[Coral-List] New Paper: Resilient corals in the Phoenix Islands

[Risk, Michael]

   Interesting.

   In our El Nino/bleaching work, we found that deeper reef areas were hit
   harder, and were slower to recover:

   "In our study area, the high thermali nstabilityin the reef base
   resultedi n the highest coral mortalities around Isla del Canio during
   the 1982-83 El Nifino event (Guzman, 1986; pers. obs.). Al-thoughs
   hallow-watera reas mightb e af-fected by additional factors such as
   salinity (Swart and Coleman, 1980) and oxygen tension (Kinsey and
   Kinsey, 1967), it seems that the disturbance in the lagoons was not as
   great as in more open reef areas, because mortalityr ates were lowest
   in the lagoons. In general, the deeper reef areas were the most
   susceptible to coral mortality during the 1982-1983 El Nino event,
   because of thermal instability."

   This got a tad cut up during pasting, but one can always read the
   original: Carriquiry et al 1988, PALAIOS 3: 359-364.

   We found that a bit counterintuitive, but I guess it's the old
   exposure-response relationship.

   Mike

   On Sep 17, 2021, at 10:39 AM, Austin Bowden-Kerby via Coral-List
   <[1]coral-list at coral.aoml.noaa.gov> wrote:

   Thanks for that David,
   I agree with you, as far as on geological timescales.  But for
   Kiribati, on
   the leading edge of the global coral reef collapse, unfortunately the
   oceanic reefs are doing as bad or worse than the lagoons. The ocean
   facing
   reefs are adapted to cooler waters so they kick the bucket as badly as
   the
   lagoonal corals when mass bleaching temperatures arrive and where they
   can
   linger for over half the year.  For the Gilbert chain, bleaching
   temperatures dominated for 30 months out of 60 since 2014, until La
   Nina
   conditions finally arrived last year, giving them a one or two year
   break.
   The thermal stress is superimposed on both ocean and lagoon habitats,
   and
   corals tend to adapt to near the upper thresholds for their symbionts.
    So
   all corals, of both lagoon and ocean reefs, are equally stressed and in
   danger of being wiped out.  I conjecture that the most resilient
   coral populations will be found at the transition between lagoon and
   oceanic conditions- the reef passes.  If this hypothesis is correct,
   then
   those reef pass areas are where our conservation efforts might best be
   focused.
   The lessons of Kiribati have taught us a lesson for Fiji and Tuvalu and
   Samoa, where it is still not too late.  Our strategy in recent years is
   to
   locate and move corals of the same species as those on the ocean facing
   reefs- from the warm lagoons, nearshore reef flats, and hot pockets,
   out to
   the cooler outer lagoon and pass areas where we establish them in gene
   bank
   nurseries. The goal is to create patches of these resistant corals on
   the
   ocean reefs themselves, where they stand a much better chance into the
   future, and where they can then begin to spread their resilience.
   Mother Earth has a fever, but she has a strategy of Her own to protect
   the
   coral reefs- sea level rise.  Imagine the positive impact that adding
   one
   or two meters of water will have on the shallow coral reefs globally.
   Vastly more area for corals to grow, increased upward scope for growth,
   and
   a cooling of the lagoons and shallows. Of course the coastal areas and
   human populations may not fare so well.  But seriously, we
   deserve every millimeter!
   Regards to all,
   Austin
   .
   Austin Bowden-Kerby, PhD
   Corals for Conservation
   P.O. Box 4649 Samabula, Fiji Islands
   [2]https://www.corals4conservation.org
   https://www.globalgiving.org/projects/emergency-response-to-massive-cor
   al-bleaching/
   <https://www.globalgiving.org/projects/emergency-response-to-massive-co
   ral-bleaching/>
   Teitei Livelihoods Centre
   Km 20 Sigatoka Valley Road, Fiji Islands
   (679) 938-6437
   http:/www.
   <http://permacultureglobal.com/projects/1759-sustainable-environmental-
   livelihoods-farm-Fiji>
   teiteifiji.org
   http://permacultureglobal.com/projects/1759-sustainable-environmental-l
   ivelihoods-farm-Fiji
   https://www.facebook.com/teiteifarmstay
   https://www.globalgiving.org/projects/happy-chickens-for-food-security-
   and-environment-1/
   On Thu, Sep 16, 2021 at 6:29 AM David Blakeway via Coral-List <
   coral-list at coral.aoml.noaa.gov> wrote:

     In assessing these reefs I think it's worth considering where
     they're at in
     terms of their natural life cycle. Kiribati, for example, looks
     pretty
     terminal to me. You could imagine that 1000 years ago it might have
     resembled Tabueran (3.86, -159.32) and 1000 years from now it might
     look
     like Washington Island (4.68, -160.38). That process (losing all
     lagoon
     corals) is completely natural. And probably wouldn't be a gradual
     incremental process (on our timescale); more likely the lagoon coral
     community would undergo massive fluctuations in the terminal stage,
     while
     heading toward long-term senescence. I agree that preserving
     Kiribati
     corals is critical insurance. My point is just that--for reefs in
     general--we shouldn't expect good stable coral cover and diversity
     in
     late-stage reefs approaching sea level.
     _______________________________________________
     Coral-List mailing list
     Coral-List at coral.aoml.noaa.gov
     https://coral.aoml.noaa.gov/mailman/listinfo/coral-list

   _______________________________________________
   Coral-List mailing list
   Coral-List at coral.aoml.noaa.gov
   https://coral.aoml.noaa.gov/mailman/listinfo/coral-list

References

   1. mailto:coral-list at coral.aoml.noaa.gov
   2. https://www.corals4conservation.org/