ASLO 2011 Aquatic Sciences Meeting location:San Juan, Puerto Rico date:13-18 February 2011
Studies on the biogeochemistry of East African rivers are few. We present results of intensive field campaigns on the Tana River Basin in Kenya, focusing on dissolved inorganic carbon (DIC). Sampling took place from 2008 to 2010, and over different seasons (end of dry season, short rains, end of long rains). Samples were taken in several tributaries and over the course of the main river, from headwaters to the delta. DIC concentrations ranged from 0.2 mmol L-1 in
the headwaters to 1.5 mmol L-1 downstream, with peaks of 4.8 mmol L-1in some tributaries. δ13C-DIC varied between -2.4‰ and -20.7‰, with the bulk of the measurements (>90%)
between -3.8‰ and -12.6‰. The water was generally supersaturated with CO2, making the river a CO2 source to the atmosphere. This supersaturation was more pronounced during wet season than during dry season. Measurements of pelagic respiration and primary production show a very
heterotrophic system with intensive carbon processing.