TROPHIC PLASTICITY IN SCLERACTINIAN CORALS: A META-ANALYSIS USING INNOVATIVE TEXT ANALYTIC TOOLS

Abstract

The increasing frequency and severity of bleaching events have caused global losses in coral cover and diversity over the last decade. Scleractinian corals capable of heterotrophic energy acquisition are thought to be better able to resist and recover from bleaching events, but it remains unclear if trophic plasticity is species specific or geographically constrained. I aimed to use the last 10 years’ worth of literature to answer these questions and to see if there were tools available to help me sort through the literature with more ease. This project had two goals: 1) test the viability of text analytic tools to categorize coral heterotrophic literature and 2) using the same literature, identify if there are genera specific differences between trophic modes, how do different trophic modes respond to stress, and if trophic modes display regional differences around the world. A topic modeling approach was utilized to conduct a more objective exploration of the existing literature and was able to automatically categorize all publications into eight major topics that represent the dominant research efforts over the last decade. I was able to use topic modeling to automate parts of the review process, namely topic formation, by grouping similar publications together that represented the focus of research. With that step, I was able identify where the most research has focused, and where it has been lacking much faster than the traditional, manual review approach. Answering the specific questions I sought about trophic modes, coral genera, and regional differences still needed to be conducted manually, however context surrounding those answers were greatly informed and expedited by topic modeling efforts. With the ever-growing body of literature, text analytic tools can help researchers facilitate their reviews and meta-analyses faster. Quicker publication of reviews and meta-analysis will lead to better informed and robust research. With my manual analysis, I found that Acropora, Pocillopora, and Stylophora coral genera were more likely to exhibit mixotrophy than other genera studied in the past 10 years. Mixotrophic genera were found to be more likely to survive a stress event than auto- or heterotrophy alone, but primarily autotrophic corals were still found to be resilient in certain situations. Trophic strategies were also found to display regional differences, and studies found more instances of mixotrophic corals in the Red Sea region than any other. I saw instances of specific corals displaying trophic differences among regions as well. This supports the existing understanding that trophic plasticity is species-specific, but also leads credence to the idea that trophic plasticity can be influenced by environmental conditions. My topic modeling and meta-analysis findings show that a more thorough understanding of individual coral trophic responses in varying locations and environmental conditions is needed to better support the continued survival of coral reefs worldwide. This knowledge is crucial to the success of conservation and management strategies regionally and on a local level.