Regulation of estuarine primary production by watershed rainfall and river flow
Regulation of estuarine primary production by watershed rainfall and river flow
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DOI：
10.3354/meps093199
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发表时间：
1993
影响因子：
2.5
通讯作者：
M. Mallin;H. Paerl;Joseph Rudek;Paul W. Bates
中科院分区：
文献类型：
--
作者：
M. Mallin;H. Paerl;Joseph Rudek;Paul W. Bates
浮游植物产量增加和藻类大量繁殖是富营养化的症状，通常是由于沿海沃茨营养物负荷增加（通常是氮）造成的。这些氮主要来自人为来源（城市、工业和农业），但通过气象和水文手段输送到沿海沃茨。我们利用一个4年的月度数据集，调查这些上游物理力量对纽斯河口（北卡罗来纳州）初级生产力的影响。研究结果表明，河口初级生产力的大小和藻华的周期性与上游流域降雨的变化及其对下游径流的调节有直接关系。因此，未来沿海地区降雨前格局的变化可能导致沿海初级生产力速率和格局的实质性改变。河口沃茨的生物生产力受到许多因素的影响，包括纬度、季节、辐照度、温度、流量、营养物负荷和再循环、放牧以及流域地貌和发展（Mann 1982，尼克松1986，Day等人1989）。上游河流流量对河口沃茨的初级生产力、盐度、营养盐负荷、光衰减、溶解氧和分层有重要影响（库珀和科普兰1973年，贾沃斯基1981年，Sellner 1987年，兰德尔和戴1987年，马龙等人1988年，克里斯蒂安等人1991年，乔丹等人1991年，Rudek等人，1991年; Gallegos等人，1992年）。控制河流流量的因素，因此，预计会影响河口初级生产力。目前地址：“美国北卡罗来纳州威尔明顿市威尔明顿市北卡罗来纳州生物科学系”“美国地质勘探局MS 469，345米德尔菲尔德路。美国加州门10公园园艺系。1575林登博士，威斯康星州，麦迪逊大学。威斯康星州53106.美国美国北卡罗来纳州的纽斯河口是典型的沿海平原河口，其流域面积大（16000平方公里），水相对较浅，城市、工业和农业来源的营养负荷较高（Stanley 1988，Christian等1991）。生物测定表明，该系统的初级生产力主要受氮限制（Rudek等人，1991年）。浮游植物群落以中心硅藻、甲藻和隐藻为主，群落结构受盐度影响;淡水输入增加有利于隐藻，而硅藻往往在更含盐的条件下占主导地位，甲藻通常处于次优势地位，除了周期性的水华（Mallin et al. 1991）。以前的研究表明，在1988-1989年期间，初级生产力与表层硝酸盐浓度密切相关，与盐度呈负相关（Mallin等人，1991年）。此外，河流流量增加的时期与硝酸盐的增加和盐度的降低有关（Rudek等人，1991年）。在此基础上，我们的目标是在目前的研究是如何相互作用的物理和化学变量影响河口初级生产力从生态系统的角度来看。因此，我们利用了一个长期的数据集，调查在何种程度上河流流量及其主要驱动力，流域降雨量，影响这个大的温带河口的初级生产力。材料和方法。我们在Channel Marker 6（一个中盐站，距离与帕姆利科湾相连的河口约10 km）采样，以测定浮游植物生产力、分类群组成和丰度、叶绿素a、营养物质和物理因子（图1）。在4年的时间里（1988年至1992年），大约每月收集一次样本。初级生产力由14 C 0 Inter-Research 1993 - 200 Mar. Ecol. Prog. 93：199-203，1993
Enhanced phytoplankton production and algal blooms, symptoms of eutrophication, are frequently caused by elevated nutrient loading, usually a s nitrogen, to coastal waters. This nitrogen is derived primarily from anthropogenic sources (urban, industrial, and agricultural) but is delivered to coastal waters through meteorological and hydrological means. We utilized a 4 yr monthly data set to investigate the effect of these upstream physical forces upon primary productivity of the Neuse River Estuary (North Carolina. USA), a large temperate coastal plain estuary Our results indicate that the magnitude of estuarine primary production and the periodicity of algal blooms can be directly related to variations in upper watershed rainfall and its subsequent regulation of downstream nver flow Future changes in preclpitatlon patterns for coastal regions may thus lead to substantlal alterations in coastal primary productiv~ty rates and patterns. Biological productivity in estuarine waters is influenced by a host of factors including latitude, season, irradiance, temperature, flow, nutrient loading and recycling, grazing, and watershed geomorphology and development (Mann 1982, Nixon 1986, Day et al. 1989). Upstream river flow has been recognized as an important influence on the primary productivity, salinity, nutrient loading, light attenuation, dissolved oxygen, and stratification of estuarine waters (Cooper & Copeland 1973, Jaworski 1981, Sellner 1987, Randall & Day 1987, Malone et al. 1988, Christian et al. 1991, Jordan et al. 1991, Rudek et al. 1991, Gallegos et al. 1992). Factors controlling river flow should, therefore, be expected to affect estuarine primary productivity. Present addresses: 'Department of Biological Sciences, University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA ' 'USGS MS 469,345 Middlefield Rd. Men10 Park, California 94025, USA ' 'Department of Horticulture. 1575 Linden Dr., University of Wisconsin, Madison. Wisconsin 53106. USA The Neuse River Estuary, North Carolina, USA, typifies coastal plain estuaries with its large drainage basin (16000 km2) , relatively shal1o.w water, and elevated nutrient loading from urban, industrial, and agricultural sources (Stanley 1988, Christian et al. 1991). Bioassays have indicated that primary productivity is predominantly nitrogen-limited in this system (Rudek et al. 1991). The phytoplankton conlmunity is dominated by centric diatoms, dinoflagellates, and cryptomonads, with community structure influenced by salinity; increased freshwater inputs favor cryptomonads, whereas diatoms tend to dominate under more saline conditions, and dinoflagellates are usually subdominant except for periodic blooms (Mallin et al. 1991). Previous research indicated that during 1988-1989 primary productivity was strongly correlated with surface nitrate concentrations and negatively correlated with salinity (Mallin et al. 1991). Also, periods of increased river flow were associated with increases in nitrate and decreases in salinity (Rudek et al. 1991). Based on this information, our objective in the present research was to examine how the interplay of physical and chemical variables affected estuarine primary productivity from a n ecosystem perspective. Accordingly, we utilized a long-term data set to investigate the extent to which river flow and its primary driving force, watershed rainfall, influenced the primary productivity of this large temperate estuary. Materials and methods. We sampled for phytoplankton productivity, taxa composition and abundance, chlorophyll a, nutrients, and physical factors at Channel Marker 6, a mesohaline station located about 10 km from the mouth of the estuary where it joins Pamlico Sound (Fig. 1). Samples were collected approximately monthly over a 4 yr perlod (1988 to 1992). Primary productivity was assessed by the 14C 0 Inter-Research 1993 200 Mar. Ecol. Prog. Ser. 93: 199-203, 1993