Growth and tissue mass cycles in the infaunal bivalve Yoldia eightsi at Signy Island, Antarctica
Growth and tissue mass cycles in the infaunal bivalve Yoldia eightsi at Signy Island, Antarctica
复制标题
南极洲西格尼岛动物体内双壳类 Yoldia Augustsi 的生长和组织质量周期
作者：
Lloyd S. Peck;J. Colman;A. W. Murray
摘要1992年在南半球的夏季和冬季，对八点云柔鱼的贝壳生长进行了测定。在长度小于12 mm的样本中，夏季和冬季的生长没有显著差异，记录的最快速度为6.3 μm d-1，是在冬季的5 mm个体。在夏季，所有长度的标本增长显着，但在冬季双壳类> 27毫米长度没有增加的长度。在1988年12月至1991年1月期间，每月对组织干重和无灰干重（AFDM）周期进行评估。ANCOVA表明该周期具有显着的年际和季节性影响。组织质量增加，在夏季，正好与浮游植物水华和期间的最大沉降的有机物质从水柱。1990年2月，标准20 mm长的动物达到最大AFDM 114 mg。最低值（68毫克AFDM）在整个2年的测量是在1988年12月初，在南方冬季结束。因此，组织质量增加的时期与壳的生长脱钩，至少在青少年。组织质量显着高于1990年比1989年，这主要是由于在夏季（1月至5月）的有机含量高。这是不一致的模式，在研究现场的沉积物中的有机含量，但在沉积物中的叶绿素a含量的周期。组织质量的增加依赖于夏季的主要资源输入，但Y。eightsi能够在冰层覆盖不足的年份利用底栖微藻维持冬季条件。每年4月至7月，组织质量下降。这是伴随着大福尔斯的组织灰分含量，并在6月初的产卵期。这是在2年期间收集的南极软体动物的第一个月组织质量数据。他们是第一个这样的数据表明，在组织质量的季节性变化，并显示了一个脱钩的壳和组织生长在一个极地双壳类。根据这些数据计算出的P/B比率为0.106，略低于该物种以前的数值，但与南极海洋底栖生物的一般数值一致。
Abstract Shell growth in Yoldia eightsi was measured over an austral summer and winter in 1992. In specimens < 12 mm length, growth was not significantly different between summer and winter periods, and the fastest recorded rate, 6.3 μm day−1 was for 5-mm individuals during the winter. In summer, specimens of all lengths grew significantly, but in winter bivalves > 27 mm length did not increase in length. Tissue dry and ash-free dry mass (AFDM) cycles were assessed at monthly intervals between December 1988 and January 1991. ANCOVA indicated significant interannual and seasonal effects on this cycle. Tissue mass increased in the summer, coinciding with the phytoplankton bloom and the period of maximum sedimentation of organic material from the water column. A standard 20-mm-length animal reached a maximum AFDM of 114 mg in February 1990. The minimum value (68 mg AFDM) throughout the 2 years of measurements was in early December 1988, at the end of the austral winter. Periods of tissue mass increase were, therefore, decoupled from shell growth, at least in juveniles. Tissue mass was significantly higher in 1990 than 1989, which was mainly due to high organic contents in the summer (January to May). This was not consistent with the pattern of organic content in the sediments at the study site, but was in phase with the cycle in sediment chlorophyll a content. Tissue mass increase depended on major resource input during the summer, but Y. eightsi was capable of maintaining winter condition from stocks of benthic microalgae in years of poor ice cover. Tissue mass declined between April and July each year. This was accompanied by large falls in tissue ash content, and coincided with the spawning period in early June. These are the first monthly tissue mass data collected over a 2-year period for an Antarctic mollusc. They are the first such data indicating seasonal variation in tissue mass and showing a decoupling of shell and tissue growth in a polar bivalve. The P/B ratio calculated from these data was 0.106, which is slightly lower than previous values found for this species, but is in line with general values for Antarctic marine benthos.