[Coral-List] FIELD OF GIANTS

[David Blakeway]

Great Keven, please send.
So how big is 'yours'? And how did you find it? Did it get into the
Guinness Book? (I expect Guinness would have been cautious in accepting it
as a record). The authors of the August 2021 article should have been more
cautious too, as they claim, at 10.4 m: "This is the largest diameter
*Porites* coral measured by scientists".
Local knowledge will probably reveal many more. AI on satellite imagery
should also be able to pick them.
Thanks for posting, Charles! (BTW the subsidence rate in the 2019 Han et al
article mentioned by Charles is 16 mm per year - few reefs could maintain
that).

On Mon, Sep 20, 2021 at 9:10 PM KEVEN REED via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Dear Chuck, Dave, & Phil,
>
> To add to the unofficial list(s) of giant & ancient domed Porites
> colonies, I reported a P. lutea colony on the north side of Ie Shima,
> Okinawa, Japan in 1995 to the Guinness Book of Records.  It was
> photographed and measured by me and Russell C. Gilbert.  The specific id
> was verified by Prof. Robert van Woesik, who later was shown the colony on
> SCUBA by us.
>
> Latitude was 26 degrees 44 minutes N.
>
> If anyone wants to see some photos, let me know:  reedkc at comcast.net
>
> Keven Reed
> mobile: 904-505-7277
> Fleming Island, FL 32003
>
> > On 09/16/2021 4:27 PM Charles Birkeland via Coral-List <
> coral-list at coral.aoml.noaa.gov> wrote:
> >
> >
> > FIELD OF THE GIANTS
> >
> > Findings on the GBR usually get a lot of notice. For example, the
> > description in a recent Nature Scientific Reports (online 19 August 2021)
> > of the largest massive *Porites* colony on the GBR (5.3 m high, 10.4 m
> > wide, 31 m in circumference and between 421 and 438 years old) received a
> > lot of attention. A few months earlier (same journal, online 7 December
> > 2020), a similar article (I was *not* an author) described a scattered
> > group of seven very large massive *Porites* cf. *lutea* at the island of
> > Ta’u, American Samoa (the two largest were 8 and 7 m high, 22.4 m wide
> > (over twice the diameter of the GBR specimen) and 17 m wide (diameter),
> > circumference 69.4 and 41.0, and I heard that growth rings from a core
> > indicated the second largest one to be 540 years old), but this article
> was
> > hardly noticed. If we assume the *Porites* colonies were hemispherical,
> > which I believe is quite reasonable, then the volume of the GBR colony
> 2πr3/3
> > is 294 m3. The volumes of the two largest in the Field of the Giants were
> > 1286 and 2942 m3, or were 4.4 and 10 times the mass of the largest on the
> > GBR. For surface area, 2πr2, the areas of the *Porites* colonies were
> 170 m2
> > (GBR) and 454 and 788 m2 for the two at Ta’u. The two at Ta’u were 2.7
> and
> > 4.6 times the area of the largest on the GBR. Twice the diameter is not
> > particularly impressive, but this indicates 4.6 times the surface area
> and
> > 10 times the mass. American Samoa is thought of as a tough and
> challenging
> > environment for corals with major crown-of-thorns outbreaks, numerous
> > cyclones, mass bleaching events, occasional extreme low tides, a tsunami,
> > and with sea level rising five times as fast as the global average
> because
> > the islands are sinking relatively (geologically) fast (Han et al. 2019
> JGR
> > Solid Earth 124: 4142-4156). Despite these harsh conditions and frequent
> > damage to coral communities, the corals of American Samoa are remarkably
> > resilient and the dynamic system deserves attention. It is good to keep a
> > log of all massive *Porites *colonies greater than 10 m in diameter, and
> > around the world, there are probably a number of colonies larger than the
> > 22.4 m diameter colony at Ta’u; but no matter how many are larger, the
> > Field of the Giants is still a marvelous sight in American Samoa.
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