Nav: Home

UM researchers study sediment record in deep coral reefs

December 02, 2015

MIAMI - A University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science-led research team analyzed the sediments of mesophotic coral reefs, deep reef communities living 30-150 meters below sea level, to understand how habitat diversity at these deeper depths may be recorded in the sedimentary record. The findings showed that sediments provide an important record of the bottom dwelling organisms that formed the architecture of coral reef ecosystems and support their high biodiversity today.

Coral reefs support more than 25 percent of ocean organisms, making them one of the most bio-diverse ecosystems on the planet. Studying how biodiversity evolved on deeper, mesophotic reefs can help scientists interpret the origins of their economically important shallow-reef counterparts.

"Understanding how these important marine ecosystems that we rely on for food and medicines evolved in the past gives us new insight into how to protect them in the future," said UM Rosenstiel School alumnus and lead author of the study David Weinstein. "The results of this study provide the first analog to understanding how habitat biodiversity in these systems has evolved since the first reef-building ancient ancestors of modern corals."

The research team collected sediments from four deep reef environments between 30-50 meters south of St. Thomas, U.S.Virgin Islands, and from two shallower water reef sites. The sediment samples were then analyzed to identify the biological, physical, and geochemical composition of the grains from the different sites. The team also examined the wave processes at the reef to show that the sedimentary deposits were primarily derived internally, with biological processes largely controlling sediment deposition.

By analyzing the sediments, scientists can predict how much coral and algae were present on mesophotic reef environment, this new information has important implications from interpreting ancient reef environments found in fossils, where the abundance of diverse habitat forming species cannot be analyzed visually.

"The mesophotic reefs of the Virgin Islands are especially vibrant and may contribute to the recovery of shallow reef systems after disturbance," said Tyler Smith, associate research professor at the University of the Virgin Islands and coauthor of the study. "Understanding ways that we can detect these systems in the sedimentary record will show us where these systems were in the past and if they also contributed to ancient reef recovery after major coral upheavals in the Caribbean."

Current research suggests that ancient coral reefs began as deep, dark communities that evolved into highly diverse systems by establishing communities in shallower water environments with more light.

Mesophotic reef coral ecosystems are thought to be extremely important for reef resiliency. Another important finding from the study was that waves do not transport harmful land-based sediment to mesophotic reefs on low-angel shelves like those in the USVI. In a different study published in July 2015, UM and UVI researchers discovered a threatened coral species that lives on mesophotic reefs off the U.S. Virgin Islands is more fertile than its shallow-water counterparts.

The study provides the initial steps necessary to investigate the origins of coral reef biodiversity from deeper reef origins.

"These findings opens the door for studying the geologic history of how these deep reefs evolved and responded to past environmental change," said James Klaus, UM associate professor of geology and coauthor of the study. "Over geologic time-scales, mesophotic environments may have played an important role in the long-term sustainability of coral reefs."
The study, titled "Habitat heterogeneity reflected in mesophotic reef sediments" was published in the Nov. 2015 issue of the journal Sedimentology Geology. The study's authors include David Weinstein, James Klaus and Tyler Smith.

About the University of Miami's Rosenstiel School

The University of Miami is one of the largest private research institutions in the southeastern United States. The University's mission is to provide quality education, attract and retain outstanding students, support the faculty and their research, and build an endowment for University initiatives. Founded in the 1940's, the Rosenstiel School of Marine & Atmospheric Science has grown into one of the world's premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. For more information, visit:

University of Miami Rosenstiel School of Marine & Atmospheric Science

Related Coral Reefs Articles:

A brave new world for coral reefs
It is not too late to save coral reefs, but we must act now.
Regular coral larvae supply from neighboring reefs helps degraded reefs recover
For reefs facing huge challenges, more coral larvae doesn't necessarily translate to increased rates of coral recovery on degraded reefs, a new Queensland study has showed.
Potential for Saudi Arabian coral reefs to shine
Careful marine management and stricter fishing laws could enable Saudi Arabia's coral reefs to thrive.
New coral bleaching database to help predict fate of global reefs
A UBC-led research team has developed a new global coral bleaching database that could help scientists predict future bleaching events.
Fish social lives may be key to saving coral reefs
Fish provide a critical service for coral reefs by eating algae that can kill coral and dominate reefs if left unchecked.
Land-based microbes may be invading and harming coral reefs
A new study suggests that coral reefs -- already under existential threat from global warming -- may be undergoing further damage from invading bacteria and fungi coming from land-based sources, such as outfall from sewage treatment plants and coastal inlets.
Dead zones may threaten coral reefs worldwide
Dead zones affect dozens of coral reefs around the world and threaten hundreds more according to a new study by Smithsonian scientists published in Proceedings of the National Academy of Sciences.
Deep reefs unlikely to save shallow coral reefs
Often highlighted as important ecological refuges, deep sections of coral reefs (30-60 m depth) can offer protection from the full force of climate change-related impacts, such as intensifying storms and warm-water bleaching.
Coral reefs grow faster and healthier when parrotfish are abundant
A new study by Smithsonian scientists and colleagues that reveals 3,000 years of change in reefs in the western Caribbean provides long-term, compelling evidence that parrotfish, which eat algae that can smother corals, are vital to coral-reef growth and health.
Rising CO2 threatens coral and people who use reefs
Damage to coral reefs from ocean acidification and sea surface temperature rise will be worst at just the spots where human dependence on reefs is highest, according to a new analysis appearing in PLOS ONE.

Related Coral Reefs Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...