Tag Archives: Udotea

Day 13: Marine debris and mangroves

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Sunrise on Middle Caye

The project of the morning consisted of quantifying the marine debris that was washed up on the windward side of Middle Caye. At four sites we measured the amount of trash that the 14 of us could collect in 15 minutes. By weight, 50% of the debris that we gathered was plastic and another 21% was Styrofoam. 14% was rope and 15% was glass, rubber, or other materials. Overall we collected 41.22 kg of debris in one hour, which is especially significant because the shore gets cleaned every week. The amount of debris that we collected on a small portion of this small island far away from the shore was staggering.

In the afternoon we ventured through a stand of mangroves to the leeward side of the island to the back reef. We were there to collect data on coral colonies that the EBIO 319 students measured last year, but we were also able to explore the area. The large quantity of sand on the back reef made it a good place to find green algae. Most of the Caulerpa that I saw were either Caulerpa cupressoides (cactus tree algae) or C. urvilleana. The Caulerpa were often found near Penicillus capitatus and Udotea flabellum. I also saw a few examples of Dictyosphaeria cavernosa (green bubble algae) on corals and in sea grass.

While we were collecting debris I noticed a fair amount of filamentous algae on the rocks along the shore. I’m not sure whether they were from the Cladophoraceae or Derbesiaceae family. Some of them might have been Rhizoclonium riparium.

I forgot to mention yesterday that I found Caulerpa racemosa (green grape algae) on the windward back reef that we visited. The algae were in very shallow water right behind the reef crest. I also have seen examples of Acetabularia calyculus (mermaid’s wine glass) in the shallow water off of the dock.

Caulerpa racemosa on the back reef at Middle Caye
Caulerpa racemosa (green grape algae), turf algae, Halimeda, and brown algae on the back reef at Middle Caye
Acetabularia
Acetabularia calyculus (mermaid’s wine glass)