1
|
Olinger LK, McClenaghan B, Hajibabaei M, Fahner N, Berghuis L, Rajabi H, Erwin P, Lane CS, Pawlik JR. Looking for the sponge loop: analyses of detritus on a Caribbean forereef using stable isotope and eDNA metabarcoding techniques. PeerJ 2024; 12:e16970. [PMID: 38410802 PMCID: PMC10896084 DOI: 10.7717/peerj.16970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/29/2024] [Indexed: 02/28/2024] Open
Abstract
Coral reefs are biodiverse ecosystems that rely on trophodynamic transfers from primary producers to consumers through the detrital pathway. The sponge loop hypothesis proposes that sponges consume dissolved organic carbon (DOC) and produce large quantities of detritus on coral reefs, with this turn-over approaching the daily gross primary production of the reef ecosystem. In this study, we collected samples of detritus in the epilithic algal matrix (EAM) and samples from potential sources of detritus over two seasons from the forereef at Carrie Bow Cay, Belize. We chose this location to maximize the likelihood of finding support for the sponge loop hypothesis because Caribbean reefs have higher sponge abundances than other tropical reefs worldwide and the Mesoamerican barrier reef is an archetypal coral reef ecosystem. We used stable isotope analyses and eDNA metabarcoding to determine the composition of the detritus. We determined that the EAM detritus was derived from a variety of benthic and pelagic sources, with primary producers (micro- and macroalgae) as major contributors and metazoans (Arthropoda, Porifera, Cnidaria, Mollusca) as minor contributors. None of the sponge species that reportedly produce detritus were present in EAM detritus. The cnidarian signature in EAM detritus was dominated by octocorals, with a scarcity of hard corals. The composition of detritus also varied seasonally. The negligible contribution of sponges to reef detritus contrasts with the detrital pathway originally proposed in the sponge loop hypothesis. The findings indicate a mix of pelagic and benthic sources in the calmer summer and primarily benthic sources in the more turbulent spring.
Collapse
Affiliation(s)
- Lauren K. Olinger
- Center for Marine and Environmental Studies, University of the Virgin Islands, St Thomas, Virgin Islands, U.S. Virgin Islands, United States of America
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States of America
| | | | - Mehrdad Hajibabaei
- eDNAtec Inc., Newfoundland and Labrador, St. John’s, Canada
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Nicole Fahner
- eDNAtec Inc., Newfoundland and Labrador, St. John’s, Canada
| | | | - Hoda Rajabi
- eDNAtec Inc., Newfoundland and Labrador, St. John’s, Canada
| | - Patrick Erwin
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States of America
| | - Chad S. Lane
- Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC, United States of America
| | - Joseph R. Pawlik
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States of America
| |
Collapse
|
2
|
Lesser MP, Sabrina Pankey M, Slattery M, Macartney KJ, Gochfeld DJ. Microbiome diversity and metabolic capacity determines the trophic ecology of the holobiont in Caribbean sponges. ISME COMMUNICATIONS 2022; 2:112. [PMID: 37938762 PMCID: PMC9723761 DOI: 10.1038/s43705-022-00196-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/24/2022] [Accepted: 10/31/2022] [Indexed: 06/18/2023]
Abstract
Sponges are increasingly recognized as an ecologically important taxon on coral reefs, representing significant biomass and biodiversity where sponges have replaced scleractinian corals. Most sponge species can be divided into two symbiotic states based on symbiont community structure and abundance (i.e., the microbiome), and are characterized as high microbial abundance (HMA) or low microbial abundance (LMA) sponges. Across the Caribbean, sponge species of the HMA or LMA symbiotic states differ in metabolic capacity, as well as their trophic ecology. A metagenetic analysis of symbiont 16 S rRNA and metagenomes showed that HMA sponge microbiomes are more functionally diverse than LMA microbiomes, offer greater metabolic functional capacity and redundancy, and encode for the biosynthesis of secondary metabolites. Stable isotope analyses showed that HMA and LMA sponges primarily consume dissolved organic matter (DOM) derived from external autotrophic sources, or live particulate organic matter (POM) in the form of bacterioplankton, respectively, resulting in a low degree of resource competition between these symbiont states. As many coral reefs have undergone phase shifts from coral- to macroalgal-dominated reefs, the role of DOM, and the potential for future declines in POM due to decreased picoplankton productivity, may result in an increased abundance of chemically defended HMA sponges on tropical coral reefs.
Collapse
Affiliation(s)
- Michael P Lesser
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA.
| | - M Sabrina Pankey
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Marc Slattery
- Department of BioMolecular Sciences, Division of Pharmacognosy, University of Mississippi, Oxford, MS, 38677, USA
| | - Keir J Macartney
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
- University of Texas Rio Grande Valley, School of Earth, Environmental and Marine Sciences, Port Isabel, TX, 78958, USA
| | - Deborah J Gochfeld
- National Center for Natural Products Research, University of Mississippi, Oxford, MS, 38677, USA
| |
Collapse
|
3
|
Freeman CJ, Easson CG, Matterson KO, Thacker RW, Baker DM, Paul VJ. Microbial symbionts and ecological divergence of Caribbean sponges: A new perspective on an ancient association. THE ISME JOURNAL 2020; 14:1571-1583. [PMID: 32203120 PMCID: PMC7242429 DOI: 10.1038/s41396-020-0625-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 02/17/2020] [Accepted: 02/25/2020] [Indexed: 12/26/2022]
Abstract
Marine sponges host diverse communities of microbial symbionts that expand the metabolic capabilities of their host, but the abundance and structure of these communities is highly variable across sponge species. Specificity in these interactions may fuel host niche partitioning on crowded coral reefs by allowing individual sponge species to exploit unique sources of carbon and nitrogen, but this hypothesis is yet to be tested. Given the presence of high sponge biomass and the coexistence of diverse sponge species, the Caribbean Sea provides a unique system in which to investigate this hypothesis. To test for ecological divergence among sympatric Caribbean sponges and investigate whether these trends are mediated by microbial symbionts, we measured stable isotope (δ13C and δ15N) ratios and characterized the microbial community structure of sponge species at sites within four regions spanning a 1700 km latitudinal gradient. There was a low (median of 8.2 %) overlap in the isotopic niches of sympatric species; in addition, host identity accounted for over 75% of the dissimilarity in both δ13C and δ15N values and microbiome community structure among individual samples within a site. There was also a strong phylogenetic signal in both δ15N values and microbial community diversity across host phylogeny, as well as a correlation between microbial community structure and variation in δ13C and δ15N values across samples. Together, this evidence supports a hypothesis of strong evolutionary selection for ecological divergence across sponge lineages and suggests that this divergence is at least partially mediated by associations with microbial symbionts.
Collapse
Affiliation(s)
- Christopher J Freeman
- Smithsonian Marine Station, Fort Pierce, FL, USA.
- Department of Biology, College of Charleston, Charleston, SC, USA.
| | - Cole G Easson
- Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA
- Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Kenan O Matterson
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA
- Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
| | - Robert W Thacker
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, USA
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Republic of Panama
| | - David M Baker
- The Swire Institute of Marine Science, School of Biological Sciences, University of Hong Kong, Hong Kong, PR China
| | | |
Collapse
|