Pan-China Ocean Carbon Alliance (COCA)——Artificial Upwelling and ocean carbon sink
Pan-China Ocean Carbon Alliance (COCA)
The led by Dr. Nianzhi Jiao was established in 2013, with members from 21 domestic Chinese institutions including universities affiliated to the Ministry of Education of China, research institutes affiliated to Chinese Academy of Sciences, institutes/centers affiliated to the State Ocean Administration, as well as enterprises including China National Offshore Oil Corporation (CNOOC). COCA aims to become a leading research cluster on frontiers of ocean carbon sink and related fields. It will act as a platform for joint and interdisciplinary research involving research groups covering biologists, chemists and geologists, and comparative studies between ancient and modern marine environments. By putting the MCP theoretical framework into practical field and laboratory studies, we hope to provide a new, integrated view of microbial mediated carbon flow in the marine environment to fill knowledge gaps in oceanic carbon sequestration. The major mission of COCA is to set up long-term time series stations for blue carbon monitoring along the Chinese coasts; to establish a series of protocols for core measurements related to marine carbon sinks and to share data. The final goal of COCA is to seek for ocean carbon storage mechanisms and make the best of both carbon emission-reduction and sink-increase through policy-industry-research cooperation strategy.A number of COCA time series observation stations have been set up in the Bohai Sea, Yellow Sea (led by Dr. Yongyu Zhang and Liu Jihua), East China Sea (led by Dr. Xu Dapeng and Zhao Shujiang), and South China Sea(led by Dr. Tang Kai and CNOOK).
Artificial Upwelling and ocean carbon sink
Upwelling can influence ocean carbon storage and the carbon exchange flux at the sea-gas interface. In most oceans, nutrient availability (nitrogen, phosphorus, silicon, and trace elements such as iron) is one of the major factors limiting primary productivity (Hlaili et al., 2006; Arrigo et al., 1999; Leinen, 2008). Upwelling can bring low-temperature and high-nutrient deep ocean waters to the euphotic zone, fertilizing the phytoplankton and allowing the accumulation of biomass in the surface waters (LFarías et al.,2014).This kind of upwelling-induced fertilization of the photic zone can stimulate phytoplanktonic development and accumulation, increase primary production and subsequently enhance the respiration of organic matter (Daneri et al 2012, Farías et al 2009).
However, the expanding area and increasing intensity of upwelling which has been influenced by global climate change in recent years also threatens local ecosystem productivity (Demarcq H et al., 2009;Narayan et al., 2010; P. M. A. Miranda et al., 2012; W. J. Sydeman et al.,2014; A. Bakun et al.,1990,2015).It is thus of critical importance to take the advantages but avoid the disadvantages of upwelling effects. The key to this goal is the extent of the upwelling (jiao et al., 2014a). The application of artificial upwelling powered by green energy (such as solar energy, wind/wave/tidal energy) (Zhang et al., 2016) to seaweeds culture system is a paradigm (Zhang et al., 2015; Jiao et al., 2015; Pan et al., 2016). By controlling the extent of the artificial upwelling flux, moderate amount of deep water can be gradually brought up to euphotic zone just to meet the demands of nutrients and DIC by the seaweeds, and thus neither acidification nor hypoxia will happen, as DIC is mostly used, and oxygen is efficiently produced by photosynthesis (Jiao et al, 2015). Under such scenarios, the microbial carbon pump (MCP) could work efficiently and the sum of the MCP and the biological pump could reach its maximum (Jiao et al., 2010; Jiao et al., 2014b). Such artificial upwelling operations also gradually release the “bomb” of rich nutrients and hypoxia, which could breakout when storms take place otherwise (Daneri et al., 2012; Jiao et al., 2015).
Fig. 1 Scenario models for upwelling on ocean carbon sequestration.
Arrows:Red -respiration flux; pink-DIC from the deep water.
a: BP prevailing; b: MCP prevailing c: non-upwelling.
Fig. 2 Pictures of a Pneumatic Lifting Artificial Upwelling System during a test. (a) Release of the system; (b) artificial upwelling visible at the surface; (C) 1-m diameter upwelling pipe; and (d) 0.4-m diameter upwelling pipe.
Fig. 3 New Pneumatic Lifting Artificial Upwelling System in field-experiments study. (Upleft) Self-power platform at the surface; (Blue) Bubble Injection Terminals in the sea..
Processes and Approaches of Coastal Ecosystem Carbon Sequestration (PACECS)
Summary of the project
Ocean is the largest carbon pool on earth, serving as the buffer of global climate change, absorbing about 1/3 of CO2 produced by human activities. Carbon sink captured by marine ecosystem is called the "Blue Carbon Sink" (hereinafter referred to as "blue carbon"), which is one of the most important mechanisms for the sea to store carbon. The initial form of blue carbon is visible plant carbon sequestration in the coastal zone. As a matter of fact, the invisible microorganisms (phytoplankton, bacteria, archaea, and protozoa), which have always been ignored, account for 90% of the marine biomass and constitute the main component of blue carbon. The marginal sea covers one third of the total territory of China, and it is of urgent need to explore the immense potential of carbon sinks. This project aims at the key processes and mechanisms of the carbon sequestration in coastal ecosystems and ways to increase ocean carbon sink.
An increasing carbon sink, on the one hand, refers to increasing the sinking and burial of particle organic carbon (POC) in sediments; and on the other hand, it is about increasing the production of refractory dissolved organic carbon (RDOC) mediated by microorganisms (the overall amount of the RDOC pool is equal to that of CO2 in the atmosphere). This project is comprised of four subprojects. Subproject 1 focuses on community structure and ecosystem function in the carbon cycle, with an emphasis on key processes concerning the POC sinking and the RDOC production. Subproject 2 focuses on physiological and molecular mechanisms of ocean carbon sinks, such as uptake, transformation, and release of carbon-containing chemical compounds by microorganism at the gene and protein levels. This subproject also focuses the impact of human activities and input of terrestrial nitrogen and phosphorus on the above processes. Subproject 3 focuses at re-establishing the evolution process of ocean carbon sinks in geologic history with sedimentary records, which should record organic carbon from burial of sinking POC in sediments studied in subject 1, the RDOC molecules studied in both subproject 1 and 2, and the human activities and input of terrestrial sources studied in subproject 2, and aims at the relationship between ocean carbon sinks and global climate changes in ancient oceans. Based on field investigation, theoretical analysis and historical representation of the subproject 1, 2, and 3, subproject 4 aims at establishing scenario models for carbon sink dynamics under global warming situation, and providing theoretical and technical foundations for engineering ocean carbon sequestration in the future.
This project is featured in its interdisciplinary cooperation and integration. Potential breakthroughs are especially expected in the following aspects:
key processes and regulatory mechanisms of ocean carbon sink and its relationship with environment and global climate changes;
an index system for carbon storage including a series of physical-chemical and biological indices and parameters and main core measurements protocols;
demonstrations of increasing carbon sink and engineering carbon sequestration in the ocean.
These outputs will support the sustainable development of marine ecosystem and national carbon emissions trading.
Area of study
Coastal oceans of China. The majority of the regions includes:
from the Yangtze River estuary to the East China Sea;
from the Pearl River estuary to the South China Sea;