摘要
文章对典型的亚热带养殖海湾——深澳湾海水中无机氮(DIN)、磷酸盐(PO4-P)浓度的时空变化特征进行了分析,研究了鱼类网箱和贝藻筏式等规模化养殖活动对营养盐时空分布特征的影响,并对营养盐的潜在限制性进行了探讨。结果显示,深澳湾DIN和PO4-P浓度及分布呈明显的季节变化:DIN在秋季最高,夏季最低;PO4-P在冬季最高,夏季最低。春季网箱区的DIN浓度和氮磷比(N/P)低于贝藻养殖区和对照区,而其他3个季节,网箱区的DIN和PO4-P浓度以及N/P均高于贝藻养殖区和对照区。贝藻养殖区和对照区之间在各个季节,氮、磷营养盐和N/P之间均无显著差异。各个季节DIN和PO4-P浓度均高于理论上浮游植物生长的营养盐阈值,不存在营养盐的绝对限制。夏、冬季的N/P分别为13.6、13.1,低于Redfield值,说明存在N的潜在限制;春、秋季的N/P分别为16.6、19.0,说明P的潜在限制性较强。深澳湾的年均N/P为14.3,全湾受N潜在限制性较强。除夏季外,硝酸盐(NO3-N)是DIN的主要组成,比例介于51.7%~92.7%,其次为NH4-N(5.2%~43.8%),亚硝酸盐(NO2-N)比例最低(2.1%~27.2%),说明深澳湾的氮营养盐达到了热力学平衡状态。与2001年相比,深澳湾海区的DIN和PO4-P浓度均有下降,由中度营养型转变成贫营养型,年平均N/P更接近Redfield值,说明深澳湾的生产力水平依然受氮限制,营养盐的时空分布特征一定程度上体现了规模化贝藻养殖的影响。
We investigated the tempo-spatial variation of disovled inorganic nitrogen (DIN) and phosphate (PO4-P) in Shen'ao Bay that is a typical subtropical aquaculture bay. Besides, we studied the effects of large-scale aquaculture activities such as fish cage and shellfish raft on the tempo-spatial distribution of nutrients, and evaluated the potential limiting factors of the nutrients. The concentration and distribution of DIN and PO4-P showed obvious seasonal variation (DIN and PO4-P reached their maximum values in autumn and winter, respectively, and both reached their minimum values in summer). The DIN nutrients concentrations and N/P ratios in fish cage area in spring were lower than those in oyster-macroalgae culture area and the control area. However, in the other three seasons, the DIN and PO4-P concentrations and N/P ratios in fish cage area were higher than those in the other areas. There was no significant difference in the nitrogen and phosphorus concentrations as well as N/P ratios between oyster-macroalgae culture area and the control area in each season. Both DIN and PO4-P were higher than the theoretical threshold for phytoplankton growth, indicating that there was no absolute nutrient limitation. The N/P ratios in summer and winter were 13.6 and 13.1, respectively, which were lower than the Redfield ratio, indicating that there was potential N limitation during these seasons. The N/P ratios in spring and autumn were 16.6 and 19.0, respectively, indicating potential P limitation. The average seasonal ratio was 14.3, indicating that N was probably the most limiting nutrient in Shen'ao Bay. DIN was dominated by nitrate nitrogen (NO3-N) except for summer with percentages of 51.7%-92.7%, followed by ammonia nitrogen (NH4-N) with percentages of 5.2%-43.8%, and nitrite nitrogen (NO2-N) was lowest with percentages of 2.1%-27.2%, indicating that the thermodynamic equilibrium of N was reached. Compared with 2001, the concentrations of both DIN and PO4-P decreased, with the trophic level changing into poor from moderate. It is shown that the productivity level of Shen'ao Bay is still controlled by nitrogen, and the tempo-spatial distribution of nutrients reflects the impact of large-scale shellfish culture to a certain extent.
作者
徐淑敏
齐占会
史荣君
刘永
韩婷婷
黄洪辉
XU Shumin;QI Zhanhui;SHI Rongjun;LIU Yong;HAN Tingting;HUANG Honghui(Key Laboratory of Open-Sea Fishery Development,Ministry of Agriculture and Rural Affairs,South China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Guangzhou 510300,China;Guangdong Provincial Key Laboratory of Fishery Ecology and Environment)
出处
《南方水产科学》
CAS
CSCD
北大核心
2019年第4期29-38,共10页
South China Fisheries Science
基金
中国水产科学研究院南海水产研究所中央级公益性科研院所基本科研业务费专项资金资助(2019ZD0102,2017YB06)
国家重点基础研究发展计划(973计划)项目(2015CB452901,2015CB452904)
国家自然科学基金青年基金(41106088)
农业部财政专项(NFZX2013)
关键词
深澳湾
氮
磷
营养盐
时空分布
限制因子
Shen'ao Bay
nitrogen
phosphate
nutrient
tempo-spatial variation
nutrient limitation
