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TRANSCRIPT
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The Ways in which Corals May or May Not Adapt
To Climate Change/Global Warming
by
Paul W. Sammarco1
and
Kevin B. Strychar2
1Louisiana Universities Marine Consortium (LUMCON)Chauvin, LA, USA
2Annis Water Resources Institute/Grand Valley State University
Muskegon, MI, USA
Current Hermatypic Coral Temperature and Latitudinal Limits
(Gross, 1977)
Atmospheric COAtmospheric CO22 and Temperature and Temperature
Over the Past 160,000 YearsOver the Past 160,000 Years
© Brooks/Cole Publishing Company / ITP
1984
2002
Mt. Hood, OregonGlacier National Park
. 1910 – 150 glaciers
. 2004 – 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 108 J per second
. Between 1960s and 1985-1994, between 10o-24o N lat.
- Pacific – increase of 1.79 x 108 J m-2 (Wong et al., 2001)
. Since the 1950s, our oceans have absorbed an extra 15 x 1022 J
. If warming ceased today, the temperature of the ocean would not begin to reverse until the year 2075 (Church, 2007).
EndosymbioticZooxanthellae
Present inHermatypic
Corals
http://www.ecotourism.ca/effectsofcoralbleaching.html
Reef Prior to Bleaching
www.cosmos.ne.jp/~kamiyama/full.htm
Reef During the Bleaching Process
www.cosmos.ne.jp~kamiyama/full.htm
1-2 Months after Bleaching
www.cosmos.ne.jp~kamiyama/full.htm
. 1979 - First recorded coral bleaching event
. 1998 - El Nino yr - 48% of reefs in the W. Indian Ocean suffered bleaching;
16% of the world’s reefs appeared to have died.
. 2002 - 60-95% 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
http://www.ncdc.noaa.gov/paleo/outreach/coral/sor/images/map7-large.gif
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 situwithin the coral Acropora hyacinthus
_Control_ _Experimentally Increased Temperature_
NormalCell
ApoptoticCell
NecroticCell
1 m 500 nm 500 nm
Morze KoralowePl.reeflex.net/tiere/a756_Favites_complanata.htm
Favites complanata(Faviidae)
Percentage (%)of Cells
F. complanata(Faviidae - coral)
Symbiodinium sp.(symbiont)
Time (hrs)
Favia complanataApoptotic Cells, Host vs. Symbiont
Normal
Necrotic Apoptotic
Contrary to popular Opinion
90% of the zooxanthellae in 90% of the zooxanthellae in bleaching corals have been found bleaching corals have been found
in various stages of cell deathin various stages of cell death
www.starfish.ch/c-invertebrates/corals.html
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?
www.korallenfarm.de/Weiche.htm
Sarcophyton ehrenbergi(Alcyoniidae)
Sarcophyton sp.
bleached
www.ratemyfishtank.com/friendemail.php/13611
28C30C
32C
34C
36C
34C
28-32C, 36C
Percentage (%)of Cells
Sarcophyton ehrenbergiNecrotic Cells
Sinularia lochmodes(Alcyoniidae)
David Robbwww.davidrobb.me.uk/Marine/Invertebrates.htm
Xenia elongata(Xeniidae)
Could this phenomenon regarding
endosymbiotic zooxanthellae and bleaching
apply to other cnidarians and other phyla
as well?
http://www.berghia.net/aiptasiaBiology.html
Aiptasia patella(Anthozoa, Actiniaria)
Aiptasia pallida, bleached
Jessie Kershnerwww.coralscience.org/main/articles/
symbiosis-3/aiptasia-a-bleaching
Cassiopeia xamachanaScyphozoa
Jonathan Dunderwww.freeinfosociety.com/site.php?postnum=833
http://www.oceanwideimages.com/Large-Image.asp?pID=15969&cID=73&rp=species%252Easp%253Fs%253DCassiopea%2Bxamachana%2526p%253D1
Ewa Barskacommons.wikimedia.org/wiki/File:Tridacna_gigas_by_Ewa_Barska.jpg
Tricacna gigas(Mollusca, Bivalvia)
Tricacna gigasBleaching
James W. Fathereewww.advancedaquarist.com/2010/8/inverts
. Zooxanthellae more sensitive to temperature than theirhosts in scleractinian corals
. Alcyonaceans - Similar to scleractinian corals
. Application to other cnidarians?
- Bleaching, yes
- Greater sensitivity in endosymbionts than hostMost likely.
. Application to zooxanthellate organisms from otherphyla?
- Most likely, yes.
Are there alternatives to endosymbiotic zooxanthellae?
And will they save the day?
Didemnum molle (Ascidea, Didemnidae)With symbiotic Prochloron didemni
http://university.uog.edu/botany/474/cyano/prochloron.html
Lissoclinum patella (Ascidea)with symbiotic cyanobacteria (e.g. Prochloron didemni)
www.eol.org/pages/65008
Spongilla lacustris (Porifera)with symbiotic Chlorella (Chlorophyceae)
Jim Novakwww.biolib.cz/en/image/id18059/
Potential Acquisition of Replacement Symbiontse.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 Symbiontse.g., Prochloron or Chlorella
. Symbiont would have to be adapted to produce O2 and sugars in the right concentrations for the host.
. Host would have to be able to accept O2 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
http://www.nature.com/scitable/knowledge/library/the-rhizosphere-roots-soil-and-67500617
Ectomycorrhizal fungi replacing arbuscular mycorrhizal fungi on tree roots
https://theaphidroom.files.wordpress.com/2013/01/figure-1_mandrioli_manicardi.jpg
Yeasts replacing Buchnera bacteria in aphids
http://www.kurzweilai.net/how-to-synthesize-a-new-kind-of-yeast-cell-or-person
http://tolweb.org/onlinecontributors/app?service=external/ViewImageData&sp=30254
http://www.polypompholyx.com/wp-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.
http://www.dreamstime.com/stock-illustration-many-dice-large-group-showing-six-points-image42162002
Oceanic Climatic ZonesToday
http://www.waterencyclopedia.com/images/wsci_01_img0100.jpg
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
http://www.cryofthewater.org/images/2.jpg
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.
http://www.ageekyworld.com/a-must-visit-place-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 insufficientafter a point.
Amphiscolopslangerhansi
(Platyhelmenthes)
Nanozine.blogspot.com/2007_05_01_archive.html
Coral Bleaching Hotspots(8/27/05)
http://python2011.globalblogs.org/files/2011/10/dice.jpg
http://www.getting-positive-karma-now.com/about-the-Nirulas.html
Implications
Zooxanthellae occur in
hundreds of
marine invertebrate species
Similar Responses in the
Other two Alcyonacean Species
(with variance)
http://www.care2.com/causes/5-of-the-worlds-most-endangered-coral-reefs.html
Outline
I.Coral Reefs and Bleaching – Background
V. Predictions for Extinction of Zooxanthellate Organisms