Net heterotrophy and low carbon dioxide emissions from biological processes in the Yellow River Estuary, China.,Water Research

当前位置： X-MOL 学术 › Water Res. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Net heterotrophy and low carbon dioxide emissions from biological processes in the Yellow River Estuary, China.
Water Research ( IF 11.4 ) Pub Date : 2020-01-06 , DOI: 10.1016/j.watres.2019.115457
Xiaomei Shen ₁ , Meirong Su ₂ , Tao Sun ₃ , Sihao Lv ₂ , Zhi Dang ₄ , Zhifeng Yang ₅

Affiliation

Although estimates of total CO2 emissions from global estuaries are gradually decreasing, current numbers are based on limited data and the impacts of anthropogenic and seasonal disturbances have not been studied extensively. Our study estimates annual and seasonal CO2 fluxes in China's Yellow River Estuary (YRE) which incorporated spatiotemporal variations and the effects of water and sediment regulation (WSR). Aquatic metabolism was estimated using Odum's open water dissolved oxygen methods and used to represent the production and assimilation of CO2. Net ecosystem production (NEP) was used to represent the CO2 flux from biological activities and estimate the major CO2 emitters in the YRE. According to our measurements, the annual CO2 release was 6.14 ± 33.63 mol C m-2 yr-1 from 2009 to 2013 and the annual CO2 efflux from the 1521.3 km2 of estuarine surface area was 0.11 ± 0.61 Tg C yr-1 in the YRE. High CO2 emissions in autumn were balanced by high CO2 sequestration in summer, leading to a lower than expected annual net CO2 efflux. The system is an atmospheric CO2 source in spring and winter, near neutral in early summer, a large sink in late summer after WSR, and finally a large atmospheric CO2 source in autumn. Discharge events and seasonality jointly affect estuarine CO2 flux. High CO2 sequestration in summer is due mainly to a combination of high water temperature, chlorophyll a levels, dissolved inorganic carbon, and solar radiation and low turbidity, discharge, and chemical oxygen demand (COD) after WSR. WSR supports the high gross primary productivity rate which exceeds the increase in ecosystem respiration. Although the YRE, as a whole, is a source of atmospheric CO2, the amount of CO2 released is lower than the average estuarine value of mid-latitude regions. Our findings therefore suggest that global CO2 release from estuarine systems is overestimated if spatiotemporal variations and the effects of anthropogenic disturbance are excluded. The NEP method is effective for estimating the CO2 flux, especially in estuaries where CO2 variation is mainly due to biological processes.

更新日期：2020-01-06

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11