Large scale, medium scale, and small scale patterns of benthic cyanobacteria & the possibility of groundwater association on a coral reef

Cyanobacteria presence in the marine ecosystem is biologically significant due to its versatile nature. This phylum is responsible for destructive red tides and black band disease as well as building up the limestone in reefs. Nodularia cf. spumigena has been an indicator of groundwater off of the coast of Bahamas and may provide insight into where Bonaire‟s groundwater enters the marine ecosystem. Bonaire is a tropical oceanic island with a fringing coral reef located in the south Caribbean Sea and, although the population of the island is small (~16,000), it has developed a population center of residential and commercial use in Kralendijk, a coastal city. To compare how the benthic cyanobacteria mats off of Bonaire relate to this growing population, a three-fold study was conducted. A large scale pattern of cyanobacteria was studied at nine sites on the leeward side, a medium scale pattern was studied at four sites off the coast of Kralendijk in between two known nutrient outputs, and tests of mean levels of Escherichia coli and total coliforms inside and outside the cyanobacteria mats were completed. Video transects were used to determine percent cover of the large and medium scale patterns and IDEXX technology was used to test pore water inside and outside the mats for two types of bacteria associated with human waste. No definite patterns of groundwater or population center were directly linked to benthic cyanobacteria cover. The large scale did show a higher average cyanobacteria cover throughout the three-year study, indicating that there may be a relationship between the hydrology of the island and nutrient circulation. The medium scale showed an inverse relationship between turf algae and cyanobacteria.

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 9-15 from CIEE Bonaire.