[Coral-List] coral calcifiction paper

[Travis Courtney]

Hello all,

To clarify the recent response in regards to the light measurements in
"Environmental controls on modern scleractinian coral and reef-scale
calcification," all light measurements were made by onset HOBO loggers
(lux) secured on the benthos at each reef site facing perpendicular to the
water surface. Maximum calcification rates (max in August to November)
lagged maximum benthic irradiance measurements (max lux in mid-June) by a
few months. The complexity of such time lags with respect to the Structural
Equation Modeling are discussed in the manuscript.

Best,
Travis Courtney

On Mon, Nov 13, 2017 at 9:00 AM, <coral-list-request at coral.aoml.noaa.gov>
wrote:

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> Today's Topics:
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>    1. Re: coral calcifiction paper (Richard Dunne)
>
>
> ---------- Forwarded message ----------
> From: Richard Dunne <RichardPDunne at aol.com>
> To: coral-list at coral.aoml.noaa.gov
> Cc:
> Bcc:
> Date: Sun, 12 Nov 2017 13:54:01 +0000
> Subject: Re: [Coral-List] coral calcifiction paper
> For measurement of solar radiation the authors chose sensors which record
> units of lux (a measure of human visual perception of brightness).  As far
> as I can tell these measurements were above water, presumably on a
> horizontal surface (they don't say), although if this was a buoy moving
> with wave motion then this would produce added variability in the readings.
> They then use this as one of their environmental inputs to their Structural
> Equation Modelling.
>
> Lux cannot be converted to units of PAR (photosynthetically active
> radiation) or irradiance unless you also know the spectral composition of
> the light at the time of measurement. As regards photobiology and coral
> calcification, measurements in lux are thus pretty meaningless. Worse still
> the fact that underwater both the spectral power distribution and
> irradiance will have varied with depth and changes in water quality, the
> net effect is not encouraging if you are using this to see if there is a
> relationship between calcification and solar radiation.
>
> The authors found that "the lack of correlation with light ......   are
> inconsistent with anticipated results". Quelle suprise! Rubbish in -
> rubbish out.
>
> Richard P Dunne
>
> On 10/11/2017 23:17, Douglas Fenner wrote:
>
>> Environmental controls on modern scleractinian coral and reef-scale
>> calcification.  Scientific Reports
>>
>> http://advances.sciencemag.org/content/3/11/e1701356?utm_cam
>> paign=toc_advances_2017-11-10&et_rid=17045989&et_cid=1656609
>>
>> Open-access
>> Abstract
>>
>> Modern reef-building corals sustain a wide range of ecosystem services
>> because of their ability to build calcium carbonate reef systems. The
>> influence of environmental variables on coral calcification rates has been
>> extensively studied, but our understanding of their relative importance is
>> limited by the absence of in situ observations and the ability to decouple
>> the interactions between different properties. We show that temperature is
>> the primary driver of coral colony (*Porites astreoides* and *Diploria
>> labyrinthiformis*) and reef-scale calcification rates over a 2-year
>> monitoring period from the Bermuda coral reef. On the basis of multimodel
>> climate simulations (Coupled Model Intercomparison Project Phase 5) and
>> assuming sufficient coral nutrition, our results suggest that *P.
>> astreoides* and *D. labyrinthiformis* coral calcification rates in Bermuda
>> could increase throughout the 21st century as a result of gradual warming
>> predicted under a minimum CO2 emissions pathway [representative
>> concentration pathway (RCP) 2.6] with positive 21st-century calcification
>> rates potentially maintained under a reduced CO2 emissions pathway (RCP
>> 4.5). These results highlight the potential benefits of rapid reductions
>> in
>> global anthropogenic CO2 emissions for 21st-century Bermuda coral reefs
>> and
>> the ecosystem services they provide.
>>
>> Cheers,  Doug
>>
>>
>
>
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