浅海鱼类网箱养殖的关键生态过程及容量评价

随着养殖规模扩大， 放养量超过水域的容纳量，养殖自身污染加重。网箱养鱼的养殖容量研究很有意义。本文对网箱养殖的关键生物过程，物理过程和生物地球化学过程进行了研究，并以模型试验进行了容纳量的评价。 关键物理过程研究得出爱莲湾海水交换周期为2.9 d。 关键生物过程研究：生物能量学模型和现场调查结合，估算了网箱养殖废物的输出。生产周期内，仅抗风浪网箱养殖区，约有48 t DO被养殖鱼类消耗，此外养殖鱼类在养成期输出3.76t氨氮，12.37t（干重）颗粒物；挂网实验和培养实验结果表明每个筏式网箱的污损生物会增加养殖水域N，P负荷的1~2%；用矩估计法，估计了野生许氏平鲉Sebastodes fuscescens的丰度为0.01ind.m-2。 关键生物地球化学过程研究：用沉积物捕捉器研究了沉积物颗粒物在网箱内外沉降同量的区位差异；经验公式并结合现场实验分析认为8月有机物的积聚速度最大，而12月积聚速度最小。 养殖容量和环境容量的评价：利用局部微分方程组和Matlab7.0成功模拟了桑沟湾浮游植物对规模化养殖的响应；以浮游植物的缺失为标志，估算了桑沟湾的养殖潜力；数值模拟了环境因子对规模化鱼类养殖的响应；提出了水生养殖系统健康的评价标准；在数值模拟的基础上，以水质标准，得到爱莲湾养殖环境总容量,0.08V（ind.; V为水域容积，m3）；以生态系统健康为标准，得到养殖总容量，0.27V；建立了筏式网箱养殖容量的简化概念模型，并在此基础上得到了爱莲湾筏式网箱（5 5 5m）养殖容量为单箱放养484尾，和目前爱莲湾筏式网箱的每箱放养量基本相当。

Planktonic foraminiferas in bottom sediments and Late Quaternary paleotemperatures of surface waters in the North Tropical Atlantic

Distribution of planktonic foraminiferal tests was studied in 15 Upper Quaternary sediment cores from the continental slope of Africa, the Canary and Cape Verde basins, and slopes of the Mid-Atlantic Ridge. In all the cores substantial variations were found in relationship between foraminiferal planktonic species reflecting fluctuations of mean annual temperatures of surface waters. Temperature difference in temperatures between present time and that of the maximum of the stadial of the last continental glaciation glacial stadial (about 18,000 yrs ago) ranges from 8.5°C in the Canary upwelling region to minimum values of 2.0°C in the central part of the ocean, i.e. the southern part of the subtropical gyre. Temperature difference the Holocene optimum and 18,000 yrs ago ranges from 10°C to 3°C. Age estimates are supported by radiocarbon dates.

Radiocarbon ages and last occurrences of Globorotalia menardii flexuosa and Globoquadrina hexagona in Atlantic sediment cores

Ranges of Globorotalia menardii menardii, Gr. menardii flexuosa and Globoquadrina hexagona at time of climatostratigraphic intervals representing oxygen-isotope stages 5-1 are determined by study of dozens of Late Quaternary sediment cores involving constructing paleotemperature curves from planktic foraminifera and oxygen isotope curves for their shells, as well as radiocarbon dating. Gr. menardii flexuosa and Gq. hexagona disappeared about 27-25 ky ago from the subtropical and tropical Atlantic and about 18 ky ago from the equatorial area.