Summary of the project
The marine carbon cycle is influenced by anthropogenic activities, affecting global climate change and casting a significant impact on ecosystems. However, the sensitivity of marine biogeochemical cycles to climate change remains unclear, especially for key processes which influence the long-term health of marine ecosystems. The biological pump (BP) and recently proposed microbial carbon pump (MCP) are major mechanisms for biological carbon sequestration in the ocean. Understanding the dynamics of the MCP in conjunction with the BP, over geological timescales, would help to predict future climate trends.Through focusing on the interaction of MCP and BP, the coupling of carbon, nitrogen and sulphur cycles, and the integration and comparison of modern days with critical periods of Earth history, the project aims to decipher the mechanisms of marine carbon storage, biogeochemical processes in response to climate change and anthropogenic activities, and their impacts on ecosystems. Four research themes focused on the South China Sea and the Bohai Sea of China will include: a) the interaction between MCP and BP; b) the elemental biogeochemical cycles across sediment-water interface (and their contribution to carbon storage); c) the variation of regional carbon pool in response to global climate change, and anthropogenic activities and; d) the coupled carbon, nitrogen and sulphur cycles in response to deep time global change and their effects on marine ecosystems. This research tries to fill the critical gap between short-term processes in modern oceans and the long-term effects through ancient times. The goal of the project is to provide a comprehensive understanding of the responses of marine carbon pool to global climate change on multiple spatiotemporal scales, and to identify the naturally or anthropogenically-driven ocean acidification processes, key processes of carbon storage, and their impact on marine ecosystems. This project will build up a platform to bring together scientists from the marine-, life- and Earth-sciences, including twenty two scientists and over thirty students from seven state key laboratories of six universities or institutes in China for the coming five years.
The themes of this project are:
- The interaction between the microbial carbon pump (MCP) and biological pump (BP) and its contribution to marine carbon storage. Key issues include 1) the time sequence of observation for biological pump, the controlling physical-chemical and biological processes and organic carbon fluxes to the deep oceans, 2) chemical and biological mechanisms for the interaction of MCP with BP, and 3) coupled physical and biogeochemical process modelling based on ROMS-CoSiNE, to evaluate the interaction between the MCP and BP.
- The effect of the carbon, nitrogen and sulphur cycles across the sediment-water interface and its contribution to marine carbon storage. Key issues include 1) sedimentary organic carbon variation in different environments, 2) microbial mediation in coupling carbon, nitrogen and sulphur cycles during sedimentation, and 3) models and patterns of elemental biogeochemical cycles across the sediment-water interface.
- The regional carbon pool in response to recent global climate change. Seasonal acidification in the Bohai Sea in East China is particularly targeted. Key issues include 1) the interaction between the MCP and BP under acidification scenarios and their response to global change, 2) the coupled carbon, nitrogen and sulphur cycles under acidification scenario, 3) the trend of ocean acidification with increasing anthropogenic influence.
- The coupling of carbon, nitrogen and sulphur cycles in response to deep-time global change. Three time intervals are selected to decipher the relationship between climate, biogeochemical cycles, oceanic chemistry and ecosystems; the last deglaciation, the Permian-Triassic boundary at 252 million years ago when the most severe mass extinction occurred in association with the sharp increase of temperature, and the Neoproterozoic age of 630 million years ago when the snowball Earth episode terminated. Key issues include 1) the coupling of carbon, nitrogen and sulphur cycles, 2) the microbial contribution to changes in oceanic chemistry, and 3) the response of elemental biogeochemistry cycles to global changes and their impact on ecosystems.
Area of study
South China Sea, and Bohai Sea
Time Table for activities
July 2016 – May 2021
- It is discovered that Bathyarchaeota, a widespread and abundant but poorly understood group of microbes living in marine sediments, can use inorganic carbon and obtain energy from breaking down lignin (Yu et al., 2018, PNAS), a complex molecule from plants and the second most abundant biopolymers on Earth after cellulose. The work suggested that group of Bathyarchaeota is instrumental in breaking down terrestrial carbon compounds that end up in marine sediments. Bathyarchaeota is considered one of the most abundant organisms on the planet and a common inhabitant of marine sediments, an important player in the earth’s carbon cycle. The discovery that Bathyarchaeota uses lignin adds another angle to our understanding of terrestrial carbon cycling. As far as the authors are aware, this is the first report of an archaea that can metabolize lignin in anoxic marine sediments.
- The ammonia oxidization (AO) inferred by lipid biomarkers of Thaumarchaeota in South China Sea for the past 160 kyr exhibited intensification in the interglacials, and moreover, showed strong precessional cycles with enhancements at the precessional maxima when boreal winter insolation was the highest (Dong et al., 2019, EPSL). The ammonia oxidizing archaea (AOA) record varied in line with isotope record of organic nitrogen (δ15Norg) that is modulated by the strength of diazotroph N2 fixation (NF), suggesting a close coupling of increased AO with enhanced NF during periods of weak east Asian winter monsoon (EAWM) and hence increase of upper water stratification. AO intensification, a step of a series of dissolved oxygen consuming processes, is hereby hypothesized to encourage NF when the EAWM weakens. This result might be a reference for the future NF trend in the current situation of enhanced ocean deoxygenation due to global warming.
- Observed monthly decline in subsurface-water pH and aragonite saturation state from spring to autumn in the North Yellow Sea (Li et al. 2018. Continental Shelf Research), and explored seasonal acidification in the Yellow Sea (Chen et al. 2018. Science China Earth Sciences).
- Discovered a universal pathway for plant, fungi and bacteria to use thiosulfate as the sulfur source for growth (Chen et al. 2018. AEM), Discovered a new method to analyze sulfane sulfur which is biologically relevant (Li et al. 2019. Redox Biol).
Capacity building activities
- Build enclosures at a harbor to test the carbon and sulfur cycling
List of 2018/19 publications
- Zhang W.*, Ni Q., Xue H. 2018, Composite eddy structures on both sides of the Luzon Strait and influence factors. Ocean Dynamics, 68: 1527-1541.
- Li C.-L., Zhai W.-D. 2018. Decomposing monthly decline in subsurface-water pH and aragonite saturation state from spring to autumn in the North Yellow Sea. Continental Shelf Research, in press.
- Zhai W.-D. 2018. Exploring seasonal acidification in the Yellow Sea. Science China Earth Sciences, 61: 647-658.
- Chen Z., Zhang X., Li H., Liu H., Xia Y., Xun L. 2018. The Complete Pathway for Thiosulfate Utilization in Saccharomyces cerevisiae. Appl Environ Microbiol, 84(22): e01241-18. doi: 10.1128/AEM.01241-18.
- Li H., Liu H., Chen Z., Zhao R., Wang Q., Ran M., Xia Y., Hu X., Liu J., Xian M., Xun L. 2019. Using resonance synchronous spectroscopy to characterize the reactivity and electrophilicity of biologically relevant sulfane sulfur. Redox Biology, 24: 101179. doi: 10.1016/j.redox.2019.101179.
- Yu T., Wu W., Liang W., Lever M. A., Hinrichs K. U., Wang, F*. 2018. Growth of sedimentary Bathyarchaeota on lignin as an energy source. Proceedings of the National Academy of Sciences, 115 (23): 6022–6027.
- Zhou Z., Pan J., Wang F. P., Gu J. D., Li M. 2018. Bathyarchaeota: globally distributed metabolic generalists in anoxic environments. FEMS Microbial Review, 42: 639-655.
- Dong L., Li Z., Jia G. 2019. Archaeal ammonia oxidation plays a part in late Quaternary cycling in the South China Sea. Earth and Planetary Science Letters, 509:38-46
- Jiao N. Cai R., Zheng Q., Tang K., Liu J., Jiao F., Wallace D., Chen F., Li C., Amann R., Benner R., Azam F. 2018. Unveiling the enigma of refractory carbon in the ocean. National Science Review, 5 (4): 459–463. doi: 10.1093/nsr/nwy020.
- Luo G., Yang H., Algeo T. J., Hallmann C., Xie S. 2018. Lipid biomarkers for the reconstruction of deep-time environmental conditions. Earth-Science Reviews, 189: 99–124. doi: org/10.1016/j.earscirev.2018.03.005.
- Tang K.*, Zhang Y., Lin D., Han Y., Chen C. T., Wang D., Lin YS., Sun J., Zheng Q., Jiao N.* 2018. Cultivation-Independent and Cultivation-Dependent Analysis of Microbes in the Shallow-Sea Hydrothermal System off Kueishantao Island, Taiwan: Unmasking Heterotrophic Bacterial Diversity and Functional Capacity. Frontiers in Microbiology, 9: 279.
- Xie S. 2018. The shift of biogeochemical cycles indicative of the progressive marine ecosystem collapse across the Permian-Triassic boundary: An analog to modern oceans. Science China: Earth Science, 61 (10): 1379–1383. https://doi.org/10.1007/s11430-017-9207-3
- Xie* W., Luo H., Murugapian S.K., Dodsworth J.A., Chen S., Sun Y., Hedlund B.P., Wang P., Fang H., Deng M., Zhang* C. L. 2018. Localized high abundance of Marine group II archaea in the subtropical Pearl River Estuary: implications for their niche adaptation. Environmental microbiology, 20(2): 734-754.
- Yu T, Li M, Niu M, Fan X., Liang W. Wang F. 2018. Difference of nitrogen-cycling microbes between shallow bay and deep-sea sediments in the South China Sea. Applied Microbiology and Biotechnology, 102(1): 447-459.
- Zhu X., Jia G., Mao S., Yan W. Sediment records of long chain alkyl diols in an upwelling area of the coastal northern South China Sea. Organic Geochemistry, 121: 1-9.
- Wu Z., Liu B., Escher P., Kowalski N., Böttcher M.E. 2018. Carbon diagenesis in different sedimentary environments of the subtropical Beibu Gulf, South China Sea. Journal of Marine Systems, 186: 68–84.
- Zhang *C.L., Dang H.Y., Azam F., Benner R., Legendre L., Passow U., Polimene L., Robinson C., Suttle C.A., Jiao N.Z. 2018. Evolving Paradigms in Biological Carbon Cycling in the Ocean. National Science Review, 5 (4): 481–499. https://doi.org/10.1093/nsr/nwy074.
- Yang Y., Gao C., Dang X., Ruan X., Lv X., Xie S., Li X., Yao Y., Yang H.*. 2018. Assessing hydroxylated isoprenoid GDGTs as a paleothermometer for the tropical South China Sea. Organic Geochemistry, 115: 156-165.