The biogeochemical cycling of carbon dioxide in the oceans — perturbations by man

Dyrssen, David

doi:10.1016/s0048-9697(01)00828-2

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Global fluvial export of carbon is now a well-documented component in the global carbon cycle and is estimated ca. ~10 15 g C.yr -1 [1-4]. Although it is relatively small compared with the fluxes at other interfaces (atmosphere-biosphere, atmosphere-ocean), the fluvial carbon flux contributes an important percentage to the regional carbon budget.…”

Section: Introductionmentioning

confidence: 99%

Human impact on the historical change of CO2degassing flux in River Changjiang

Wang

Zhang

et al. 2007

Geochem Trans

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The impact of water quality changes in River Changjiang (formally known as the Yangtze River) on dissolved CO 2 and silicate concentrations and seasonal carbon flux in the past several decades (1960s-2000) was evaluated, based on monitoring data from hydrographic gauge. It was found that dissolved CO 2 and silicate in Changjiang decreased dramatically during this decades, as opposed to a marked increase in nutrient (e.g. NO 3 -) concentrations. Our analyses revealed that dissolved CO 2 in Changjiang was over-saturated with the atmosphere CO 2 , and its concentration had showed a declining trend since the 1960s, despite that fluvial DIC flux had maintained stable. Analysis results also suggested that the decrease in dissolved CO 2 concentration was attributed to changes on the riverine trophic level and river damming activities in the Changjiang drainage basin. Due to the economic innovation (e.g. agriculture and industry development) across the Changjiang watershed, fertilizers application and river regulations have significantly altered the original state of the river. Its ecosystem and hydrological condition have been evolving toward the "lacustrine/reservoir" autotrophic type prevailing with plankton. Accordingly, average CO 2 diffusing flux to the atmosphere from the river had been reduced by three-fourth from the 1960s to 1990s, with the flux value being down to 14.2 mol.m -2 .yr -1 in the 1990s. For a rough estimate, approximately 15.3 Mt of carbon was degassed annually into the atmosphere from the entire Changjiang drainage basin in the 1990s.

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Section: Introductionmentioning

confidence: 99%

Human impact on the historical change of CO2degassing flux in River Changjiang

Wang

Zhang

et al. 2007

Geochem Trans

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“…It has been shown that the ocean is a net sink for atmospheric carbon dioxide and can absorb 2 pg C every year (Sabine et al, 2000;Dyrssen, 2001;Miller et al, 2002;Takahashi et al, 2002). However, the role of shelf seas has not been fully understood yet.…”

Section: Introductionmentioning

confidence: 99%

Role of the Jiaozhou Bay as a source/sink of CO<sub>2</sub> over a seasonal cycle

Li¹,

Song²,

Niu³

et al. 2007

Sci. Mar.

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The seasonal evolution of dissolved inorganic carbon (DIC) and CO 2 air-sea fluxes in the Jiaozhou Bay was investigated by means of a data set from four cruises covering a seasonal cycle during 2003 and 2004. The results revealed that DIC had no obvious seasonal variation, with an average concentration of 2035 µmol kg-1 C in surface water. However, the sea surface partial pressure of CO 2 changed with the season. pCO 2 was 695 µatm in July and 317 µatm in February. Using the gas exchange coefficient calculated with Wanninkhof's model, it was concluded that the Jiaozhou Bay was a source of atmospheric CO 2 in spring, summer, and autumn, whereas it was a sink in winter. The Jiaozhou Bay released 2.60 × 10 11 mmol C to the atmosphere in spring, 6.18 × 10 11 mmol C in summer, and 3.01 × 10 11 mmol C in autumn, whereas it absorbed 5.32 × 10 10 mmol C from the atmosphere in winter. A total of 1.13 × 10 12 mmol C was released to the atmosphere over one year. The behaviour as a carbon source/sink obviously varied in the different regions of the Jiaozhou Bay. In February, the inner bay was a carbon sink, while the bay mouth and the outer bay were carbon sources. In June and July, the inner and outer bay were carbon sources, but the strength was different, increasing from the inner to the outer bay. In November, the inner bay was a carbon source, but the bay mouth was a carbon sink. The outer bay was a weaker CO 2 source. These changes are controlled by many factors, the most important being temperature and phytoplankton. Water temperature in particular was the main factor controlling the carbon dioxide system and the behaviour of the Jiaozhou Bay as a carbon source/sink. The Jiaozhou Bay is a carbon dioxide source when the water temperature is higher than 6.6ºC. Otherwise, it is a carbon sink. Phytoplankton is another controlling factor that may play an important role in behaviour as a carbon source or sink in regions where the source or sink nature is weaker.

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