珠江口初级生产力和新生产力研究

1996年12月和1997年8月在珠江河口湾及其毗邻海域对浮游植物生物量、初级生产力和新生产力及其环境制约机制的研究.结果表明,调查海区的叶绿素a、初级生产力和新生产力均是夏季高于冬季,冬、夏两季的平均值分别为(0.95±0.41)和(1.08±0.52)μg/dm3,(69.2±75.5)和(198.7±119.1)mg/(m2·d),(1.46±0.79)和(3.05±3.09)mg/(m3·h).冬、夏两季平均f-比分别为0.45和0.38.分级叶绿素a结果显示,冬、夏两季均以微型和微微型级分(<20μm)占优势,其对海区叶绿素a的贡献分别为796%和81.6%,对初级生产力的贡献分别为70.7%和896%.调查海区具显著的空间区域化特征,叶绿素a和潜在初级生产力的高值出现在冲淡水区的中部,向口门区和远岸区逐渐降低.现场初级生产力的高值出现在远岸区,它与复合参数B_eZ_pI₀(B_e为真光层平均叶绿素a,Z_p为真光层深度,I₀为海面光辐射强度-PAR)呈很好的正相关,说明光是研究海区初级生产力的主要限制因子.新生产力冬、夏两季的高值分别出现在交椅湾和伶仃洋西南部.

Studies on primary production and new production of the Zhujiang Estuary, China

The distribution of chlorophyll a concentration (Chl a),primary production (PP) and new production (NP) were observed in the estuary of Zhujiang River (the Pearl River) during December.1996 and August.1997.The results show that the average concentration of Chl a,PP and NP in winter and summer are (0.95×0.41) and (1.08×0.52) μg/dm3,(69.2×75.5) and (198.7×119.1) mg/(m2·d),and (1.46×0.79) and (3.05×3.09) mg/(m3·h),respectively.The values are higher in summer than in winter.The average-fratio are 0.45 and 0.38 in winter and summer,respectively.The results of size-fractionated Chl a and PP show that the contribution of nano-and pico-plankton (<20 μm) to total Chl a and PP are in dominant position in phytoplankton community biomass and production.The average contributions to total Chl a are 79.6% and 81.6% in winter and summer,respectively,and to primary production are 70.7% and 89.6%,respectively.There are marked features of spatial zonation characteristics of Chl a and PP in the surveyed area.The highest value of Chl a and potential PP appears in the middle area of the dilution zone and decreases both mouth ward and offshoreward gradually.The high PP appears in the offshore areas.The euphotic production has a good relationship with the composite variable B_eZ_pI₀ (B_e is average euphotic zone Chl a;Z_p euphotic depth;I₀ surface irradiance-PAR),which suggests that light is main limiting factor to the production.The highest value of new production appears in the Jiaoyi Bay during winter and in southwest part of the Lingding Yang during summer.