River nutrient control of Quaternay Productivity in Bay of Bengal Heather M. Stoll, Geoscience Dept. Williams College, Williamstown MA 01267 Andrea Burke, Williams undergraduate Record of past productivity variations in response to climate changes: Since marine algae consume CO2, changes in their productivity can stabilize or perturb climate. Variations in the earth’s orbit triggered changes in intensity and location of tropical summer monsoon rainfall. We sought to evaluate whether wetter climate cycles released more nutrients to fuel higher production by algae in the Bay of Bengal . Northern Bay of Bengal (RC12-343)
-9
3
-7
2.5 glacial
productivity (Sr/Ca mmol/mol)
In the northern Bay, Himalayan River flux is higher during the interglacial and fuels steep productivity increase.
high
interglacial
Himalayan river runoff (from eNd)
-11
3.5
less
glacial
-5 2 90
In both regions productivity cycles are closely tied to the cycles in river flux.
more
4
110
130
150 age (ky)
Andaman Sea (MD77-169)
170
190
2 high
3
1.5
2
1
Irrawaddy River flux
MD77169
productivity (Sr/Cammol/mol)
RC12-343
ÅWe analyzed high sediments 200,000 to 90,000 years old from Northern Bay of Bengal (RC12-343) and more southerly Andaman Sea (MD77-low 169).
1 0.5 interTo the south in Andaman Sea, river flux is highest low glacial glacial glacial low when orbital configuration amplified the monsoon 0 0 90 110 130 150 170 190 every 23,000 years. Productivity peaks during high thousands of years ago eNd record from Stoll et al., 2007; clay mineral record from Colin et al 1999) river flux. These data suggest climate’s influence on river nutrient supply does regulate productivity.
