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Single-cell visualization indicates direct role of sponge host in uptake of dissolved organic matter

Authors :
Sophie Dove
Ove Hoegh-Guldberg
Kathryn Green
Paul Guagliardo
Mathieu Pernice
Michelle Achlatis
Jasper M. de Goeij
Matt R. Kilburn
Freshwater and Marine Ecology (IBED, FNWI)
Source :
Proceedings of the Royal Society B-Biological Sciences, 286(1916):20192153. Royal Society of London, Proc Biol Sci
Publication Year :
2019

Abstract

Marine sponges are set to become more abundant in many near-future oligotrophic environments, where they play crucial roles in nutrient cycling. Of high importance is their mass turnover of dissolved organic matter (DOM), a heterogeneous mixture that constitutes the largest fraction of organic matter in the ocean and is recycled primarily by bacterial mediation. Little is known, however, about the mechanism that enables sponges to incorporate large quantities of DOM in their nutrition, unlike most other invertebrates. Here, we examine the cellular capacity for direct processing of DOM, and the fate of the processed matter, inside a dinoflagellate-hosting bioeroding sponge that is prominent on Indo-Pacific coral reefs. Integrating transmission electron microscopy with nanoscale secondary ion mass spectrometry, we track 15 N- and 13 C-enriched DOM over time at the individual cell level of an intact sponge holobiont. We show initial high enrichment in the filter-feeding cells of the sponge, providing visual evidence of their capacity to process DOM through pinocytosis without mediation of resident bacteria. Subsequent enrichment of the endosymbiotic dinoflagellates also suggests sharing of host nitrogenous wastes. Our results shed light on the physiological mechanism behind the ecologically important ability of sponges to cycle DOM via the recently described sponge loop.

Details

Language :
English
ISSN :
09628452
Volume :
286
Issue :
1916
Database :
OpenAIRE
Journal :
Proceedings of the Royal Society B-Biological Sciences
Accession number :
edsair.doi.dedup.....00955b38b9163af8698730d2c3761aff