细弱红翎菜(Solieria tenuis)的物种鉴定及其在青岛市琅琊台湾海域的生长调查研究

2021年7月末至10月初,位于黄海沿岸的青岛市西海岸新区琅琊台湾贡口拦海坝处出现大量悬浮生长的大型红藻。为明确该类群的分类地位,探究其生物学特征,对该处红藻群体展开了实地调研,并采集相关样本开展了形态鉴定和分子系统发育分析。该群体主要由一种红藻组成,藻体紫红色、圆柱形,质软多肉,高度可达20cm,不规则互生分枝,分枝基部强烈缢缩、顶端尖细;藻体主轴横截面观可见较小的含色素外皮层细胞以及较大的近圆形假薄壁细胞和分布在髓层中央的散乱、疏松的丝状细胞。结合分子标记rbc L和cox I基因的系统发育分析结果,该物种被鉴定为细弱红翎菜(Solieria tenuis Zhang et Xia)。与历史研究记录不同,贡口拦海坝处的细弱红翎菜群体缺乏固着器和繁殖结构,悬浮性营养生长,所在海域丰富的氮磷营养可能为其快速生长提供了物质基础,在生长高峰期该群体总生物量约6 t (干重),是一次局部区域性小规模“藻华”。细弱红翎菜的悬浮生态型和暴发性增殖现象表明该物种可能具有较强的环境适应性,其生理特征和潜在的生态风险需进一步关注。

A SOLIERIA TENUIS BLOOM IN LANGYATAI BAY, QINGDAO: SPECIES IDENTIFICATION AND GROWTH INVESTIGATION

From July to October 2021, suspending red algae bloomed near Gongkou Dam, Langyatai Bay in the West Coast New Area of Qingdao City by the Yellow Sea. To identify the species and its biological characteristics, samples were collected for morphological anatomy studies and phylogenetic analysis. The algal bloom species was purplish red, cylindrical, soft and pulpy, in height of up to 20 cm, and having irregular alternate branches that strongly constricted at the base, and tapering apices. The cross section of the main axis showed small pigmented outer cortical cells, large and sub-circular inner cortical cells, and scattered and loose filamentous cells in the medullary layer. In terms of morphology and phylogeny of rbcL and coxI genes, this species was identified as Solieria tenuis Zhang et Xia. Unlike those in historical records, this species lacked holdfast or reproductive structures, and had suspended vegetative growth and fast proliferation due to favorable abundant nutrient supply in the ambiance. At the peak of growth, the biomass of the blooming species was estimated upto about 6t (dry weight), which could be termed as a local small-scale algal bloom. This suspending ecotype in vegetative reproductive lifestyle showed a strong environmental adaptability of S. tenuis, and its physiological characteristics and potential ecological risks shall be further studied.