[Coral-List] New Model of Caribbean Reef Accretion Published

Paul Blanchon blanchons at gmail.com
Thu Oct 12 15:01:21 EDT 2017

We are pleased to announce the following open-access publication:

Blanchon P, Richards S, Bernal JP, Cerdeira-Estrada S, Ibarra MS,
Corona-Martínez L, Martell-Dubois R, (2017). Retrograde accretion of a
Caribbean fringing reef controlled by hurricanes and sea-level rise.
Frontiers in Earth Science 5: 78. doi: 10.3389/feart.2017.00078

You can also view a video presentation of the paper on You Tube


Predicting the impact of sea-level (SL) rise on coral reefs requires
reliable models of reef accretion. Most assume that accretion results from
vertical growth of coralgal framework, but recent studies show that reefs
exposed to hurricanes consist of layers of coral gravel rather than
in-place corals. New models are therefore needed to account for hurricane
impact on reef accretion over geological timescales. To investigate this
geological impact, we report the configuration and development of a
4-km-long fringing reef at Punta Maroma along the northeast Yucatan
Peninsula. Satellite-derived bathymetry (SDB) shows the crest is set-back a
uniform distance of 315 ±15 m from a mid-shelf slope break, and the
reef-front decreases 50% in width and depth along its length. A 12-core
drill transect constrained by multiple 230Th ages shows the reef is
composed of an ∼2-m thick layer of coral clasts that has retrograded 100 m
over its back-reef during the last 5.5 ka. These findings are consistent
with a hurricane-control model of reef development where large waves trip
and break over the mid-shelf slope break, triggering rapid energy
dissipation and thus limiting how far upslope individual waves can fragment
corals and transport clasts. As SL rises and water depth increases, energy
dissipation during wave-breaking is reduced, extending the clast-transport
limit, thus leading to reef retrogradation. This hurricane model may be
applicable to a large subset of fringing reefs in the tropical
Western-Atlantic necessitating a reappraisal of their accretion rates and
response to future SL rise.

*Paul Blanchon *Ph.D.
Marine Geoscience Lab., Reef Systems Unit, Puerto Morelos,
Institute of Marine Sciences & Limnology
National Autonomous University of Mexico (UNAM)
Tel: +52  (998) 87-10009
Email: blanchons at gmail.com
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