Naitauba's sea temperature monitoring program underway! - Part II

With two men in the boat and three in the water, anchoring the loggers in place was a great chance to develop teamwork. We had pre-planned as much as we could, but coordinating everything from with free-divers at 10 meters depth was a real learning experience, especially at our first location outside the reef. Fortunately, weather and sea conditions cooperated beautifully, with excellent visibility.

Installation of Onset’s HOBO data loggers on Naitauba’s reef

Our anchors were cement-filled cinder blocks, with rope handles and a tether rope for lowering them. We added some floats to help us maneuver them down into position.

Once we had chosen a location on the reef, we clipped the loggers onto the blocks, lowered them to the proper depth, and settled them securely in place. After we had confirmed the depth with a tape measure, we took off the tether rope. Then we took underwater site photos, GPS coordinates, and photos of shoreline reference points to help us find our way back.

Working outside the reef is always a treasured opportunity to see parts of the reef that are usually beyond our reach.  But even so, this was something special. How to describe it - the afternoon sun filtering to the depths where we were suspended, compression perfectly canceling buoyancy and gravity into a calm that even forgot about breathing, at least for a moment - gazing down the inconceivably vast slopes and cliffs of the undersea mountaintop that we live on, and the blue immensity that extends everywhere out and beyond and down. Well, soon enough, the urgency of breath re-emerged and we started the long glide back up.

We saw many new fish and added six species to our identification list.

We also got a chance to see some very different reef environments. On the relatively sheltered west side of the Island, the coral growth overall is more dense and the coral formations larger.

In contrast, the exposed eastern side seems much more stark and bare, a bit like a mountain top above treeline. There are thousands of coral colonies scattered over the reef slope, smaller and with more space between than on the sheltered side.

But the fish life there is incredibly dynamic, with schools of small fish constantly hovering and darting around and above the slopes, and occasional schools of larger fish speeding by and vanishing quickly into the vast blue again.

Once the outer reef loggers were in place, we crossed back inside the reef and placed the remaining two loggers near easily identifiable coral formations. The shallower of the two is in the midst of corals that were bleached in January’s hot sunny weather, so it will serve as an early warning outpost when temperatures start to rise again.

Now, the loggers are all in place, doing their steady silent work. We look forward with anticipation to see the unfolding story that they will tell.

So much hangs in the balance for the reef, for the oceans, and for the world!