Quantifying surface and bottom seawater chemistry variability on shallow coral reefs in Puerto Rico

The ongoing global decline of coral reefs under climate change and other human impacts poses an alarming threat in the ability of coral reefs to provide ecosystem services, directly affecting the livelihood of coastal communities. Ocean acidification is a direct threat to the maintenance of coral reef calcium carbonate structures and has even been projected to shift many coral reefs towards net loss of calcium carbonate annually before the end of the century. The effects of global ocean acidification vary locally, making it essential to understand how local-based factors such as benthic community composition and hydrodynamics interact with global-scale climate change to improve predictions for future changes to coral reef systems. In this study, we quantified spatial, temporal, and vertical differences in seawater chemistry across 42 shallow coral reef sites (5-30 meters) around Puerto Rico throughout 2024. Surface and bottom samples were collected for temperature, salinity, dissolved oxygen (DO), and biological oxygen demand (BOD), as well as the carbonate chemistry parameters total alkalinity (TA) and dissolved inorganic carbon (DIC) that were used to calculate seawater saturation state with respect to aragonite (Ωarg) and pH (total scale). We propose that vertical differences in the physicochemistry of seawater in coral reefs are positively correlated with depth, showing greater variability in areas with a higher percentage of coral coverage. To this end, our ongoing project aims to provide a comprehensive assessment of the physicochemical conditions related to the health and resilience of coral reefs around the island of Puerto Rico.

Presentation Preference: Poster

Primary Presenter: Juanita Carballeira Martínez, University of Puerto Rico- Mayagüez Campus (juanita.carballeira@upr.edu)

Authors:

Juanita Carballeira Martínez, University of Puerto Rico-Mayagüez Campus  (juanita.carballeira@upr.edu)

Martha Ricaurte-Chica, University of Puerto Rico-Mayagüez Campus  (martha.ricaurte@upr.edu)

Catherine Hernández Rodriguez, University of Puerto Rico-Mayagüez Campus  (catherine.hernandez2@upr.edu)

Manuel Nieves-Ortíz1, University of Puerto Rico-Mayagüez Campus  (manuel.nieves1@upr.edu)

Juan Cruz-Motta, University of Puerto Rico-Mayagüez Campus  (juan.cruz13@upr.edu)

Travis Courtney, University of Puerto Rico-Mayagüez Campus  (travis.courtney@upr.edu)