Cissell, E.C.

Shotgun metagenomic sequencing reveals the full taxonomic, trophic, and functional diversity of a coral reef benthic cyanobacterial mat from Bonaire, Caribbean Netherlands

Anthropogenic forcing is spurring cyanobacterial proliferation in aquatic ecosystems worldwide. While planktonic

cyanobacterial blooms have received substantial research attention, benthic blooms of mat-forming

cyanobacteria have received considerably less attention, especially benthic mat blooms on coral reefs.

Resultingly, numerous aspects of coral reef benthic cyanobacterial bloom ecology remain unknown, including

underlying biodiversity in the mat communities. Most previous characterizations of coral reef cyanobacterial

mat composition have only considered the cyanobacterial component. Without an unbiased characterization of

full community diversity, we cannot predict whole-community response to anthropogenic inputs or effectively

determine appropriate mitigation strategies. Here, we advocate for the implementation of shotgun sequencing

techniques to study coral reef cyanobacterial mats worldwide, utilizing a case study of a coral reef benthic

cyanobacterial mat sampled from the island of Bonaire, Caribbean Netherlands. Read-based taxonomic profiling

revealed that Cyanobacteria was present at only 47.57% relative abundance in a coral reef cyanobacterial mat,

with non-cyanobacterial members of the sampled mat community, including diatoms (0.78%), fungi (0.25%), Archaea

(0.34%), viruses (0.08%), and other bacteria (45.78%), co-dominating the community.We found numerous

gene families for regulatory systems and for functional pathways (both aerobic and anaerobic). These gene families

were involved in community coordination; photosynthesis; nutrient scavenging; and the cycling of sulfur,

nitrogen, phosphorous, and iron. We also report bacteriophage (including prophage) sequences associated

with this subtidal coral reef cyanobacterial mat, which could contribute to intra-mat nutrient cycling and

bloom dynamics. Overall, our results suggest that Cyanobacteria-focused analysis of coral reef cyanobacterial

mats underestimates mat diversity and fails to capture community members possessing broad metabolic

Date
2020
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire

Consumption of benthic cyanobacterial mats on a Caribbean coral reef

Herbivory is an important process in the general structuring of coral reef benthic communities. However, evidence of its ability to control coral reef benthic cyanobacterial mats, which have recently proliferated on reefs worldwide, remains ambivalent. Here, we report that the French Angelfish (Pomacanthus paru), Striped Parrotfish (Scarus iseri), Rock Beauty (Holacanthus tricolor), Ocean Surgeonfish (Acanthurus bahianus), Blue Parrotfish (Scarus coeruleus), and Atlantic Blue Tang (Acanthurus coeruleus) consume benthic cyanobacterial mats on coral reefs in Bonaire, Netherlands. We documented the foraging patterns of P. paru and S. iseri, and found that benthic cyanobacterial mats comprised 36.7% ± 5.8% and 15.0% ± 1.53% (mean ± standard error) of the total bites taken by P. paru and S. iseri respectively. This magnitude of consumption suggests that grazing by reef fishes may represent a potentially important, but previously undocumented, top-down control on benthic cyanobacterial mats on Caribbean reefs.

Date
2019
Data type
Scientific article
Theme
Research and monitoring
Document
Geographic location
Bonaire
Author