Intro to Sampling Strategy

The sampling is ramping up here in Reunion, and the checkboxes are filling up next to target corals. In the last three days, we have collected samples from 27 corals, representing 22 species from 16 genera, 11 families, and 2 classes. Since the actual physical taking of a sample involves just rubbing a syringe against it and breaking off a tiny chunk, our number may not actually seem very high. However, there are a few things that make the process take longer than theory would predict. As Amelia mentioned in the last post, one thing that’s slowing us down is the environment. We’ve discovered before that working in shallow water is not easy. In the lagoon here on Reunion, the water is often so shallow that we are trying to spot live corals in ankle-deep water, then having to find a way to lie down to examine them without crushing the reef or sitting on a poisonous stonefish. In other places, the water is about waist-deep, and the huge waves breaking on the crest continue into the back-reef, sloshing us around amongst the sharp corals and stinging fire-corals, and making it very difficult to stay steady enough for photos and sampling. Plus, it’s winter here, and the water is ‘cold’. 76 degrees Fahrenheit seems warm at first, but after ~4 hours of being submersed in it, the water still saps out all of our body heat. We’re getting cold, sunburned, and beat up!


But if that was the only problem, I’d say we’d just have to suck it up and get the work done! But another, bigger problem is that we have to find the corals. Not just any, but a relatively specific list of coral types. We’re only planning to take a small number of samples from each type while we’re here, and I’d prefer not to take them all from the same location at the same time. I mentioned before that confounding factors can make it difficult to determine which variable is responsible for a given trend. If all we found on Day 1 were Porites and Acropora, and we immediately took all of the trip’s samples for those species, we would have confounded our species variable with time and location. Later, if we took all of our Fungia samples on a single, different day, it would be hard to be confident that differences in the microbes between our Porites and Fungia samples were actually attributable to host specificity. An equally good alternative explanation would be that microbes on corals on Day 1 were different than microbes on corals on Day 5, no matter which species we sampled on each day. This is likely to be true for many microbes due to differences in disease prevalence, tidal height, current direction, light level, etc. To be confident that differences are due to coral species, we need to have a clear sampling plan. A solution is to find and sample replicates from many different coral species on the same day. Differences among these samples would be more confidently attributable to individual colonies and, through replication, to coral species. So we are doing our best to find locations that have high levels of diversity. High diversity reefs were easy to find at Lizard Island and KAUST and made our sampling there go great!

We are not having problems finding Porites (massive) and Acropora (branching)...

We are not having problems finding Porites (massive) and Acropora (branching)…

This Fungia, however, is the only one we’ve found, so far.

The first couple of days that we were here in Reunion, we spent a lot of time exploring the lagoon just down the street from our rental house. We chose the house hoping that the majority of our sampling could be just a short walk and swim away. However, we weren’t finding much in those reefs. Of the ~16 families of corals that we hoped to find here, only 2 were common, and we only found 5 there in total. So after a weekend of exploring the island for fun (escaping the critical eyes of the heavy crowds at the beach), we began our sampling in the lagoon of Trou d’Eau, a short drive south of us. The reefs there were, if anything, less abundant and diverse than the ones here. We got samples from 5 families. So the next day we went even further south, to Saint-Leu, to see if our luck would be better. Indeed, we found a reef that had much more cover and much more diversity than those up north. We collected samples from 8 families, 5 of which were new! Still, with a total of 10 families, we were still missing a few that have been very common and conspicuous in other wide-ranging Indo-Pacific reefs that I have sampled. So we decided yesterday to try a different environment and brave the shark-infested fore-reefs via scuba. The day was great – I absolutely love the feeling of being on a boat in the tropics, and the feeling of breathing clean, cool air through a regulator while suspended underwater. Plus, the sampling is way easier while diving under the waves, and doesn’t tend to get us all beat up. But the reef wasn’t very diverse. We found 5 families of corals – only 1 of them new.


Ahh, I love being on the water!


Thought this was a Montipora – closer inspection reveals it’s just another species of Porites!


Weekend getaway


Cold mists of the volcano

As the trip reaches its half-way point, we are ready to buckle down and get going on replicates of what we already have. We’ll keep our eyes out for the missing coral families, but would be relatively satisfied with the current repertoire if it’s all we wind up finding. Today, we head south again, this time diving on the fore-reef, where we hope to find a beautiful combination of easy sampling and diverse corals.


Finding the moon and meeting Tiki

We had spent the weekend with Jerome’s family and after an evening of food and laughter we were ready to explore the island. Réunion has many different microclimates with landscapes ranging from arid forests to tropical beaches. On our way to the Piton de la Fournaise volcano we reflected on how these different microclimates reminded us of a mixture of places across the globe. We even found the moon!

Mountain or moon?

Mountain or moon?

Piton de la Fournaise is a shield volcano and is one of the world’s most active volcanoes. It is around 530,000 years old and 2,631m high. Piton de la Fournaise is one of two volcanoes, the other being Piton des Neiges, that make up Réunion. Up until a few weeks ago, it’s most recent eruption was in 1986. Due to its activity, the hikes circling its peak were closed, but we were still able to get an awesome view of it!


Piton de la Fournaise!

Of course, we couldn’t have done any of this without our awesome matching hats!

Jerome's mom outfitted us with matching hats to protect us from the sun.

Jerome’s mom outfitted us with matching hats to protect us from the sun.

Now that the weekend is over it’s time to get down to business. Monday came bright and early with birds chirping and the smell of science in the air! Like all good scientists we had our ritual morning coffee and then rolled out into the field. Spending the majority of the day sampling we were able to see most of the lagoon in Saint-Gilles. In the lagoon alone we were able to find five different clades of coral, a plethora of sea cucumbers and zero sharks.


A snapshot of some of the corals we collected! (Montipora sp., Porites cylindrica and Porites lichen)

The main thing that I have to say about Monday is this: weight belts. Even though we were in a shallow lagoon our buoyant weight kept on pushing us up, making it difficult – but not impossible – to sample. From shore I’m sure we looked like two poorly coordinated synchronized swimmers with our feet flapping in the air as we tried to stay down.

Today, we hopped in the car and went to a different section of the island in hopes of finding a more biodiverse reef. We struck gold and were met by beautiful reefs in crystal clear water. But there was one catch: strong currents (everyone’s favorite). The currents quickly introduced Ryan and I to the fire corals in the surrounding area and by the end of the field day I’d say we all became good friends.

Fortunately, we had brought Tiki with us so we weren’t scathed too badly. Tiki is the good luck charm of the Vega-Thurber lab and has been on almost every field trip the lab has gone on. That being said, Tiki has traveled a lot and spent many days in the sea (his black hair turned blond is proof). I’ll allow Tiki to introduce himself:

And so folks, that concludes the past few days in Réunion!

Bienvenue à la Réunion!

Hi guys! My name is Amelia Foster. I’m currently an undergrad in Becky’s lab though I graduate soon (woo!). By the end of this summer, in fact, I will have finished my majors in Microbiology and International Studies. I started volunteering in Becky’s lab as a sophomore in 2012. Under her mentorship I have learned important molecular biology techniques associated with coral reef ecology. Recently, I have been given the opportunity to learn fieldwork techniques with Ryan and Jerome in Réunion Island, France.

Our flight pattern from Oregon to Réunion

Our flight pattern from Oregon to Réunion

After 30+ hours of flying, an inordinate amount of babies crying and lots of bread and cheese we arrived in Réunion just as the sun was coming up over the water. Originally named Bourbon, Réunion is a French department located in the Indian Ocean just east of Madagascar. Volcanic eruptions beginning 5 million years ago formed the island that today houses around 850,000 people. The island was uninhabited until 1643 when the French sent twelve convicts there into exile. In the mid 17th century the island was further colonized. The settlers recruited a large amount of slave labor, from Africa, Madagascar, India and Tamil until the year 1848, which marked the abolition of slavery. Now, Réunion has a multi-cultural identity with people from all over the world.

Since arriving on the island just a few short days ago we have become fully immersed (though I still can’t speak at all) in French and have begun setting up field studies. From the house to the market to the beach, my daily life has become a game of charades. Picking up a few words here and there I can currently string together a few sentences that are inapplicable to almost all situations:

Je ne sais pas et jáime l´pomme et l´chat.  

Ryan is doing much better than I am and can almost carry a conversation in French. But Jerome, who is from Réunion, remains our savior in almost every situation.


Hanging out with Jerome’s family

Jerome has not only introduced us to his family and friends on the island but has told us of the terrifying homme-coq. The homme-coq has the body of a chicken and the legs of a man. It roams around the island, terrorizing the people and stealing children. So, we better watch out.

But even in the face of the perilous homme-coq -and not to mention the bull sharks– we have been able to begin the preliminary steps in setting up our fieldwork. Ryan has already given me a crash course in coral identification as we were scouring the lagoon near our house in Saint Gilles for different genera of corals. And the other night we helped Jerome collect water samples to later analyze for viral content.


La bobine beach, where we are currently sampling

Today, we are coordinating with local dive shops to acquire tanks and begin sampling a few of the corals we identified.