Komorita Tomohiro, Kajihara Rumiko, Tsutsumi Hiroaki, Shibanuma Seiichiro, Yamada Toshiro, Montani Shigeru
Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan ; Faculty of Environmental and Symbiotic Science, Prefectural University of Kumamoto, Tsukide, Kumamoto, Japan.
Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
PLoS One. 2014 Jan 28;9(1):e86732. doi: 10.1371/journal.pone.0086732. eCollection 2014.
The relationship between the food demand of a clam population (Ruditapes philippinarum (Adams & Reeve 1850)) and the isotopic contributions of potential food sources (phytoplankton, benthic diatoms, and organic matter derived from the sediment surface, seagrass, and seaweeds) to the clam diet were investigated. In particular, we investigated the manner in which dense patches of clams with high secondary productivity are sustained in a coastal lagoon ecosystem (Hichirippu Lagoon) in Hokkaido, Japan. Clam feeding behavior should affect material circulation in this lagoon owing to their high secondary productivity (ca. 130 g C m(-2) yr(-1)). Phytoplankton were initially found to constitute 14-77% of the clam diet, although phytoplankton nitrogen content (1.79-4.48 kmol N) and the food demand of the clam (16.2 kmol N d(-1)) suggest that phytoplankton can constitute only up to 28% of clam dietary demands. However, use of isotopic signatures alone may be misleading. For example, the contribution of microphytobenthos (MPB) were estimated to be 0-68% on the basis of isotopic signatures but was subsequently shown to be 35 ± 13% (mean ± S.D.) and 64 ± 4% (mean ± S.D.) on the basis of phytoplankton biomass and clam food demand respectively, suggesting that MPB are the primary food source for clams. Thus, in the present study, the abundant MPB in the subtidal area appear to be a key food source for clams, suggesting that these MPB may sustain the high secondary production of the clam.
研究了菲律宾蛤仔（Ruditapes philippinarum (Adams & Reeve 1850)）种群的食物需求与潜在食物来源（浮游植物、底栖硅藻以及源自沉积物表面、海草和海藻的有机物质）对蛤仔食物的同位素贡献之间的关系。具体而言，我们研究了在日本北海道的一个沿海泻湖生态系统（蛭子浦泻湖）中，具有高次级生产力的密集蛤仔斑块是如何维持的。蛤仔的摄食行为因其高次级生产力（约130 g C m(-2) yr(-1)）而应会影响该泻湖的物质循环。最初发现浮游植物占蛤仔食物的14 - 77%，尽管浮游植物的氮含量（1.79 - 4.48 kmol N）和蛤仔的食物需求（16.2 kmol N d(-1)）表明浮游植物最多只能占蛤仔饮食需求的28%。然而，仅使用同位素特征可能会产生误导。例如，基于同位素特征估计微型底栖植物（MPB）的贡献为0 - 68%，但随后分别基于浮游植物生物量和蛤仔食物需求显示其为35 ± 13%（平均值 ± 标准差）和64 ± 4%（平均值 ± 标准差），这表明MPB是蛤仔的主要食物来源。因此，在本研究中，潮下带区域丰富的MPB似乎是蛤仔的关键食物来源，这表明这些MPB可能维持了蛤仔的高次级产量。
