Contribution of Riverine Dissolved Inorganic Nitrogen Flux to New Production in the Coastal Northern Indian Ocean: An Assessment

Table 1

DIN flux (mmol N m⁻² d⁻¹) in the course river and its contribution (in %) to the new production (mmol N m⁻² d⁻¹) in the northern Indian Ocean.

River	Season	DIN flux	New Production^×	Export production€	% Contribution	References
Rivers debouching into the Bay of Bengal
Ganga^$	Annual average	76.41	2.13^+	169	3587*	[23, 26]
Ganga	April-1989	0.01	2.47	196	0.4	[20, 21, 26]
Ganga	August-2003	2.44	2.13	169	115*	[22, 26]
Brahmaputra	Annual average	3.74	2.13^+	169	175*	[23, 26]
Brahmaputra	Three years average	1.47	2.13^+	169	69	[9, 26]
Mahanadi	—	NA^†	4.48	356	—	[26]
Godavari	Annual average	3.55	3.87	308	92	[23, 26]
Krishna	-do-	0.41	0.17	14	243*	[23, 26]
Krishna	September-2002	0.15	0.17	14	88	[6, 21, 26]
Cauvery	Annual average	2.24	0.63	50	356*	[23, 26]
Rivers debouching into the Arabian Sea
Indus	Annual average	3.87	2.48	197	156*	[23, 25]
Indus	-do-	0.83	2.48	197	34	[11, 25]
Narmada	-do-	0.21	4.25	338	5	[23, 25]
Netravati	—	NA^†	0.46	37	—	[27]
Mahi	-do-	0.001	—	—	—	[23]
SWKR^+	-do-	0.42	1.56	124	27	[23, 27]

^×New production is measured as uptake rate of nitrate during the deck incubation, €export production (mg C m⁻² d⁻¹) is calculated using Redfield ratio, ^$also known as Ganges, ⁺new production near the Ganga and Brahmaputra is taken to be the same as they debouch at the same place, ^†data not available, *high values can be attributed to either the eutrophication of the coastal ocean or where much of the DIN could be removed prior to discharge into the coastal ocean, and ⁺small west-flowing Kerala Rivers (average of 15 rivers).