The experimental studies on the carbon and nitrogen budgets of Pseudeuphausia sinica

Abstract-The carbon and nitrogen budgets were estimated on the adult females, juveniles and post-furcilia larvae of Pseudeuphausia sinica fed on newly hatching nauplii of Artemia salina in the laborato-ry. It was found that the ingestion rate was linearly related to the food concentration, suggesting highfeeding potential. The linear correlation could be established between the respirating rate (carbon con-sumption rate) and carbon ingestion rate, as well as carbon assimilation rate. The regression coefficients(i.e.specific dynamic action coefficients) were in the range from 9% to 16% (ingested C) or 10% to17% (assimilated C) respectively, with lower in the post-furcilia larvae. There also existed a linearcorrelation equation between estimated total nitrogen excretion rate and the rates of nitrogen ingestionand assimilation separately, except for the juveniles. The defecation rates increased with the increase ofthe ingestion rate; as a result, assimilation efficiency was not related to the ingestion rat     

Effect of regional warming on the abundance of Pseudeuphausia sinica Wang et Chen (Euphausiacea) off the Changjiang River (Yangtze River) Estuary

Distribution and abundance of Pseudeuphausia sinica off the Changjiang River Estuary (30 ° 00′ - 32 ° 00′ N, 122 ° 00′ -123 ° 30 ′E), the East China Sea were studied in relation to environmental features associated with the regional warming. P. sinica is a subtropical species. Off the Changjiang River Estuary, its abundance reached maximum in summer. To examine spatial and temporal changes of P. sinica off the Changjiang River Estuary, the authors have combined all available sampling data in 1979, 1981, and 2000-2007. This database shows that a significant increase in abundances of P. sinica was observed in spring of 2000-2007 as compared with 1979, 1981. The abundance of P. sinica increased from 0.18-0.21 ind./m 3 in 1979 and 1981 to 0.68-4.00 ind./m 3 in 2000-2007. Accordingly, the sea temperature increased obviously from spring of 1979, 1981 to the 2000s. The authors further found a positive relationship between average surface temperature and average abundance of P. sinica. Regional warming, together with the release of predator induced stress due to a sharp decline in the abundance of its predator (e.g., fishes), were thought to be responsible for the increase in abundance of P. sinica in water off the Changjiang River Estuary.     

中华假磷虾碳氮收支的实验研究

实验室培养条件下,以新近孵化的卤虫(Artemiasalina)为食物,观测中华假磷虾(Pseudeuphau siasinica)雌性成体、仔虾和后期带叉幼体的碳氮收支.实验表明摄食率随食物浓度的升高呈线性提高,成体未出现饱和现象,反映其较高的摄食潜力.呼吸率(碳消耗率)与碳的摄食率及同化率分别呈线性正相关,比动力作用分别为9%~16%(摄入碳)和10%~17%(同化碳)以后期幼体更小.总氮排泄率与氮的摄食率及同化率也分别呈显著正相关,但仔虾例外.排粪率随摄食率升高而提高,从而同化效率与摄食率无关,介于0.84~0.95.食物氮源是中华假磷虾生长的主要限制因子,当摄食率低于10μg/(mg·d)(干重)时,假磷虾呈负生长.同化的氮以排泄消耗为主,体质生长次之,而蜕皮损失最少.同化的碳也以呼吸消耗和体质生长居多,但随摄食率有变化,蜕皮损失最少.在成熟雌体,估算的生殖生长(碳、氮)比蜕皮损失略高.净生长效率随摄食率(及同化率)升高而升高.达一定值后,仔虾和后期带叉幼体净生长效率略有下降.