Wednesday, July 21, 2010

Testing the Waters!

Hello from Week 3! To a Senior Marine Educator such as myself, the third week means that I'm at completely new sites in our biweekly rotation around the Harbor. And I couldn't have asked for a better farewell to my sites last week, nor a better start to the new week!

I wrapped up a phenomenal week at Piers Park with a great group of truly enthusiastic and engaged Harbor Explorers. We caught our first fish, took a field trip to a local pier to see our harbor habitat from a different angle, and really bonded as a group of people excited about the water and what it has to offer. They'll be on my mind for the rest of the summer. Thank you everyone!
At both Piers Park and Courageous Charlestown, we were charged with two special projects during our second week. Dr. Judy Peterson, a great friend of Save the Harbor / Save the Bay, came to us asking us to join a large network of "citizen scientists" across the area in a large-scale effort to better understand the Harbor and how it is changing. Piers Park and Charlestown are specifically measuring the water for clarity - how clear or not clear the water is-- and salinity - the amount of salt in the water. The tests were great hands-on tools for the kids at both locations to consider the water in our Harbor a little differently, and to see how its composition isn't the exact same every single day, for various reasons.

We used a Secchi Disk-- a fairly simple tool, in fact-- to measure the water's clarity. The Secchi Disk consists of a black and white disk on the end of a nylon line, along which little beads are placed every meter. All our citizen scientists (like our very enthusiastic explorers at Piers Park) needed to do was hold on the line and slowly drop the disk deeper and deeper into the water until they cannot see the white part of the disk any longer. However deep the disk is when the white goes out of sight, according to the beads along the line, was our measurement. At both Piers Park and Courageous, our measurements were falling between 3 meters and 4 meters all week, with much higher measurements (more clarity) as the week went on, which also happened to correspond with the rain half way through the week.

To measure salinity, we were privileged to use a portable refractometer provided to us by Dr. Judy. If we place a little drop of water on the lens of the refractometer, it measures the deflection of light through the drop of water, which is affected by the amount salt (measured in parts per thousand, or PPT) in the water. When we did the test at Courageous last week we got readings of 26 PPT on Tuesday (7/13), 27 PPT on Wednesday (7/14), and 21 PPT on Thursday (7/15-- again, after the rain!). Both tests were a great activity for everyone to gather together and do at both sites, not to mention a great effort to be a part of across the Harbor!

Lots of Harbor Love,


1 comment:

Bruce Berman said...

Thanks for this Michelle.