Title:

Trophic Ecology of Caribbean Emergent Sponges in the Mesophotic Zone

Sponges are a crucial component of Caribbean coral reef ecosystem structure and function, they provide food and habitat for reef species and are important contributors to benthic-pelagic coupling on coral reefs. In the Caribbean, sponges show a predictable increase in percent cover or abundance as depth increases from shallow (<30 m) to mesophotic (30-150 m) depths. Given that sponge cover and abundance are predicted to increase in the Caribbean as coral cover declines, understanding the ecological factors that control their distribution is critical. Bottom up processes affecting sponge trophodynamics is a significant factor in their ecology, Here, we use compound-specific isotopic analysis of amino acids (CSIA-AA) for 13C and 15N to provide increased resolution on the trophic ecology of sponges along a shallow to mesophotic depth gradient. By measuring CSIA-AA on three common sponges from the Caribbean, Xestospongia muta, Agelas tubulata and Plakortis angulospiculatus, we show that as depth increases there is enrichment in the 13CAA and 15NAA ratios which indicate that sponges rely more heavily on live particulate organic matter (POM) consumption in the mesophotic zone. The 13CAA and 15NAA values of these sponges also reflect species-specific patterns of host utilization for both POM and dissolved organic matter (DOM), and the subsequent resynthesis, and translocation, of DOM by their microbiomes. The use of CSIA-AA can increase our understanding of sponge trophic strategy and underscores the complexities of studying symbioses in an ecological context.

Name

Comment*

Comments are viewable only by submitter

Captcha*