| 摘要: |
| 甲藻孢囊可以为赤潮提供种源, 还可用于指示海区富营养化状态。以往对甲藻孢囊分布的研究多集中于开放性水域和自然形成的海湾中, 在半封闭性人工海湾中的研究较少。梅山湾原属南北开放水域, 但于2012~2017年在向陆侧建设了北坝和南坝, 使其成为半封闭式人工海湾。通过对梅山湾内外海域采集到的6份表层沉积物样品分析, 共鉴定出37种甲藻孢囊, 其丰度介于237~1 054 cysts/g。甲藻孢囊平均丰度湾内高于湾外, 推测是筑堤后湾内水动力减弱, 悬浮物质浓度降低, 水体透明度升高, 水中颗粒物质沉积速率降低和水体富营养化所导致。调查海域甲藻孢囊物种多样性指数介于1.63~2.47, 均匀度指数介于0.58~0.82, 两者湾外均显著高于湾内, 反映出湾内生态系统稳定性更弱, 发生赤潮的可能性更高。研究共检出16种赤潮种和9种有毒甲藻孢囊, 产毒种及赤潮种丰度和种类占比湾内都高于湾外, 优势种有原多甲藻(Protoperidinium sp.)、美利坚原多甲藻(Protoperidinium americanum)、透镜翼甲藻(Diplopsalis lenticula)、微小亚历山大藻(Alexandrium minutum)、链状裸甲藻(Gymnodinium catenatum)和锥状斯氏藻(Scrippsiella trochoidea)。“筑堤效应”加剧了湾内外表层沉积物中甲藻孢囊分布的差异性, 也加重了湾内有毒有害赤潮发生的风险, 故应重视对湾内有毒有害甲藻的监测。 |
| 关键词: 有害赤潮 筑堤效应 半封闭人工海湾 甲藻孢囊 |
| DOI：10.11693/hyhz20230500115 |
| 分类号: |
| 基金项目:国家自然科学基金,42276131号,41876139号;宁波市自然科学基金,2022J195号,2022S116号。 |
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| DISTRIBUTION AND DIVERSITY OF DINOFLAGELLATE CYSTS IN SURFACE SEDIMENTS IN MEISHAN BAY, ZHEJIANG |
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LENG Tian-Ze1, GUO Zhuo-Ran1, SHAO Qian-Wen2, LU Dou-Ding1, DAI Xin-Feng1
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1.Second Institute of Oceanography, Ministry of Natural Resources, Key Laboratory of Marine Ecosystem Dynamics, Hangzhou 310012, China;2.Ningbo institute of Oceanography, Ningbo 315832, China
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| Abstract: |
| Dinoflagellate cysts can serve as seed banks for algal blooms and be also used to indicate water eutrophication. Previous studies on the distribution of dinoflagellate cysts have predominantly focused on open waters and natural bays, with fewer investigations conducted in semi-enclosed artificial bays. Meishan Bay was once an open bay and accessible from the north and south, and underwent a transformation into a semi-enclosed artificial bay following the construction of dams from 2012 to 2017. In this study, six surface sediment samples were collected from the inner and outer waters of the bay. A total of 37 species of dinoflagellate cysts were identified in abundance ranging from 237 to 1 054 cysts/g. The average cyst abundance was higher in the inner water than in the outer water due to the decreases in suspended matter content, hydrodynamics, and sedimentation rate, and the increases in water transparency and the water eutrophication inside the bay. The Shannon-Wiener diversity index(H′) ranged between 1.63~2.47, and Pielou’s evenness index(J′) ranged between 0.58~0.82. Both indices were significantly higher outside than inside of the bay, reflecting lower ecosystem stability and a higher possibility of red tides inside the bay. A total of 16 species capable of causing red tides and 8 toxic species of dinoflagellate cysts were identified in this study. Both the percentage of abundance and species number of toxic and red tide dinoflagellate cysts were higher inside the bay than outside. Dominant species included Protoperidinium sp., Protoperidinium americanum, Diplopsalis lenticula, Alexandrium minutum, Gymnodinium catenatum, and Scrippsiella trochoidea. The construction of dams not only exacerbated the disparity in dinoflagellate cysts in surface sediments between inner and outer regions of the bay but also increased the risk of toxic and harmful red tides within the bay. Therefore, monitoring toxic and harmful dinoflagellate within the bay shall be strengthened in the future. |
| Key words: harmful algal blooms the effect of construction of dam semi-enclosed artificial bay dinoflagellate cyst |
