Tuesday, October 23, 2007

Coral Sampling Day 1

The monitoring program is basically to go see how different coral species grow under different conditions on the Moloka'i south shores. The water is really muddy. The mountains get a decent amount of rain near the peaks but the mountain faces don't have much cover. They've had the vegetation mostly removed or changed over the last century (I think). The south shore is protected from big waves by the surrounding islands, and it's quite gradual. You can walk out 1000ft and still only be in water waist deep. There's a lot of mud that settles down on the coral in this environment. Algae grows there too.

They put trays of different corals out at specific depths and locations and let them grow for a year or so. They stained the coral so that you can measure how much they grow, and have a good idea on how much they're breaking or spreading. Many have pieces break off, decreasing the weight. Having the "linear extension" gives you an independent estimate of the growth. The surprising thing was that a lot of them had grown really well. I think the expected amount was about 5-20%, but they were doing more like 40% with many almost doubling in size.

This is a quick histogram of sample "C". It shows how many corals increased by a certain % weight. So, 5 samples increased by 20%, 8 samples by 30 and 40%, 6 by 50% and one or two in each bin up to 110%. A lot of them grew by a really significant length too. They also had temperature loggers that recorded the temp hourly. It was kind of cool seeing this stuff.


Hourly Temperature:

I also had the job of photographing these sediment plates - ceramic tiles that allow the mud to settle on them. Coral and algae also grow on them and help record what the environment did over the last year. Some had nothing on them, and others were covered in stuff....

While all this was going on, I was doing some timelapse of West Maui and Lanai with the NIR filter. It comes out really clearly, even when there's way too much haze.


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