Toolik Lake, Alaska Rivers, Lakes, and Ocean: Climate and land use change. Change at one location can induce large changes elsewhere. Example to follow: Arabian Sea

High NO 3 in the Arabian Sea and connections with Eurasian climate

Surprisingly high concentrations of NO3 in the Arabian Sea

350 % Increase in Chlorophyll a in 6 years!

Chlorophyll concentrations increased during monsoon period as sea surface temperatures decreased. The cooler water is indicative of deeper upwelling.

During winter monsoon, air flows from land to water. During summer monsoon, air flows from water to land. Upwelling is induced along the Somali coast.

What caused winds to intensify during the summer monsoon? Snow cover decreased in Eurasia Beginning in late 1990s. Land warmed more rapidly in spring. Rising warm air led to more rapid Inflow of cooler air – Monsoon intensified!

Consequences: Increased rain with monsoon and increased flooding

Consequences Massive phytoplankton blooms lead to increased decomposition Increased anoxic zones at depth Fish kills Increased production of nitrous oxide – heat trapping potential is 300 x that of CO 2

Consequences: Melting of glaciers with concommitant Effects on water supply for people in India, Pakistan, and Tibet

Increased River Discharge to the Arctic Ocean Increases due to global warming and North Atlantic Oscillation Similar to story to MONO LAKE! The freshwater induces a layer with higher buoyancy and mixing is reduced. Impacts on the thermohaline circulation of the ocean and ultimately a wide diversity of organisms!

Lake Victoria Increased deforestation and subsistance agriculture led to increased loading of nutrients, increased primary production, and shifts in species composition from edible diatoms to cyanobacteria. Introduced fish species modified food webs Increased anoxia and loss of endemic fishes resulted.

Gulf of Mexico Increased use of fertilizers led to increased nutrient loading to the Mississippi River. Species composition shifted from diatoms to blue greens. Anoxia developed in the Gulf of Mexico ( km 2 < 2mg/l O 2 ) ( ,000 to km 2 < 2 mg/l O 2 ) Shrimp fishery disrupted!

Global Change is Occuring NOW! What can we do? Kyoto Protocols! Atmospheric Emissions Improved modeling for understanding! The principles you have learned in class are fundamental for understanding global change!