Abstract
The three large marine ecosystems (LMEs) bordering China (Yellow Sea/Bohai Sea, East China Sea, and South China Sea) have received excess nitrogen (N) and phosphorus (P) in the past decades with detrimental consequences for ecosystem functioning, such as increased productivity, loss of biodiversity, and proliferation of harmful algal blooms (HABs). N loading increased much faster than that of P. Here, we show that HABs in the three LMEs started to proliferate after the N:P molar ratio exceeded the threshold value of 25 in the 1980s. The mismatch of N and P inputs is not only related to differences in loads but also inherent to the differences in their biogeochemical cycles which more efficiently filter P than N in land- and waterscapes. Future Shared Socioeconomic Pathways show that high N:P ratios will persist for decades to come, even worsening in a future oriented toward sustainability, and indicate that HABs may be a persisting problem in China’s coastal waters. While efforts in agricultural systems are governed by the agronomic crop requirements and are not easy to manage with respect to N:P ratios, the separate collection of urine in urban and rural areas could contribute to decreases in both total nutrient loads and N:P ratios.
| Original language | English |
|---|---|
| Pages (from-to) | 276-284 |
| Number of pages | 9 |
| Journal | Environmental science & technology letters |
| Volume | 8 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 9 Mar 2021 |
Bibliographical note
Funding Information:This work was supported by funding from the China Scholarship Council Grant (No. 201806330024) and Earth and life sciences (ALW) Open Programme 2016 project (No. 476 ALWOP.230) financed by The Netherlands Organization for Scientific Research (NWO) (J.W.), Green Card Talents project (No. 841912031) financed by Ocean University of China (A.F.B.), PBL Netherlands Environmental Assessment Agency through in-kind contributions to The New Delta 2014 ALW projects (No. 869.15.015 and No. 869.15.014) (A.F.B. and A.H.W.B.), Horizon 2020 Framework Programme (VERIFY, No. 776810) (F.D.), China Scholarship Council Grant (No. 201806190149) (Y.Y.), The Netherlands Earth System Science Center (J.J.M.), U.S. National Science Foundation (No. DEB 1911349) (P.M.G.), National Natural Science Foundation of China projects (No. 41776089 and No. 41930862) (X.R.), and Strategic Priority Research Program of Chinese Academy of Sciences (CAS, No. XDA19060203) (R.Y.). We thank the reviewers for constructive comments and suggestions that have helped to improve this paper.
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