Manipulating the coral-algal holobiont

Transcription

1 Manipulating the coral-algal holobiont Todd C. LaJeunesse Interventions to Increase the Resilience of Coral Reefs (May 31, 2018)

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4 Preface Skipping over most of the details to get the punch lines. My perspectives are based on:

5 - Red Sea (Saudi Arabia) - Persian/Arabian Gulf (Saudi Arabia) - Thailand - Tanzania, Zanzibar - GBR Australia - Palau - Japan (Honshu Island) - Hawaii 1. Broad habitat and biogeographic sampling Distribution of Coral Reefs Taiwan Gulf of California, Mexico Puerto Vallarta, Mexico Belize, Cancun, Mexico Curacao Bahamas Barbados

6 2. Multiple genetic makers

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8 3. Species-level resolutions

9 How stable or flexible are these mutualisms? And to what extent can they be manipulated?

10 Stability vs. change over space and time (between host-symbiont partnerships) Spatial Temporal (from the host s perspective) Colony Population species

11 Ecological time scales: months years decades centuries (?)

12 Stability in symbiont populations in a coral colony over space & time.

13 Allison Lewis 10 meters

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18 Oulastrea crispata

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24 Transfer to grow-out platforms

25 C21 S. trenchii < 6 months

26 S. trenchii C years

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28 Evolutionary time scales: 1000 s to tens of millions of years

29 Probable origin of coral-dinoflagellate mutualisms

30 These symbioses have persisted through immense time.

31 Drivers of Symbiodinium speciation

32 Niche (host) diversification

33 Invasive microbe in the Greater Caribbean

34 Symbiont Speciation and Evolution Species Diversity through: - Allopatric speciation (Caribbean vs. Pacific vs. Red Sea) - Habitat/Host specialization (establishment of specific associations) Evolutionary patterns: - Characterized by periods of stability and symbiont diversification punctuated by extinction events: Episodes of boom and bust. - The spread of successful host-generalists whose populations undergo an adaptive radiation of ecologically specialized species.

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36 Glimpse into the Future

37 In-shore animal symbioses Durusdinium (Symbiodinium) trenchii Off-shore animal symbioses Cladocopium (Symbiodinium) species

38 Final Words We can manipulate these symbioses, but nature often has a mind of its own....and will most likely swamp out any attempts by us to create new combinations artificially.

39 We search for something that will seem like truth to us; we search for understanding; we search for that principle which keys us deeply into the pattern of all life. - John Steinbeck; The log from the Sea of Cortez Funding Acknowledgments

40 Trade-offs of hosting an invasive, but thermally tolerant symbiont.

41 Early successional turnover in symbiont diversity 0-6 months Coffroth et al. > 1 year

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43 Photo credits: Pat Collin

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45 Current Biology 2018

46 Sea Surface Temperatures

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48 Brooders Life history strategies of corals Broadcast spawning

49 Host-symbiont flexibility in broadcast spawning corals Environment 1 Environment 2

50 Most Indo-Pacific Corals

51 Stress tolerant host-generalist

52 Phylogenetic species concept Species Concepts Biological species concept Ecological species concept Morphological species concept Genotypic cluster concept

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55 Holosymbiont tolerance curves symbiont sp. 1 symbiont sp. 2 Coral 1 tolerance (Iglesias-Prieto & Trench 1997)

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59 Inter-individual variation 0.50 Fv/Fm fluorescence Photosynthesis/respiration (PR) Symbiodinium C40 (offshore) Symbiodinium trenchii (offshore) Symbiodinium spp.? (offshore) Treatment Day 32 C Symbiodinium trenchii (inshore)

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61 Members of a species can display a wide (generalized) or narrow (specialized) pattern of resource utilization and tolerance to environmental change. Growth/performance/fitness Light and/or temperature

62 Temporal stability Baums et al. 2014

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64 Pettay et al Molecular Ecology

65 Most Symbiodiniaceae cannot be cultivated in vitro (~ 90-95% of putative species) Those that can are as follows: Host-generalist species (e.g. S. trenchii, S. goreauii) Free-living species (e.g. S. pilosum, S. natans, S. voratum, Clade Fr5) Those associated with giant clams or jellyfish (e.g. S. tridacnidorum, S. microadriaticum, C2 )

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68 Originally referred to as Genotypes A, B, and C A Orbicella spp. B C Rowan & Knowlton 1995; Rowan et al Nature

69 The upgrade/refinement to ITS types A3 B17 B1 C7 B19

70 The ecological and functional diversity of these symbioses is considerable. The presence of a particular symbiont has a huge effect on the physiology of the host The nature of the host-symbiont relationship will be the most critical in the ecological response to regional, or global, climate change. In the future, look for a small number of Symbiodinium species to dramatically expand their ecological (host) and geographic range.

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73 Niche (host) diversification