不同养殖模式池塘沉降颗粒营养物质组成特征

2012年4~10月采用自制沉降颗粒收集装置收集主养草鱼和黄颡鱼池塘生态系统中沉降颗粒物,开展了颗粒物质的垂直沉降量以及沉降颗粒中碳氮磷等营养物质的组成及沉降通量的季节变化特征的研究。结果表明:养殖可以显著提高池塘颗粒物质的垂直沉降量,主养草鱼池塘中颗粒物质垂直沉降量显著高于主养黄颡鱼池塘(p0.01),且两种养殖模式池塘颗粒物质沉降量随着养殖时间推进有显著增加的趋势。主养草鱼的池塘中颗粒物质垂直沉降量在100.39~414.66g/(m2·d)之间变化,平均为224.46g/(m2·d),主养黄颡鱼池塘中沉降颗粒物质垂直沉降量在34.14~272.91g/(m2·d)之间变化,平均为155.18g/(m2·d)。两种养殖模式沉降颗粒的碳氮磷成分在养殖周期内的变化规律不明显但具有相似的变化趋势,主养黄颡鱼池塘沉降颗粒中TN、TC、TOC和TON的含量均比同时期主养草鱼高,且均随着养殖时间的推进,沉降颗粒中碳氮磷的总量呈增加趋势。两种养殖模式池塘沉降颗粒中的C/N比值与沉积物中的C/N比值较为接近,表明沉降颗粒与沉积物营养物质来源具有一定的相似性,同时养殖系统内养殖对象与其所处环境的相互依存和相互影响对颗粒物质的产生以及沉降具有重要作用。

CHARACTERISTICS OF NUTRIENT IN SEDIMENTARY PARTICLES IN DIFFERENT AQUACULTURE MODELS PONDS

Aquaculture pond is a relatively closed and fragile ecosystem type, and sediment is an important part of the pond ecosystems. In order to ensure sustainable expansion of fresh water fish farming, it is essential to quantitatively understand how fish farming affects the sedimentary flux of the sedimentary particles between the Ctenopharyngodon idellus ponds and Pelteobaggrus fulvidraco ponds. The sedimentary flux variation and correlations with the culture activities were discussed in this paper. The objective of this study was to quantify the sedimentary flux and analyze nutrient characteristics of sedimentary particles from April to October of 2012 in two aquaculture models ponds. The sedimentary particles were collected respectively by self made sediment trap in different aquaculture models ponds. The sedimentary flux of total nitrogen (TN), total carbon (TC), total phosphorus (TP), total organic carbon (TOC) and total organic nitrogen (TON) were also measured in sedimentary particles. Results showed that vertical sedimentary weight of settling particles flux in the Ctenopharyngodon idellus cultured ponds were significantly higher than in the Pelteobaggrus fulvidraco cultured ponds. Meanwhile, the sedimentary weight of the sedimentary particles showed an increasing trend in two aquaculture models ponds. The sedimentary weight was found to range between 10039 to 41466 g/(m2·d) and with an average of 224.46 g/(m2·d) in Ctenopharyngodon idellus cultured ponds, while range from 3414 to 27291 g/(m2·d) and 155.18 g/(m2·d) on average in Pelteobaggrus fulvidraco cultured ponds. Temporal variations of sedimentary flux of TN, TC, TOC and TON were not obvious in two aquaculture models ponds. The sedimentary flux of TN, TC, TOC and TON of the sedimentary particles were significantly higher in the Pelteobaggrus fulvidraco cultured ponds than in the Ctenopharyngodon idellus cultured ponds during the culturing period. The content of carbon, nitrogen and phosphorus of sedimentary particles also showed increasing trends during culturing period. The sedimentary flux of TN, TC, TP, TOC and TON in sedimentary particles varied from 37.1 to 194.2 mg/(m2·d), 5.42 to 8.57 mg/(m2·d), 108.9 to 426.1 mg/(m2·d), 225.3 to 1409.7 mg/(m2·d), 26.2 to 172.4 mg/(m2·d) in the Pelteobaggrus fulvidraco cultured ponds, and varied from 88.2 to 182.6 mg/(m2·d), 638.1 to 1503.7 mg/(m2·d), 254.4 to 560.5 mg/(m2·d), 567.1 to 1 084.8 mg/(m2·d), 65.5 to 131.9 mg/(m2·d) in the Ctenopharyngodon idellus cultured ponds, respectively. Positive correlation was found among TN, TC, TP, TOC and TON in sedimentary particles matter in the Pelteobaggrus fulvidraco cultured ponds. The temporal variation of carbon/nitrogen ratio of sedimentary particles was similar with that in surface sediments in two aquaculture models ponds, which suggested it was similar material source between sedimentary particles and sediment. Therefore, the interaction between cultured fish and environment played an important role during sedimentary particles formation in aquaculture system.