Until now, computer models have been the primary tool for estimating photosynthetic productivity on a global scale. They are based on estimating a measure for plant energy called gross primary production (GPP), which is the rate at which plants capture and store a unit of chemical energy as biomass over a specific time. Joe Berry was part of a team that took an entirely new approach by using satellite technology to measure light that is emitted by plant leaves as a byproduct of photosynthesis as shown by the artwork.

The plant produces fluorescent light when sunlight excites the photosynthetic pigment chlorophyll. Satellite instruments sense this fluorescence yielding a direct observation of photosynthesis on a large scale for the first time. The team measured the fluorescence from large areas of crops in the Midwestern Corn Belt and the Indo-Gangetic Plain. The new data produced values that are 50% to 75% higher than state-of-the-art carbon cycle models, indicating that the models are severely underestimating. Image courtesy Pat Rawlings, Keck Institute for Space Studies

Scientific Area: 
Global Ecology
Reference to Person: 
Joseph Berry - Acting Director
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The sea anemone Aiptasia, photo by Ken Caldeira
Who controls whom: Algae or sea anemone?
November 12, 2019

Washington, DC— Bleached anemones—those lacking symbiotic algae—do not move toward light, a behaviour exhibited by healthy, symbiotic anemones. Published in Coral Reefs, this finding from Carnegie’s Shawna Foo, Arthur Grossman, and Ken Caldeira, along with Lauren Liddell of the NASA Ames Research Center, is a fascinating case study for exploring the concept of control in a symbiotic relationship.

Anemones are closely related to coral and can help scientists understand coral reef ecosystems. Like corals, they host algae that convert the Sun’s energy into food by a process called photosynthesis. The algae share some of the nutrients they produce with

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Khanka image made by Norman Kuring, NASA’s Ocean Color web, and Lauren Dauphin.
Lakes worldwide are experiencing more-severe algal blooms; climate change is likely hampering recovery efforts
October 14, 2019

Washington, DC— The intensity of summer algal blooms has increased over the past three decades, according to a first-ever global survey of dozens of large, freshwater lakes, which was conducted by Carnegie’s Jeff Ho and Anna Michalak and NASA’s Nima Pahlevan and published by Nature.

Reports of harmful algal blooms—like the ones that shut down Toledo’s water supply in 2014 or led to states of emergency being declared in Florida in 2016 and 2018—are growing.  These aquatic phenomena are harmful either because of the intensity of their growth, or because they include populations of toxin-producing phytoplankton. But before this research

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Energy efficient house by Mikhail Grachikov, Shutterstock.
Would a carbon tax help to innovate more-efficient energy use?
August 27, 2019

Washington, DC— Taxing carbon emissions would drive innovation and lead to improved energy efficiency, according to a new paper published in Joule from Carnegie’s Rong Wang (now at Fudan University), Harry Saunders, and Ken Caldeira, along with Juan Moreno-Cruz of the University of Waterloo.

Despite advances in solar, wind, and other renewable energy sources, fossil fuels remain the primary source of the climate-change-causing carbon emissions. In order to halt global warming at the 2 degrees Celsius limit set by the Paris Agreement, we must reduce and eventually stop or completely offset carbon released into the atmosphere by burning of oil, coal, and gas.

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USGS photo of Mount Pinatubo erupting
Geoengineering versus a volcano
August 5, 2019

Washington, DC— Major volcanic eruptions spew ash particles into the atmosphere, which reflect some of the Sun’s radiation back into space and cool the planet. But could this effect be intentionally recreated to fight climate change? A new paper in Geophysical Research Letters investigates.

Solar geoengineering is a theoretical approach to curbing the effects of climate change by seeding the atmosphere with a regularly replenished layer of intentionally released aerosol particles. Proponents sometimes describe it as being like a “human-made” volcano.

“Nobody likes the idea of intentionally tinkering with our climate system at global scale,

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Water Quality

Anna Michalak’s team combined sampling and satellite-based observations of Lake Erie with computer simulations and determined that the 2011 record-breaking algal bloom in the lake was triggered by long-term agricultural practices coupled with extreme precipitation, followed by weak lake circulation and warm temperatures. The bloom began in the western region in mid-July and covered an area of 230 square miles (600 km2). At its peak in October, the bloom had expanded to over 1930 square miles (5000 km2). Its peak intensity was over 3 times greater than any other bloom on record. The scientists predicted that, unless agricultural policies change, the lake will continue to experience

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Ocean Acidification Research

Coral reefs are havens for marine biodiversity and underpin the economies of many coastal communities. But they are very sensitive to changes in ocean chemistry resulting from greenhouse gas emissions, as well as to pollution, warming waters, overdevelopment, and overfishing. Reefs use a mineral called aragonite, a naturally occurring form of calcium carbonate, CaCO3, to make their skeletons.  When carbon dioxide, CO2, from the atmosphere is absorbed by the ocean, it forms carbonic acid—the same stuff that makes soda fizz--making the ocean more acidic and thus more difficult for many marine organisms to grow their shells and skeletons and threatening coral reefs globally.

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Global Change Experiment, Jasper Ridge

Chris Field is a co-principal investigator of the Jasper Ridge Global Change Experiment at the Jasper Ridge Biological Preserve in northern California. The site, designed to exploit grasslands as models for understanding how ecosystems may respond to climate change, hosts a number of studies of the potential effects from elevated atmospheric carbon dioxide, elevated temperature, increased precipitation, and increased nitrogen deposition. The site houses experimental plots that replicate all possible combinations of the four treatments and additional sampling sites that control for the effects of project infrastructure. Studies focus on several integrated ecosystem responses to the

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Intergovernmental Panel on Climate Change

In March 2014, a technical support unit (TSU) of ten, headquartered at Global Ecology, had successfully completed a herculean management effort for the 2000-page assessment Climate Change 2014: Impacts, Adaptation, and Vulnerability, including two summaries. They were issued by the United Nations (UN) Intergovernmental Panel on Climate Change (IPCC), Working Group II co-chaired by Chris Field, Global Ecology director, with science co-directors Katie Mach and Mike Mastrandrea managing the input of over 190 governments and nearly 2,000 experts from around the world.

The IPCC, established in 1988, assesses information about climate change and its impacts. In September 2008, Field was

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Moises Exposito-Alonso

Evolutionary geneticist Moises Exposito-Alonso joined the Department of Plant Biology as a staff associate in September 2019. He investigates whether and how plants will evolve to keep pace with climate change by conducting large-scale ecological and genome sequencing experiments. He also develops computational methods to derive fundamental principles of evolution, such as how fast natural populations acquire new mutations and how past climates shaped continental-scale biodiversity patterns. His goal is to use these first principles and computational approaches to forecast evolutionary outcomes of populations under climate change to anticipate potential future

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Kamena Kostova

Staff Associate Kamena Kostova joined the Department of Embryology in November 2018. She studies ribosomes, the factory-like structures inside cells that produce proteins. Scientists have known about ribosome structure, function, and biogenesis for some time. But, a major unanswered question is how cells monitor the integrity of the ribosome itself. Problems with ribosomes have been associated with diseases including neurodegeneration and cancer. The Kostova lab investigates the fundamental question of how cells respond when their ribosomes break down using mass spectrometry, functional genomics methods, and CRISPR genome editing.

Kostova received a B.S. in Biology from the

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Sally June Tracy

Sally June Tracy applies cutting-edge experimental and analytical techniques to understand the fundamental physical behavior of materials at extreme conditions. She uses dynamic compression techniques with high-flux X-ray sources to probe the structural changes and phase transitions in materials at conditions that mimic impacts and the interiors of terrestrial and exoplanets. She is also an expert in nuclear resonant scattering and synchrotron X-ray diffraction. She uses these techniques to understand novel behavior at the electronic level.  Tracy received her Ph.D. from the California Institute of

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William Ludington

The Ludington lab investigates complex ecological dynamics from microbial community interactions using the fruit fly  Drosophila melanogaster. The fruit fly gut carries numerous microbial species, which can be cultured in the lab. The goal is to understand the gut ecology and how it relates to host health, among other questions, by taking advantage of the fast time-scale and ease of studying the fruit fly in controlled experiments. 
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