In situ calcium carbonate dissolution in the Pacific Ocean

TitleIn situ calcium carbonate dissolution in the Pacific Ocean
Publication TypeJournal Article
Year of Publication2002
AuthorsFeely, RA, Sabine, CL, Lee, K, Millero, FJ, Lamb, MF, Greeley, D, Bullister, JL, Key, RM, Peng, TH, Kozyr, A, Ono, T, Wong, CS
JournalGlobal Biogeochemical Cycles
Date PublishedDec 31
ISBN Number0886-6236
Keywordsanthropogenic co(2), anthropogenic co2, aragonite saturation, atmospheric carbon, caco(3) dissolution, calcite saturation, carbonate lysocline, chemical lysocline, coccolithophore emiliania-huxleyi, indian-ocean, north pacific, organic-matter, Pacific Ocean, panama basin, particulate matter

Over the past several years researchers have been working to synthesize the WOCE/JGOFS global CO(2) survey data to better understand carbon cycling processes in the oceans. The Pacific Ocean data set has over 35,000 sample locations with at least two carbon parameters, oxygen, nutrients, CFC tracers, and hydrographic parameters. In this paper we estimate the in situ CaCO(3) dissolution rates in the Pacific Ocean water column. Calcium carbonate dissolution rates ranging from 0.01-1.1 mumol kg(-1) yr(-1) are observed in intermediate and deepwater beginning near the aragonite saturation horizon. In the North Pacific Intermediate Water between 400 and 800 m, CaCO(3) dissolution rates are more than 7 times faster than observed in middle and deep water depths (average=0.051 m mol kg(-1) yr(-1)). The total amount of CaCO(3) that is dissolved within the Pacific is determined by integrating excess alkalinity throughout the water column. The total inventory of CaCO(3) added by particle dissolution in the Pacific Ocean, north of 40degreesS, is 157 Pg C. This amounts to an average dissolution rate of approximately 0.31 Pg C yr(-1). This estimate is approximately 74% of the export production of CaCO(3) estimated for the Pacific Ocean. These estimates should be considered to be upper limits for in situ carbonate dissolution in the Pacific Ocean, since a portion of the alkalinity increase results from inputs from sediments.