Biogeographical structure of the microphytoplankton assemblages in the region of the Subtropical Convergence and across a warm-core eddy during austral winter
Biogeographical structure of the microphytoplankton assemblages in the region of the Subtropical Convergence and across a warm-core eddy during austral winter
复制标题
南半球冬季副热带辐合区和暖核涡旋附近微型浮游植物群落的生物地理结构
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
E. Pakhomov
中科院分区：
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作者：
P. Froneman;R. Perissinotto;E. Pakhomov
在南非南极海洋生态系统研究（SAAMES）III航次期间，于1993年晚冬（6 - 7月）沿沿着两条断面调查了亚热带辐合区（STC）和跨越从厄古拉斯回流流出的暖心涡旋的微型植物群落的分布。取样是为了分析营养物，以及计数和鉴定微型浮游植物种类。沿着两条样带，叶绿素浓度最高的站点在南部边界的STC和暖心涡的外围。在叶绿素浓度相关的变异中，温度占总变异的65%。沿着两个样带，物种丰富度从北到南减少。两个断面硅藻数量优势种的空间分布相似。的微型浮游植物组合占主导地位的亚热带硅藻种类Chactoccros constnctus北部的STC，和Pseudoeunotia doliolus内的涡流和南部的STC。使用聚类和排序分析，三个显着不同的分组的站点被确定为沿着的组合样带。这与STC南北的站点以及暖心涡旋本身相吻合，证实STC代表了一个强的地理边界。暖水物种P.doliolus和Planktoniella sol在STC南部的暖心涡旋内和周围的优势表明，涡旋是重要的micTophytoplankton转移跨越这个强大的地理边界。
The distribution of microphytopla nkton in the region of the Subtropical Convergence (STC) and across a warm-core eddy shed from the Agulhas Return Current was investigated along two transects in late austral winter (June-July) 1993, during the South African Antarctic Marine Eco- system Study (S AAMES) III cruise. Sampling was undertaken for the analysis of nutrients, and for the enumeration and identification of microphytoplankton species. Along both transects, chlorophyll con- centrations were highest at stations at the southern boundary of the STC and at the periphery of the warm-core eddy. Of the variance associated with chlorophyll concentration, temperature accounted for 65% of the total. Along both transects, a decrease in species richness from north to south was observed. The spatial distribution of the numerically dominant diatom species was similar in both tran- sects. The microphytoplankton assemblage was dominated by the subtropical diatom species Chactoccros constnctus north of the STC, and by Pseudoeunotia doliolus within the eddy and south of the STC. Using cluster and ordination analyses, three significantly different groupings of stations were identified along the combined transects. These coincided with stations located north and south of the STC and with the warm-core eddy proper, confirming that the STC represents a strong biogeograph- ical boundary. The predominance of the warm-water species P.doliolus and Planktoniella sol in and around the warm-core eddy south of the STC suggests that eddies are important in the transfer of micTophytoplankton across this strong biogeographical boundary.