Description
The goal of this project is to determine the impact of OAE deployment on key ecosystem species of high cultural and commercial value in the Pacific. Through direct stakeholder engagement, culturally valuable species that represent different functional roles will be selected: primary producers (e.g., kōauau / bladder kelp, rimurapa / bull kelp), suspension feeders (e.g., kūtai / Greenlip mussels, tuaki / cockles), deposit feeder (e.g., rori / Sea cucumber), and grazers (e.g., kina / sea urchin, pāua / Blackfoot abalone). It is hypothesised that under realistic deployment conditions, OAE will have limited effects on early life stages of the selected marine species. This hypothesis will be tested by a series of experiments on larvae and juveniles, designed to mimic OAE field trials; (i) exposure to a pulse of elevated alkalinity for 12h (tidal transport of an alkalinity plume), and (ii) exposure to constant elevated levels of alkalinity (locations near the alkalinity release). Alkalinity will be added in dissolved form, and via powdered Greenhills dunite, a regionally important mineral feedstock primarily composed of olivine with a meaningful quantity of fast-dissolving brucite (~7%), that presents a uniquely promising feedstock for OAE. The biological impact will be assessed by determining survival, growth, shell thickness, and photosynthetic performance. These short-term experiments will be complemented by determining the ecosystem structure in a natural analogue for long-term olivine additions near the Greenhills quarry. Additionally, species harvested for consumption for potential Ni accumulation that could impact the food value of culturally important species will be sampled. This research will be enabled by the University of Otago’s long-standing expertise in ocean acidification research with support from private sector partners. This project will provide novel data on the impact of OAE on marine species from the Southern Hemisphere, a chronically understudied region. At the same time, the research will be done through engagement with local communities in Aotearoa New Zealand and through scientific exchange with Pacific researchers. Hence, this project will drive the next stage of OAE research and implementation in an important, yet understudied region.