THECAMOEBIANS (TESTATE AMOEBAE) AND FORAMINIFERA FROM THREE ANCHIALINE CENOTES IN MEXICO: LOW SALINITY (1.5-4.5 psu) FAUNAL TRANSITIONS
THECAMOEBIANS (TESTATE AMOEBAE) AND FORAMINIFERA FROM THREE ANCHIALINE CENOTES IN MEXICO: LOW SALINITY (1.5-4.5 psu) FAUNAL TRANSITIONS
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墨西哥三个近岸天然井中的 Thecamoebians（睾丸变形虫）和有孔虫：低盐度 (1.5-4.5 psu) 动物群转变
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发表时间：
2008
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通讯作者：
Jeremy J. Gabriel
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作者：
P. J. Hengstum;E. Reinhardt;P. Beddows;R. J. Huang;Jeremy J. Gabriel
这项研究首次系统地记录了墨西哥金塔纳罗奥的无脊椎生物（天坑）中的有孔虫和囊变形虫。从Carwash（1.5 psu）、Maya Blue（2.9 psu）和El Eden（.3.3 psu）天然井采集了33个表层沉积物样本（上部5 cm）。Q-模式聚类分析的动物群分布隔离四个低多样性（香农多样性指数1.0- 1.5）和盐度控制的组合。组合1（1.5 psu）由棘突棘尾虫Centropyxis aculeata“”（53%）和Arcella vulgaris（21%）占主导地位。组合2（2.9 6 0.2 psu）以Centropyxis aculeata“discoides "（41%）和Centropyxis aculeata”aculeata"（27%）为主。矮小（50毫米）Centropyxis constricta '' aerophila ''（20%）与一个自生的测试和Jadammina macrescens（29%）占主导地位组合3（3.4 6 0.2 psu）。最后，Ammonia tepida（51%），Tritaxis sp.（29%）和Elphidium sp.（11%）占优势组合4（3.7 6 0.4 psu）。亚热带生物群落中的变形虫和有孔虫种群的分布与其他温带水生系统中的盐度变化一致。随着盐度的增加，Centropyxid类群趋向于无刺的生态表型，并且矮化和自生壳Centropyxis constricta“aerophila”被确定为最广盐性的泡囊变形虫，持续存在于该组的生态边界（3.3 psu）。重要的是，从thecamoebian为主的组合有孔虫为主的组合的过渡发生在约3.5 psu的盐度。
This study presents the first systematic documentation of thecamoebians and foraminifera in anchialine cenotes (sinkholes) from Quintana Roo, Mexico. Thirty-three surface sediment samples (upper 5 cm) were collected from cenotes Carwash (1.5 psu), Maya Blue (2.9 psu) and El Eden (.3.3 psu). Q-mode cluster analysis of the faunal distributions isolated four low-diversity (Shannon diversity index 1.0– 1.5) and salinity-controlled assemblages. Assemblage 1 (1.5 psu) is dominated by the thecamoebians Centropyxis aculeata ‘‘aculeata’’ (53%) and Arcella vulgaris (21%). Assemblage 2 (2.9 6 0.2 psu) is dominated by Centropyxis aculeata ‘‘discoides’’ (41%) and Centropyxis aculeata ‘‘aculeata’’ (27%). Dwarfed (,50 mm) Centropyxis constricta ‘‘aerophila’’ (20%) with an autogenous test and Jadammina macrescens (29%) dominate Assemblage 3 (3.4 6 0.2 psu). Finally, Ammonia tepida (51%), Tritaxis sp. (29%) and Elphidium sp. (11%) dominate Assemblage 4 (3.7 6 0.4 psu). Thecamoebian and foraminiferal populations in the subtropical cenotes are distributed according to salinity variations as found in other temperate paralic systems. The centropyxid taxa trended towards ecophenotypes without spines with increasing salinity, and dwarfed and autogenous-shelled Centropyxis constricta ‘‘aerophila’’ were determined as the most euryhaline thecamoebian, persisting at the ecological boundary of the group (,3.3 psu). Importantly, the transition from a thecamoebian-dominated assemblage to a foraminiferan-dominated assemblage occurs at a salinity of approximately 3.5 psu.