Bockel, ThomasRinkevich, Baruch2019-10-092019-10-092019-10-092019-09-0110.3390/jmse7090306https://infoscience.epfl.ch/handle/20.500.14299/161901WOS:000487981700018While the early acquisition of Symbiodiniaceae algae into coral host tissues has been extensively studied, the dynamics of the migration of algal cells into rapidly expanding coral tissues still lacks a systematic study. This work examined two Red Sea branching coral species, Pocillopora damicornis and Stylophora pistillata, as they were growing and expanding their tissue laterally on glass slides (January-June, 2014; 450 assays; five colonies/species). We measured lateral tissue expansion rates and intratissue dinoflagellate migration rates. Tissue growth rates significantly differed between the two species (with Stylophora faster than Pocillopora), but not between genotypes within a species. Using a "flow-through coral chamber" under the microscope, the migration of dinoflagellates towards the peripheral edges of the expanding coral tissue was quantified. On a five-day timescale, the density of the endosymbiotic dinoflagellate cells, presenting within a 90 mu m region of expanding coral tissue (outer edge), increased by a factor of 23.6 for Pocillopora (from 1.2 x 10(4) cells cm(-2) to 2.4 x 10(5) cells cm(-2)) and by a factor of 6.8 for Stylophora (from 3.6 x 10(4) cells cm(-2) to 2.4 x 10(5) cells cm(-2)). The infection rates were fast (5.2 x 10(4) and 4.1 x 10(4) algal cells day-1 cm(-2), respectively), further providing evidence of an as yet unknown pathway of algal movement within coral host tissues.OceanographyOceanographyalgal movementcoral tissueendosymbiont proliferationlateral skeleton preparativenubbin assaypocilloporared seastylophorasymbiodiniaceaezooxanthellaecalcificationcirculationinfectiontransportoctocoralnubbinsgrowthtext::journal::journal article::research article