The genus Phaeocystis is globally distributed, with blooms commonly occurring on continental shelves. This unusual phytoplankter has two major morphologies: solitary cells and cells embedded in a gelatinous matrix. Only colonies form blooms. Their large size (commonly 2 mm but up to 3 cm) and mucilaginous envelope allow the colonies to escape predation, but data are inconsistent as to whether colonies are grazed. Cultured Phaeocystis can also inhibit the growth of co-occurring phytoplankton or the feeding of potential grazers. Colonies and solitary cells use nitrate as a nitrogen source, although solitary cells can also grow on ammonium. Phaeocystis colonies might be a major contributor to carbon flux to depth, but in most cases, colonies are rapidly remineralized in the upper 300 m. The occurrence of large Phaeocystis blooms is often associated with environments with low and highly variable light and high nitrate levels, with Phaeocystis antarctica blooms being linked additionally to high iron availability. Emerging results indicate that different clones of Phaeocystis have substantial genetic plasticity, which may explain its appearance in a variety of environments. Given the evidence of Phaeocystis appearing in new systems, this trend will likely continue in the near future.

中文翻译：

---

棕囊藻：全球之谜


褐囊藻属分布于全球，通常发生在大陆架上。这种不寻常的浮游植物有两种主要形态：孤立细胞和嵌入凝胶状基质中的细胞。只有菌落形成花朵。它们的大尺寸（通常为 2 毫米，但可达 3 厘米）和粘液包膜使菌落能够逃脱捕食，但关于菌落是否被吃草的数据不一致。培养的棕囊藻还可以抑制同时存在的浮游植物的生长或潜在食草动物的摄食。集落和孤立细胞使用硝酸盐作为氮源，尽管孤立细胞也可以在铵上生长。棕囊藻菌落可能是深度碳通量的主要贡献者，但在大多数情况下，菌落在上层 300 m 处迅速再矿化。大量棕囊藻水华的发生通常与低光照和高变化光照以及高硝酸盐水平的环境有关，南极棕囊藻水华还与高铁利用率有关。新的结果表明，棕囊藻的不同克隆具有很大的遗传可塑性，这可以解释其在各种环境中的出现。鉴于棕囊藻出现在新系统中的证据，这种趋势可能会在不久的将来继续下去。