Acropora millepora colony

This colony is made up of multiple branches, and each branch has multiple little polyps. Here's a picture of some polyps close-up under the fluorescent microscope:

Acropora up close and personal

You can see here that up close, Acropora makes these calcium carbonate 'scales' and within each of these 'scales' is a little polyp, which looks like an anemone and has different colored tentacles.

I haven't yet written on this blog who I am and what my intentions are for this coral spawning. I spoke with my objectives in Mr. Ryan's Aquatic Science periods 1-3 at Round Rock High School, however I feel like I should spell it out here too....

My name is Marie Strader and I'm a graduate student at the University of Texas at Austin studying Ecology, Evolution and Behavior. I have spent the last 2 years of my life staring at my computer and out the window of the fourth floor of the Patterson building. Patterson labs hold the spirit of decades of impressive research, which I'm honored to sit amongst every day.

Patterson Labs at UT Austin

What do I do while I'm sitting in this old building? I'm usually thinking about my research, analyzing data, thinking of new experiments and writing. My research revolves around corals, which are the animals that make up coral reefs. Coral reefs are very intriguing ecosystems to study and corals themselves lend themselves to many interesting biological questions. I'm a member of the Matz lab whose research focuses on the ecological and evolutionary genetics of corals, particularly how corals evolve and adapt to environmental stressors. My research on the other hand is on the ecological role of fluorescence in corals. I use genomics and experimental biology to understand this system.

But what is a coral and why is it important to study them? Corals are animals, related to jellyfish, that create habitats for numerous invertebrate and vertebrate communities. Coral reef habitats are important for maintaining fish population which are critical for many coastal populations around the world. 

Anatomy of a coral

My dissertation is investigating the role of fluorescence in early life stages of a reef-building coral, Acropora millepora. The corals that I study spawn once a year in a mass 

Coral Spawning on the Great Barrier Reef.
Picture: Stuart Ireland, Calypso Productions

spawning event on the Great Barrier Reef, Australia. These corals are unable to be spawned after being kept in aquariums for long periods of time since their spawning is coordinated through numerous environmental factors, including annual sea temperature increases (summer), day length and the lunar cycle. Because of this my fieldwork is limited to once a year, 5-8 days after the full moon in November. I intend to complete three experiments while I'm there since larvae are incredible fragile and it's impossible to transport them halfway around the world alive. 

So these corals, if you shine certain colors of light on them, they fluoresce different colors. Why is that? What causes them to fluoresce? Well, corals produce fluorescent proteins (FPs). These proteins exist in the corals cells and encoded by genes. These proteins absorb specific colors (wavelengths) of light and emit (or let out) a different color of light. The coral color that we see is due to these proteins emitting, or producing, their own light. So this explains how they fluoresce, but WHY do they fluoresce? That is one of the questions I'm attempting to address with my dissertation. 

I've been working on Acropora millepora for 2 years now. I've analyzed a bit of data which has led me to create a few hypotheses about why larvae, specifically, fluoresce different colors. 

I think that the different colored fluorescent proteins may play roles in growth and the ability to tolerate environmental stress. Green fluorescent protein, for example, is really strongly visible in tentacle tips and growing edges of colonies.

My first experiment examines the differences in thermal tolerance between larval color morphs. Knowing this may help us understand differences in the ability of larvae to disperse long-distances in the water, or in other words, move to more far off reefs. 

My second experiment will be to quantify differences in cell proliferation between larval color morphs. This adds to my hypothesis that redder larvae are more stress tolerant and reduce cell division in order to be able to live longer in the water column and perhaps disperse longer distances. 

My third experiment aims to develop a method of RNAi in coral larvae. RNAi (or RNAi interface) is a method where the transcript of a gene (the mRNA that will lead to protein being produced) will be broken up in the cell, resulting in a reduction of a particular protein. Knocking down proteins is one way to examine their function. I will attempt to knock-down expression of red fluorescent protein (RFP), green fluorescent protein (GFP) and a control metabolic gene and look at effects on traits, or characteristics, of the larvae. 

Sorry for the long post, just wanted to get everyone up to speed on what I'm trying to do! Please write to me if you have any questions! :)