Latest Expedition Journal
October 11: Day 9
On Thursday, more than a week since we left San Diego, we are still heading west toward the gyre and into an ocean plush with plastic. In the last couple of days, crew and scientists alike have observed changes in the climate (at dawn it’s a warm 66°F), let alone increasing plastics. It feels like we’re entering the tropics.
In the first week underway, logging everything that we saw floating by us, a researcher recorded per hour, at most, a half dozen objects—from a three-foot square, floating dock to bits of Styrofoam. But yesterday as many as 20 pieces floated by each hour.
To understand these changes and what it means to lose the coastal California Current and hit the North Pacific gyre, I stroll to the cramped mid-ship science lab to look at our course and print out a surface data log. The science lab is a nerve center bustling with round-the-clock specimen gathering and data analysis. By 9am Alaska daylight time—the captain refers to this as “8 hours behind Zulu (or Greenwich time)” —we are 549 miles from the nearest California land; past estimates of navigation show we should enter the gyre within the next 120 miles. To guarantee our arrival in this area of the ocean, we will use real-time data. Because the gyre is dynamic and ever changing, this is the only way to figure out if we have entered it.
The lab printout shows our ship’s arcing course plotted in temperature, surface currents, fluorescence, and salinity. Over the last 250 miles sea surface temperatures have increased from 63°F to 68°F, while the currents have slowed, and the fluorescence indicating chlorophyll (and surface life forms) has also decreased. These are all the indicators that we use to determine if we are into the gyre.
The light-blue gyre that we’re entering is the ocean’s version of a desert. While the dark-blue ocean along the coast holds literal forests of life, the desert gyre is relatively devoid of surface life. It’s also a magnet for plastic detritus. Unlike the rich and shallow upwelling along the continental edges of the ocean, the downwelling gyre flushes its life into the deeps. Like a toilet bowl, the floating plastic remains on its surface.
The world’s five subtropical ocean gyres (spinning clockwise north of the equator, counter-clockwise to the south) are created by wind and the Coriolis effect that drive ocean currents. Here in the North Pacific, the gyre is built by the North Pacific Current merging with the cold California Current sweeping down from Alaska, spun by the westward Equatorial Countercurrent, all deflected back north and then east by the Kuroshio Current whirling off the Asian coast. For a sense of scale, this oceanic, whirling dervish dwarfs the North American continent.
To those accustomed to more biologically-fecund land or seascapes, an alien beauty possesses the great Pacific gyre. In addition to its mesmerizing blueness, these hinter-seas have no light pollution and the stars shine with a brightness that sailors—their eyes accustomed to the dark from hours on night watch—will substitute for headlamps. There are no other ships to be seen, no noise except for the wind humming through rigging and the slap of waves on the hull, and dolphins no longer bioluminescently cross our bow.