Symbiodinium biogeography tracks environmental patterns rather than host genetics in a key Caribbean reef-builder, Orbicella annularis.
The physiological performance of a reef-building coral is a combined outcome of both the coral host and its algal endosymbionts, Symbiodinium While Orbicella annularis-a dominant reef-building coral in the Wider Caribbean-is known to be a flexible host in terms of the diversity of Symbiodinium types it can associate with, it is uncertain how this diversity varies across the Caribbean, and whether spatial variability in the symbiont community is related to either O. annularis genotype or environment. Here, we target the Symbiodinium-ITS2 gene to characterize and map dominant Symbiodinium hosted by O. annularis at an unprecedented spatial scale. We reveal northwest-southeast partitioning across the Caribbean, both in terms of the dominant symbiont taxa hosted and in assemblage diversity. Multivariate regression analyses incorporating a suite of environmental and genetic factors reveal that observed spatial patterns are predominantly explained by chronic thermal stress (summer temperatures) and are unrelated to host genotype. Furthermore, we were able to associate the presence of specific Symbiodinium types with local environmental drivers (for example, Symbiodinium C7 with areas experiencing cooler summers, B1j with nutrient loading and B17 with turbidity), associations that have not previously been described.
College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK emma.kennedy@griffith.edu.au.|Australian Rivers Institute, Griffith University, Nathan, 4111 Queensland, Australia.
Emma V
0000-0003-1821-9740
EV
Kennedy
Coral Reef Ecosystems Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072 Queensland, Australia.
Linda
L
Tonk
College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.|School of Marine Science and Engineering, Plymouth University, Drake Circus, Plymouth PL4 8AA, UK.
Nicola L
0000-0001-9796-1753
NL
Foster
Smithsonian Marine Station, Smithsonian Institution, Fort Pierce, FL 34949, USA.
Iliana
I
Chollett
Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072 Queensland, Australia.
Juan-Carlos
JC
Ortiz
Coral Reef Ecosystems Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072 Queensland, Australia.
Sophie
S
Dove
Coral Reef Ecosystems Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072 Queensland, Australia.
Ove
O
Hoegh-Guldberg
College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.|Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072 Queensland, Australia.
Peter J
PJ
Mumby
College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
Jamie R
0000-0002-1317-6721
JR
Stevens
D000818:Animals; D037421:Anthozoa / Q000235:genetics / Q000382:microbiology*; D017691:Caribbean Region; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D004141:Dinoflagellida / Q000235:genetics / Q000502:physiology*; D005838:Genotype; D013312:Stress, Physiological; D013559:Symbiosis; D013696:Temperature
D021903:DNA, Ribosomal Spacer
Internal Transcribed Spacer 2; Zooxanthellae; coral bleaching; denaturing gel gradient electrophoresis; environmental drivers; symbiont diversity