China GLOBEC-IMBER

The China GLOBEC programme has reached its third phase after nearly 10 years of endeavour of China GLOBEC I (BoSEC, 1997-2000) and China GLOBEC II (EYSEC, 1999-2004) on ecosystem dynamics and sustainable utilization of marine living resources in the coastal ocean of China.

A new 5 year programme on GLOBEC and IMBER has been approved by the Ministry of Science and Technology of China (MOST) with a total funding of US$4.0 million from 2006 to 2010. Prof Qisheng Tang is the chief scientist and nearly 70 scientists will be involved in the programme. The programme is entitled "Key Processes and Sustainable Mechanisms of Ecosystem Food Production in the Coastal Ocean of China" and will carry out integrated studies on multidisciplinary subjects by focusing on core subjects such as coupling mechanisms of the marine biogeochemical cycles and the end-to-end food web in the China seas. It aims at gaining a better understanding of supporting, regulating and producing functions of food production, and the sustainable mechanisms in the coastal ocean ecosystems of China seas from the perspectives of both anthropogenic impacts and natural changes.

The four major scientific questions to be addresses by the new programme are:

  • the supporting role of the main biogeochemical processes in food production
  • key physical processes of biogenic element cycles
  • primary production coupling with main biogeochemical processes
  • food production processes of biological functional groups together with their sustainable models

The goal of the programme is to improve knowledge and provide a scientific basis for ensuring food supply in the new century, by establishing a marine management system based on both sustainable food production and ecosystems. Individual components of the programme are listed below:

1. Biogenic silica in the China Seas

Because diatoms have a requirement for silicon to build up their frustules, silicon availability plays a key role in controlling both productivity and phytoplankton species composition. The alterations of phytoplankton species composition are likely to have had a large effect on levels of CO2 in the atmosphere, and have a strong potential as a proxy for paleoproductivity reconstructions. However, because of spatial variations in the biogenic silica preservation, and in the degree of coupling between the marine Si and C biogeochemical cycles, paleoreconstructions are not straightforward. A better calibration of this proxy in the modern ocean is required. Nonetheless, understanding of the silicon cycle in the near-surface ocean, and its relationship to biotic processes, has lagged behind that of other major nutrients, especially in China.

The China Seas are characterized by high turbidity due to riverine transport with anthropogenic perturbation. Although the concentrations of silicate in the coastal and continental seas are higher than the open ocean, phytoplankton species composition changes from diatom to dinoflagellate in the China Seas in spring bloom (i.e. in the Changjiang Estuary and its adjacent coastal areas). Studies on the biogeochemical cycling of silica in these regions are significant. So far knowledge on biogenic silica is mainly from the other world seas than the China Seas. The characteristics of silica cycle in coastal ocean of China may be different from the European Waters.

2. Application of biomarkers to understand the fate of terrestrial materials

Riverine organic matter is of geochemical interest both as an integrator of processes within drainage basins and as a source of organic matter to continental margin sediments, ultimately preserved in the geological record. Studies on the inputs, transport and distribution of terrigenous organic matter are thus necessary to infer the quantity and composition of organic matter flowing into marine environments and particularly within continental margins where more than 90% of all organic carbon burial occurs. Lignin fluxes from terrestrial to coastal and deep sea environments are usually related to natural export processes of dissolved and particulate vascular plant materials from soils and/or marsh environment. The Yellow River and the Yangtze River transport large amount terrestrial organic matter to the Yellow Sea and the East China Sea. But in the history, the shift of their entry to the sea has rise the interesting question about how much organic matter buried and how to trace the variation in the coastal environment. At the modern time, the land-use and land-changing are going on over the drainage basins frequently for the economic reason, it also could be an important factor for the changing of composition and fates of land-derived organic matter.

3. Bio-kinetics of P and Fe in plankton uptake by radio-tracer technology

P has been observed to limit phytoplankton production in both coastal waters and the open ocean and Fe is essential for nitrogen utilization and metabolism, chlorophyll biosynthesis, and numerous cellular respiratory functions in phytoplankton. Recently, both of those elements uptake and intracellular composition of plankton are thought to be different function on the plankton in the aquatic system.

Natural occurring nuclides 32P, 33P and man-made nuclides 55Fe and 59Fe can provide powerfully tracer technology to study of P and Fe recycle in the plankton which is important for prime productivity of food web.

We hope to cooperate with international research groups on laboratory and field studies to understand the bio-kinetics of P and Fe in plankton by radio-tracer technology.

4. Comparison of ecosystems in temperate climate zone

The size spectrum across ecosystem

  • In order to compare the size structure and healthy status of different ecosystems, the proposed cooperation is intended to be carried out within the frame of China “973-2” Program, including living organisms at different trophic level. Some technical assistant is needed from the future cooperative partner.

The effect from human induced changes in freshwater volume on marine ecosystem

  • The objective of this proposed study is to understand the effect of dam construction of the Yangtze River on the function of ecosystems in the East China Sea

Comparison between marine ecosystems in the temperate zone

  • The objective is to determine the ecosystem structure, production, function, exploitation, influence from human activities etc.

5. Studies on biogenic gases (i.e. CH4, N2O and PH3) in estuarine and coastal waters

To determine N2O production and consumption rates in water column and sediments to resolve the relative importance of nitrification and denitrification in Yangtze River Estuary. Determination of the sediment-water fluxes of CH4 and N2O to assess the inputs by sediments to the water column from the Yangtze River Estuary and East China Sea. Understanding of PH3 in the water column and sediments is of critical importance to evaluate the biogeochemical cycling of P in Yangtze River Estuary

6. Phytoplankton study

Scientific themes for cooperation:

  • Blooming mechanisms of marine phytoplankton and its population dynamics, and the modern, real-time observation methods;
  • Derivation technology of the ocean color remote sensing for Case II water;
  • Molecular biology methods for the taxonomy of marine nano- and pico-phytoplankton.

Proposed activities:

  • Development and application of the modern, real-time observation techniques and the data transmission technology, e.g. Fast Repetition Rate Fluorometry (FRRF), remote control technique etc. for the observation of phytoplankton blooms;
  • Studies and development on the derivation algorithms of ocean color remote sensing for case II water;
  • Studies and application on simple, fast and accurate molecular biology methods for nano- and pico-phytoplankton taxonomy.

7. Bacteria denitrification in the Changjiang Estuary of hypoxia

Bacterial nitrification is not only a major source of nitrate for denitrification, but is often an important component of oxygen consumption, accounting for as much as 30% of oxygen demand in estuarine and coastal marine sediments. Rates of denitrifying bacteria were high in the area, a greater percentage of organic nitrogen remineralized by the bacteria (38 to 72%). This process contributes to the production of greenhouse gases such as nitric and nitrous oxides in the atmosphere. How to understand and estimate marine bacterial denitrification is a problem in the Changjiang Estuary of hypoxia.

8. Microzooplankton dynamics during bloom process in the Yellow Sea and East China Sea

The scientific question of this cooperation would be the role of microzooplankton in the development of a bloom. Field work would serve to testify a hypothesis: in the bloom process, microzooplankton would be released from mesozooplankton grazing because mesozooplankton turn to large algae as their major food item. As a reult, the small-sized algae would be grazed down by microzooplankton. We want to cooperate with international research groups in the study of the microzooplankton dynamics during bloom process in the Yellow Sea.

9. A process study on the role of microbial loop in regeneration of N/P nutrients in Changjiang estuary and Donghai Sea ecosystems

In this plan, the process of nutrient (nitrogen and phosphorus) regeneration within the microbial loop will be studied by the means of isotope approaches and general chemical analysis methods, coupling with the study of trophic dynamics along the microbial food chain. The proportion of regenerated nutrients at each trophic link (viz. bacteria, nanoflagellate, ciliate and micro-zooplanktons) will be studied in detail, and finally combined to assess the role of microbial loop in the recruitment of N/P nutrients in Changjiang Estuary and East China Sea ecosystems.

10. Functional groups of ultraphytoplankton and coupling with nutrient biogeochemistry in East China Sea and Yellow Sea

The functional groups of ultraphytoplankton will be studied using diagnostic pigments and molecular techniques (DNA) Coupling between the groups and nutrients will also be studied using metabolic enzymes such as alkaline phosphatase (AP), nitrate reductase (NR) and so on.