CHANGES IN COMPOSITION OF BOTTOM FAUNA OF A TIDAL-FLAT AREA DURING A PERIOD OF EUTROPHICATION
CHANGES IN COMPOSITION OF BOTTOM FAUNA OF A TIDAL-FLAT AREA DURING A PERIOD OF EUTROPHICATION
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DOI：
10.1007/bf01319712
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发表时间：
1991-01-01
期刊：
影响因子：
2.4
通讯作者：
BEUKEMA, JJ
中科院分区：
文献类型：
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作者：
BEUKEMA, JJ
在过去的20年中，荷兰瓦登海的西半部经历了显着的富营养化：浓度的P和N化合物和浮游藻类大约翻了一番，初级生产。虽然氧气水平在夏季通常很低，但由于强烈的潮汐混合，缺氧区域很小而且很少。在1970年至1990年期间，每年在瓦登海最西部50平方公里的潮坪地区Balgzand的15个站点对大型底栖动物进行取样。在这20年中，不仅总数、生物量和产量的估计数翻了一番，而且还观察到底栖生物群落的组成发生了重大变化：（1）多毛类动物数量比例的增加是以软体动物和甲壳动物为代价的，（2）大型底栖动物个体的总体平均重量下降（3）虽然各种食性的绝对数量和生物量都有所增加，但食肉动物所占的比例下降，而存款食性动物所占的比例增加。悬浮饲养者的比例变化不大。本研究仅涉及真正的大型底栖动物（1毫米筛），并进一步排除了两个分类群（Corophium spp.）和Hydrobia ultimate），偶尔会对数量产生不适当的影响。低氧浓度造成的大规模死亡只是小规模的。物种总数的波动没有一个明确的趋势。由于数量密度的增加，物种数量的趋势在每单位面积表示时略有增加，在每100个个体估计时略有减少（稀疏）。
During the last 20 yr the western half of the Dutch Wadden Sea has undergone significant eutrophication: concentrations of P and N compounds and planktonic algae have roughly doubled, as has primary production. Though oxygen levels are often low in summer, anoxic areas are small and rare due to strong tidal mixing. During the 1970 to 1990 period, macrozoobenthos was sampled annually at 15 stations at Balgzand, a 50-km2 tidal-flat area in the westernmost part of the Wadden Sea. Not only did the estimates of total numbers, biomass, and production double during these two decades, but significant changes in the composition of the benthic community were observed, too: (1) the numerical proportion of polychaetes increased at the expense of molluscs and crustaceans, (2) the overall mean weight per individual of the macrozoobenthos decreased (numbers of individuals of small-sized species increased more rapidly than those of large-sized species), and (3) though absolute numbers and biomass of all feeding types increased, the share of carnivores declined and that of deposit feeders increased, the proportion of suspension feeders showed little change. This study refers to true macrobenthos only (1-mm sieve) and further excludes two taxa (Corophium spp. and Hydrobia ulvae) which occasionally exercised an undue influence on numbers. Mass mortalities caused by low oxygen concentrations were of a small-scale nature only. Total number of species fluctuated without a clear trend. As a consequence of the increasing numerical densities, trends in species numbers were slightly increasing when expressed per unit of area and slightly decreasing when estimated per 100 individuals (by rarefaction).