Abundance and distribution of testate amoebae bearing siliceous plates in freshwater lakes and ponds along the east coast of North America: Importance of water depth and pH.
Abundance and distribution of testate amoebae bearing siliceous plates in freshwater lakes and ponds along the east coast of North America: Importance of water depth and pH.
复制标题
北美东海岸淡水湖泊和池塘中带有硅质板的有睾变形虫的丰度和分布：水深和 pH 值的重要性。
DOI：
10.1086/711691
复制
发表时间：
2020
影响因子：
1.8
通讯作者：
Siver, Peter A.
中科院分区：
文献类型：
--
作者：
Siver, Peter A.
睾丸变形虫是一种高度多样化和多物种的异养、自由生活的变形虫原生生物，由一个封闭在壳或测试中的单个细胞组成。这些生物栖息在广泛的栖息地，包括湖泊、池塘、河流、沼泽、湿地和泥炭地，在那里它们捕食细菌、藻类、其他原生生物，有时还捕食小型微后生动物。一组无睾丸的变形虫用重叠的硅质板进行测试，硅质板在细胞内单独形成，然后分泌并粘在一起形成一个有组织的外壳。在变形虫死亡后，硅质板块会积聚在湖泊沉积物中，成为化石记录的一部分。当前研究的目标是记录北美东海岸水体中硅质板块形态的浓度，检查分布模式，并确定环境变量与板块丰度之间的关系。从美国北卡罗莱纳到加拿大纽芬兰的125个水体的表层沉积物中，列举了7种硅质板型，它们代表了主要属于Euglyphida目的无遗存变形虫的遗骸。圆形板是分布最广泛的形态，在95%的水体中发现，与椭圆形板一起，占所有标本的75%。其他板型包括四边形、长方形、菱形和鳞片形也很常见，所有板型都表现出独特的分布模式。我们使用最佳子集回归来评估环境变量与板块浓度/沉积物干质量之间的关系，并评估不同地点之间的差异。水深和pH值一直被证明可以解释遗嘱板丰度的最大变化。钾和硫酸盐的浓度不太重要。在浅水和酸性水体中发现了较高浓度的硅质板块，这表明在古代水体中重建这两个变量的估计是可能的。
Testate amoebae are a highly diverse and polyphyletic group of heterotrophic, free-living amoeboid protists that consist of a single cell enclosed within a shell, or test. These organisms inhabit a broad range of habitats, including lakes, ponds, rivers, bogs, wetlands, and peatlands, where they prey on bacteria, algae, other protists, and in some cases small micrometazoans. One group of testate amoebae produce the test out of overlapping siliceous plates that are formed individually within the cell and then secreted and glued together to make an organized shell. Upon amoebae death, the siliceous plates can accumulate in lake sediments and become part of the fossil record. The goals of the current study were to document the concentrations of siliceous plate morphotypes in waterbodies along the east coast of North America, examine distributional patterns, and determine the relationships between environmental variables and abundances of plates. Seven siliceous plate morphotypes representing remains of testate amoebae belonging largely to the Order Euglyphida were enumerated in surface sediments from 125 waterbodies situated from North Carolina, USA, to Newfoundland, Canada. Circular-shaped plates were the most widely distributed morphotype, found in 95% of the waterbodies, and along with oval-shaped plates, they accounted for 75% of all specimens enumerated. Other plate morphotypes, including quadrangular, rectangular, rhomboidal, and scutiform, were also common, and all morphotypes exhibited distinctive distribution patterns. We used best subset regression to evaluate the relationships between environmental variables and the concentration of plates/dry mass of sediment and to assess differences among sites. Water depth and pH were consistently shown to explain the most variation in testate plate abundance. Concentrations of potassium and sulfate were of lesser importance. Higher concentrations of siliceous plates were found in shallow and acidic waterbodies, indicating the possibility of reconstructing estimates of these 2 variables in ancient waterbodies.