Beneath the waves of Arno

Diane and I went to the Marshall Islands with the goal of locating corals that would make good candidates for climate records.  At Arno, this involved three dives per day for five days.  That’s a lot of time underwater, especially since each dive was roughly an hour long.  Though Diane was unfortunately unable to dive with us until the last day, I was lucky enough to dive with Kalena de Brum, who works for the Marshall Islands Marine Resources Authority, instead.  She has a sharp eye for hidden wonders underwater!

Simon and Sara identify, measure, and photograph corals along a transect at each site.  Kalena and I swim in the general area of each transect, scouting for corals.  We’re looking for corals of the genus Porites, which you might know as lobe coral.  The ideal Porites for sampling is a solid, tall mound, without any bore holes from clams or worms.

Good Porites, as it turns out, are really hard to find.  When we spot one, I note its size, depth, and condition, and my dive buddy takes pictures.

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Assessing the size and health of a Porites coral. (Photo by Kalena de Brum)

Since it’s impractical to bring meter sticks along with us, I pose in the pictures for scale.  I’m exactly five-foot-twelve, and I know the length of my arms, so I become a useful unit of measurement.  There are probably a hundred pictures of me in these various Superman poses.

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This coral is close to one Emma tall. (Photo by Kalena de Brum)
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Corals don’t have to be alive to be valuable paleoclimate records.  This one is nearly taken over by crustose coralline algae, but might be useful nonetheless. (Photo by Kalena de Brum)

Some sites have a higher abundance of Porites than others.  At the low-Porites sites, my buddy and I will often help Sara and Simon with their transects by collecting data on coral morphology.

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Sara Cannon identifying and measuring corals along a transect. (Photo by Kalena de Brum)

On rare occasions, though, we still finish early, and have a brief chance to observe the wildlife around us.  There’s plenty to see!

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Barracuda were frequent spectators on our dives. (Photo by Kalena de Brum)
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We found Nemo! (Photo by Kalena de Brum)
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We saw white tip reef sharks on almost every dive. (Photo by Kalena de Brum)
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A well-camouflaged stonefish. (Photo by Kalena de Brum)

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