Monday, May 13, 2013

Notes from Puget Sound

We went today on a five-hour Pacific Marine Research cruise through Puget Sound operated by and I highly recommend it. The class was very well-structured, with trained instructors who managed to pack in a lot of learning in a short time. We were there with a group of fifth graders from Sanislo Elementary school, which has apparently been sending kids to this tour for at least fifteen years.  At $40/person, to continue such repeat visits so long is a big endorsement and I know why. I would highly recommend this trip to anyone interested in hands-on oceanography.

Here's what we did during the time we were onboard the ship:

Measuring the ocean: the class dropped real Nansen and Niskin bottles into the water, the same instruments oceanographers use for collecting seawater at different depths. These devices have special triggers that can trap water at its existing temperature and pressure, so that it can be measured carefully when brought to the surface. The water today was 49 degrees (brrr!) and the salinity was about 28 -- quite a bit less than the low-30s you'd see if we were out on the open ocean, where the saltwater is less diluted by various streams and rivers that flow into the area we are patrolling today.

Plankton nets: we dropped two kinds of nets, one for smaller organisms and another faster for larger ones. Even at a reasonably shallow depth of twenty-five feet or so, it was surprising how many living organisms come up in the nets.

Microscope station: after filling some cups with seawater collected from nets, we looked at them under the microscope. At 10x to 30x, you see tons of interesting lifeforms: some (photosynthesizing plankton) that just sit there, and others (zooplankton) whose small flagella let them move quickly through the water. Many of the organisms looked like small shrimp or crabs (and some probably were!)

Hands-on with animals: at the top of the boat, the instructors set up stations with small water tanks containing many interesting larger creatures: starfish, sea anemones, California sea cucumber, crabs, and more. They let the kids touch them and see up-close the various features on the animals. I hadn't heard of the marine pill bug before, for example, though apparently it's quite numerous just outside the tidal basins.

Environmental protection: the scientists who run the cruise obviously care a lot about the environment, and Puget Sound in particular, so they devoted return part of the ride to a discussion of the problems facing marine areas near Seattle. Nobody pollutes the ocean on purpose, but there are many ways we pollute without knowing it, just by not being aware of the little ways our carelessness can hurt. 

The key word of the day, Watershed, describes the area in which all Northwest people live: all land areas between the Olympic Mountains and the Cascades where waters flow into the Puget Sound. Until a hundred years ago, the Sound was protected by marshland and the various habitats that naturally recycled water and more from the land. Now that half or more of the marshlands are gone, much of the rainwater goes directly -- too directly -- into the Sound, producing muddier rivers that scare away salmon, which in turn create problems for the sea creatures, like Orca whales, that eat salmon and other fish.

I left feeling like I understand more about oceanography in general, and looking forward to another trip like this one.