Abstract
Widespread coastal eutrophication is known to increase the prevalence of harmful algal blooms (HABs). Increased HABs have also been linked to climate change, with ocean warming predicted to lead to increased prevalence and earlier timing of HABs. Testing the predictions of warming to HABs is difficult due to the lack of long-term observations across spatial scales. Here, we use a 45 year (1970-2015) record of the occurrence and duration of HABs along Chinese coast to show that the HAB frequency has increased at a rate of 40 ± 4% decade-1, with earlier timing by 5.50 ± 1.78 days decade-1. The increasing frequency of blooms varied with latitude and is significantly correlated with warming at an average rate of 0.17 ± 0.03 °C decade-1, with the positive relationship being strongest in more eutrophic provinces. HAB frequency increased with elevated dissolved inorganic nutrient concentration, but this increase was amplified further with warming. Warming and eutrophication showed additive roles in triggering HABs. Swift action to mitigate eutrophication is essential to avoid a sharp increase in the HABs in coastal waters with further warming.
Original language | English (US) |
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Pages (from-to) | 13031-13041 |
Number of pages | 11 |
Journal | Environmental Science & Technology |
Volume | 53 |
Issue number | 22 |
DOIs | |
State | Published - Oct 15 2019 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: The authors thank Dr. Li Hongjun, Dr. Shao Kuishuang, and
Li Dongmei at the National Marine Environment Monitoring
Centre, SOA, for valuable information and discussion
regarding monitoring programs conducted by their agencies,
and Xu Caicai at Zhejiang University for her assistance in
drawing Figures 3, and 4. We thank Jin Runjie at Zhejiang
University for his assistance in making the cover art, and Dr.
Mao Zhihua and Dr. Tao Bangyi at Second Institute Of
Oceanography, Ministry of Natural Resources, China for
providing the original remote sensing data. This research was
supported by the National Natural Science Foundation of
China Grant 21677122 and 21876148 (to X.X.) and the
International Science and Technology Cooperation Program
of China Grant 2015DFA01410 from Ministry of Science and
Technology, China (to J.W. and C.M.D.). This work was also
supported by King Abdullah University of Science and
Technology (to S.A. and C.M.D.)