深圳湾及邻近水域溶解有机磷的分布和来源及其生物利用率

摘要

为了解深圳湾的生态环境质量状况,利用2000-2014年逐月的水质监测资料,分析了深圳湾及珠江口东南沿岸水体中DOP(溶解有机磷)的时空分布特征,并结合盐度、ρ(BOD5)、ρ(POM)(POM为颗粒有机物)实测数据,应用二元混合质量平衡模式和简单回归分析法,定量确定了DOP的来源和生物利用率.结果表明,研究期间深圳湾水体中ρ(DOP)为(0.073±0.077) mg/L,总体上丰水期(4-9月)低于枯水期(10月一翌年3月),2000-2004年呈上升趋势,而2005-2014年呈下降趋势;珠江口东南沿岸水体中ρ(DOP)为(0.022 ±0.013)mg/L,夏季(7月)和冬季(1月)较高,春季(4月)和秋季(10月)较低,其年际变动略呈下降趋势.深圳湾和珠江口东南沿岸水体中DOP均呈现为保守,具有同源性.二元混合质量平衡模式估算结果表明,深圳湾DOP主要来自陆源,而珠江口东南沿岸DOP主要来自海源.依据实测数据和回归分析结果估算,深圳湾和珠江口东南沿岸水体中DOP生物利用率分别约为14.5％和15.5％,与珠江口下段高盐水体中的实测溶解有机碳生物利用率相近.研究显示,周边人为向海排放对深圳湾生态环境质量的影响较为严重.%To uderstand the quality condition of the ecological environment in Shenzhen Bay,monthly data from 2000 to 2014 were used to analyze and study temporal and spatial distributions of dissolved organic phosphorus (DOP) in Shenzhen Bay and coastal southeastern Pearl River Estuary.The sources and bioavailability of the DOP were investigated by a two-component mixing mass balance model and a simple regression analysis method in combination with salinity,5-d biochemical oxygen demand and particulate organic matter measurements.The results showed that the DOP concentration was (0.073 ± 0.077) mg/L,with an increase from 2000 to 2004 and a decrease from 2005 to 2014.It was higher in the dry season than the wet in the bay,and was slightly higher in the summer and winter than the spring and autumn in the estuary.The DOP appeared conservative,and was from simultaneous sources in both the bay and estuary.The DOP terrestrial fraction,estimated by the two-component mixing mass balance model,was about 81％ in the bay and 44％ in the estuary,suggesting that the DOP was mainly from the terrestrial sources in the bay but from the marine sources in the estuary.On the basis of the measurements and regression results,the DOP bioavailability was found to be about 14.5％ in the bay and 15.5％ in the estuary,nearly eaqual to the dissolved organic carbon bioavailability observed in the lower Pearl River Estuary.Phosphorus bioavailability impacts community composition,species distribution and productivity of plankton in the global open oceans and coastal waters.The impact of the seaward discharges from the cities of Hong Kong and Shenzhen on the ecological environment quality in the Shenzhen Bay was heavy.