We’re doing geology in the Ross Sea, mapping the ocean bottom, and the rock beneath the ocean bottom. To map the bottom of an ocean, you can sail over it with various kinds of sonar, ping the bottom and listen to what comes back. But that only gets you depth to the sea floor, the skin of the rock. To really get an image of what’s down there you need seismic. Seismic surveying goes like this: first get a big ship. Then tow a large air gun thirty or forty meters behind it. Next send out a huge blast of air, a percussion that hurls a shock wave through kilometers of water. Now listen for seven or eight seconds as the cake layers of rock below the sea floor reflect the shock wave back. Do all this again, and again, and again as you sail back and forth for a couple of weeks over vast stretches of the ocean like you’re mowing a lawn that’s hundreds of miles across.

A bunch of computers with impossible software will turn fuzzy wave signals into a picture of the cake layers. It’s magic: blank quadrants on the map become shaded beneath you; the picture is filled in, and with it, all sorts of inferences about geologic history, glacial cycles, past climate (which seems to be the question everyone wants the answer to lately).

Unfortunately the Ross Sea is also home to lots of whales this time of year. Whales love krill, and the Ross Sea in summer, with continuous daylight, is a big krill factory. What whales don’t enjoy are huge air cannons that send shock waves for kilometers. In fact it hurts them. A lot (internal hemorrhaging, maimed sonar–both bad if you like to swim around and eat krill or happen to use sonar to find your way around and talk to other whales). So here’s how we fix that: we send someone (usually a lowly graduate student) up the mast to the pilot house (picture a crow’s nest enclosed with glass) with binoculars and a radio. That person perches eight stories above the water, in the tipsiest part of the boat, and looks for whales so we can sop ’shooting’ before we shatter shamoo’s eardrums. This is my second seismic survey cruise on the NBP, and I’ve seen us stop shooting for whales exactly zero times. I assumed whale watch was one of the things researchers cooked up to test the mettle graduate students: wrap them in Gore-Tex and make them climb eight stories up an icy, swaying tower over frozen seas (also see the cell-phone buoy gag: “oh sure, we’re passing one tonight at 3am”).

Here’s a secret: I actually enjoy whale watch. You get some alone time on a crowded boat. You watch the light change across the waves, the sea birds soaring in our draft, the icebergs gliding by. I was five minutes into my whale watch this morning at 3a (the cell-phone buoy must have been Verizon ’cause my AT&T didn’t get any signal at all). I hadn’t even caught my breath from climbing the ladder when six minke whales surfaced 300 meters off the bow like a fleet of Russian submarines shedding water off their black hulls. My hand held radio somehow became the most complicated apparatus I’d ever used; It seemed to take forever to hail down to the control room where I knew people were lazing around with crosswords and Harry Potter novels while the computers crunched signals.

“Stop the guns!”

Protocol says we should stop shooting before the whales reach 50 meters of the guns. Our minkes took off to our starboard before they came inside 200m, but whales have been known to indulge their curiosity and come closer to air guns (who says intelligence pays?), so we kept the guns silent while the pod gamboled their way to the next krill buffet. With the guns off, we left a few blank patches on the map, but I did something I didn’t really think was possible, something that bumper stickers have been exhorting me to do for decades: I saved whales.