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NOAA Teacher at Sea
Julia Harvey, Aboard NOAA Ship Hi’ialakai, June 25 – July 3rd 2016
Mission: WHOI Hawaii Ocean Timeseries Station (WHOTS)
Geographical Area of Cruise: Pacific Ocean, north of Hawaii
Date: June 29th, 2016
Professor Nicholas Meskhidze earned his first Physics degree from Tbilisi State University (Georgia). He completed his PhD at Georgia Institute of Technology (USA). He is now an Associate Professor at NC State University Department of Marine Earth and Atmospheric Sciences.
Meskhidze’s study on this cruise is looking at sea spray aerosol abundance in marine boundary layer and quantifying their flux values. Sea spray is formed from breaking waves. Sea spray analysis begins by collecting the aerosol. Using electrical current, particles of a given size (for example 100 nanometer (nm)) are selected for. This size represents the typical size of environmental climatically important particles (70-124 nm). The next step is to remove all other particles typically found in the marine boundary layer, such as ammonium sulfate, black carbon, mineral dust and any organics. The remaining particles are sea salt.<See the full story>
Dust, pollution, and decreasing oxygen in the tropical Pacific: For the past several decades, researchers have been tracking the decline in dissolved oxygen in the tropical Pacific Ocean. Less dissolved oxygen means that fewer aquatic creatures can survive there, which is bad news for that region’s ecosystem. But while they could agree on the decline, researchers had trouble deciphering the cause. Now a new theory, put forth by scientists at Georgia Tech, NASA, NC State and the University of Washington and based on computer modeling, may provide part of the answer – air pollution. Air pollution doesn’t just sink into the ocean and disrupt the environment. Instead, there’s a chain of events that begins with dust and ends with decomposition and oxygen use. <See the full story>. (NC State News Center, May 16, 2016)
Polluted Dust Can Impact Ocean Life Thousands of Miles Away, Study Says: As climatologists closely monitor the impact of human activity on the world’s oceans, researchers at the Georgia Institute of Technology have found yet another worrying trend impacting the health of the Pacific Ocean. A new modeling study conducted by researchers in Georgia Tech’s School of Earth and Atmospheric Sciences shows that for decades, air pollution drifting from East Asia out over the world’s largest ocean has kicked off a chain reaction that contributed to oxygen levels falling in tropical waters thousands of miles away. “There’s a growing awareness that oxygen levels in the ocean may be changing over time,” said Taka Ito, an associate professor at Georgia Tech. “One reason for that is the warming environment – warm water holds less gas. But in the tropical Pacific, the oxygen level has been falling at a much faster rate than the temperature change can explain.” <See the full story>. (Georgia Tech News Center, May 16, 2016)
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A biogeochemist is keen to find out whether oceanic plankton can help to keep our planet cool: For years I have been fascinated by the idea that oceanic plankton can play a significant part in controlling climate. This concept is, of course, at the heart of gaian ideas of the Earth as a self-regulating system, proposed by James Lovelock. It was given expression through the CLAW hypothesis (published two decades ago by R. Charlson, J. Lovelock, M. Andreae & S. Warren), which supposes that the gas dimethyl sulphide produced by marine plankton influences cloud formation and hence albedo and climate. However, direct evidence for a link between plankton and clouds has been slow to emerge. A recent paper (N. Meskhidze & A. Nenes Science 314, 1419–1423; 2006) shows a tantalizing seasonal and spatial association between sea-surface chlorophyll (an indicator of biological activity) and atmospheric properties for a six-year period over a substantial area of the Southern Ocean. <See the full story>. (Peter Liss, Nature 447, 356-357 (24 May 2007) | doi:10.1038/447356a)
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Atmospheric science: Plant food from pollution: Iron is an essential nutrient for phytoplankton, the tiny aquatic plants that carry out almost half of all photosynthesis on Earth. Dust storms in northern China and Mongolia carry iron from the soil of the Gobi desert to the northern Pacific Ocean. But the iron in desert dust is in a mineral form that has low solubility in seawater and so is not readily available to phytoplankton. Nicholas Meskhidze and colleagues have found that sulphur dioxide pollution from industrial plants in China can acidify the dust, which converts iron to a more soluble form. <See the full story>. (Nature 433, 818 (24 February 2005) | doi:10.1038/433818a)
Dust Storm Surprise: Pollution Can Convert Airborne Iron into Soluble Form Required for Phytoplankton Growth: A surprising link may exist between ocean fertility and air pollution over land, according to Georgia Institute of Technology research reported in the Feb. 16 issue of the Journal of Geophysical Research - Atmospheres. The work provides new insight into the role that ocean fertility plays in the complex cycle involving carbon dioxide and other greenhouse gases in global warming. <See the full story>. (Research news & publications office, Georgia Institute of Technology, February 10, 2005)
Pollution Can Convert Airborne Iron into Soluble Form Required for Phytoplankton Growth: A surprising link may exist between ocean fertility and air pollution over land, according to Georgia Institute of Technology research reported in the Feb. 16 issue of the Journal of Geophysical Research — Atmospheres. The work provides new insight into the role that ocean fertility plays in the complex cycle involving carbon dioxide and other greenhouse gases in global warming. <See the full story>. (ScienceDaily, February 17, 2005)
Pollution May Feed Plankton: A surprising chain of events and chemical reactions link a rise in air pollution over land to a decrease in a common greenhouse gas over the sea, announced researchers at the Georgia Institute of Technology on Thursday. The chain includes the participation of dust storms in the Gobi Desert, the buildup of harmful sulfur dioxide over coastal industrial zones, and a burst in the population of tiny plants in the sea known as phytoplankton, said the researchers. The end result is a decrease in atmospheric carbon dioxide, they said. Carbon dioxide contributes to global warming by preventing heat from escaping the atmosphere, the way the walls of a greenhouse prevent heat from escaping an enclosed space. <See the full story>. (Wired news, February, 11, 2005)
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Atmospheric chemistry: Iron injection: Sulphur dioxide, a gas emitted by industrial processes and implicated in acid rain, may be a cloud with a silver lining, according to N. Meskhidze and colleagues. They propose that SO2 converts iron in mineral dust into a form that can be assimilated as a nutrient by phytoplankton, encouraging primary production in the oceans. As this process 'fixes' atmospheric carbon dioxide in biological tissues, it alleviates global warming. The limited availability of iron restricts primary production in some regions of the oceans: atmospheric dust is considered to be the main source. But iron in the dust from arid lands is mostly in the form of Fe(III), which is poorly soluble in sea water and thus has low bioavailability. It can be made soluble by acid, and Meskhidze and colleagues think that a prime source of such acid is the SO2 that dust plumes encounter over urban areas. They confirm that mineral dust transported from the Gobi desert to the Yellow Sea shows a fingerprint of pollutant gases from China. This doesn't necessarily mean, however, that SO2 is good on balance for the global climate: the molecules also become oxidized to form sulphate aerosol particles, which have complex effects on the Earth's radiation budget and cloud cover. <See the full story>. (Nature 426, 242 (20 November 2003) | doi:10.1038/426242a)
Pollution may alter ocean photosynthesis: Sulfur emitted from industrial and power plants can affect oceanic CO2 uptake [Geophys. Res. Lett., 30, 2085 (2003)]. Earth and atmospheric sciences graduate student Nicholas Meskhidze and coworkers at Georgia Institute of Technology, Atlanta, and NASA Langley Research Center, Hampton, Va., knew that large dust storms from the Gobi deserts of northern China could carry iron to phytoplankton in remote regions of the North Pacific Ocean, facilitating photosynthesis and CO2 uptake. <See the full story>. (Science concentrates, Chemical & Engineering News, Vol 81, No48, p.33, 2003)
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