Algal cover and the effects of various nutrient levels on Bonaire's coral reefs
A reoccurring problem facing a majority of the coral reefs in the Caribbean for the past few decades has been the fear of a changing community structure from primarily reef-building corals to algal dominance. A shift in such ecosystems could inhibit coral growth and recruitment, eventually killing corals and lowering the diversity of fish in the area. Recent developments in agriculture and technology have advanced the dispersal of various inorganic nutrients into water systems, where excess nitrogen or phosphorous levels may lead to an increase in algal photosynthesis and thus growth. For my study I looked at relationships between algal growth and nutrient levels in seawater, specifically ammonia and nitrates + nitrites. Using photography and underwater transects I looked for differences in the amount of algae at sites with high or low nutrient levels as measured in March 2006 by the Bonaire Marine Park (BMP). The site with the highest nitrate + nitrite levels had a mean algal cover of 30.6% (std. dev. 30.4), which was not statistically different from the site with lowest concentrations (mean algal cover = 22.9%, std. dev. = 23.1). Algal cover was highest at 18 Palms (mean = 38.6% std. dev. = 39.5), where the lowest ammonia concentration was found. This research showed that nutrient levels did not influence the percent algal cover at my sites. Possible reasons for these findings are discussed.