Emerging Hotspots of Surface Chlorophyll Trend in the Tropical Oceans

doi:10.1029/2023JC020681

IOCAS-IR > 海洋环流与波动重点实验室

	Emerging Hotspots of Surface Chlorophyll Trend in the Tropical Oceans
	Tian, Feng 1,2,3; Zhang, Rong-Hua3,4
	2024-07-01
发表期刊	JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
ISSN	2169-9275
卷号	129 期号:7 页码:23
通讯作者	Tian, Feng([email protected]) ; Zhang, Rong-Hua([email protected])
摘要	Recent studies show that climate change signals in the long-term trend of the tropical ecosystems have emerged earlier than projected by climate models. However, it remains unclear whether tropical ocean surface chlorophyll (SChl) shows a robust trend in the available satellite data era, and what possible physical mechanisms can be responsible for this trend. Here, using combined data from observations, hindcast biogeochemical simulations, and climate model outputs, we document consistently decreasing trends of SChl in the three ocean basins (Indian Ocean, Pacific Ocean, and Atlantic Ocean) with varying magnitude from -1.6% to -10.0% per decade during 1998-2020, with tropical ocean SChl showing a decreasing trend of -7.1% per decade. In the Indo-Pacific Ocean, mechanisms for the two hotspots with significantly decreasing SChl trends are identified. (a) In the northern tropical Pacific, under the anthropogenic forcing, enhanced stratification associated with frequent interannual surface warming overwhelms the Ekman pumping effect due to positive wind stress curl, leading to a decrease in SChl. (b) In the southern tropical Indian Ocean, the downwelling process dominates the decreasing SChl trend due to the Ekman pumping associated with the negative wind stress curl prevailing in the Indian Ocean, while the contribution from the stratification change is negligible. This study identifies two hotspots with consistently decreasing SChl trends in the tropical ocean which are influenced by the complex physical processes under a warmer climate and calls for more comprehensive understanding of the interactions between physical processes and biogeochemical cycles in the tropical ocean ecosystems. Predicting the response of phytoplankton to climate change is vital to the global biogeochemical cycle and marine economic activities. Previous studies indicated that more than 30 years of continuous data are needed to detect the tropical biogeochemical trends driven by climate change. However, recent studies reveal that climate change signals have emerged in the tropical marine ecosystem, earlier than climate models projected. Nonetheless, it remains unclear whether tropical ocean surface chlorophyll (SChl) shows a robust trend (i.e., hotspots) in the available satellite data era, and what physical mechanism controls this trend. Here, we document that tropical ocean SChl exhibits a decreasing trend of -7.1% per decade from 1998 to 2020. Two emerging hotspots (the northern Tropical Pacific and the southern Tropical Indian Ocean) are identified with sharply decreasing SChl trends, which can be attributed to the enhanced ocean stratification due to external forcing (i.e., a greenhouse warming climate scenario) and downwelling process suppressing nutrients supply due to internal variability (i.e., the atmosphere-ocean interaction), respectively. These diverse but consistent SChl trends suggest that the contribution from a greenhouse warming to the SChl trend during available satellite data (September 1997 to present) needs to be clarified. Two hotspots with remarkably decreasing surface chlorophyll (SChl) trends are identified in the northern tropical Pacific and the southern tropical Indian Ocean Tropical SChl exhibits a decreasing trend by -7.1% (-4.4%) per decade when extreme ENSO effects are included (excluded) for periods up to 2020 Increased upper ocean stratification and downwelling are major factors driving the SChl trend in the two hotspots, respectively
DOI	10.1029/2023JC020681
收录类别	SCI
语种	英语
资助项目	Laoshan Laboratory[LSL202202402]; National Natural Science Foundation of China (NSFC)[42030410]; National Natural Science Foundation of China (NSFC)[42006001]; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42000000]; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42040100]; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42040103]; Startup Foundation for Introducing Talent of NUIST
WOS研究方向	Oceanography
WOS类目	Oceanography
WOS记录号	WOS:001261504400001
出版者	AMER GEOPHYSICAL UNION
WOS关键词	MARINE PRIMARY PRODUCTION ; EL-NINO ; EQUATORIAL PACIFIC ; CLIMATE-CHANGE ; VARIABILITY ; MODEL ; CARBON ; TEMPERATURE ; DRIVEN ; PHYTOPLANKTON
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/186309
专题	海洋环流与波动重点实验室
通讯作者	Tian, Feng; Zhang, Rong-Hua
作者单位	1.Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Observat & Forecasting, Qingdao, Peoples R China 2.Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Circulat & Waves, Qingdao, Peoples R China 3.Laoshan Lab, Qingdao, Peoples R China 4.Nanjing Univ Informat Sci & Technol, Sch Marine Sci, Nanjing, Peoples R China
第一作者单位	中国科学院海洋研究所; 海洋环流与波动重点实验室
通讯作者单位	中国科学院海洋研究所; 海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	Tian, Feng,Zhang, Rong-Hua. Emerging Hotspots of Surface Chlorophyll Trend in the Tropical Oceans[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2024,129(7):23.
APA	Tian, Feng,&Zhang, Rong-Hua.(2024).Emerging Hotspots of Surface Chlorophyll Trend in the Tropical Oceans.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,129(7),23.
MLA	Tian, Feng,et al."Emerging Hotspots of Surface Chlorophyll Trend in the Tropical Oceans".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 129.7(2024):23.