Temporal and spatial nutrient variations in nearshore waters of Bonaire 2021-2023

Abstract

Coral reefs are vital ecosystems that face significant challenges such as eutrophication, an increase in nutrient levels in aquatic systems, contributing to the decline of coral reefs. This poses a global threat (Ban, Graham, & Connolly, 2014; Adam et al., 2021), often resulting in shifts from coral-dominated to algae-dominated ecosystems (López-Londoño et al., 2021). As part of the project "Restoration of Resilience of Nature and Society in the Caribbean Netherlands," extensive research and data collection are carried out on various Caribbean islands, including Bonaire, St. Eustatius, and Saba. To gain deeper insights into land-sea interactions, water quality monitoring, including nutrient data collection, is conducted across these islands.This study investigates the variations in nutrient concentrations across the West Coast of Bonaire and Klein Bonaire. With the focus on key nutrients PO43-, NH4+, NO2−, NO3−, and the sum parameter DIN, in the marine environment, insight into the water quality state is gained. The data utilized for this research spans from November 2021 to January 2023, with the focus on the year 2022. The nutrient measurements were systematically conducted at 11 locations across the gradient of the West Coast of Bonaire and around Klein Bonaire, covering both 5-meter and 10-meter depths.

For this research, the significant influence of the temporal and spatial factors; Month, Location, and Depth were examined for each nutrient, in combination with the established thresholds.The results revealed a consistent, increasing, or decreasing trend for the different nutrients over time, all significantly influenced by both temporal and spatial factors.Although high concentrations were found for all locations and nutrients, only two locations in the North of Bonaire were found to pose a risk to the health of the coral reefs and water quality.

This study provides crucial insights into nutrient dynamics, temporal variations, and spatial changes in Bonaire's marine environment. The identified patterns and risk assessments offer valuable guidance for targeted conservation efforts aiding in the preservation of Bonaire's coral reef ecosystems amid ongoing environmental challenges.

More information; https://research.wur.nl/en/publications/temporal-and-spatial-nutrient-va...