A Deep Dive

A view of the Pacific Ocean from La Jolla, California

What do you see when you look out over the Pacific Ocean?  One time, I saw a colorful sunset with promise of a green flash. Another time, I saw a pod of dolphins jumping along the coastline. Now, I see the opportunity to dive deep into chemistry and the vast complexity of the atmosphere and ocean.  

Microscopic marine algae, called phytoplankton, turn carbon dioxide from the atmosphere into different chemicals. Some of these chemicals store energy, while others may be incorporated into cell walls.  An individual phytoplankton lives only a few days, and ultimately returns these chemicals back into the ocean. Some of these newly formed chemicals accumulate on the ocean surface, similar to oil rising to the surface of a puddle. The chemicals at the ocean surface can be transferred back into the atmosphere as sea spray particles when waves crash. Once in the atmosphere, these particles interact with sunlight, act as seeds for clouds and ice, and undergo chemical reactions that can alter these properties.

Glorianne Dorcé and Elias Hasenecz, graduate students at the University of Iowa, preparing equipment to collect sea spray aerosol particles that have undergone chemical aging.

In the Sea Spray Chemistry And Particle Evolution Experiment (called SeaSCAPE for short), dozens of talented, dedicated, and inspiring scientists are working tirelessly to study sea spray particle chemistry, transformations, and impacts on the environment. Sea spray particles are collected onto carefully cleaned filters and then shipped to the University of Iowa where we analyze the naturally occurring and man-made chemicals. Other particles first undergo chemical reactions, similar to those that occur in the atmosphere in the presence of sunlight and oxidants, and are then collected. In this case, we examine how reactions alter the chemistry of sea spray particles. 

Our journey only begins this summer and will be followed by years of chemical measurements, discussions, and research collaborations.

Written by: Betsy Stone, Associate Professor, University of Iowa

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).


Let’s get it started!

SeaSCAPE (Sea Spray Chemistry And Particle Evolution) 2019 is ramping up this week! As you look around the Hydraulics Laboratory “H-Lab” at UC San Diego’s Scripps Institution of Oceanography, you will find NSF CAICE researchers working hard to set up and calibrate their instruments for summer long experiments. You can feel the excitement!  The collaborative team of researchers will soon fill the glorious 33-meter-long wave channel with seawater (see video of waves with the test waters, courtesy of CAICE researcher Prof. Betsy Stone at University of Iowa), and sampling will start next week and last all summer. Bulk seawater, sea surface microlayer (SSML), and sea spray aerosol (SSA) will be collected and measured around the clock, as the crashing waters within the wave tank experiences blooms of biological activity similar to that found in open oceans and seas.

Video of the wave channel in action, courtesy of CAICE researcher Prof. Betsy Stone at the University of Iowa.

For our group, this is a key chance to test how these biological blooms impact the physical chemical phase of SSA. We will take the samples back to our laboratory at the University of Minnesota to use custom build microfluidic (lab-on-a-chip) platforms with on-chip temperature control, to study water uptake and ice nucleation of these sea spray waters and aerosols. In collaboration with the Prather group at UC San Diego, we recently published work on multistep phase transitions that can occur in samples of SSML samples spiked with an organic acid common in the aerosol.  In the time-lapsed 11 second video, you will that as the relative humidity drops, the samples evolve through steps of crystallization, liquid-liquid phase separation, a second crystallization, and a second liquid-liquid phase separation. Each of these phase states impacts how the aerosol particle interacts with the environment, reflects and absorbs solar radiation, forms clouds, and nucleates ice crystals in the atmosphere.

Multistep phase transitions of SSML sample spiked with an organic acid, from Nandy et al. ACS Earth and Space Chemistry (2019). 
DOI: 10.1021/acsearthspacechem.9b00121

We are so excited to collaborate this summer with the many outstanding CAICE groups participating in SeaSCAPE 2019, to collectively tackle the big unanswered questions of SSA properties and dynamics, and their impacts on our climate.

Written by: Associate Professor Cari Dutcher, Mechanical Engineering, University of Minnesota

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

Where the circle of life meets the colors of the wind

Like many people, I grew up watching Disney animated movies. But now as a Ph.D. student who studies connections between ocean and atmospheric chemistry, these childhood ideas are much more real than I ever expected.

We’ve all heard the story: lions eat the antelope. And when they die, their bodies become the grass and the antelope eat the grass. What most people don’t realize is that this same process can be seen in the ocean with a microscope.

Mitch Figure
Concentrated colored (yellow) organic matter, including humic substances, extracted during a phytoplankton bloom

Tiny algae in the ocean grow in number, and when they die, their bodies are broken down by bacteria in the ocean to provide nutrients for other organisms. During this microscopic circle of life, a class of molecules is made called “humic substances”, and these are the molecules I study.

Humic substances are special because they are colored, in other words they can absorb light. They can be also launched from the ocean into the air via sea spray (what I call here the “colors of the wind”).

And when they absorb light in the air, they can start reactions that transform the chemistry of the atmosphere. This exchange from the ocean to the air doesn’t always happen, so my work tries to uncover when and how these molecules get into the air during these ocean life-and-death processes.

The part that I love the most about this research is that you quickly learn that everything is connected. Ocean chemistry is linked to atmospheric chemistry, what happens on the microscopic scale can affect the global scale, and the ocean’s circle of life can give rise to the colors of the wind.

Mitch Photo
Mitch Santander sitting next to a spectrofluorometer, a tool used to measure the relative abundance of humic substances.






— Mitch Santander, CAICE 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

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?

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, 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 Summer 2018

Does Aerosol Size Matter?

The three of us, Lee, James, and Young, have been fortunate enough to participate in research for the first time in our undergraduate careers, down at the SIO Hydraulics lab with CAICE.

Lee James and Young
Lee, James & Young working on the wave channel to measure the size distribution of aerosol particles generated by breaking waves

As students with backgrounds in chemistry and the environment, it’s hard to think of a better situation to be in, helping save the planet and all. Young and Lee are UCSD seniors studying chemistry, and James is a sophomore studying environmental science at Warren Wilson College.

So far in the lab, we have been trained to be in charge of instruments that measure the size and count the number of particles in the air. More specifically, we look at sea spray aerosols that are produced from bubbles bursting.

Wave Channel
33 m long wave channel at Scripps Institution of Oceanography Hydraulics Laboratory

With the new 33-meter wave flume (see photo) that was designed to mimic waves breaking and bubbles bursting in the ocean, we hope to find out what biological and chemical phenomena are characteristic of different particle sizes. If all goes well, this will help researchers improve existing climate models with more knowledge and understanding of the effects of sea spray aerosols on the atmosphere.

Besides using cool instruments and working on experiments, one of the best parts of research at CAICE is the people of CAICE. The other undergraduate students, graduate students and postdocs are incredibly generous and fun to work with. Not a single birthday is missed without some sort of celebration and cake. And, of course, we always look forward to coffee runs and playing frisbee together at the end of a long day.

–Lee Elmont, James Mayer, Young Jeong

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

A New Beginning

As I made my way back to California from Washington, D.C., I wondered how the next chapter of my life would unfold.  Although I had been a research intern for the past two summers at UC San Diego, I knew it would be very different as a first year graduate student.  After listening to all of the research projects at the CAICE meeting, I began counting down the days until I could start working in the lab.

Alexia Moore
Alexia Moore in the Hydraulics lab next to the Marine Aerosol Reference Tanks and two spot samplers collecting aerosol samples

I couldn’t wait to get integrated with the group and the projects.  At the CAICE meeting, I heard all about the three Marine Aerosol Reference Tank (MART) experiment and the new wave flume.  I knew that being a part of this was going to be special. Once I begin in the lab, I quickly learned that my part of the project would be counting bacteria and viruses in seawater and sea spray aerosols (SSA).  I would also be concentrating viruses for the virus addition.  With 1031 viruses on earth and the ocean containing half of that population, it’s important to understand how the biology of the ocean affects SSA. In order to concentrate viruses, a 0.22 um filter and 100 kDa Tangential flow filtration (TFF) are used. TFF is a method to separate and purify biomolecules. A 0.22 um filter is used to filter out the bacteria and TFF is used to filter and concentrate viruses. By using this process we are able to get a volume of viruses that will increase the concentration of the MART by two orders of magnitude. The technique we use for counting cells is flow cytometry. Flow cytometry creates a single stream of cells and as they pass by a laser the light scatter is measured and correlated to the size of the cell. This allows us to separate bacteria and viruses by size and obtain the concentration in a sample.

Alexia Plot compiled

There have been many long days and a lot of hard work but overall a very rewarding experience. I’m happy that I was able to start working this summer and that am getting to participate in the work done in the CAICE labs. This summer has got me excited to begin my PhD program. Oh and on top of all that, I got to participate in the 4th of July fireworks research.  If this is any indication of what the next chapter of my life is going to look like, I’m in for a very exciting time!

— Alexia Moore

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

Contamination Conundrum

I am an incoming first year PhD student in the Prather research lab.  My project for this summer isn’t currently tied to what is happening with the main wave channel experiment – but it is hopefully going to help to improve data collection in the future.

Ice Nucleation Counting
Software used to monitor when water samples contained in a well-plate freeze.

My main research focus is INPs (otherwise known as ice nucleating particles).  The presence of these particular particles is what causes water to freeze at warmer temperatures than pure water normally would.  In other words, the more of these particles are present, the quicker the water will freeze.

So far this summer I have been attempting to decrease the background contamination of INPs in our AIS (automated ice spectrometer).

These contamination particles could be from places such as dust in the air, or debris from plastics used to make the sterile tools we use in these experiments. Decreasing contamination will allow us to reduce the freezing temperature of the background (pure water), allowing us to measure a wider range of INPs during our experiments.  Previously we had a concentration of 10 INP/mL at -20֯C, and after making adjustments to try and reduce contamination a concentration of 4-6 INP/mL at -23֯C has been achieved.


This is a step in the right direction and we hope to continue to get the background signal of INPs down, so we can measure SSA (sea spray aerosols) with confidence in the AIS.

 –Brooke Rasina



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

A Timely CAICE Summer Experiment

Summers are always an incredibly exciting time for all of us in the NSF Center for Aerosol Impacts on Chemistry of the Environment (CAICE) at UC San Diego. Every June, the new smiling faces of incoming graduate and undergraduate students in the CAICE summer program walk through the door. It is a boost of energy for everyone. It is truly a privilege to serve as Director of CAICE and be able to work with these students, helping train them how to think about complex environmental problems, while becoming fearless leaders equipped to take on and tackle new environmental challenges.

Hydraulics Lab 2018
The Hydraulics Laboratory building sits on Scripps Institution of Oceanography campus overlooking the Pacific Ocean

But this summer is different than others for several pressing reasons. Mother Earth has clearly intensified her cries for help: numerous heat waves around the world, the state of California experiencing a record number of wildfires, and an increasing number of extreme weather events. Locally here in La Jolla this summer we have witnessed the hottest ocean temperatures at the Scripps Institution of Oceanography (SIO) pier since temperatures started being recorded 102

In CAICE, we are scrambling to ramp up our summer experiments designed to understand the natural ocean-atmosphere system.  Ware all feeling a deeper sense of urgency and commitment to our research efforts than ever before. 

Bacterial Addition
Graduate Student, Matt Pendergraft, adding bacteria to the Marine Aerosol Reference Tank during the Summer 2018 Experiment

This summer’s project is being conducted at the unique CAICE ocean-atmosphere facility in the SIO hydraulics laboratory. Right now, the researchers are performing experiments designed to improve our understanding of how ocean biology influences the chemical composition of sea spray aerosol particles and cloud formation in the atmosphere, which ultimately affect the temperature of our planet. A major focus of CAICE involves probing the factors contributing to the release of microbes from the ocean to the atmosphere in the form of viruses and bacteria.

These bioparticles play an important role in forming clouds and their release from the ocean has been hypothesized as a way the Earth regulates the temperature of the planet.

This summer’s experiment wraps up 5 years of CAICE studies focused on understanding how seawater chemistry influences the atmosphere and climate.

CAICE 2018
Expert marine microbiologist Dr. Farooq Azam comes down to the Hydraulics lab to see the experimental set up and to go over the plans for the phytoplankton bloom experiments

We have been working to understand how the natural ocean-atmosphere system worked before humans entered the picture.  We are asking how much ocean biology can influence climate by inducing phytoplankton blooms in mesocom studies using novel Marine Aerosol Reference Tanks filled with Pacific Ocean seawater—by adding known bacteria and viruses, we are working on unraveling the steps involved in the microbial loop while measuring the sea spray and gases that are emitted.

Scripps Sunset
Sunset at Scripps Pier with smoke from a nearby forest fire visible on the horizon over the ocean.

One particular question inspired by this summer’s conditions is how the ocean biology will change in a warmer climate.  How will future ocean microbe distributions affect the chemistry of our atmosphere and climate?  Over the next 5 years, we will build and use a one-of-a-kind, state of the art wind-wave facility (SOARS) funded by the NSF to control winds, ocean temperature, biological species, as well as add human-pollution to the mix. Studies will unravel how chemical interactions between humans and ocean microbes are influencing the composition and climate of our planet. We are looking for motivated scientists and communicators with a broad range of backgrounds (i.e. chemists, data scientists, microbiologists, engineers) to join us. Please contact us if you are interested!

Prof. Kim Prather –Prof. Kim Prather, Director of CAICE

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

Bubbles and Aerosol Particles in the Hydraulics Lab

The Hydraulics Lab at Scripps Institution of Oceanography is probably one of the best places on the Earth to study bubbles and aerosols. When I joined CAICE in 2014, my first experiment was in the Hydraulics Lab during a study called “IMPACTS” — You can read previous blogs to learn more about it! Interestingly, my experiences have come full circle as I soon will be leaving to start a faculty position in China but my last CAICE experiment is also taking place in the Hydraulics Lab. I feel very fortunate to have had so many opportunities to study great science relating bubbles and aerosols in this beautiful place.


Bubble formation and bursting is a fascinating process. You can easily see this process if there is an interface between liquid and gas. When ocean waves hit the water surface, bubbles form and burst. When raindrops hit soil, bubbles form and burst. When you open a soda can, bubbles also form and burst. Bubble bursting can eject many aerosols in a variety of sizes. However, people do not fully understand how this process actually happens. In my opinion, no one knows the exact production mechanism of submicron aerosols following bubble bursting. Bubbles not only produce aerosols in the air, but can also enhance gas emission from water. Some of these gases could go on to form secondary aerosol in the air. This process is also fascinating and extremely important to the climate. It will be a major focus for CAICE during the next five years.

Dr. Xiaofei Wang

Life in Hydraulics Lab is not always easy, but it is fun! Long working hours, pump noise and high temperature do not hinder our curiosity to explore unknowns. Experiments within this facility are always large and involve many people. It is really a fun experience to work with a lot of people where everyday everyone is excited about science and always try to help. I am sure we have a lot of new findings when the experiment concludes!

— Xiaofei Wang, Assistant Project Scientist at CAICE

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).