【摘要】 2 0 0 0年 5月～ 2 0 0 1年 5月对粤东大规模增养殖区柘林湾及湾外附近海域进行了大量营养盐、浮游生物和一般理化因子的周年调查。结果表明 ,调查海域溶解性无机氮、磷、硅含量都明显偏高 ,年平均值分别达到 2 2 .64、1 .95和5 9.7μmol/ L。其中 ,氮、磷含量均超过国家三类海水的水质标准。由于湾顶黄冈河和湾周边排污排废的影响 ,营养盐的分布基本表现为由湾内向湾外 ,近岸向离岸递减的格局。大规模增养殖业造成的 2次污染对该湾营养盐的时空分布具有重要的影响。柘林湾氮、磷、硅含量虽全面偏高 ,但如以 Justic和 Dortch等的标准来衡量 ,该湾浮游植物生长受控于单一营养盐限制因子的出现率为氮 41 .75 % ,磷 2 2 .9% ,硅 2 .3 6%。更多还原

【Abstract】 Zhelin bay is one of the most important estuaries for marine culture in Guangdong Province of China. With the constantly increasing human population and marine culture in the last 10 years, the ecological environment has significantly changed. Although Phaeocystis blooms had brought tremendous economic loss and ecological damage in this area in 1997 and 1999, few studies followed and previous investigation of nutrients are very little. To understand why Phaeocystis blooms frequently hit this area and how the increased marine culture affects this ecosystem, we investigated the temporal and spatial distribution of phytoplankton, zooplankton, nutrients, trace element, dissolve oxygen, etc. from May 2000. This paper describe the distribution of nutrients in a 1\|year period (05/2000~05/2001).\;Zhelin Bay (116°E,23°N) is a land\|locked estuary. Its surface area is 68~70km\+2 and mean depth is 4\^8m, and its sediments mainly consist of sandy and sand muddy. Tide in this bay is typical semidiurnal and its mean range is 1\^69m with the maximum of 3\^06~3\^33m.\;Water samples were collected from eight stations weekly (March to November) or biweekly (December to February). Sampling was scheduled to cover the period around high tide (±1\^5h). At each station, water samples for nutrient analysis were collected from 0\^5m below the surface and 0\^5m above the bottom and filtered with 0\^45μm cellulose filters immediately. Samples were then kept in a cooler and transported to the laboratory for further analysis. The dissolved inorganic nitrate, nitrite, ammonium, phosphate and silicate were analyzed with the SKALAR SAN+4\|Channel Seawater segmented flow nutrient analyzer and SHMADZU UV\|2501 PC equipped with routine spectrophometric methods modified for the analysis of waters of variable salinity. In detail, silicate was analyzed by silico\|molybdenum yellow; phosphate was analyzed by phospho\|molybdenum blue; nitrate was analyzed by the copper\|cadmium reduction; nitrite was analyzed by diazo\|azo and sodium hypobromite oxidation for ammonia. Water temperature and salinity were measured in situ with YSI meter (model 6600). Because Zhelin Bay is shallow and the water is well\|mixed, the data were recorded as the average of samples from surface and bottom unless otherwise indicated.\;The annual water temperature decreased from 23 6℃ at the inner bay (station 1) to 22 0℃ at the outer bay (station 8). On the contrary, salinity increased from station 1(19 6) to station 8 (29 6). Temporally, water temperature was high in July (27 8℃) and low in January (16 4℃). Salinity was high in November (31 9) and low in July (24 7), which derives from the dilution of monsoon in July. Nutrients decreased gradually from the inner bay to the outer bay. On average, dissolved inorganic nitrogen (DIN) was high (35 3 μmol/L) at station 1 and low (15μmol/L) at station 8. Silicate decreased gradually from 110 9μmol/L at station 1 to 34 6μmol/L in station 8. Salinity had negative correlations with silicate ( r =-0 6; P <0 0001) and DIN ( r =-0 51; P <0 0001), which suggested that the discharge of freshwater from Huanggang river diluted the salinity while loaded the nutrients in the inner bay. However, the highest dissolved phosphate (2 66μmol/L) was found at station 3, not at station 1 where is the mouth of Huanggang River. This is due to the high turbidity in the mouth area inhibited the transformation of phosphate from particulate to dissolved phase. The phosphate-salinity relationship indicated the non\|conservative in Zhelin Bay. Nutrients also showed significant seasonal changes. The highest DIN (39 18μmol/L) was in April, but dropped to 9 93~14 14μmol/L between July and October with the increasing temperature. The highest phosphate (monthly mean 3 38μmol/L,) was in December, and it decreased to the lowest (monthly mean 0 72μmol/L) in May. But it started to increase from June and reached to 1 54μmol/L in August and 1 94μmol/L in September. Monthly mean showed the lowest silicate (30 95μmol更多还原