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PRESS RELEASE: The Ocean Census Embarks on First Deep-sea Expedition in Japan, Partnering with JAMSTEC 
3rd June 2025 | maya
Founded By

Exploring Deep-Sea Habitats of the
Marshall Islands with Participant Scientist
Luisa F. Dueñas

Deep-Sea Habitats of the Marshall Islands

24/07/25 | maya

Luisa F. Dueñas, a member of the Ocean Census Science Network and Associate Professor in the Biology Department at the Universidad Nacional de Colombia, will be on the upcoming Marshall Islands deep-sea expedition aboard Ocean Exploration Trust’s E/V Nautilus.

Luisa’s research focuses on evolutionary processes in the deep sea, particularly on understanding the drivers of diversification and the mechanisms that maintain diversity and population structure over time. Her broader interests include marine ecology, molecular biology, systematics, conservation, phylogeography, and phylogenomics.

This 21-day telepresence-enabled expedition will explore the largely unmapped and unsurveyed deep-sea regions of the Republic of the Marshall Islands—an atoll-based nation comprising over 1,200 islands and surrounded by 2.13 million square kilometers of ocean.

This effort is funded by NOAA Ocean Exploration through the Ocean Exploration Cooperative Institute.

Feature Image Credit: National Geographic Pristine Seas

Deep Sea Evolution & Diversification

Why is preserving population structure in the deep sea important, and what could happen if that balance is disrupted?

Preserving population structure in the deep sea is essential because it maintains genetic diversity, which allows species to adapt to environmental changes and guarantees ecosystem resilience. Most deep-sea species have slow growth rates and limited dispersal, making them very vulnerable to disturbances, such as habitat destruction, resource extraction, or climate change. If population structure is disrupted, it can lead to reduced connectivity and local extinctions, threatening the stability and diversity of deep-sea ecosystems.

Have you observed any unique examples of species adaptation or speciation during your work on deep-sea biodiversity?

My main line of research is related to deep-sea corals, although I’ve switched organisms depending on the opportunities for biological sampling and the availability of samples in biological collections.

Regarding octocorals, I find it fascinating that the polyps of the bottle-brush octocoral Tokoprymno maia change their morphology when they are incubating larvae, so it’s obvious when a colony is “pregnant”. As a brooding colony, the larvae, when fully developed, leave the adult colony and settle near it. This means that the distribution of this coral’s populations is restricted, with little genetic flow with other populations. These conditions can lead to speciation events. Having worked on the phylogeography of Tokoprymno maia and complementing the study with morphological traits, we have discovered new species that are in the process of being described.

Photographs of the bottlebrush deep-sea octocoral colonies from the South Pacific and Southern Ocean. Each letter represents an example of the colonies from each population: a- New Zealand, b- Tasmania, c- Macquarie Ridge, d- Antarctica. The bar next to each colony corresponds to a 1 cm scale. Image Credits: Luisa F. Dueñas et al.

Biodiversity & Population Dynamics

What inspired your focus on evolutionary processes in the deep sea?

The extraordinary biodiversity of the deep sea has always fascinated me. Despite being one of the most remote and extreme environments on Earth, it hosts an incredible variety of strange life forms with unique adaptations. Understanding the evolutionary processes that drive such diversity in these extreme habitats, and its relationship to shallow water habitats, is both a scientific challenge and a source of endless curiosity for me.
Your work investigates the drivers of diversification—what are some of the most surprising factors you’ve discovered that shape life in the deep ocean?
Marine barriers and natural history traits of each species play pivotal roles as drivers of diversification. Both hard (land barriers) or soft (currents, sea floor features) barriers have different effects on the connectivity of marine organisms. Additionally, history traits like the reproductive mode, can determine the extent of distribution of a species. The combination of both factors shapes the diversity and biogeography of marine organisms.
What tools or techniques do you use to study evolutionary processes in these extreme and often inaccessible habitats?
To study evolutionary processes in the deep sea, we rely on a combination of advanced tools. ROVs and submersibles are commonly used to access these extreme environments and sample the organisms. After sampling, we also use molecular techniques like DNA sequencing and phylogenetic analyses to understand evolutionary relationships and species boundaries. Together with the geological history of the site and morphological studies of the organisms, these approaches help us uncover patterns of diversification, adaptation, and biogeography in deep-sea organisms.

Applications, Impacts & Conservation

How might the findings from this expedition to the Marshall Islands contribute to our global understanding of deep-sea diversity?

The Marshall Islands have a submerged area of more than 98% of its territory and lie in a relatively unexplored part of the Pacific. Most of the deep areas in the Marshall Islands have never been explored, so the possibility of finding new species is huge. Findings from this expedition will help fill critical gaps in the knowledge of deep-sea biodiversity and will provide valuable information for decision makers that will translate in effective conservation strategies. By documenting new species and biogeographic patterns, this expedition will help improve our understanding of how deep-sea communities evolve and are distributed globally.

Image Credit: Luisa F. Dueñas

Want to learn More?

Using advanced mapping, remotely operated vehicle (ROV), and telepresence systems, the expedition aims to collect vital baseline information to support the Marshall Islands’ Marine Spatial Planning process. It also contributes to broader U.S.–Marshall Islands collaborations focused on sustainable fisheries, marine conservation, and regional security.

We’re excited for the discoveries this expedition will bring and proud to support scientific expertise from the global south in the quest to illuminate Earth’s final frontier: the deep ocean.

Find out more

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