbon and nitrogen ranging 3577-18118 mg C·g-1·d-1 and 6.08-14.28 mg N·g-1·d-1, respectively. The feeding rates of carbon and nitrogen increased with the increasing carbon and nitrogen contents of self-pollutants. The established budget showed that the carbon loss from feces accounted for the majority of the ingested carbon (59.3%-97.1%), and the carbon used for growth (-70%-61%) was less than the carbon loss in respiration (99%-373%). As for nitrogen budget, the nitrogen loss in excretion accounted for the majority of the respiration nitrogen (531%-631%), the nitrogen loss in defecation ranged 277%-392%, and the nitrogen used for growth was -2.3%-16.7%. The scavenging efficiencies of carbon and nitrogen (SEC,SEN) in the sea cucumbers fed with the particulate wastes were 0.83-4.57 mg C·g-1·d-1 and 0.28-076 mg N·g-1·d-1, respectively. Moreover, a trend was observed that the SEC and SEN increased with the increasing carbon and nitrogen contents of the wastes, with the regression equations being SEC=07368+14.9488C and SEN=0.2281+0.2202N, respectively.