刺参对筏式贝藻养殖系统不同碳、氮负荷自污染物的生物清除

针对我国北方浅海筏式贝藻养殖系统自身污染输出导致的环境问题,以滤食性贝类生物沉积物和海藻粉的不同配比来模拟贝藻筏式养殖系统不同碳、氮负荷的颗粒自污染物,研究了刺参摄取这些颗粒物后的碳、氮收支,评估了其对碳和氮生源要素的生物清除潜力。结果表明,刺参对筏式贝藻养殖系统不同配比颗粒自污染物中的碳和氮具有较强的摄食能力,摄食率分别为35.77～181.18mgC·g-1·d-1和6.08～14.28mgN·g-1·d-1;颗粒自污染物中碳和氮的含量越高,其摄食碳、氮的能力越强。刺参摄取的碳以粪便碳形式排出居多(59.3%～97.1%),其次是呼吸消耗的碳(9.9%～37.3%),而用于生长的碳最少(-7.0%～6.1%);刺参摄取的氮主要用于排泄消耗为主(53.1%～63.1%),粪便氮次之(27.7%～39.2%),用于生长的氮最少(-2.3%～16.7%)。通过建立的碳、氮收支方程,估算出刺参对筏式贝藻养殖系统不同碳、氮负荷自污染物的生物清除效率(SE)分别为0.83～4.57mgC·g-1·d-1和0.28～0.76mgN·g-1·d-1;而且其清除效率随着颗粒自污染物中碳、氮含量的升高而增大,呈明显的正相关关系;清除效率和碳(C)、氮(N)含量之间回归关系可用SEC=0.7368+14.9488C和SEN=0.2281+0.2202N来描述。

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 iaponicus Selenka

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 (SEC,SEN) 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 SEC and SEN increased with the increasing carbon and nitrogen contents of the wastes, with the regression equations being SEC=0.7368+14.9488C and SEN=0.2281+0.2202N, respectively.