EAS Fall 2018 Seminar Series Presents: Dr. Yuanzhi Tang

Small is big: Toward a molecular scale understanding of element (re)cycling

In the natural environment, the fate and transport of contaminants, nutrients, and metals are intimately linked to our daily life, thus significantly influencing the sustainable development of human society. 

Biogeochemical reactions have also been widely recognized as critical components for sustainable agriculture, wastewater treatment, as well as the evolution of Earth’s solid surface and atmosphere. Yet, in our long march trying to understand the biogeochemical cycles of elements among geosphere, biosphere, hydrosphere, and atmosphere, one of the biggest challenge is to bridge the measurements and interpretations at different spatial and temporal scales. 

Particularly, in geochemistry, one fundamental knowledge gap is to correlate the molecular scale speciation (defined as the physical and chemical states of an element) with larger scale reactivity (such as mobility and bioavailability). Over the past five years, my research group has focused on revealing such speciation-reactivity correlations at mineral-microbe-metal interfaces, such as those related to microbially impacted mineral formation and transformation (e.g. biomineralization and bioweathering), contaminant transport (e.g. remediation and long term stability), and metal/nutrient cycling and recycling (e.g. resource recovery). 

In order to isolate, quantify, and integrate the fundamental mineralogical and biogeochemical factors influencing these processes, we conduct multidisciplinary investigations spanning macro-, micro-, nano-, and molecule-scales and across multiple fields. 

In this talk, a few examples will be given to demonstrate our research efforts on metal/nutrient cycling and recycling, as well as the importance of understanding molecular scale interfacial processes. 

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EAS Fall 2018 Seminar Series Presents: Dr. Jennifer Glass

Ironing Out Early Microbial Metabolisms

Methane and nitrous oxide are potent greenhouse gases that contribute to modern climate change, and may have maintained habitable temperatures in ancient anoxic, iron-rich oceans when radiative heating was lower under the Faint Young Sun. 

I will present results from my Georgia Tech lab on the influence of iron speciation on methane production and microbial diversity in ferruginous sediments, and nitrous oxide production in ferruginous seawater (or "chemodenitrification"). 

These findings suggest that anoxic iron-rich seas emitted significantly higher atmospheric fluxes of these two greenhouse gases than modern anemic oceans, and that nitrous oxide, possibly arising from chemodenitrification, played a key role in the evolution of aerobic respiration. 

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EAS Fall 2018 Seminar Series Presents: Dr. Sarah Purkey, Scripps Institution of Oceanography

New Insight into Deep Ocean Warming from Tracer Data and Another Decade of Repeat Hydrography

Previous comparisons of repeated hydrographic sections between the 1990s and 2000s revealed a global pattern of deep and abyssal ocean warming in regions of the ocean fed by dense waters of Southern Origin.  However, the mechanisms driving the deep warming are still poorly understood.  First, I will use new data to present updated deep ocean warming rates in the Pacific and present new insight through a deep ocean heat budget.  Second, I will show how transient tracers can be used to explore deep circulation and detect decreases in ventilation rates of Antarctic Bottom Water in the Pacific sector of the Southern Ocean, possibly driving the observed abyssal warming.

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EAS Fall 2018 Seminar Series Presents: Dr. Celine Grall, Lamont-Doherty Earth Observatory, Columbia University

Subsidence and Relative Sea Level History in the Ganges Delta and Other Large Delta Plains

The subsidence and the relative sea level history in the world largest delta plain, the Ganges Delta will be addressed in this presentation. 

Results that will be presented include the first stratigraphic reconstruction of the Holocene relative sea level history in this region, numerical modelling that aims to quantify the Holocene subsidence driving forces and a quick comparison between the Holocene subsidence rates and the present shoreline migration. This will give us the opportunity to open the discussion about subsidence driving forces in other large delta plains and the negative impact that human modification may have on subsidence and relative sea level in large delta plains.

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December 31, 1969 |

The College of Sciences has named Jennifer Hom, Takamitsu Ito, and Scott Moffat as the 2018 recipients of the Cullen-Peck Faculty Fellowship Awards in the College of Sciences. The awards recognize innovative research by faculty at the associate professor or advanced assistant professor level. The goal is to help recipients take their research programs in new directions.

The fellowships are made possible by a generous gift to the College of Sciences from alumni Frank H. Cullen (B.S. in Mathematics with Honors 1973, M.S. in Operations Research 1975, Ph.D. Engineering 1984) and Libby Peck (B.S. in Applied Mathematics 1975, M.S. in Industrial Engineering 1976). The alumni couple wish to recognize and support faculty development in the College of Sciences

“We continue to be grateful for the generosity of alumni who encourage our faculty to take intellectual risks in their research,” says College of Sciences Dean and Sutherland Chair Paul M. Goldbart. “The Cullen-Peck fellowships help ensure that our research is pushing the frontiers of knowledge. Congratulations to the latest Cullen-Peck fellows.”

Knot Theory

Jennifer C. Hom is an associate professor in the School of Mathematics. The award recognizes her outstanding research in knot theory, which has led to fundamental contributions to the study of knots and development of powerful tools in topology.

 

Knots can be conceived as loops of strings with ends glued together. Their study is a beautiful subject, central to understanding low-dimensional space, as well as some modern trends in physics.  Hom’s work centers on knots in three-dimensional space. She has enriched the field by introducing deep new ideas.

A much-studied question asks whether a knot can bound a disk in four-dimensional space in certain nice ways. Such knots were previously known. But Hom was able to find a huge new family of such knots, inspiring a flurry of activity in the use of Heegaard-Floer theory to study such objects.

The Heegard-Floer theory is a much-studied technique that revolutionized low-dimensional topology. Yet, Hom found new subtle features, which she formalized as the epsilon invariant. The epsilon invariant is a number associated to each knot. By using the properties of these numbers, Hom proved that an infinite number of knots could bound certain disks in four-dimensional space and not others.

​Her work inspired leaders in the field, including the developers of Heegaard-Floer theory themselves, to pursue ​new avenues of research​. Among other things, this work gives a new proof that in a sense there is more than one way to do calculus in four dimensions.

The epsilon invariant is now part of the Heegard-Floer theory; it is taught in graduate courses around the world; it is considered one of the top five spectacular advances in the past decade. A mark of top-notch mathematics is that it inspires other people and takes a life of its own. Hom’s epsilon invariant belongs to this category. 

“It's a great honor to receive this award,” Hom says. “I look forward to using this fellowship to help develop new techniques for studying knots and low-dimensional spaces.”

Biogeochemical Cycling and Ocean Deoxygenation

Takamitsu “Taka” Ito is an associate professor in the School of Earth and Atmospheric Sciences. The Cullen-Peck award recognizes his outstanding research in biogeochemical cycling and ocean deoxygenation.

Ito uses models to better understand the interactions of physical, chemical, and biological processes that regulate the cycling of chemical elements in the ocean. He develops theories of the partitioning of dissolved gases between the ocean and the atmosphere. He is renowned for recent work on the distribution of dissolved oxygen in the subsurface ocean.

In the 2017 paper “The Upper Ocean Oxygen Trend: 1958-2015,” Ito analyzed historical, global datasets of dissolved oxygen. He found that the amount of dissolved oxygen in the water – an important measure of ocean health – has been declining for more than 20 years.

This paper garnered media attention for the implications of declining oxygen in the ocean: It could affect the habitat of marine organisms worldwide. It could lead to more frequent “hypoxic events,” which kill or displace populations of fish, crabs, and other organisms.

Furthermore, the analysis showed that ocean oxygen is falling more rapidly than anticipated from the rise in water temperature due to climate change.

Ito has also been exploring the previously under-appreciated role of polluted aerosols in altering ocean biogeochemistry. In a 2016 paper in Nature Geoscience, he and his collaborators showed that air pollution can deliver additional iron and reactive nitrogen to the ocean and affect oxygen levels.

The transport of highly insoluble iron to the ocean and its availability for biological productivity are not well understood. Ito’s modelling approach will help translate into new insights the oceanic iron data from the large observational program GEOTRACES. His research could reveal how iron cycling affects ocean productivity, carbon uptake, and oxygen concentrations over various time scales.

Cognitive Neuroscience of Aging

Scott Moffat is an associate professor in the School of Psychology. His selection as Cullen-Peck fellow is based on his outstanding research in the cognitive neuroscience of aging.

With aging comes cognitive decline, which affect mental faculties including memory and the ability to navigate. Moffat has embarked on research addressing metabolism and aging. In particular, he studies the role of diabetes in cognitive aging.

Peripheral insulin crosses the blood–brain barrier to modulate memory processes. Insulin resistance in the periphery goes with insulin resistance in the brain and memory impairment. The hope is to associate variations in peripheral insulin secretion and insulin sensitivity to cognitive and neural endpoints.

Meanwhile, type 2 diabetes is a public health crisis in the U.S. and many developed countries. The disease is a risk factor for other serious health conditions, such as brain and cognitive dysfunction, as well as Alzheimer’s disease. Using functional magnetic resonance imaging, Moffat is examining the association of glucose and insulin metabolism with cognitive and brain function.

The research is still in its early days, but already Moffat and his colleagues are realizing remarkable results. For example, they’ve found that individuals with higher fasting glucose levels or insulin insensitivity – even within the non-diabetes range – have poorer performance in episodic and working memories. They also have thinner gray matter in key prefrontal cortical areas. 

The implications for prediabetes are profound. Prediabetes is prevalent among adults; the National Center for Chronic Disease Prevention reports that majority of all adults older than 65 have prediabetes. Discovering the impact of prediabetes on cognition and cognitive decline could bring about interventions, pharmaceutical or otherwise.

Please join the Ray C. Anderson Center for Sustainable Business and the Georgia Tech School of Earth and Atmospheric Sciences at the Carbon Reduction Challenge Final Poster Expo! 

With support from the Ray C. Anderson Foundation NextGen Fund and the Scheller College of Business Dean’s Innovation Fund, Professors Kim Cobb and Beril Toktay collaborated to expand Professor Cobb’s successful Carbon Reduction Challenge class to enable students participating in an internship or co-op to plan and implement a carbon reduction project with their employers.

Individual students or a team took the initiative to identify and execute a plan that reduces their employer’s carbon emissions, most often saving their employer money, over the course of their internship.

Project examples from the class range from creating employee challenges to reduce their personal carbon emissions, to changes in building lighting schedules, to more capital-intensive projects such as HVAC modifications. 

The winners of the Carbon Reduction Challenge will be decided based on

  • the amount of carbon emissions avoided (whether actual or potential), and  
  • the level of awareness fostered through the project.

The winning team(s) will be announced at the conclusion of the Finalist Poster Expo and will receive cash prizes for their work. First prize is $5,000, second place is $3,000 and third place is $1,000.  Refreshments will be available. 

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Role of Thiols in Microbial Metal Reduction and Importance of Organic-Fe(III) Complexes on the Benthic Flux of Iron from Continental Margin Sediments

Iron and manganese transformation reactions greatly impact a variety of environmental and biogeochemical processes in the environment, including the transport and degradation of inorganic and organic contaminants, the cycling of organic carbon, and the transformation a variety of other biogeochemically important chemical species. In addition, as essential nutrient, iron exerts a substantial control on ocean productivity and export of organic matter to the deep ocean.

Science Showcase at Ponce City Farmers Market

Georgia Tech will be at Ponce City Farmers Market one Tuesday a month from June to November. Graduates in Earth and Atmospheric Sciences and faculty from the Georgia Tech School of Earth and Atmospheric Sciences will share with customers and passersby science about our planet that they could apply to their daily lives.

Climate Change is the last of six programs making up "Science Showcase at Ponce City Farmers Market." Kim Cobb, professor in the School of Earth and Atmospheric Sciences will talk about her research and its implications on climate change.

If you are in the farmers' market, you can ask Kim Cobb how burning fossil fuels leads to global warming and what climate science says we can expect in the coming years, decades, and centuries.

 

Series Schedule
Following are the topics for "Science Showcase at Ponce City Farmers Market" through November, as well as the Georgia Tech volunteers:

The showcase is an initiative of Ph.D. student Tiegan Hobbs. Georgia Tech's science presence at Ponce City Farmers Market was made possible by Hobbs's collaboration with its market manager, Stephanie Luke.

 

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Science Showcase at Ponce City Farmers Market

Georgia Tech will be at Ponce City Farmers Market one Tuesday a month from June to November. Graduates in Earth and Atmospheric Sciences and faculty from the Georgia Tech School of Earth and Atmospheric Sciences will share with customers and passersby science about our planet that they could apply to their daily lives.

Dark Skies Protection is the fifth of six programs making up "Science Showcase at Ponce City Farmers Market." The goal of this program is to inform the public of the growing problem of "dark skies." If you are at the farmers' market you can also learn   

  • why dark skies are important
  • what is causing loss of dark skies
  • about the impact of loss of dark skies to nocturnal animals
  • about amateur stargazing

 

Series Schedule
Following are the topics for "Science Showcase at Ponce City Farmers Market" through November, as well as the Georgia Tech volunteers:

The showcase is an initiative of Ph.D. student Tiegan Hobbs. Georgia Tech's science presence at Ponce City Farmers Market was made possible by Hobbs's collaboration with its market manager, Stephanie Luke.

 

Event Details

Date/Time:

Science Showcase at Ponce City Farmers Market

Georgia Tech will be at Ponce City Farmers Market one Tuesday a month from June to November. Graduates in Earth and Atmospheric Sciences and faculty from the Georgia Tech School of Earth and Atmospheric Sciences will share with customers and passersby science about our planet that they could apply to their daily lives.

DIY Meteorology Kits is the fourth of six programs making up "Science Showcase at Ponce City Farmers Market." The goal of this program is to demonstrate how anyone can make a basic meteorology kit at home from common items. If you are at the farmers' market you can also learn   

  • how weather works
  • what the "highs' and "lows" in weather reports mean and how they affect the formation of storms 
  • about high-end meteorology kits 

 

Series Schedule
Following are the topics for "Science Showcase at Ponce City Farmers Market" through November, as well as the Georgia Tech volunteers:

The showcase is an initiative of Ph.D. student Tiegan Hobbs. Georgia Tech's science presence at Ponce City Farmers Market was made possible by Hobbs's collaboration with its market manager, Stephanie Luke.

 

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