Tag Archive | "rosenstiel school of marine and atmospheric science"

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Fertile Corals Discovered in Deeper Waters off U.S. Virgin Islands


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Researchers find reproductive refuge for threatened coral species

Diverse and vibrant deep coral reefs of the Grammanik Bank, St. Thomas, US Virgin Islands The dominant corals are boulder star corals (Orbicella franksi).  The two groupers are yellowfin groupers (Mycteroperca venenosa).

The dominant corals in the diverse and vibrant deep coral reefs of the Grammanik Bank off the coast of St. Thomas in the U.S. Virgin Islands are boulder star corals (Orbicella franksi). Photo by Tyler B. Smith

MIAMI, Fla. (July 27, 2015) — Researchers have discovered a threatened coral species that lives in deeper waters off the U.S. Virgin Islands is more fertile than its shallow-water counterparts. The new study showed that mountainous star corals (Orbicella faveolata) located at nearly 140 feet (43 meters) deep may produce one trillion more eggs per square kilometer (247 acres) than those on shallow reefs. The findings from scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science and the University of the Virgin Islands have important implications for the future of coral reefs worldwide.

Caribbean coral reefs have declined 50 percent in the past 50 years, according to the 2014 Status and Trends of Caribbean Coral Reefs report. In 2005, coral reefs in the U.S. Virgin Islands were severely impacted by high temperatures and disease.

“Coastal pollution, storms, and warm water can stress a coral out, which is why we’re looking at what’s going on in deeper offshore habitats,” said Daniel Holstein, a Rosenstiel School alumnus and current postdoctorate researcher at the University of the Virgin Islands. “These deeper habitats tend to be cooler and less strenuous for corals—and thus, coral spawning may be more spectacular.”

Mountainous star corals reproduce by broadcast spawning, releasing their eggs and sperm in the water during a highly synchronized event. The researchers used remote cameras at a field site off the island of St. Thomas and laboratory observations during broadcast spawning events to show that the mesophotic corals, which live in deeper reef waters typically between 30 to 150 meters (98 to 492 feet), released their eggs in near synchrony with shallow-water corals.

“The reefs that produce more larvae are more likely to be successful in seeding the reefs with their offspring,” said Claire Paris, associate professor of ocean sciences at the Rosenstiel School and co-author of the study. “Protecting these potent reproductive deep refuges could represent the key to the survival of coral reefs for future generations.”

Mesophotic coral ecosystems are buffered from environmental disturbances by their depth and distance from shore. These deeper coral reef ecosystems may offer reproductive refuge to neighboring shallow-water coral reefs that are in decline, according to the research team.

“These deep reefs offer a glimmer of hope,” said Tyler Smith, research associate professor at the University of the Virgin Islands. “They may be an incredible resource for the U.S. Virgin Islands, and for the entire Caribbean, if they can supply consistent sources of coral larvae.”

The study, titled “Fertile fathoms: Deep reproductive refugia for threatened shallow corals,” was published in the July 21 issue of Nature Publishing Group’s journal Scientific Reports. In addition to Holstein, Smith, and Paris, the coauthors include Joanna Gyory of Tulane University. The study was funded by the National Science Foundation – Virgin Islands Experimental Program ROA #0814417 and the Black Coral Penalty Fund ROA #260225. Additional funding was provided by Natural Environmental Research Council (NERC) subcontract to Paris from Exeter University:  “Climate change and habitat fragmentation in coral reef ecosystems”  and NSF OCE-0928423 to Paris and historical work funded by the Paris Lab. The study and a supplementary video may be accessed at www.nature.com/articles/srep12407.

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Abrupt Climate Change May Have Rocked Cradle of Civilization


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UM Rosenstiel researchers uncover the effects of climate on human societies 

FertileCresentClimateChange

Professor Ali Pourmand (right) and Ph.D. candidate Arash Sharifi inspect the physical properties of a meter-long sediment core collected from northwest Iran that recorded the environmental conditions in the region  for the past 2,000 years.

MIAMI, Fla. (July 28,2015)—New research reveals that some of the earliest civilizations in the Middle East and the Fertile Crescent may have been affected by abrupt climate change. The findings show that, while socio-economic factors have long been considered to have shaped ancient human societies in this region, the influence of abrupt climate change should not be underestimated.

A team of international scientists led by researchers from the Rosenstiel School of Marine and Atmospheric Science found that during the first half of the last interglacial period, known as the Holocene epoch, which began about 12,000 years ago and continues today, the Middle East most likely experienced wetter conditions compared to the latter 6,000 years, when conditions were drier and dustier.

“Evidence for wet early Holocene was previously found in the eastern Mediterranean Sea region, north and east African lakes, and cave deposits from southwest Asia, and is attributed to higher solar insolation during this period,” said Ali Pourmand, assistant professor of marine geosciences at the Rosenstiel School, who supervised the project. “Our study, however, is the first of its kind from the interior of west Asia and unique in its resolution and multi-proxy approach.”

The Fertile Crescent, a region in west Asia that extends from Iran and the Arabian Peninsula to the eastern Mediterranean Sea and northern Egypt, is one of the most climatically dynamic regions in the world and is widely considered the birthplace of early human civilizations.

“The high-resolution nature of this record afforded us the rare opportunity to examine the influence of abrupt climate change on early human societies,” said Arash Sharifi, Ph.D. candidate in the Department of Marine Geosciences and lead author of the study. “We see that transitions in several major civilizations across this region, as evidenced by the available historical and archeological records, coincided with episodes of high atmospheric dust; higher fluxes of dust are attributed to drier conditions across the region over the last 5,000 years.”

The researchers investigated climate variability and changes in paleoenvironmental conditions during the last 13,000 years based on a high-resolution (sub-decadal to centennial) peat record from Neor Lake in northwest Iran. Abrupt climate changes occur in the span of years to decades.

Funded by the National Science Foundation, the study, “Abrupt climate variability since the last deglaciation based on a high-resolution, multi-proxy peat record from NW Iran: The hand that rocked the Cradle of Civilization?” will be published in the September 1 issue of the journal Quaternary Science Reviews, and is currently available online.

In addition to Sharifi and Pourmand, the study coauthors include Larry C. Peterson and Peter K. Swart, of the Rosenstiel School; Elizabeth A. Canuel and Erin Ferer-Tyler, of the Virginia Institute of Marine Science, College of William and Mary; Bernhard Aichner and Sarah J. Feakins, of the University of Southern California; Touraj Daryaee, of the University of California, Irvine; Morteza Djamali, of the institut méditerranéen de biodiversité et d’ecologie, France; and Abdolmajid Naderi Beni and Hamid A.K. Lahijani, of the Iranian National Institute of Oceanography and Atmospheric Science.

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Study Investigates ‘Landscape of Fear’ with Sharks and Turtles

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Study Investigates ‘Landscape of Fear’ with Sharks and Turtles


Special to UM News

SharksandTurtles_GraphicMIAMI, Fla. (July 23, 2015)–Scientists at the Rosenstiel School of Marine and Atmospheric Science and the Abess Center for Ecosystem Science and Policy who examined predator-prey interactions between tiger sharks and sea turtles in the northwestern Atlantic Ocean found that tiger sharks alter their movements to take advantage of nesting turtles.

The research team used long-term satellite tagging data from large tiger sharks and adult female loggerhead sea turtles—common prey of tiger sharks—to examine their movement patterns and evaluate if turtles modify their behaviors to reduce their chances of a shark attack when turtle and shark home ranges overlapped.

The study revealed that tiger sharks undergo seasonal movements to take advantage of the turtles nesting off the Carolinas during the summer. Tiger sharks are ambush predators, primarily attacking surfacing turtles from below. In theory, loggerhead turtles should reduce their exposure at the surface in regions of high habitat overlap with tiger sharks. However, surprisingly, the researchers found that when shark-turtle overlap in the study region was high, turtles did not alter surfacing behavior to reduce the risk. But sharks did exhibit modified surfacing behavior believed to enhance predation opportunity.

“We suggest that sharks may not be an important factor influencing the movements of turtles,” said Neil Hammerschlag, research assistant professor at the Rosenstiel School and Abess Center. “In fact, it is possible that fishing of tiger sharks in our study area has reduced their populations to levels that no longer pose a significant threat to turtles at the individual level, with other factors becoming more important for turtles, such as the need to avoid boat strikes, which is a huge threat to turtle survival.”

The study is one of the first to test if the “landscape of fear” model, a scientific theory used to explain how animals move and interact with the environment based on their fear of being attacked by their predators, is applicable to large open marine systems involving wide-ranging species, like sharks and turtles.

“This is one of the first studies to compare the large-scale, long-term movements of sea turtles with their natural predators, tiger sharks,” said study co-author Lucy Hawkes of the University of Exeter’s Centre for Ecology and Conservation.

“These data are essential for setting and prioritizing marine protection for these species, which are both of conservation concern,” said another co-author, Matthew Witt of the University of Exeter’s Environment and Sustainability Unit.

The study, titled “Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape,” was published in the July 23 online edition of the journal Ecology. Other co-authors include Kyra Hartog and Emily Rose Nelson of the University of Miami; Annette C. Broderick and Brendan J. Godley of the University of Exeter; John W. Coker, DuBose B. Griffin, Sally R. Murphy, and Thomas M. Murphy of the South Carolina Department of Natural Resources; Michael S. Coyne of SeaTurtle.org; Mark Dodd of the Georgia Department of Natural Resources; Michael G. Frick of the University of Florida’s Archie Carr Center for Sea Turtle Research; Kristina L. Williams of the Savannah Science Museum’s Caretta Research Project; and Matthew H. Godfrey of the North Carolina Wildlife Resources Commission.

 

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Researcher Helps Provide Better Forecasts to U.S. Navy

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Researcher Helps Provide Better Forecasts to U.S. Navy


Special to UM News

COMPASSMIAMI, Fla. (July 14, 2015)—The U.S. Navy is seeking tools for extended environmental forecasts, which can aid in planning missions, training schedules, and transit routes. Charles River Analytics is designing big data machine learning tools that could support an extended range weather prediction service under the Climatological Observations for Maritime Prediction and Analysis Support Service effort, known as COMPASS, and partnering with the Rosenstiel School of Marine and Atmospheric Science’s Benjamin Kirtman on the effort.

“This project is an excellent example of how short-term climate predictions can be used to provide operational support in planning national security missions,” said Kirtman, professor of atmospheric sciences.

COMPASS will produce a unified forecast up to twelve months in advance using the North American Multi-Model Ensemble (NMME). It will incorporate multiple forecast models from different meteorology and climatology modeling centers to produce a single unified and improved forecast for a specific time period and location. Kirtman is the lead principal investigator on the National Oceanic and Atmospheric Administration’s (NOAA) NMME program.

“In COMPASS, we’re using newly available extended-range forecasts to produce a unified and more accurate long-range probabilistic forecast for a specific time period and location of interest,” explained Joe Gorman, division software engineer at Charles River and principal investigator on COMPASS.

Charles River will apply machine learning techniques and its Figaro probabilistic programming language to learn how to combine multiple models to better predict environmental conditions (e.g., temperature, wind stress, and cloud cover). Figaro is a free, open-source probabilistic programming language for probabilistic modeling.

“We will evaluate available weather data and determine how to optimally combine multiple weather and climate models to produce a single, improved forecast using Figaro,” Gorman said. “We will use Figaro’s built-in machine learning and inference capabilities to produce in an effective manner a coherent unified forecast from individual time, location predictions.”

 

 

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Study Could Improve Hurricane Intensity Forecasts

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Study Could Improve Hurricane Intensity Forecasts


By Robert C. Jones Jr.
UM News

David Nolan, right, professor and chair of the Department of Atmospheric Science at the Rosenstiel School, and Ph.D. student Kieran Bhatia are testing a new system that could improve hurricane intensity forecasts

David Nolan, right, professor and chair of the Department of Atmospheric Science at the Rosenstiel School, and Ph.D. student Kieran Bhatia are testing a new system that could improve hurricane intensity forecasts.

VIRGINIA KEY, Fla. (June 11, 2015) – If all goes well over the next six months, a pair of University of Miami researchers will provide the National Hurricane Center with something it has wanted ever since it started tracking tropical cyclones—a way to more accurately forecast storm intensity.

David Nolan, professor and chair of atmospheric sciences at UM’s Rosenstiel School of Marine and Atmospheric Science, and graduate student Kieran Bhatia will accomplish that goal not by flying through storms in a hurricane hunter aircraft, but with the use of technology. Throughout the 2015 Atlantic hurricane season, they will gather a wealth of data from four existing storm intensity models, feed the information into a computer, then produce results that show which of the four models performs best under certain conditions.

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