| WANG Baodong,XIN Ming,SUN Xia,WEI Qinsheng,ZHANG Xuelei. 2016. Does reduced sediment load contribute to increased outbreaks of harmful algal blooms off the Changjiang Estuary?. Acta Oceanologica Sinica, 35(8):16－21 |
| Does reduced sediment load contribute to increased outbreaks of harmful algal blooms off the Changjiang Estuary? |
| 入海泥沙的减少对长江口赤潮增加有贡献吗? |
| Received:September 30, 2015 Revised:February 18, 2016 |
| DOI：10.1007/s13131-016-0846-5 |
| Key words:harmful algal blooms phytoplankton biomass sediment load chlorophyll Changjiang (Yangtze River)Estuary |
| 中文关键词: 有害藻华 浮游植物生物量 泥沙通量 叶绿素 长江口 |
| 基金项目:The National Natural Science Foundation of China under contract No. 41576084; the Natural Science Foundation of ChinaShandong Joint Fund for Marine Ecology and Environmental Sciences under contract No. U1406403; the Key Project of Fundamental Research Funds for the First Institute of Oceanography, State Oceanic Administration under contract No. GY0215G12. |
| Author Name | Affiliation | E-mail | | WANG Baodong | The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China | wangbd@fio.org.cn | | XIN Ming | The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China | | | SUN Xia | The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China | | | WEI Qinsheng | The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China | | | ZHANG Xuelei | The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China | |
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| Abstract: |
| Harmful algal blooms (HABs) have been increasingly frequent in coastal waters around the world over the last several decades. Accelerated coastal eutrophication, resulting from the increased anthropogenic loadings of nutrients, is commonly assumed to be the primary cause of this increase. However, although important, accelerated coastal eutrophication may not be the only explanation for the increasing blooms or toxic outbreaks in estuarine waters. Changes in riverine material fluxes other than nutrients, such as sediment load, may significantly affect biological activities and HAB incidence in estuarine and coastal waters. A case study off the Changjiang (Yangtze River) Estuary indicated that with the increasing riverine loadings of nutrients, the sediment load from the Changjiang River has been reduced by 70% over the past four decades. A comparison of long-term data revealed that the phytoplankton biomass maximum has expanded to a region of much lower salinity due to the drastic reduction in riverine sediment load and the subsequent improvement in light penetration in the Changjiang River plume. Furthermore, there was an apparent mirror-image relationship between the sediment load from the Changjiang River and the HAB incidence off the Changjiang Estuary over the past four decades, and the number of HAB incidents was significantly negatively correlated with the sediment load. Therefore, it is argued that the drastic decline in sediment load from the Changjiang River reduced turbidity in the Changjiang Estuary and thus contributed to the increased frequency of HABs in the buoyant discharge plumes. |
| 中文摘要: |
| 过去几十年来全球近海有害藻华（又称赤潮）发生频率持续增加。人类活动造成的河口-近海富营养化程度的加剧，被认为是导致全球有害藻华增加的主要原因。但是，富营养化程度的加剧可能不是全球有害藻华增加的惟一原因。河流入海的非营养盐类的其他物质通量变异（如泥沙），也可能显著影响河口-近海的生物活动乃至赤潮的发生。过去40年来随着长江入海营养盐通量的增加，长江入海泥沙通量减少了70%。长期观测资料显示，由于泥沙减少使得长江口羽状流区光照条件显著改善，长江口浮游植物生物量最大值区已扩展至更低盐度的区域。此外，过去40年来长江口赤潮发生频率变化与长江入海泥沙通量变化呈现镜像关系，且二者呈显著的负相关关系。因此认为，长江入海泥沙的剧烈减少降低了羽状流区水体浊度，从而对长江口区赤潮频率的增加有一定贡献。 |
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