New Comprehensive Ecosystem Model for Hawai‘i
New Comprehensive Ecosystem Model for Hawai‘iPosted May 21, 2020
The Hawaiian Island Chain is an oasis in the middle of the Pacific Ocean, providing an area of increased nutrients, coral reefs, and other benefits to ocean life. The PacIOOS ocean modeling team, led by co-investigator Professor Brian Powell, has recently developed a comprehensive ecosystem model that captures the physical and chemical dynamics of the ocean, as well as the base of the food web to better understand the ocean waters around Hawaiʻi and the life contained within.
Building on the existing PacIOOS Regional Ocean Modeling System (ROMS), which focuses on the physical ocean circulation (including water temperature, currents, salinity, and sea surface height), Brian and his team combined ROMS with the Carbon, Ocean Biogeochemistry and Lower Trophics (COBALT) model developed by NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) for use around Hawaiʻi.
Pairing these two models allows for a seamless integration of physical and biogeochemical parameters. The goal is to incorporate the ecosystem output into PacIOOS’s daily ocean modeling forecasts; and to seek funding to produce long-term estimates that examine the impacts of continued warming on fisheries and ocean acidification around Hawaiʻi.
Using the 10-year ROMS reanalysis along with the newly added COBALT model, PacIOOS research scientist, Dr. Tobias Friedrich, has produced estimates of the water’s physical properties, ocean chemistry, as well as marine biology (three classes of phytoplankton, three classes of zooplankton, and microbes) for the period from 2010 through 2017. First results have shown that the availability of light is the most significant driver in the seasonal cycle of organisms around Hawaiʻi.
The figure above shows the model domain and a snapshot of simulated near-surface chlorophyll (vertically averaged over 0–50 m, µg/kg) present in the water from photosynthesis of phytoplankton as well as currents (for clarity, only every 5th current vector is shown in the figure). A strong oceanic cyclone in the lee of the Hawaiian Islands brings nutrients from deeper waters into the surface where it can be utilized by photosynthetic organisms. Results will be published in a peer-reviewed journal and made available through PacIOOS.