CAICE Summer 2018

Particles for Days

Aerosols influence the climate and the environment directly by interacting with incoming and outgoing radiation and indirectly by acting as cloud seeds.  Because of their influence on climate, it is important to measure aerosols, but what are the different ways that our group analyzes them?

ATOFMS
The Aerosol Time of Flight Mass Spectrometer

The pinnacle instrument of the Prather research group is the aerosol time-of-flight mass spectrometer, known as the ATOFMS.  The ATOFMS measures the aerodynamic diameter and the positive and negative chemical spectra for a single aerosol particle in real time. This instrument allows us to look at the chemical signature of the sea spray aerosols released from a breaking wave. With this instrument we can distinguish between different aerosol particle types including sodium rich aerosols, organic rich aerosols, or biological aerosols.  To distinguish between these particle types, we analyze the chemical spectrum from a particle and look for distinct chemical peaks.

However, we have another instrument used to distinguish between biological and non-biological single particles.  This instrument is known as the wideband integrated bioaerosol sensor (WIBS) and determines if a particle is biological based off fluorescence of known biological compounds.  Specifically, the WIBS uses ultra-violet light to excite an aerosol particle and, if it is biological,

The Wideband Integrated Bioaerosol Sensor

the WIBS will then collect the fluorescent signal.  Fluorescence in biological particles occurs because they often contain the amino acid tryptophan and/or the biological co-factor NADH, both of which contain conjugated bond systems and allows for the absorption and transfer of the excitation light source. In addition to the fluorescence signature of a single particle, the WIBS provides information on the particles’ diameter and the asphericity of the particle.

This summer, both of these instruments will be used in tandem to analyze sea spray aerosols released from breaking waves to better understand the role of sea spray on cloud formation and climate.

Brock_Mitts

 

 

-Brock Mitts, Graduate Student

 

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).
CAICE Summer 2018

Is the Ocean Healthy? Let’s Sniff it to Find Out!

This summer I have been fortunate to be a part of the CAICE summer experiment at the Scripps Institution of Oceanography. My mentor, Jon Sauer, and I have been using a Chemical Ionization Mass Spectrometer (CIMS) to analyze the carbon-containing gases, also known as volatile organic compounds (VOCs), produced from the ocean.

CIMS summer expt 2018
The CIMS instrument next to the wave channel

In conjunction with the Aerosol Time of Flight Mass Spectrometer (ATOFMS), which measures the chemical composition of individual aerosol particles, and aerosol particle sizing equipment we can effectively measure the chemical nature of gases and particles produced from seawater in our experiment. The CIMS plays a crucial role in analyzing the health and stability of the phytoplankton bloom in the ocean water within our sampling tanks. To do this, we use the CIMS to sample gases produced in the headspace above the ocean water in our tanks. Looking for specific species reassures us that successive phytoplankton communities are similar to one another and remain healthy.

Along with a lot of amazing knowledge, one of the most important and useful things I will take away from this experience is the importance of communication. This large of an experiment requires constant communication between everyone involved and the people in this group set an amazing example for how to communicate effectively. From group meetings to day to day problem solving, constant sharing of ideas and findings never go unheard.

Summer Expt 2018
Dr. Kim Prather talking to Ben Rico and Jon Sauer about their experiment

The environment promotes curiosity and collaboration and the people I’ve been so lucky enough to work with are always willing to help. I owe a great deal of thanks to my mentor Jon who not only went out of his way to make me feel a part of the group but who made the long days of work enjoyable. Whether we were acquiring data from the CIMS or he was telling me about all the fish he caught from his last fishing trip, Jon managed to make every day of my summer experiment a memorable one.

 

I am looking forward to the rest of my time being a part of this summer experiment and cannot wait to see the results of all the hard working people that are a part of it.

— Ben Rico, Undergraduate Researcher

— Jon Sauer, Graduate Student Researcher

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).
CAICE IMPACTS 2014

The study of ocean – atmosphere interactions

When waves crash and underwater bubbles burst at the surface, tiny particles are ejected from the ocean into the atmosphere. As the water evaporates away, a particle is left behind that we call sea spray aerosol. Our research through the Center for Aerosol Impacts on Climate and the Environment (CAICE) is focused on understanding the physical, chemical, and biological processes that affect the composition sea spray aerosol. Knowledge of this composition is critical to understanding the effect of sea spray in the atmosphere, such as how it reacts and how it affects cloud formation.

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Marine Aerosol Reference Tanks (MART) provide a unique opportunity to capture sea spray aerosol in the laboratory

During the IMPACTS field experiment at Scripps Institute of Oceanography in La Jolla, California, we are collecting samples of ocean water, sea surface microlayer, sea foam, and sea spray aerosol from the wave flume and Marine Aerosol Reference Tanks (MART). We transport these samples back to our laboratories at the University of Iowa, where we measure individual organic molecules and inorganic ions. We use liquid chromatography (LC for short) that allows us to separate compounds of interest from the complex environmental sample. Conductivity, electrochemistry, and mass spectrometry provide sensitive methods of detection that allow us to quantify trace amounts of compounds. By determining the distribution of chemicals across the phases of the ocean and atmosphere relative to one another, we can characterize the selective processes that lead to organic molecule enrichment in sea spray aerosol. Collaborating in the IMPACTS field study means that we can combine our knowledge of chemistry with evolving ocean biology and the physical properties of the sea spray aerosol.

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CAICE researchers (clockwise) Hosiana Abewe, Olga Laskina, Jon Trueblood, Thilina Jayarathne, and Grace de Dieu Irumva testing a laboratory experiment on the measurement of surface reflectivity (a.k.a. albedo)

In addition to conducting research, CAICE provides an opportunity to engage with students and the community in learning about climate science. I had the pleasure of teaching at the California State Summer School for Mathematics and Science (COSMOS) while at UCSD earlier this month. I worked with undergraduate and graduate students to design and adapt curricula about global change and climate for high school students. Together, we explored how the earth’s surface affects our energy balance with the sun, how some gases cause greenhouse warming, and how different molecules interact with solar energy.

I am thrilled to be part of a dynamic research center that combines cutting-edge research, innovation, and education about climate science. Through this summer’s IMPACTS experiment, we have new capabilities to understand complex environmental processes through intricately-designed laboratory experiments.

Elizabeth Stone, Assistant Professor, Department of Chemistry, University of Iowa