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

Researcher to Study Effect of Smoke on the Climate

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Researcher to Study Effect of Smoke on the Climate


Ascension-Island

Located midway between Africa and Brazil, Ascension Island, which supports British and American air forces, communications, space agencies, and global positioning systems, will be the base of operation for the smoke experiments.

Special to UM News

MIAMI, Fla. (May 26, 2016)—A scientist at the Rosenstiel School of Marine and Atmospheric Science is leading an upcoming international research campaign to study a significant contributor to regional climate warming—smoke.

The first-of-its-kind research experiment begins on June 1, from Ascension Island in the southeastern Atlantic Ocean. Called LASIC (Layered Atlantic Smoke Interactions with Clouds), the experiment is part of a broader international scientific collaboration led by the Atmospheric Radiation Measurement (ARM) Climate Research Facility and detailed in the July Bulletin of the American Meteorological Society.

Southern Africa is the world’s largest emitter of smoke particles in the atmosphere, known as biomass-burning aerosols, from the burning of grasslands and other biomass. The project will help researchers better understand the effects of widespread biomass burning on Earth’s climate.

The study will investigate how smoke particles flowing far offshore from the African continent affect the remote and cloudy southeast Atlantic climate. Smoke, which absorbs sunlight, is a warming agent in the climate system when located above a bright surface, such as clouds. The smoke overlying the southeast Atlantic provides one of the largest aerosol-based warming of climate on the planet, since the region is also home to one of the largest low-cloud decks on the planet.

“Ascension Island is an ideal location since it is very remote and allows us to sample the smoke after it is well-aged, about which less is known,” said Paquita Zuidema, professor of atmospheric sciences at the Rosenstiel School and principal investigator of the research experiment. “The long deployment time will allow us to characterize the marine low clouds both with and without the presence of smoke. This is ultimately valuable for understanding the Earth’s energy balance.”

By evaluating how the low clouds respond to the presence of sunlight-absorbing aerosols, scientists can better understand low cloud behavior, which is currently an uncertainty in model predictions of future climate, since no fundamental theory on low cloud processes is yet in place.

Low clouds dominate the atmosphere over the southeast Atlantic Ocean all year. Bright white cloud appears darker when viewed from above when smoke is present. The southeast Atlantic overall is brighter, not darker when smoke is present, suggesting that the clouds become thicker and more extensive when smoke is present.

Zuidema received a $365,050 seed grant from the U.S. Department of Energy to plan the study and a $440,225 grant from NASA, which further supports related aircraft investigations as part of the NASA Earth Venture Suborbital-2 ORACLES project.

NASA will complement the DOE surface-based measurements with airborne experiments during a month of each year from 2016-2018. This will allow researchers to take airborne samples of smoke particles as they age, information that will improve satellite retrievals of this mixed smoke-cloud regime. The United Kingdom will also participate with its research aircraft, and French, Namibian, and South African scientists will collect and interpret aircraft and ground-based measurements closer to the Namibian coast.

The Rosenstiel School-led research team will study how smoke is transported through the atmosphere and across the Atlantic, how the aerosols change when transported, and the response of the low-lying clouds to the smoke. The information from the experiments will ultimately be used to improve global aerosol models and climate change forecasts.

To read more about the University of Miami’s climate change research and field work, view the Climate Change Special Report.

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Nick Shay Honored for Hurricane Research

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Nick Shay Honored for Hurricane Research


Special to UM News

Shay was honored for his work on oceanic impacts and air-sea interactions during tropical cyclones.

Lynn ‘Nick’ Shay is the recipient of the Office of the Federal Coordinator of Meteorology’s Richard H. Hagemeyer Award.

MIAMI, Fla. (May 12, 2016) — Rosenstiel School of Marine and Atmospheric Science Professor Lynn “Nick” Shay was recently honored with the Richard H. Hagemeyer Award by the Office of the Federal Coordinator of Meteorology at the 70th Interdepartmental Hurricane Conference in Miami. He joins a prestigious list of previous awardees from the Office of the Federal Coordinator of Meteorology.

Shay received the award for his work using experimental research from aircraft in coupled ocean-atmosphere measurements during hurricanes as well as combining in-situ data with satellite altimetry measurements to develop an evaluated ocean heat content product suite that is used in  forecast models of hurricane intensity at the National Hurricane Center and the National Centers for Environmental Prediction. The daily space-based ocean heat content product suite is used in operations at NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) for the North Atlantic and Pacific Ocean basins.

“The work that Nick Shay and his team have performed and continue to perform is absolutely vital to the viability of NOAA’s suite of satellite-derived Oceanic Heat Content products,” said David Donohue, NOAA scientist with the NESDIS.

Shay’s research include experimental and theoretical investigations of the ocean response and coupled air-sea interactions during hurricanes, oceanographic profiling of upper ocean variability using expendables and floats, coastal oceanographic process studies, and high-frequency and satellite radar remote sensing to examine the linkages between surface signatures and upper ocean structure. These activities are housed within the Upper Ocean Dynamics Laboratory at the Rosenstiel School, where Shay is a professor in the Department of Ocean Sciences. He has authored more than 100 peer-reviewed manuscripts and book chapters and has chaired or served on more than 30 student committees.

The Office of the Federal Coordinator of Meteorology is an interdepartmental office established between Congress and the Executive Office of the President to coordinate federal meteorological activities. It is comprised of 15 federal departments and agencies currently engaged in meteorological activities to ensure effective use of federal meteorological resources by leading the systematic coordination of operational weather requirements and services and supporting research among the federal agencies.

 

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Reefs Dissolving Faster Than Projected

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Reefs Dissolving Faster Than Projected


Special to UM News

Carysfort.ReefMIAMI, Fla. (May 4, 2016) — In a new study, Rosenstiel School of Marine and Atmospheric Science researchers found that the limestone that forms the foundation of coral reefs along the Florida Reef Tract is dissolving during the fall and winter months on many reefs in the Florida Keys. The research showed that the upper Florida Keys were the most impacted by the annual loss of reef.

Each year the oceans absorb CO2 from the atmosphere and become more acidic, a process called ocean acidification. Projections, based largely on laboratory studies, led scientists to predict that ocean pH would not fall low enough to cause reefs to start dissolving until 2050-2060.

For two years, the researchers collected water samples along the 200-kilometer (124-mile) stretch of the Florida Reef Tract north of Biscayne National Park to the Looe Key National Marine Sanctuary. The data provide a snapshot on the health of the reefs, and establish a baseline from which future changes can be judged.

The results showed that reef dissolution is a significant problem on reefs in the upper Keys with the loss of limestone exceeding the amount the corals are able to produce on an annual basis. As a result these reefs are expected to begin wasting away leaving less habitat for commercial and recreationally important fish species. Florida Keys’ reefs have an estimated asset value of $7.6 billion.

In the natural scheme of things, environmental conditions in the ocean, such as water temperature, light, and seagrass growth, are favorable for the growth of coral limestone in the spring and summer months. But during the fall and winter, low light and temperature conditions, coupled with the annual decomposition of seagrass, result in a slowing, or small-scale loss of reef growth.

However, as atmospheric CO2 is absorbed by seawater, ocean pH declines. The result is that the natural summer growth cycle of coral is no longer large enough to offset the effects of dissolution from ocean acidification.

“We don’t have as much time as we previously thought,” said Chris Langdon, professor of marine biology and ecology, and a senior author of the study, who discuss the findings in a video. “The reefs are beginning to dissolve away.”

“This is one more reason why we need to get serious about reducing carbon dioxide emission sooner rather than later,” he said.

The data for the study were collected in 2009-2010. The researchers suggest that a more recent analysis should be conducted to see how the reefs are faring today.

“The worst bleaching years on record in the Florida Keys were 2014-2015, so there’s a chance the reefs could be worse now,” Langdon said.

The study, titled “Dynamics of carbonate chemistry, production and calcification of the Florida Reef Tract (2009-2010): evidence for seasonal dissolution,” was published in the May 2 issue of the journal Global Biogeochemical Cycles. In addition to Langdon, the study coauthors include Rosenstiel School alumnae Nancy Muehllehner and Alyson Venti, and David Kadko, now at Florida International University. The National Science Foundation funded the study.

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Scientists Use Ultrasound to Study Shark Reproduction

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Scientists Use Ultrasound to Study Shark Reproduction


Special to UM News

A female tiger shark at Tiger Beach, Bahamas. Photo by Neil Hammerschlag.

A female tiger shark at Tiger Beach, Bahamas. Photo by Neil Hammerschlag.

MIAMI, Fla. (March 2, 2016) — Researchers from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and the University of New England have used the same ultrasound imaging technology used by medical professionals on pregnant women to study the reproductive biology of female tiger sharks. Their study offers marine biologists a new technique to investigate the reproductive organs and determine the presence of embryos in sharks without having to sacrifice the animal first, which was commonly done in the past.

In the study, published in the latest edition of the Journal of Aquatic Biology, researchers performed in-water ultrasounds on live tiger sharks (Galeocerdo cuvier) and took blood samples for hormone analysis to determine the reproductive status of females at Tiger Beach in the Bahamas, a site known for its year-round abundance of tiger sharks. The new method allows researchers to determine if the female sharks at Tiger Beach were mature and pregnant.

“Using the same ultrasound imaging technology used on pregnant women, we discovered Tiger Beach was important for females of different life stages, and that a high proportion of tiger sharks were pregnant during winter months,” said James Sulikowski, a professor in the University of New England’s Department of Marine Science.

“Our data suggests that Tiger Beach may function as a refuge habitat for females to reach maturity as well as a gestation ground where pregnant females benefit from calm, warm waters year round that help incubate the developing embryos and speed up gestation,” said study co-author Neil Hammerschlag, research assistant professor at the Rosenstiel School and Abess Center for Ecosystem Science and Policy.

Populations of many migratory marine predators such as sharks are experiencing large declines across the globe and fishing aggregations of pregnant females can significantly impact the health of local and regional populations. Tiger Beach is located within the Bahamas Exclusive Economic Zone, where shark fishing has been prohibited since 2011. The relatively high abundance of tiger sharks in the Bahamas compared to the rest of the Caribbean where populations are much lower could be attributed in part to the protection of mature and gravid females in the Bahamas shark sanctuary.

“It is crucial for marine biologists to understand their behaviors to provide information for resource managers to effectively protect and manage them,” said Hammerschlag

 

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Shark Hotspots and Commercial Fishing Overlap

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Shark Hotspots and Commercial Fishing Overlap


Researchers who tracked movements of sharks and longline fishing vessels in North Atlantic found significant overlap driving shark declines.

Mako SharkMIAMI, Fla. (January 25, 2016)—A new study from an international team of scientists found commercial fishing vessels target shark hotspots, areas where sharks tend to congregate, in the North Atlantic. The researchers suggest that sharks are at risk of being overfished in these oceanic hotspots.

Neil Hammerschlag, research assistant professor at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and Abess Center for Ecosystem Science and Policy, was part of the scientific team that published its findings in the January 25 issue of the journal Proceedings of the National Academy of Sciences. The authors report in the study that catch quotas for sharks by commercial fishers might be necessary to protect oceanic sharks.

“Our research clearly demonstrates the importance of satellite tagging data for conservation,” said Hammerschlag, director of the UM Shark Research and Conservation Program who conducted the satellite tagging and tracking of several shark species in the northwestern Atlantic for the study. “The findings both identify the problem as well as provide a path for protecting oceanic sharks.”

During a four-year period from 2005 to 2009, the researchers tracked more than 100 sharks equipped with satellite tags from six different species in the North Atlantic while concurrently tracking 186 Spanish and Portuguese GPS-equipped longline fishing vessels. They found that the fishing vessels and sharks occurred in ocean fronts characterized by warm water temperature and high productivity, including the Gulf Stream and the North Atlantic Current/Labrador Current Convergence Zone near Newfoundland.

“Many studies have tracked sharks, and many studies have tracked fishing vessels, but fine-scale tracking of sharks and fishing vessels together is lacking, even though this should better inform how shark fisheries should be regulated,” said David Sims of the Marine Biological Association, and the senior author of the study.

According to the researchers, about 80 percent of the range for two of the most heavily fished species tracked—the blue and mako sharks—overlapped with the fishing vessels’ range, with some individual sharks remaining near longlines for over 60 percent of the time they were tracked. Blue sharks were estimated to be vulnerable to potential capture 20 days per month, while the mako sharks’ potential risk was 12 days per month.

“Although we suspected overlap might be high, we had no idea it would be this high. Space-use overlap on this scale potentially increases shark susceptibility to fishing exploitation, which has unknown consequences for populations,” said Nuno Queiroz of the University of Porto, Portugal, the lead author of the study.

Tens of millions of ocean-dwelling sharks are caught by commercial fishing operations each year. The researchers suggest that a lack of data on where sharks are likely to encounter fishing vessels has hampered current shark conservation efforts.

The researchers propose that because current hotspots of shark activity are at particularly high risk of overfishing, the introduction of conservation measures, such as catch quotas or size limits, will be necessary to protect oceanic sharks that are commercially important to fleets worldwide at the present time.

In addition to Queiroz and Hammerschlag, co-authors of the study, titled “Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots,” include Nicolas E. Humphries, Gonzalo Mucientes, Fernando P. Lima, Kylie L. Scales, Peter I. Miller, Lara L. Sousa, Rui Seabra, and David W. Sims. Instituations contributing to the research were the Marine Biological Association of the United Kingdom, Universidade da Porto in Portugal, National Oceanography Centre Southampton, University of Southampton, Fundación CETMAR, University of Miami, Plymouth Marine Laboratory, University of California Santa Cruz, National Oceanic and Atmospheric Administration, and Faculdade de Ciências da Universidade do Porto.

Hammerschlag’s work was supported by the Disney Worldwide Conservation Fund, Batchelor Foundation, and West Coast Inland Navigation District in Florida. The research study was part of the European Tracking of Predators in the Atlantic (EUTOPIA) initiative.

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