Rivers, Estuaries, and the Coastal Ocean

The world s 25 largest rivers transport approximately 40% of the fresh water and particulate materials entering the ocean (Milliman and Meade, 1983 Meade, 1996) (also see tables 4.2 and 4.3). Rivers transport an estimated 20 Pg y 1(l Pg = lO1 = 1 gigaton) of fluvial sediments to the coastal margin (Meybeck, 1982 Meade, 1996) associated with this sediment loading is an estimated 0.21 Pg of POC y-1 (Hedges and Keil, 

The role of estuaries in the exchange of CO2 within the coastal zone has received considerable attention in recent years (Gattuso et al., 1998 Cai et al., 2004 Borges, 2005). 

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