Page 69 - (DK) Ocean - The Definitive Visual Guide

OCEANS AND CLIMATE 67

Carbon in the Oceans FORAMINIFERAN
SHELL
The oceans contain Earth’s largest store of carbon dioxide (CO )—the main
2
greenhouse gas implicated in global warming. Huge amounts of carbon are held
in the oceans, some in the form of CO and related substances that readily convert
2
to CO , and some in living organisms. The oceanic CO is in balance with the
2 2
atmospheric content of the same gas. For many years, the oceans have been alkaline,
and acted as an important store for the excess CO released by human activity.
2
Biological and chemical processes turn some of this CO into the calcium carbonate
2
shells and skeletons of organisms, other organic matter, and carbonate sediments. CARBON CONVERSION
However, the increasing CO concentration is beginning to acidify the oceans, CO released from burning
2
2 fossil fuels (right), after
threatening shell and skeleton formation in marine organisms, as acid tends to absorption into the oceans,
dissolve carbonates. Further, some scientists fear that the rate at which the oceans can eventually end up in the
can continue to absorb CO will soon slow shells of marine organisms
2
down, further aggravating global warming. in the form of carbonate.
CO released by CO absorbed by CO released by
2 2 2
plant respiration photosynthesis volcanic eruption
CO released by
2
CO released by CO in rain CO absorbed by fossil-fuel burning
2
2
2 weathers photosynthesis
fossil-fuel burning
limestone by phytoplankton
CO released by
2
land animal
respiration CO released by
2
marine animal
respiration
CO removed
2
from storage
by coal
METHANE HYDRATE DEPOSIT mining
This substance is found as a solid on some CO released by
2
areas of sea floor. There are concerns that carbon phytoplankton
from plant
ocean warming could release this into the and animal respiration
atmosphere as methane gas, which traps remains
more heat than CO . stored in carbon released by
2 decomposition of
form of coal
deposits carbon released marine organisms
CARBON SOURCES AND STORES oil and
At present, more CO is added to than subtracted by decomposing gas
2 phytoplankton
from the atmosphere. Some of the excess is carbonate in
absorbed by the oceans, where some is held carbon in sediment sediment turns
turns into oil and gas
in solution and some incorporated into living into limestone
organisms and sediments.

GOLDEN GATE FOG INTRODUCTION
The climate of San Francisco is influenced
by exceptionally cold water, produced by
upwelling, off the California coast. Fog is
produced as westerly winds blow moist
air over this cold water.