Oceanographic Center, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, Florida 33004, USA.
J Eukaryot Microbiol. 2009 Mar-Apr;56(2):194-200. doi: 10.1111/j.1550-7408.2008.00388.x.
From January to December 2004, monthly samples were collected from the mangrove salt marsh of J.U. Lloyd State Park, Florida, to examine the spatial and temporal distributions of heterotrophic diatoms in this subtropical region. Four non-pigmented (i.e. apochlorotic), heterotrophic diatom morphotypes were isolated from mangrove neuston and plankton sites. Colorless diatoms were numerically significant in neuston during the fall and winter months and counts peaked at 174 x 10³ cells/L in December. Heterotrophic diatoms were most prevalent in mangrove plankton in October and averaged 55.5 x 10³ cells/L. Valve morphology was detailed for mangrove morphotypes (I, II, V, and VI). However, only one type (I) was named with confidence (Nitzschia leucosigma). The other three types failed to conform closely to published diagnostic features suggesting that either characters are more variable than accepted or these types were new species. Growth responses to changes in salinity and irradiance were detailed in the laboratory. All morphotypes were euryhaline, tolerating salinities between 10% and 40%; N. leucosigma was most salt tolerant and grew from 10% to 60%. Maximum growth was achieved between 20% and 40%. Growth was not significantly different for heterotrophic diatoms during light and dark treatments or for diatoms grown with or without bacteria.
2004 年 1 月至 12 月，从佛罗里达州 J.U.劳埃德州立公园的红树林盐沼每月采集样本，以研究亚热带地区异养硅藻的时空分布。从红树林浮叶和浮游生物中分离出四种非色素（即无叶绿素）异养硅藻形态。无色硅藻在秋季和冬季的浮叶中数量显著，12 月达到 174×10³ 个细胞/L。异养硅藻在 10 月的红树林浮游生物中最为普遍，平均为 55.5×10³ 个细胞/L。对红树林形态类型（I、II、V 和 VI）进行了详细的瓣壳形态描述。然而，只有一种类型（I）被自信地命名（Nitzschia leucosigma）。其他三种类型与已发表的诊断特征不太吻合，这表明特征要么更加多变，要么这些类型是新物种。在实验室中详细研究了对盐度和光照变化的生长反应。所有形态类型均广盐性，耐受盐度为 10%至 40%；N. leucosigma 对盐度的耐受性最强，从 10%到 60%都能生长。在 20%至 40%之间达到最大生长。在光照和黑暗处理、有或没有细菌生长的情况下，异养硅藻的生长没有显著差异。
