Document of bibliographic reference 404492

BibliographicReference record

Type

Bibliographic resource

Type of document

Journal article

BibLvlCode

AS

Title

Heart cockle shells transmit sunlight to photosymbiotic algae using bundled fiber optic cables and condensing lenses

Abstract

Many animals convergently evolved photosynthetic symbioses. In bivalves, giant clams (Cardiidae: Tridacninae) gape open to irradiate their symbionts, but heart cockles (Cardiidae: Fraginae) stay closed because sunlight passes through transparent windows in their shells. Here, we show that heart cockles (Corculum cardissa and spp.) use biophotonic adaptations to transmit sunlight for photosynthesis. Heart cockles transmit 11–62% of photosynthetically active radiation (mean = 31%) but only 5–28% of potentially harmful UV radiation (mean = 14%) to their symbionts. Beneath each window, microlenses condense light to penetrate more deeply into the symbiont-rich tissue. Within each window, aragonite forms narrow fibrous prisms perpendicular to the surface. These bundled “fiber optic cables” project images through the shell with a resolution of >100 lines/mm. Parameter sweeps show that the aragonite fibers’ size (~1 µm diameter), morphology (long fibers rather than plates), and orien?tation (along the optical c-axis) transmit more light than many other possible designs. Heart cockle shell windows are thus: (i) the first instance of fiber optic cable bundles in an organism to our knowledge; (ii) a second evolution, with epidermal cells in angiosperm plants, of condensing lenses for photosynthesis; and (iii) a photonic system that efficiently transmits useful light while pro?tecting photosymbionts from UV radiation.

Bibliographic citation

McCoy, D.E.; Burns, D.H.; Klopfer, E.; Herndon, L.K.; Ogunlade, B.; Dionne, J.A.; Johnsen, S. (2024). Heart cockle shells transmit sunlight to photosymbiotic algae using bundled fiber optic cables and condensing lenses. Nature Comm. 15(1). https://dx.doi.org/10.1038/s41467-024-53110-x

Topic

Marine

Is peer reviewed

true

Access rights

open access

Is accessible for free

true