Biology Reference
In-Depth Information
FIELDWORK: TESTING BAY CONDITIONS
The captain of the
Polaris
pulls back on the throttle, hits a red button, checks the
numbers on a GPS screen, and speaks into an intercom in a firm, even tone: “Sta-
tion 36, 25.” A voice from the other end of the 96-foot-long science research yacht
says, “thank you,” back through the intercom, noting the location and the depth.
The two voices will repeat their exchange 36 times in the course of the next 12
hours as the
Polaris
tests how salty, cloudy, and deep the bay water is at set sta-
tions between Alviso in the far South Bay and Rio Vista on the Sacramento River.
The
Polaris
has been taking this two-day trip—passing under six bridges and travel-
ing 80 nautical miles upstream the first day and retracing its route downstream
the next—once every month since 1988. It is from the data gathered by the USGS
and other scientists on board that we've glimpsed a small part of the action be-
neath the 470-square-mile surface of San Francisco Bay.
Polaris
crew in action. (Francis Parchaso)
The sun is just backlighting the South Bay hills with flamingo pink when the
captain hits that red button at Station 36, our first sampling spot. It is 6:30 a.m.
A scientist in jeans and Keds steps out into the dark dawn and onto the teak deck
to unclip an instrument dangling from a pole so that it swings freely over the
water. This is actually not one instrument, but many. To me, it looks like a diver's
oxygen tank encrusted with gadgets. This conductivity, temperature, and depth
