Biology Reference
In-Depth Information
samples from the bottom of the bay. Once the sample is grabbed, the crew com-
pares the water from the bottom with that from the surface of the bay back in the
yacht's lab.
Heading north under the Richmond Bridge, we pass Red Rock, where three
counties meet in the middle of the bay: San Francisco, Marin, and Contra Costa.
The turbo-charged Vallejo ferry streaks past us. On-screen, captains can distin-
guish ferries from other vessels by the high speed of the yellow dots. The Vallejo
ferry sends a wake the size of a small tsunami under the
Polaris
, and she rolls.
The
Polaris
follows the ferry out into the open waters of San Pablo Bay, where
suddenly the shorelines seem less distinct. Our video sounder flashes a sonar
reading of less than six feet—the average depth of most of San Pablo Bay. The
water is a browner hue here: it's easier for the wind tickling the surface to reach
the shallow bottom and stir up sediments. The crew checks the water samples for
suspended sediments by flushing them through quarter-sized paper filters.
Soon the
Polaris
reaches the narrowest spot in the entire estuary—the Carqui-
nez Strait. Four crewmates climb into red waterproof suits and prep a small Bos-
ton whaler for some specialized sampling in the shallows. The captain soon has
the whaler winched up and suspended from three ropes in mid-air. Then he lowers
the small boat over the side.
Steaming into the strait, the captain describes making this trip in both fair
weather and foul. During floods, this estuary bottleneck can be clogged with dead
cows, torn-up trees, refrigerators, and, most hazardous, propane tanks from
flooded households, ready to explode on impact.
Past the strait the estuary opens out again into Suisun Bay, which at this time
of year is as placid and glassy as a bathtub. It suddenly gets hot. We pass the
mothball fleet of decommissioned naval vessels and watch a sea lion circle a red
buoy, stick its nose in the air, then heave its 800-pound body up onto a small
ledge. The buoy swings madly.
Farther along, as dusk gathers, small fishing boats appear here and there,
harking back to older, quieter pastimes than watching CNN and TV autopsies. Two
men near the marshy edge sit in a rowboat staring at us, unblinking, holding two
beers and two rods.
Out on deck at Station 5 it's so still I can hear the radar and GPS gear—three
black cups and three white wings spinning on the cabin top—move the air. We
pass the confluence of the largest rivers in the state, the San Joaquin and Sacra-
mento. It doesn't look like much: wide waters, an island, a few trees on a levee.
At Station 2 we winch the whaler back up onto the deck of the
Polaris
and its
crew begins sifting muddy bay-floor samples through a screen in search of small
life forms. Around sunset, we reach the delta town of Rio Vista. We have come
through four bays and into the central delta, seen the path of water from land to
sea, and measured the water's physical condition at each of 36 stations along the
way. We batten down hatches and wash coffee cups.
ARO
