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The Ways in which Corals May or May Not Adapt To Climate Change/Global Warming by Paul W. Sammarco 1 and Kevin B. Strychar 2 1 Louisiana Universities Marine Consortium (LUMCON) Chauvin, LA, USA 2 Annis Water Resources Institute/ Grand Valley State University Muskegon, MI, USA

Current Hermatypic Coral Temperature and Latitudinal Limits (Gross, 1977)

Atmospheric CO 2 and Temperature Over the Past 160,000 Years © Brooks/Cole Publishing Company / ITP

Mt. Hood, Oregon Glacier National Park – 150 glaciers – 30 glaciers, each reduced by 2/3 in size Glaciers – The Integrators of Atmospheric Temperature

Climate Change / Global Warming.Energy required to lift an apple to a table = One (1) Joule (J).500 MW power plant produces 5 x 10 8 J per second.Between 1960s and , between 10 o -24 o N lat. -Pacific – increase of 1.79 x 10 8 J m -2 (Wong et al., 2001).Since the 1950s, our oceans have absorbed an extra 15 x J.If warming ceased today, the temperature of the ocean would not begin to reverse until the year 2075 (Church, 2007).

Endosymbiotic Zooxanthellae Present in Hermatypic Corals

Reef Prior to Bleaching

Reef During the Bleaching Process

1-2 Months after Bleaching

First recorded coral bleaching event El Nino yr - 48% of reefs in the W. Indian Ocean suffered bleaching; 16% of the world’s reefs appeared to have died % of the 110,000 sq mi of the Great Barrier Reef bleached. Many more events since this time Coral Bleaching

Regions of bleaching over the past 25 years Country reporting coral bleaching Locations of major bleaching events

Experimentation with Scleractinian Corals – Great Barrier Reef

Programmed Cell Death Apoptosis.Series of biochemical events leading to characteristic cell morphology and death (incl. blebbing, cell membrane changes, shrinkage, nuclear fragmentation, chromatin condensation, and c-DNA fragmentation.).e.g., Differentiation of human fingers and toes in development of a fetus. Necrosis.Premature death of cells caused by acute cellular injury by external factors, such as infection, toxins, or trauma..e.g., Necrotic tissue resulting from a recluse spider bite (LA).

Symbiodinium sp. cells in situ within the coral Acropora hyacinthus _Control_ _Experimentally Increased Temperature_ Normal Cell Apoptotic Cell Necrotic Cell 1  m 500 nm

Morze Koralowe Pl.reeflex.net/tiere/a756_Favites_complanata.htm Favites complanata (Faviidae)

Percentage (%) of Cells F. complanata (Faviidae - coral) Symbiodinium sp. (symbiont) Time (hrs) Favia complanata Apoptotic Cells, Host vs. Symbiont

Normal Necrotic Apoptotic Contrary to popular Opinion 90% of the zooxanthellae in bleaching corals have been found in various stages of cell death

Acropora hyacinthus (Acroporidae)

Zoo2.zool.kyoto-u.ac.jp/~hirose/Marine/corals/porites.htm Porites solida (Poritidae) Similar Response to Same Experimental Treatments

. Adaptation -Requires natural selection by these temperature conditions in the evolutionary history of this group. Exaptation -Requires that some other physiological trait, previously existing, function known or unknown, serves to enhance temperature tolerance. Adapatation or Exaptation in the Coral Hosts?

. Is this temperature adaptation / exaptation restricted to only the zooxanthellate scleractinian corals?.Does it extend to other coelenterate groups?

Sarcophyton ehrenbergi (Alcyoniidae)

Sarcophyton sp. bleached friend .php/13611

28C 30C 32C 34C 36C 34C 28-32C, 36C Percentage (%) of Cells Sarcophyton ehrenbergi Necrotic Cells

Sinularia lochmodes (Alcyoniidae)

David Robb Xenia elongata (Xeniidae)

Could this phenomenon regarding endosymbiotic zooxanthellae and bleaching apply to other cnidarians and other phyla as well?

Aiptasia patella (Anthozoa, Actiniaria)

Aiptasia pallida, bleached Jessie Kershner sis-3/aiptasia-a-bleaching

Cassiopeia xamachana Scyphozoa Jonathan Dunder

Image.asp?pID=15969&cID=73&rp=species%252Easp%253Fs%253DCa ssiopea%2Bxamachana%2526p%253D1

Ewa Barska commons.wikimedia.org/wiki/File:Tridacna_gigas_by_Ewa_Barska.jpg Tricacna gigas (Mollusca, Bivalvia)

Tricacna gigas Bleaching James W. Fatheree

.Zooxanthellae more sensitive to temperature than their hosts in scleractinian corals.Alcyonaceans - Similar to scleractinian corals.Application to other cnidarians? -Bleaching, yes -Greater sensitivity in endosymbionts than host Most likely..Application to zooxanthellate organisms from other phyla? -Most likely, yes.

Are there alternatives to endosymbiotic zooxanthellae? And will they save the day?

Didemnum molle (Ascidea, Didemnidae) With symbiotic Prochloron didemni

Lissoclinum patella (Ascidea) with symbiotic cyanobacteria (e.g. Prochloron didemni)

Spongilla lacustris (Porifera) with symbiotic Chlorella (Chlorophyceae) Jim Novak

Potential Acquisition of Replacement Symbionts e.g., Prochloron or Chlorella.Would require host to recognize new symbiont immunologically as “self”.Would require symbiont to recognize new host immunologically as “self”.Would require new symbiont to be adapted to reproduce inside host tissue, even if only asexually.Host would have to be adapted to produce nutrients in concentrations acceptable to the symbiont.Symbiont would have to be adapted to accept nutrients from host – in a balanced manner

Potential Acquisition of Replacement Symbionts e.g., Prochloron or Chlorella.Symbiont would have to be adapted to produce O 2 and sugars in the right concentrations for the host..Host would have to be able to accept O 2 and sugars from the symbiont.Host would have to be able to expel the new symbionts when there was an imbalance in resource transfer or symbiont mortality.

Has this ever happened before? Yes. Three precedents of replacement

rhizosphere-roots-soil-and Ectomycorrhizal fungi replacing arbuscular mycorrhizal fungi on tree roots

1_mandrioli_manicardi.jpg Yeasts replacing Buchnera bacteria in aphids yeast-cell-or-person

ewImageData&sp= content/uploads/2013/05/endosymbiotic_matryoshka.png Endosymbiotic algae replacing plastids in some peridinin dinoflagellates.

Could such a substitution happen again – particularly in this case?.Possible, but tall order..Imagine rolling this many dice simultaneously and hoping to come up with all of them yielding the right formula..Probability exceedingly low.

large-group-showing-six-points-image

Oceanic Climatic Zones Today

Poleward Migration of Oceanic Climatic Zones Expansion of Tropical Zone; Movement of Sub-Tropical, Temperate, and Sub-Polar Zones; Compression of Polar Zones

Shrinking of Arctic Polar Cap and Permafrost Boundary Maps.grida.no/go/graphic/ shift-in-climatic-zones-arctic- scenario

Predictions (cont.).Emergence of a “Hyper-Tropical Oceanic Climatic Zone”.Decrease in species diversity of corals and other zooxanthellate organisms -Due to species-specific sensitivity to increasing seawater temperatures

Possible Emergence of a Hyper-Tropical Zone Possible introduction of new Hyper-Tropical Zone, and decrease in species of diversity of corals and other zooxanthellate organisms therein ?

Predictions (cont.).No net gain in coral reef cover with time -Increase in higher latitudes, but – -High coral mortality in the warmer regions – lower latitudes -Probably a decrease in species diversity overall, due to pushing corals to the limits of their distribution and mortality in the hyper-tropical zone.

great-barrier-reef/ Thank you

Predictions.Latitudinal Expansion of Corals and other temperature- limited zooxanthellate organisms -e.g., Acropora cervicornis off Broward County, FL.Similar observations made in Japan.Latitudinal limits due to light – PAR in winter?.Adaptation of zooxanthellae for low light levels -Mesophotic zones -Deep-water on Jamaican deep reefs -Probably acclimation to low light levels insufficient after a point.

Amphiscolops langerhansi (Platyhelmenthes) Nanozine.blogspot.com/ 2007_05_01_archive.html

Coral Bleaching Hotspots (8/27/05)

the-Nirulas.html

Implications Zooxanthellae occur in hundreds of marine invertebrate species

Similar Responses in the Other two Alcyonacean Species (with variance)

endangered-coral-reefs.html

Outline I.Coral Reefs and Bleaching – Background V.Predictions for Extinction of Zooxanthellate Organisms