ABSTRACT

The filamentous green alga Chaetomorpha ligustica (Cladophoraceae, Cladophorales) was recorded covering seagrass meadows at Pāuatahanui Inlet, New Zealand. Species of the genus Chaetomorpha are difficult to identify by their morphologically, and the identification of C. ligustica was confirmed by sequencing the 28S rRNA large subunit providing a high level of confidence in the species designation. In November 2019, we found C. ligustica intertwined with Ulva spp. forming dense, heavy and entangled structures. Here we report, for the first time, negative impacts of this species upon meadows of the New Zealand seagrass Zostera muelleri. We observed a significant loss of seagrass cover and evidence of anoxia under C. ligustica mats two weeks from the first sighting. Chaetomorpha ligustica can easily be misidentified in the field. This may lead to over- and under-reporting of species, and we recommend the need for more careful identification of macroalgal blooms in the future and further research on growth requirements and origins of strains.

摘要

据记录，新西兰帕瓦塔哈努伊湾的海草草地上覆盖着丝状绿藻Chaetomorpha ligustica（刚毛藻科，刚毛藻目）。Chaetomorpha属的物种很难通过形态学来识别，而C. ligustica的鉴定是通过 28S rRNA 大亚基测序得到证实的，为物种命名提供了高度的可信度。2019 年 11 月，我们发现C. ligustica与石莼属 ( Ulva spp) 交织在一起。形成致密、沉重和纠缠的结构。在此，我们首次报告该物种对新西兰海草Zostera muelleri草地的负面影响。从第一次发现两周后，我们观察到意大利海草覆盖面积显着减少，并出现缺氧的迹象。意大利毛毛虫在田间很容易被误认。这可能会导致物种的多报和少报，我们建议未来需要更仔细地识别大型藻华，并进一步研究菌株的生长要求和起源。