Discovering Deep Sea Corals of the Phoenix Islands

Courtesy: NOAA OER

The Phoenix Islands Protected Area (PIPA) is the largest and deepest UNESCO World Heritage Site on Earth. Approximately the size of California, PIPA was the first Marine Protected Area (MPA) of its kind. Created in 2008, it is about halfway between Hawaii and Fiji within the territorial waters of the Republic of Kiribati. Above the water, eight low-lying islands exist in the MPA, but the real beauty is below the surface. Huge tracts of deep ocean are pierced by over 25 underwater volcanoes. Seamounts along with atolls and submerged reefs create one of the last isolated coral archipelago ecosystems, virtually untouched by mankind. The biological density is phenomenal with more than 500 fish species, an abundance of sharks and turtles, and at least 120 types of coral – but that is just in the shallows. PIPA is also the first protected area in Pacific where depths exceed 16,400 feet (5,000 meters), and entirely unknown species are sure to live at those depths.

In October, Dr. Erik Cordes (Temple University) and his team will explore never seen before seamounts and atolls within PIPA. Along with Remotely Operated Vehicle (ROV) SuBastian, the science team will conduct some of the first ROV dives in these locations, some down to 4,000 meters. The dive missions will provide a first glimpse of many of these habitats that will help determine what PIPA is protecting at these depths, and inform the future management of this area. In previous seamount expeditions high proportions of new species have been found, and therefore the team is expecting to observe new types of deep-sea corals and their associated species. Scientists also plan to explore how countercurrents running through the study area could create boundaries, providing a better understanding of coral connectivity across the Pacific.

Studying the Deep

The goal of this study is to greatly increase knowledge of deep-sea coral life and functions in one of the largest marine protected areas on the planet. At this time, the studies and measurements completed in PIPA have primarily focused on shallow coral habitats. Research on reef systems to the depth of approximately 450 feet show that there is a plentiful and flourishing network of coral, algae and other life forms. But in depths beyond, there is no information about deep corals or other communities living in these benthic zones.

To get to these depths, the science team will use video from ROV SuBastian to make detailed observations on the community and organisms along with physical samples to provide the proper identifications of the species observed. Some of the observations will be conducted with specialized camera systems to look for bioluminescence and biofluoresence. Water samples and specialized sensors will compliment these studies to provide an understanding of their habitat and associations. This type of research will allow for future comparisons over time as part of an important coral monitoring process.

Findings will make progress towards fundamental scientific questions, such as identifying what species of corals live there, and the diversity of these ecosystems. The data gathered will be used to fill in the puzzle of much larger, global oceanic systems, such as the biogeographic relationship among the Southwest Pacific, Central Pacific, and Hawaiian Islands deep coral communities. The products of this expedition have the potential to advance many fields of research, including understanding the carbonate system and ocean acidification in the deep Central Pacific, symbiotic relationships between corals and associates, and even inter-specific communication.

Acidifying Waters

The main goal in creating this MPA was granting protection from disruptive human actions. While PIPA is currently protected from fishing activity, the effects of ocean acidification cannot be stopped by lines on a map. Researchers fear that deep-water corals could be affected by this process, especially certain types of hard corals. Rising temperature and declining ocean concentrations in ocean waters could also influence deep-water corals and other important species. These conditions could be very serious in the Pacific, where an amassing of CO2 in older, deep waters coexist with some of the lowest pH values that have been recorded. The conditions in the study locations may provide insight into deep-water corals surviving and growing in low CO2 saturation states.

PIPA Process and Outcomes

The size of this protected area, including significant deep-sea regions and seamount habitats, offers a rare chance to establish the effects of “no-take” zones on the deep-sea environment. A baseline habitat evaluation will be critical to understanding the influence of the MPA over time. There is currently no existing baseline for deep-sea communities in the massive central Pacific. Without diagnostic information about the current state of coral and other communities living at deeper depths within the PIPA, there are no records to gauge and describe the results of these protective actions or assess future impacts. This expedition will give insight to an entirely unexplored region of the deep sea and demonstrate the importance and use of baseline data for evaluation of MPAs.

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Data & Publications

The resulting shipboard dataset is being archived at Rolling Deck to Repository and is now available.

Processed acoustic backscatter and swath bathymetry from Falkor and Images, Event logs, and Navigation from ROV SuBastian have been archived at MGDS.

Water temperature, salinity, total alkalinity, carbonate chemistry, and other parameters from CTD casts and water samples collected during the cruise are archived in NOAA’s NCEI, NCEI accession #0182941).

ADCP data is curated and archived by University of Hawaii.

Genome sequencing from microbial samples with the boundaries of the Phoenix Island Protected Area are archived in NCBI.

The sequencing data from the Moritella microbe sequences found on this expedition are archived in NCBI.

  • Vogt, D., Becker, K., Phillips, B., Graule, M., Rotjan, R., Shank, T., Cordes, E., Wood, R. and Gruber, D. (2018). Shipboard design and fabrication of custom 3D-printed robotic manipulators for the investigation of delicate organisms. PLoS ONE 13 (8): e0200386, doi: 10.1371/journal.pone.0200386. [This article has been published as OPEN ACCESS].
  • Auscavitch, S., Deere, M., Keller, A., Rotjan, R., Shank, T., and E. Cordes. (2020).  Oceanographic Drivers of Deep-sea Coral Species Distribution and Community Assembly on Seamounts, Islands, Atolls, and Reefs within the Phoenix Islands Protected Area. Fron. Mar. Sci., 7, doi: 10.3389/fmars.2020.00042. [This article has been published OPEN ACCESS].
  • Amon, D., Kennedy, B., Cantwell, K., Suhre, K., Glickson, D., Shank, T. and R. Rotjan. (2020). Deep-sea Debris in the Central and Western Pacific Ocean. Front. Mar. Sci. 7:369, doi: 10.3389/fmars.2020.00369.
  • Cordes, E. (2019). What are the Limits of Deep-sea Coral Distribution? Invited Keynote Lecture, International Symosium on Deep-sea Corals, Cartagena, Colombia.
  • Gauthier, A., Chandler, C., Poli, V., Gardner, F., Tekiau, A., Smith, R., et al. (2021). Deep-sea microbes as tools to refine the rules of innate immune pattern recognition. Science Immunology, 6(57), doi: 10.1126/sciimmunol.abe0531.

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