Written by Andrea Melina Fonseca-Tovar
In October of 2025, the 13th Mexican Coral Reef Congress and 4th Pan-American Coral Reef Congress were held in Cozumel, Mexico, bringing together researchers, students, and reef professionals. In this edition, we highlight the work of Diego Leonardo Mojica Guzmán, a student at the University of Yucatán, who won first place in the undergraduate poster category. His research is titled Biodiversity Associated with Dead Coral in Tropical Reefs.
Corals and Complex Structures
Coral reefs are best known for their extraordinary biodiversity, supporting an estimated 25% of marine species. This is due to the complex structures that reef-building corals create on reefs. As corals grow, the polyps excrete calcium carbonate skeletons, which, over long periods of time, create three-dimensional structures. Not only do these structures shape the underwater landscape, but they also generate a wide variety of microhabitats (Castro & Huber, 2010). These structures provide shelter, food, and living space for many marine organisms, making coral reefs one of the most diverse ecosystems on the planet.
Invertebrates Associated with Corals
For over a century, scientists have been interested in the animals associated with coral reefs. Research has shown that many invertebrates live within and near coral structures (Glynn & Enochs, 2010). These organisms belong to the epifauna, which live on the surface of the coral, and the cryptofauna, which remain hidden within cavities and internal spaces of the reef structure. For example, some damselfish actively select and defend specific areas of the reef for algal farming, illustrating epifaunal associations. At the same time, certain brittle stars reside within sponges or crevices, exemplifying cryptofaunal habitats.
Several studies have also shown that reef structural complexity, often described in terms of relief or rugosity, influences the abundance of associated invertebrates. Generally, the more complex the reef structure is, the greater the diversity it can support. However, this pattern is not consistent across all regions. For instance, some studies in Caribbean and Indo-Pacific reefs have reported weak or context-dependent relationships between structural complexity and invertebrate diversity, suggesting that local environmental conditions, such as hydrodynamics, predation pressure, and resource availability, may mediate these interactions (Wee et al., 2019).
Life After Death?
Over the past few decades, disturbances affecting coral reefs have increased coral mortality. However, the death of corals does not mean that their structures immediately disappear. In fact, dead coral skeletons continue to play an important ecological role.
These structures still function as substrate, refuge, and habitat for a variety of benthic organisms. In some cases, dead corals host a different composition of invertebrates and can even support a greater number of individuals and species than living corals (Fraser et al., 2021).
Diego’s Research: Skeleton Morphologies
The main objective of Diego’s research is to compare communities of invertebrate epifauna associated with two distinct types of dead coral skeletons in Río Indio, Mahahual, Mexico. Preliminary results suggest that the morphology and structural complexity of coral skeletons influence the composition and structure of epifaunal communities. This may be related to the characteristics of the available microhabitats, which can differ in size, regularity, and stability. Environmental variables may also play an important role in shaping these distribution patterns.
These initial findings highlight the role of coral skeletons in reef ecosystems, particularly in providing habitat for epifaunal communities. As this research is ongoing, Diego continues to analyze additional samples and environmental variables as part of his thesis, which will enable a more comprehensive understanding of the factors influencing these communities.
Cover image and more information
Diego Leonardo Mojica Guzmán
Undergraduate researcher at the Autonomous University of Yucatán
Email: Mojica.guzm.diego07@gmail.com
Instagram: @oceanides._
References
Castro, P., y Huber, M. E. (2010). Biología marina. McGraw-Hill.
Fraser, K. M., Stuart-Smith, R. D., Ling, S. D., y Edgar, G. J. (2021). Alta biomasa y
productividad de invertebrados epifaunales que viven entre coral muerto.
Marine Biology, 168(7), 102
Glynn, P. W., y Enochs, I. C. (2011). Invertebrados y su papel en los ecosistemas de
arrecifes de coral. En Z. Dubinsky y N. Stambler (Eds.), Coral reefs: An
ecosystem in transition. SpringerWee, C., Sam, S. Q., Sim, W. T., Ng, C. S. L., Taira, D., Afiq-Rosli, L., Kikuzawa, Y.,
Toh, T. C., y Chou, L. (2019). El papel de los viveros de coral in situ en el
apoyo a la epifauna de invertebrados móviles. Journal for Nature
Conservation, 50, 125710.
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