Protistan pathogens have been found to infect populations of some large brown macroalgae. Infection could reduce the ability of macroalgae to withstand hydrodynamic pressures through weakening tissues and reducing flexibility. Widespread mortality of macroalgae if disease outbreaks were to occur could have important flow-on consequences for biodiversity and ecosystem function. Recent discoveries of the protistan pathogen Maullinia infecting the ecologically keystone southern bull kelp Durvillaea in Chile, Australia, and on Marion Island, raise the possibility that this pathogen is dispersing across ocean basins with buoyant hosts. To determine whether Maullinia also infects southern bull kelp in New Zealand, samples of gall-like tissue from Durvillaea antarctica, D. poha, and D. willana were collected from intertidal sites, and genetic analyses (sequencing of partial 18S rRNA) carried out. Maullinia infections were detected in all three species of Durvillaea. Phylogenetic analyses show a close relationship of New Zealand Maullinia to M. braseltonii previously detected in Chile and on Marion Island. Based on its genetic similarity to distant lineages and its presence on buoyant hosts that have been shown to drift long distances at seas, we infer that Maullinia has dispersed across the Southern Ocean through rafting of infected bull kelp. Understanding the capacity of pathogens to disperse across oceans is critical part of forecasting and managing ecosystem responses to environmental change.

已经发现原生动物病原体感染一些大型棕色大型藻类的种群。感染可能会通过削弱组织和降低柔韧性来降低大型藻类承受水压的能力。如果发生疾病暴发，大型藻类的广泛死亡可能会对生物多样性和生态系统功能产生重要的持续影响。原生动物病原体毛利氏菌的最新发现感染了智利，澳大利亚和马里恩岛上的生态基石南部公牛海带杜氏藻，这增加了这种病原体在具有活跃寄主的海洋盆地中散布的可能性。为了确定毛利人是否还感染了新西兰南部的海带，从潮间带采集南极杜氏藻，D。poha和D. willana，并进行遗传分析（部分18S rRNA测序）。Maullinia在所有三个物种中都检测到的感染丛梗藻。系统发育分析表明，新西兰毛利尼氏菌与以前在智利和马里恩岛上发现的M. braseltonii密切相关。基于其与遥远世系的遗传相似性以及其在浮力寄主上的存在（已证明在海上漂流了很长一段距离），我们推断毛利尼娅通过漂流被感染的海带散布在南大洋。了解病原体在海洋中扩散的能力是预测和管理生态系统对环境变化的反应的关键部分。