Biometry and trophodynamics of Salpa thompsoni foxton (Tunicata: Thaliacea) near the Antarctic Peninsula in austral summer, 1983–1984
Biometry and trophodynamics of Salpa thompsoni foxton (Tunicata: Thaliacea) near the Antarctic Peninsula in austral summer, 1983–1984
复制标题
1983-1984年南极半岛附近的Salpa thompsoni Foxton（被囊目：Thaliacea）的生物特征和营养动力学
作者：
M. Huntley;P. Sykes;V. Marín
摘要索氏盐碱草聚集体具有与中纬度盐碱地相似的生物特征，大约96%是水，只有大约1%的有机质。在其无灰干重中，约13.6%是碳，3.1%是氮。所有体重参数均与体长呈∼2.3的幂函数相关。1983年-1984年夏季，桑普森螺旋藻是南极半岛附近海域浮游动物群落的主要成员，3月中旬的生物量分别为49~671mgCm−2和9.6~146mgNm−2。3个亚群分布在不同的区域：(1)布兰斯菲尔德海峡，(2)南设得兰群岛以北，(3)象岛以西，分别由20，30和40 mm个体组成。布兰斯菲尔德海峡的生物量最大，南设得兰群岛附近的生物量最少。汤普森链霉菌对自然产生的颗粒物的清除率测量结果显著低于以前报道的中纬度盐碱地的清除率，我们将这一结果主要归因于低生境温度(约1℃)的影响。直接测量表明，21 mm囊胚的排泄量相当于10.2%的体碳d−1和6.6%的体氮d−1。桑普森链霉菌的捕食可能在3月份减少了大部分的日初级生产量，但在1月份只减少了1%。1983-1984年磷虾幼体相对较低的生物量可能部分归因于盐分对食物的竞争性清除，但同样重要的影响也可能是直接捕食。
SummarySalpa thompsoni aggregates have a biometric profile similar to that of mid-latitude salps, being approximately 96% water and only about 1% organic matter. Of its ash-free dry weight about 13.6% is carbon and 3.1% is nitrogen. All weight parameters were related to body length by a power function of ∼2.3. S. thompsoni was a dominant member of the zooplankton community in waters near the Antarctic Peninsula in the austral summer of 1983–1984, with biomass in mid-March ranging from 49 to 671 mgCm−2 and 9.6 to 146 mgNm−2. Three subpopulations occurred in separate regions: (1) the Bransfield Strait, (2) north of the South Shetland Islands, and (3) west of Elephant Island; these were dominated by 20, 30 and 40 mm individuals, respectively. Biomass was greatest in the Bransfield Strait and least near the South Shetland Islands. Clearance rate measurements of S. thompsoni on naturally occurring particulate matter were significantly lower than those previously reported for mid-latitude salps, a result which we attribute primarily to the effect of low habitat temperature (ca. 1°C). Direct measurements suggest that fecal production by 21 mm blastozoids is equivalent to 10.2% body carbon d−1 and 6.6% body nitrogen d−1. Grazing by S. thompsoni may have removed a majority of the daily primary production in March, but <1% in January. The comparatively low biomass of krill larvae in 1983–1984 may be attributed partially to competitive removal of food by salps, but an equally important effect may have been direct predation.