Regional variation in the life cycle of Rhincalanus gigas (Copepoda: Calanoida) in the Atlantic Sector of the Southern Ocean--re-examination of existing data (1928 to 1993)
Regional variation in the life cycle of Rhincalanus gigas (Copepoda: Calanoida) in the Atlantic Sector of the Southern Ocean--re-examination of existing data (1928 to 1993)
复制标题
南大洋大西洋区Rhincalanus gigas（桡足类：Calanoida）生命周期的区域差异——现有数据的重新审查（1928年至1993年）
DOI：
10.3354/meps157261
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
A. W. Murray
中科院分区：
文献类型：
--
作者：
P. Ward;A. Atkinson;S. Schnack;A. W. Murray
根据1928至1993年间在南大洋大西洋区段收集的选定净拖网数据，对长头菊头蝠的生活史进行了区域比较。数据汇集成3个区域，从斯科舍海延伸到次南极锋的北部区域(NR)，包括极锋和极锋带、韦德尔-斯科舍交汇处(WSC)和东部韦德尔海(EWS)。自然环境有明显的地区差异，与EWS发现的9个月的冰盖相比，北非地区全年基本上没有冰。长尾轮虫在北半球，特别是在极锋，比WSC或EWS更丰富，所有区域的丰度季节波动都很低。在北极洲和北极洲发现了明显的季节性垂直迁徙模式，两者的种群数量在2月份开始下降；然而，在北极洲，回到表层水域的时间提前了2-3个月，招募开始的时间也相应更早。在WSC中，没有明确的季节模式可以解决，这可能反映了该区域的动态性质。越冬期结构在越冬期结构上也有明显的差异。在前者中，新世代主要以CIII越冬，而在EWS中则主要以CII越冬。自然保护区中CIV/CVI丰度的冬季下降及其从10月份开始的明显补充表明，部分种群具有1年的生命周期。相反，在EWS中，CIV到CVI的强烈越冬现象表明更有可能是2年。在这两个地区，雌性全年都存在，这表明它们有能力越冬，并可能再次产卵。这两个地区秋冬季的低死亡率(<；0.004 d-1)为两年的生命周期提供了进一步的支持。
A regional comparison of the life cycle of Rhincalanus gigas was undertaken on the basis of selected net haul data collected in the Atlantic sector of the Southern Ocean between the years 1928 and 1993. Data were pooled into 3 regions, a northern region (NR) extending from the Scotia Sea to the sub-Antarctic Front and incorporating the Polar Front and Polar Frontal Zone, the Weddell-Scotia Confluence (WSC) and the Eastern Weddell Sea (EWS). There are distinct regional contrasts in the physical environment, the NR being largely ice-free throughout the year compared to the 9 mo ice cover found in the EWS. R. gigas was more abundant in the NR, particularly at the Polar Front, than in either the WSC or EWS and seasonal fluctuations in abundance in all regions were low. A clear seasonal vertical migration pattern was found in the NR and EWS, with the population commencing its descent in February in both; however, arrival back in the surface waters was up to 2-3 mo earlier in the NR and recruitment commenced correspondingly sooner. In the WSC no clear seasonal pattern could be resolved, which probably reflects this region's dynamic nature. Clear differences in overwintering stage structure were also seen between the NR and EWS. In the former, the new generation overwinters mainly as CIII, compared to CII in the EWS. A winter decline in the abundance of CIV to CVI in the NR and their clear recruitment from October onwards suggests that a proportion of the population has a 1 yr life cycle. In contrast in the EWS a strong overwintering presence of CIV to CVI suggests that 2 yr is more likely. In both regions females were present throughout the year indicating their ability to overwinter and possibly spawn again. Low mortality rates (<0.004 d-1) in both regions during the autumn and winter offer further support for a 2 yr life cycle.