Fun with HOBOs

We use HOBOs extensively for our work in the Elwha coastal zone, and I have become a huge fan of these relatively inexpensive but robust little devices. They are inexpensive enough that when I was starting to plan for this quarter's Introduction to Oceanography class I thought that maybe, just maybe, I could figure out a way to get students using them to collect oceanographic data.

My relationship with the Feiro Marine Life Center (I am on their board) paid dividends immediately. I mentioned my desire to build oceanographic "moorings" with students in my class to the FMLC director, Deb Moriarity, and she suggested that we might be able to use a bit of funds that the FMLC and the North Olympic Peninsula Skills Center Natural Resources program (via Dan Lieberman and Tara Morrow) were granted to enhance educational opportunities in the marine sciences for local students. I had a number of local students in my course and they also wanted to create connections with colleges. Perfect! To really do it right though, I needed a few more HOBOs, and I was able to get them simply by making a request of Onset, the company that manufacturers HOBOs. They were fantastic, and quickly donated four additional sensors in support of this education project.

a student engineered mount...for temperature and light measurements on the bottom...

What do HOBOs add? With my class we've taken temperature and salinity measurements off of the P.A. Pier. That was a great exercise, especially because many of my students had never before used any sort of data collection device. We were even able to use a Van Dorn bottle to collect samples from "depth". But single samples are lacking in context - to really start to look at patterns in the ocean we need to collect data in time and space. Usually the instruments to do this are prohibitively expensive or difficult to use, but HOBOs are relatively cheap and very easy to use. So I developed an activity in which my students would build three "oceanographic moorings" with multiple HOBOs on each mooring, deploy them off of the pier, recover them and analyze the temperature and light intensity data that they log every 30 minutes.

a mid-depth sensor. The engineering challenge was to mount the HOBO such that its light sensor is always pointed up towards the sky.

The HOBOs arrived in the mail Thursday morning, and by Thursday afternoon the students from my class had built simple moorings and had them in the water. The feedback was great and students seemed to love the exercise of trying to work out how to best mount and deploy the HOBOs to maximize data quality. This was an element that I had hoped for...if my interest was only in time-series data for my students to look at I could get it off of the NANOOS or NOAA NDBC websites. But the process of building and deploying the moorings was instructive in and of itself. Students had to think about tides and currents and how they might influence their moorings. They had to think about the various sources of energy in shallow water and build a durable enough system to withstand at least a week in the water.

A gentle deployment off of the pier

So they are in the water now...check them out:

There will be more to come as we recover and analyze our data. And once more, I can't thank the FMLC, the North Olympic Peninsula Skills Center Natural Resources program and Onset enough for their contributions.

in the water...if you see them please don't take them home...