Midway Day 1

We have reached Midway Atoll! We got into midway a day early so we were able to have a extra half-day of diving. Today was a total switch from the conditions that we had at Maro. It was shallow, completely flat, no current or surge, and really clear. This was a nice break after the kind of hectic/intense days that we had at Maro.

At Midway, we are working on two different projects: the “Holey Holes” Project and a bioerosion study.  This site, however, has a different set-up for the bioerosion study than the other forereef sites at French Frigate Shoals, Lisianski, and Pearl and Hermes.  At Midway we are working on a site within the lagoon.

 The red pin is our research site. Everything that looks light blue is the lagoon.

Lagoon reefs are well-protected from waves and the water is typically low-energy with a high residence time (meaning that there is not much water movement).  This allows for a really variable chemical environment which is not seen on forereefs.  For example, the pH on a lagoon reef might change from 7.7-8.2 in a given day while the forereef might only change 0.1 or 0.2 pH units in a diurnal cycle. Additionally, different areas of a lagoon reef (high coral cover vs. high algal cover vs. sandy areas) can have diverse, but consistent, chemical environments (see Gagliano et al. 2010 for some examples). I am hoping to capture this variability in the environment and see how different parameters affect bioerosion.  Do low pH areas have more bioerosion? Do high nutrient areas have higher erosion? I am answering this question in much more detail on a reef in Kaneohe Bay right now (where I can spend more than 3 days at a site). Midway is really interesting because there is almost no anthropogenic influences whereas in Kaneohe Bay there are a lot.  I have set-up the Midway site in a way that I can compare it to our lagoon site in Kaneohe Bay. This way we can see if  human impacts have an effect on bioerosion rates.

References:

Gagliano, M., M. I. McCormick, J. A. Moore, and M. Depczynski. 2010. The basics of acidification: baseline variability of pH on Australian coral reefs. Marine Biology 157:1849-1856.

This slideshow requires JavaScript.

Advertisements

2 responses to “Midway Day 1

  1. this is great! thanks for sharing!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s