High resolution mapping in the monument has been sparse. The goal for the upcoming expeditions will be to fill in as many of these open white spaces as possible. Credit: Christopher Kelley
The Papahānaumokuākea Marine National Monument in the Northwestern Hawaiian Islands is the largest U.S. marine protected area, comprising some 362,000 square kilometers—an area almost as large as the state of Montana. The monument includes a range of critical marine habitats, yet over half its seafloor has never been mapped in detail due to limited availability of the high-resolution sonar systems required. On two upcoming cruises, Schmidt Ocean Institute will collaborate with researchers from several US, Canadian, and Australian institutions to produce detailed seafloor maps of a significant portion of that remaining area. In keeping with the mission of Schmidt Ocean Institute, these will be made publicly available as quickly as possible as a starting point for future discoveries and critical research in the region.
The project depends on R/V Falkor’s state-of-the-art seafloor mapping sonar systems, which are among the most advanced in the world. The first cruise goes from March 7th to April 11th, and the second runs from May 2nd to June 6th. Christopher Kelley, a marine biologist at the University of Hawaii (UH) at Manoa will lead both cruises, which will also include scientists from NOAA’s Pacific Islands Fisheries Science Center, the Papahānaumokuākea Marine National Monument, the University of Sydney, and the University of British Columbia, as well as other UH researchers. At least eight students will also be aboard for the second cruise as part of a UH graduate-level course on sonar mapping.
Why We’re Going
The monument is a unique and spectacular resource with some of the healthiest and most extensive shallow coral reefs on the planet. However, some 98 percent of the monument’s area is deeper than 100 meters. Within that realm there are features as remarkable as the shallow reef–though lesser known–including seamounts, ridges, and submerged banks. These are critical habitats for corals, fish and other animals, but researchers simply can’t identify the most important structures for research and protection until they are mapped.
For much of the monument, the best available maps are based on satellite data with resolutions in the 1-kilometer range—much too coarse for identifying any but the largest features of interest. In stark contrast, Falkor’s sonar systems will produce maps 20 to 200 times better, in the 5- to 50-meter resolution range depending on the depth.
One key goal will be to identify likely sites of deep-sea coral and sponge beds Only recently did scientists discover the existence of these beds within the monument in more than 1,000 meters of water. Exploration of the few known sites has already led to the discovery of more than fifty new sponge and coral species. Such results strongly suggest that there are many more new species yet to be discovered in the monument once new beds are mapped.
More common species of deep corals are also of great concern, especially black and gold corals, which are harvested from other parts of Hawaii and used to make jewelry and other items. Gold corals are of added interest because they grow so slowly—sometimes for thousands of years—that they hold important records of past ocean conditions.
Scientists are also working to learn more about coral reefs in the 50- to 150-meter “mesophotic” range. This is deeper than normal scuba depth, but shallow enough that many of the species found there are the same as those on the shallowest reefs. Ongoing research is exploring whether such mesophotic reefs might be havens less susceptible to exploitation, climate change, and other threats and therefore an important source of recruitment for shallower counterparts. Mapping where all the different types of deeper reefs might be found is an essential first step in enabling future research.
There is also significant interest in the region’s geology. For instance, ancient shallow coral reefs that drowned as the earliest Hawaiian Islands formed and receded now hold a detailed record of that process that has spanned millions of years. The big picture mapping offers can help researchers better understand these changes over time.
Many once active volcanoes in the monument are now seamounts found in the 800 to 2,500 m depth range. These are also intriguing because, at these depths, manganese and other important minerals precipitate out of seawater, forming crusts. Manganese is used in various industrial processes, including production of stainless steel. Other minerals from the crusts are similarly valuable. Multiple countries are now working to develop the technology to mine such crust in other parts of the world. Due to the potentially destructive nature of such deepwater mining activities, deep seamounts need to be mapped and surveyed to better understand the communities at risk.
What Will Be Accomplished
The two planned cruises are expected to map up to three quarters of the currently unmapped seafloor area, and most of the significant features in the 50-meter to 4,000-meter range. Once that is accomplished, researchers will be able to analyze the acquired maps to identify areas that are likely to include deepwater corals beds, manganese crust zones, and other key features.
While no commercial extraction activities are allowed within the monument, it is important to understand the extent of natural resources present in order to assess the proportion of what is being protected. The bathymetric maps that will be produced, pending final permit approvals, will aid researchers in this evaluation.
To date, insufficient mapping data has restricted the pace at which scientific discoveries have been made in the region as researchers’ knowledge of areas most critical for exploration and research has been so limited. The planned extensive Falkor mapping work should therefore lead to greatly expanded understanding of and further research in the Papahānaumokuākea Marine National Monument.
The research team will be publishing processed mapping data via multiple routes to ensure that the information is publicly available. Maps will be added to Google Earth, and archived at NOAA’s National Geophysical Data Center, UH, MBARI, and through the national monument. The rapid release of the data will ensure that benefits to discovery, research and protection can be quickly realized.
For links to the blog and map for the project's first leg, please visit the current expedition page.
--by Mark Schrope
Schmidt Ocean Institute provides ship time aboard Falkor and the equipment required at no cost to our collaborators. Support for research and data processing related to this expedition was provided by the National Science Foundation, NOAA's Coral Reef Ecosystem Division, NOAA's National Marine Sanctuaries program, NOAA's Pacific Islands Regonal Office, the University of British Columbia, the University of Hawaii's Hawaii Undersea Research Laboratory, and the University of Sydney.