Spotlight on a Researcher – Joana Figueiredo, Ph.D. (HCAS)

 

Joana Figueiredo, Ph.D., joined Nova Southeastern University in 2014 as an Assistant Professor and is currently an Associate Professor in the Department of Marine and Environmental Sciences at the Halmos College of Natural Sciences and Oceanography. Dr. Figueiredo also serves as the Executive Director of the National Coral Research Institute (NCRI) https://hcas.nova.edu/research/ncri.html . She is originally from Lisbon, Portugal, where she completed her B.S. and Ph.D. in Marine Sciences at the University of Lisbon. After completing her Ph.D. Dr. Figueiredo secured postdoctoral fellowships to conduct research at James Cook University, Australia, and the University of the Ryukyus, Japan. Her research at NSU focuses on understanding environmental factors that adversely influence coral populations and developing management strategies to improve this recovery rates.

One key area of Dr. Figueiredo’s research is understanding larval development dynamics of marine invertebrates such as dispersal, recruitment and connectivity and how these are altered by climate change. This involves collaborating with engineers to develop bio-physical models to project how ocean warming will weaken reef connectivity and its ecological and evolutionary implications. In one of her recent publications in the peer-reviewed journal Nature Climate Change, she and her research collaborators reported on how global warming negatively impacts coral populations by decreasing population connectivity in Australia’s Great Barrier Reef.  https://www.nature.com/articles/s41558-021-01248-7

In this article Dr. Figueiredo and her collaborators combined experimental calibration of biological models of larval survival and competency for the stony coral Acropora millepora with a high-resolution (up to 200 m) hydrodynamic model of physical transport on the southern Great Barrier Reef to determine how patterns of connectivity are influenced by a 2 °C increase in temperature. She conducted experiments in laboratory conditions to measure long-term larval survival and competency dynamics of A. millepora under current and future temperature conditions. They also simulated water currents through the Great Barrier Reef during three recent successive spawning seasons for which good observational data were available (2008–2010) and estimated the dispersal of A. millepora larvae and the resultant inter-reef connectivity network. The findings from all these studies show that temperature-induced changes in larval survival and settlement competence will on average reduce larval dispersal distance by 6.6% and the number of outgoing connections by 8.1%.  Consequently, the larvae will reach a fewer number of reefs. This study also indicates that rising water temperature will result in 75% of the reefs in the southern Great Barrier Reef experiencing a decrease in both connectivity metrics, with some experiencing a decrease of more than 15%. Higher temperature will increase the proportion of larvae settling on the reef they originated from (local retention) on average by 15.0%. Dr. Figueiredo’s work provides evidence of how climate change-induced rise in water temperature will result in coral reefs becoming more isolated and more dependent on locally produced larvae for replenishment after disturbances thus making them more vulnerable.

 

 

In addition to studying the effect of rising ocean temperatures on the coral population of the Great Barrier Reef, Dr. Figueiredo and her graduate students also studied our local reefs in Florida and published the findings of this study in the peer-reviewed journal Frontiers In Marine Science. https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1038463/full For this study she collected larval survival and competency data and applied a very high-resolution hydrodynamic model (up to 100 m) to understand dispersal patterns of corals belonging to genus Acropora along the Florida’s Coral Reef. These findings from her study when incorporated in metapopulation model will enable researchers to compare different management strategies for restoring Acropora populationsin Florida. The findings reported in this paper published by Dr. Figueiredo indicate there is high potential for system-wide larval exchange between all regions of the Florida’s Coral Reef, indicating that historically, it was a well-connected system. She also shows that spatially selective restoration may be able to stimulate natural recovery. The data of dispersal of Acropora larvae show that larvae are predominantly transported northward along Florida’s Coral Reef, however southward transport also occurs, driven by tides and baroclinic eddies. These findings can be applied to design restoration plans. Researchers demonstrated through model simulations that it will be beneficial to spread restoration effort across more reefs, rather than focusing on a few reefs. The two species, A. cervicornis and A. palmata were found to differ in population patchiness, which shows the necessity of applying different approaches for their management and restoration plans. The model reported in this paper can be applied to restore genotypically diverse Acropora populations on the Florida’s Coral Reef, and these methods could be extended to restore other vulnerable coral populations. The connectivity matrix reported in this study by Dr. Figueiredo and colleagues can be applied to identify sites that will be best suited for restoration efforts which can be used for outplanting colonies or possibly seeding with competent larvae.

The chances of these Acropora species surviving climate change and under stressors can be improved if sexual reproduction is incorporated in their propagation and restoration initiatives since this will result in higher genetic diversity and transgenerational acclimation. Dr. Figueiredo has been facilitating this process through her efforts of coral propagation at the National Coral Reef Institute (NCRI) located in the NSU Halmos College of Natural Sciences and Oceanography.

 

 

As the Executive Director of the NCRI, she and her graduate students have been focusing their efforts to develop strategies for sexually propagating corals that are responsible for building the coral reefs in South Florida. Dr. Figueiredo and her team successfully propagated several coral species, including the great star coral (Montastraea cavernosa) in a land-based nursery. They achieved this by using lighting to mimic the natural cycles of temperature, sun and moonlight necessary for coral spawning in NSU’s coral nursery. The researchers at NCRI managed to produce over 500,000 coral embryos of this species which are being  raised in the nursery until they reach a size suitable for being  planted in the local reef. This species of coral is essential for restoring the reefs in South Florida  but their local population has experienced a severe decline over the past few decades owing to disease, local pollution and abnormally warm Summers. Therefore, these efforts from Dr. Figueiredo’s team at NSU are essential in protecting the corals and facilitating faster restoration of the coral reefs.

This initiative led by Dr. Figueiredo successfully induced gonad maturation and synchronous spawning of the coral Montastraea cavernosa in a laboratory. The research team at NCRI achieved this by mimicking the annual temperature, sun and moon cycles experienced in the northern portion of Florida’s Coral Reef. The findings of Dr. Figueiredo’s work published in the peer-reviewed journal Coral Reefs describe the first ex situ induction of gonad maturation and spawning of Montastraea cavernosa over multiple, consecutive years. https://link.springer.com/article/10.1007/s00338-024-02546-0

The colonies in the laboratory at NCRI displayed spawning patterns that were similar to field observations. For M. cavernosa colonies in the laboratory peak spawning was observed 8-9 nights after the full moons of July and August, 75–125 min after sunset. During the efforts of initiating spawning in the laboratory, repeated observations over a period of four years of the same colonies spawning, combined with histological analysis, revealed a new finding about M. cavernosa. Dr. Figueiredo’s team discovered that this species, which was previously documented as gonochoric species, is in reality a bidirectional hermaphrodite, i.e. while each colony only acts as a female or a male each year, it can change sex between years, , likely driven by energetic constraints.

Montastraea cavernosa has suffered severe population declines in Florida and throughout the Caribbean due to disease, bleaching, and other natural and anthropogenic stressors. The induction of natural sexual reproduction ex situ as developed by Dr. Figueiredo’s research team at NSU and reported in this study will be essential in enhancing genetic diversity of the corals used for reef restoration initiatives. Moreover, it will enable researchers to gain better understanding of the reproductive biology of coral species, its drivers, how they are influenced by various environmental changes and develop strategies of maximizing reproductive output of corals.

 

Coral reefs are an essential part of the marine ecosystem that supports a large variety of organisms and even offer protection to our land-based structures by acting as a physical barrier against storm waves and hurricanes. Unfortunately, this valuable component of the ecosystem has suffered severe decline all around the world including Florida owing to various natural and anthropogenic stresses. The work being done by Dr. Figueiredo at NSU will enable scientists to gain a better understanding of how reefs are being negatively affected by climate change and other natural or human-induced stressors and develop more efficient strategies for propagation, management and restoration of coral reefs so that their destruction can be prevented or mitigated.   Dr. Figueiredo has published her work in 42 peer-reviewed research articles in top scientific journals, such as Nature Climate Change, Global Change Biology, PNAS and Ecology, and serves as a Topic Editor for the journal Coral Reefs. In 2024 Dr. Figueiredo received The Provost’s Research and Scholarship Awards (https://sites.nova.edu/nsuresearch/featured/provosts-research-and-scholarship-award-winners-2/) for her outstanding research accomplishments.