Biology Reference
In-Depth Information
sea had filled the bay to its modern shorelines. Conditions cooled sud-
denly again about 3,600 years ago; large cobbles in estuary cores suggest a
devastating flood had poured into the bay, helping to build marshes and
support oyster beds. Though the state then entered a cooler, drier time, the
climate of the most recent millennium has been more erratic. Two “epic”
droughts parched the state for about 150 years each, followed by a 300-
year cold period known as the “Little Ice Age.”
The last 150 years have been among the most welcoming in California's
known climatic history. In fact, the twentieth century was the third wettest
in 1,000 years. This spate of good weather supported a burgeoning human
population and a strong state economy, “providing us with a limited,
somewhat optimistic perspective on the carrying capacities of California's
landscapes and resources, including our water supply and flood control
structure,” writes UC Berkeley climate scientist Frances Malamud-Roam
and colleagues. Such skewed expectations are due for a jarring adjustment.
The warmer years projected for the next century, resulting in earlier snow-
melts and floods, are expected to bring a harsher future.
Under the bay's temperate skies and surface lie more than islands, dunes,
and plain water. The water can be cold or hot, salty or sweet. It can come
from far away or near at hand, from a spring in the Sierra or the middle of
the Pacific Ocean. It can move straight or sideways, or it can sink to the
bottom or be whipped into a wave by wind. In the water can drift bits of
sand and silt, shreds of plants, fish, and even monsters of Jaws propor-
tions. No human can fully grasp what it's like beneath the bay's mirrored
surface.
Those who have put their minds to it have learned, however, a number
of attributes of the bay and its watershed that escape initial notice. One
insight has been that the rivers, delta, bay, and ocean cannot be subdivided
into distinct ecosystems. The water has a way of connecting all corners,
seeping through the boundaries erected by human perceptions of the
landscape.
“It's a whole different ballgame thinking of our water and fish as mov-
ing through a mixing bowl, rather than through a series of one-way ca-
nals,” says Kim Taylor, a USGS manager who oversaw some of the most
interdisciplinary science research ever done concerning the estuary.
Not so long ago, scientists believed rivers dominated the estuary be-
tween the Sierra and the sea. Now they know tides may be an even bigger
influence. Recent grand-scale changes in the Pacific have in turn sug-
