Research expedition to the Southern Red Sea
I’m skipping Spain adventures (I’ll try to get back to it) but first I wanted to tell you a bit about the research cruise I’m currently on with some fellow members omf the Reef Ecology Lab at KAUST. We are going on a 12 day trip from Al Lith down into the Farasan Banks in an effort to support individuals research, as well as to do surveys to assess how corals are responding after bleaching back in 2015. In the region, the lab has data for a few years before bleaching, right after, and now a few years after recovery. For those of you who don’t know what coral bleaching means, I’ll do my best to explain it. Coral, which is an animal, is so important because it provides structure to the reef which attracts fish and all the other sea life. And within these corals are tiny algae, called Zooxanthellae, which photosynthesize and provide coral with extra nutrients. These algae also make up the coloration of the corals. But, when corals get stressed (often due to a sudden increase of temperature), the corals will expel and get rid of the zooxanthellae. Thus, the corals are left white, which we refer to as bleached. When a coral is bleached, it isn’t dead quite yet, it has the chance to recover and accept zooxanthellae back. But unfortunately, when the coral no longer has zooxanthellae, it is more susceptible to disease, starvation, and death.
Anyways, one of the goals of the cruise is to look at the corals and see the recovery rates, because the last bleaching event had such a high prevalence, I think up to 80% of the coral was bleached in this one stress event, which is huge. So one of the teams on this cruise will be setting out three 50m transects at each site. Darren takes the lead doing fish surveys, recording every fish and it’s size estimation. Behind him is usually Amr, who lays the transect on the reef. And following, is me, Aislinn, and Claire. We are in charge of doing photo surveys, recording the size of live corals, recording the rugosity, and doing three Algae quadrants along the transect, where you record the length of specific species of algae’s. I was on photo transect duty the first few days of the cruise. The objective is simple, using a camera to take a 1 meter by two meter photo, along each 50 m transect. Sounds a lot easier than it was. The point was to take images of the benthos of the whole 50 m, so someone can look at the images in the future and use them if they are studying algae, or corals, or sponges, etc. After the cruise, coral point count will be used to analyze each photo. Claire (a current Master’s student, did the coral surveys and rugosity. For those of you who don’t know, rugosity is a measure of reef complexity and how 3D it is. You basically lay out a chain of known length around the transect, and if there are any crevices or holes in the reef the chain gets draped down. Then you measure on the transect how far the chain reaches. So basically if it’s a flat sandy surface the transect length will be the same as the chain length, but if it is a super complex and 3D reef structure it will read shorter. The algae quadrant is another sampling technique that was previously used on one of the past expeditions down in the Farasan Islands, and will be used to compare how things have changed. Typically, if there is a lot of algae growing, it’s a bad sign that means that a lot of the coral has died and has been out-completed. Fortunately, at least in the beginning part of the cruise, I don’t think that these corals look that dead. Of course I didn’t see them before the bleaching event, but there’s still a lot of “massive” corals, like porites, and not as much branching and structurally complex corals. Which is actually a pretty positive finding I think.
There are also three new post docs in our lab, each doing separate projects on this cruise. Laura has been collecting corals which she will later extract DNA from in the lab to assess connectivity in this are, and how genetically related the corals are across different reefs. Her husband, Tom, has been collecting coral cores from porites species. Once these cores are taken to KAUST, a CT scan will be used to look at the rings. Corals are similar to trees, with growth rings. And you can even find years with high stress and climate anomalies, and count back in time to follow the history of these corals. Corals are super long lived, and the big ones can be hundreds of years old. The last post doc, John, is collecting samples of anemone fish.
When we are near sandy islands, the Masters and PhD students will do our individual projects. I will be surveying for turtle nesting activity, collecting sand samples to measure heavy metals (which have negative impacts on the embryos). I’ll be using the drone to survey sea grass areas, which are an important food for turtles. If I find any turtle carcasses I’d like to dissect the stomachs to look for plastic, and take tissue samples for DNA analysis in the lab.
Aislinn is putting out these huge incubation chambers over coral heads to measure their respiration, photosynthesis, and other parameters in both light and dark conditions. Collin is using a new to find bonefish and take DNA samples and otoliths. Ashlie is using BRUV (Baited Remote Underwater Videos) to assess shark populations in mangrove areas to see if they are a nursery.
Lastly, there is a team of snorkelers who are doing “quick surveys”. Basically, an organization called the Living Oceans Foundation used satellite imagery to categorize different habitat types (mangroves, seagrass, coral, sand, etc). So this team is groundtruthing these surveys by snorkeling and taking GPS points and assessing the habitat type, as well as finding percent cover of algae. They are also collecting water samples to assess nutrients and chlorophyll a.
We left KAUST on February 5th and took a bus about three hours to Al Lith, where I’ve been many times before for research and dive trips. Here, we loaded up the boat with our equipment and belongings, and arranged ourselves. We had dinner onboard, and went to bed by 9. The next morning we left the dock by sunrise and were on our way to our sampling site. We arrived by noon and was able to do our first reef survey. The first dive was on a reef called “brown reef”, despite the name, it was a pretty healthy spot. The second spot was called Shim Ammar. This day we were still getting familiar with how to do our surveys. The hardest part of the photo transects was uploading them onto the computer and naming all the files, it could take up to a few hours. In the evening I helped Laura process her coral samples that she would be doing DNA work on later.