Shedding Light on the Effects of Biology and Organic Matter in the Ocean

Living near the ocean for almost my entire life, I grew up in a coastal town called Quy Nhon in Vietnam and moved to San Diego almost 10 years ago. Despite this, I was aware that I knew very little about the sea. I did, however, understand how we all tend to take the ocean for granted: for our mini weekend vacation, for the amazing seafood, and many more reasons!

The ocean is threatened by the negative effects from our now-changing climate. The key to mitigation is being able to first understand the underlying chemistry and interactions between the ocean and the atmosphere. A great example of this was the discovery that chlorofluorocarbons (CFCs) could form ozone-destroying radicals on the surfaces of polar stratospheric cloud aerosols; knowledge that allowed us to ban such chemicals to help reverse the progression of the ozone hole in the 80’s and 90’s.

The ocean is home to a diverse ecosystem, whose activities directly and indirectly control its surroundings. It becomes very fascinating once we begin to understand the activities of the microscopic species, such as bacteria, phytoplankton, viruses, etc. These microbes are able to emit volatile organic compounds (VOCs) as resistance to environmental stresses, communications, and allelopathic and defense mechanisms. Once emitted into the air, these VOCs can act as a sink for hydroxyl radicals and form secondary marine aerosols – a focus of the SeaSCAPE study. Such aerosols are the single largest uncertainty in our quest to understand climate change (see IPCC AR5). 

For my project, bloom water collected from the wave flume is irradiated with a solar simulator for approximately 2 to 3 hours. The reaction chamber is a horizontal column capped with quartz windows on both sides and inlet/outlet at the top for N2 gas flow through the headspace, carrying the emitted VOCs into the Orbitrap Elite mass spectrometer. The VOCs are ionized using a modified gas-phase atmospheric pressure chemical ionization (APCI) method to directly measure gases using high resolution mass spectrometry. We use a timeline to collect samples for each bloom for a temporal analysis, going from when the seawater is added, to the addition of nutrients, to the peak and the death phase of the bloom. We also analyze both unfiltered and filtered (0.2 microns) bloom water to specify the biotic and abiotic VOCs. During the first bloom cycle, we observed little signal overall with the bloom water collected on June 5th, when the nutrients were just added. However, the sample on June 10th, 6 days after the nutrients are added, showed promising details with the detection of isoprene, fatty acids, aldehydes, and other compounds such as dimethyl sulfide (DMS) and terpenes that are commonly known as algal VOCs. Some signals were observed on sample collected on June 15th, just a day after the nutrient spike on the second bloom cycle; however, it was very weak. Though, similar to the first bloom cycle, an enhanced signal was observed in the sample collected on June 18th on the second bloom, 4 days after the nutrients were added! The signal intensities seem to be confidently detected with at least 4 days after the nutrients. An interesting point to make is that samples from the second bloom presented a trend in an enhancement of VOCs approximately 30 to 60 minutes from when the irradiation started. Furthermore, another enhancement typically occurred around 60 minutes after the first mysterious peak. It was hypothesized that there may be delayed (and probably multiple) metabolic processes among the marine species, that caused the pattern.

With the complexity of the biology inside the bloom water, it is difficult to pinpoint the environmental factors and species that are responsible for those mysterious peaks. The next step in this project will involve analyzing the VOC emissions of monocultures of bacteria and phytoplankton observed in the microbiome of the wave flume blooms, to create a library of VOC emissions distinctive to each bacteria strain as the reference point for future analysis.

In addition to the analysis of the volatile components of the bloom water, I work closely with David Gonzales on his project on characterizing the composition of the marine-dissolved organic matter (m-DOM), which we collected from the same water using solid-phase extraction. Together, our data presents the whole temporal compositional change of the water in the wave flume, with respect to the change of its biology. Perhaps we may be able to understand how light affects the composition of the gaseous and liquid phase at our ocean surface.

Written by: Duyen Dang, Undergraduate Student in the Grassian Research Group at UC San Diego

As I grew up, I noticed the human impacts on the environment – the increasing occurrence of hurricanes near my home, flash flooding, tornado warnings, and smog-laden air. Our daily routines affect the ecosystems around us. I started to think about how we influence our surroundings in ways in which I could study and possibly mitigate these impacts. This brought me to study chemistry at Pace University in New York City in order to gain experience that could be applied to my research and future career on the environment. 

I wanted to work at CAICE to experience the approach that atmospheric science has in studying environmental chemistry. My project in SeaSCAPE, is to characterize the broad structure and reactivity of marine dissolved organic matter (m-DOM) in the bulk water of the 30 m long wave flume. With the help of Duyen, working on VOC characterization, much of our work overlaps in terms of identifying chemical components found in seawater. To date, m-DOM is poorly understood in terms of its composition as well as its role in the ocean and atmosphere (as an aerosol). It can have anywhere from 1,000 to 10,000 or more molecular signatures. m-DOM, or specifically the chromophoric (light interacting) portion of it, has been shown to chemically enhance photo-induced reactions in the lab. This marine photochemistry is important to how m-DOM, being entrained in aerosols, can affect the composition of its surroundings.  

Throughout the summer, I have been working on different ways in which we can achieve our goal of characterizing m-DOM. We’ve tried direct injection into the Orbitrap to see if we can account for any differences with respect to biology and time. In the first bloom experiment, I’ve seen the Hydrogen:Carbon (H:C) ratio decrease with time suggesting that there are processes that are converting compounds into unsaturated molecules. An unsaturated compound of interest is benzothiazole, a natural marine product formed from the photolysis of 2-mercaptobenzothiazole. Benzothiazole was found to be the highest peak in mass spec the last day of the first wave experiment. It’s possible that this could have come from photo products as mentioned above or naturally produced from bacterium in the wave flume. We further want to characterize m-DOM by using infrared spectroscopy as another perspective on the different functional groups within the samples. We are currently in the process of thinking of different ways in which we can characterize or potentially look at its reactivity.

Written by: David Gonzales, Undergraduate Student in the Grassian Research Group at UC San Diego

There is nothing more fulfilling and exciting than to contribute through these collaborations with other researchers here at CAICE, in an attempt to answer some of the many uncertainties concerning the ocean and the atmosphere. We are extremely grateful for our mentor, Michael Alves, for his guidance throughout this summer. We would also like to give thanks to Dr. Vicki Grassian for her advisements and continued support. Finally, we want to express our gratitude to CAICE for this opportunity and other fellow researchers who have helped us along the way.  

Header photo credit: Nigella Hillgarth

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).

Those Pesky but Important Ice Nucleating Particles — Honest, It Is Not an Obsession

This ain’t my first rodeo, as they say, but I love it just the same and I still have so much to learn. That sums up my feelings about SeaSCAPE. I participated in my first wave flume study of sea spray aerosols in the Scripps Institution of Oceanography Hydraulics Laboratory in 2011, and then again in 2014. We were blown away at the possibilities for studying the production and properties of nascent sea spray particles. I was blown away by the ability to isolate oceanic emission of ice nucleating particles, or INPs, which have an outsized ability to transform clouds and precipitation due to the action of very small numbers of ice crystals on scavenging water vapor and transforming otherwise stable populations of supercooled cloud droplets into larger ice crystals that sediment and bring water to the surface as snow or rain.

Do you think that all water freezes at 0 °C? You are wrong then, as Tom Hill, my colleague and also a SeaSCAPE participant, will enthusiastically tell you. Pure water distributed in the volumes present in clouds will not freeze spontaneously until close to -40 °C, and otherwise freezing must be initiated by a particle (an INP) present in the water. This makes them special and powerful.

Ice nucleation is my thing, and the INPs that come from oceans are both unique and vitally important amongst the atmospheric populations (mineral dust being the most well-known) of INPs. Oceanic INPs emitted via sea spray production mechanisms are wholly organic, unless the near-surface ocean has been seeded by terrestrial emissions. While we know that SSA INPs emanate both from dissolved and particulate carbon compartments in varying proportions, we do not yet understand these sources chemically to the degree necessary for accurately predicting their emissions using large scale coupled ocean-atmosphere models. Yet this is critically important for understanding influences on clouds over vast remote oceans that control both the amount of solar energy reaching the ocean surface or scattered to space, and the global hydrological cycle. 

Photo (credit: Paul DeMott): Tom Hill, Josephine Rudd, Kathryn Moore and Russell Perkins (front to back) chat over details around our sampling location for INPs in SeaSCAPE.

During SeaSCAPE, our team of Kathryn Moore, Russell Perkins, Thomas Hill, summer student Josephine Rudd and myself will use real-time and offline techniques, in concert with our collaborators in the Grassian, Tivanski, and Stone groups, to further isolate the chemical compositions that constitute the few (“needles in the haystack”) INPs present in SSA. Furthermore, we will seek to understand the fate of these particles following atmospheric oxidation that will occur following emission, using flow reactors. 

I am energized once again in seeing and working in a laboratory full of young scientists. They are learning together with career scientists. Learning about discovery, the process as much as any success, learning to work within a team, learning about the value of patience and persistence. These are the days you will remember.

Written by: Paul DeMott, Senior Research Scientist, Dept. of Atmospheric Science, Colorado State University

Header photo credit: Erik Jepsen/UC San Diego Publications

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).

Acidic Aerosols and Supporting Scientists: A Tale of Two Atmospheres

Some of my happiest memories are of walking on the beach with my family. There is something so relaxing about being by the vast ocean and smelling the salty air. But even while relaxing, we have to be careful. Laying in the sun feels good, but too much of it is definitely bad. Is the same true for the air by the sea? How good or bad for our health is breathing in the sea spray from crashing waves?

This is a very involved question, and answering it correctly will require many little pieces to be understood first. My piece involves looking at some of the smaller aerosols emitted from the ocean and figuring out how acidic or alkaline they are. To do this, I first use an instrument called a MOUDI to separate the aerosols based on size, and then impact them onto litmus paper. I can then use computer methods to analyze the color and calculate a pH, that is, put a number on how acidic the aerosols are. This is key to our understanding of the safety of sea spray, since the most acidic aerosols are correlated with negative health effects. In particular, I am planning to track how aerosol acidity changes over the course of a bacterial bloom. Ultimately, this could allow us to predict ocean air conditions and determine which days are and are not safe for strolls along the beach.

Need to size-separate your aerosols? Don’t be moody, use a MOUDI!

In addition to allowing me to investigate some important scientific questions, being a member of SeaSCAPE has been very valuable to me personally. Until this summer, most of my past research projects have been largely solo efforts. Although I have always had supportive advisors, I performed most experiments by myself or with a single mentor. Initially, the thought of working with so many other people was very stressful to me. If I make a mistake and it only impacts me, that is fine, but it is much harder to forgive myself if I waste someone else’s time. Fortunately, everyone has been very supportive. Many people have gone out of their way to help me and teach me things, and despite the stresses and difficulties, I can always find plenty of smiles. Being here has made me more comfortable working with many different kinds of people and appreciate the power of a team effort coming together to achieve common goals. I am thankful for the opportunity to be part of the SeaSCAPE team and excited for the rest of the summer!

Suds (left) and Kyle (right) measuring chlorophyll

Written by: Kyle Angle, Grassian Research Group, Department of Chemistry & Biochemistry at UC San Diego

Header photo credit: Erik Jepsen/UC San Diego Publications

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).

Water Water Everywhere

Walking up to the Hydraulics Lab for the start of each day of SeaSCAPE sampling is a truly awe-inspiring experience.  From the parking lot outside I have a breathtaking view over the endless misty extent of the Pacific Ocean; as soon as I walk through the doors I am greeted by the eerie breathing and hypnotic motion of the 30 m wave flume hard at work.  For a researcher who has previously focused on aerosols from forests, born and raised in the decidedly arid, landlocked state of Colorado, that is a disconcerting, and at times deeply frustrating, amount of water.  

My name is Emily and I am a graduate student researcher in the Goldstein Group at UC Berkeley.  I study the organic ‘goo’ that previous CAICE studies have observed coating salty sea spray particles during algal blooms.  Breaking waves cause tiny, salty droplets to be flung into the air, and in the presence of intense biological activity, many of these particles in the size range with the longest atmospheric lifetime become coated with an outer layer of carbon-based compounds from the microorganisms in the water.  The compounds in this coating can play a variety of different roles in aerosol fate and climate; they can alter how the aerosols interact with each other, how clouds form, and how light scatters from particles. My instrument is ‘offline’, meaning that instead of directly connecting to the wave tank itself, I collect particles on filters for analysis on an offsite instrument.  I do this by sucking air out of the wave flume just past the breaking wave, running it through a cyclone to screen out large droplets, then passing it through a filter which captures all of the tiny, salty, gooey particles. When I return to Berkeley, I will separate and identify the organic compounds in the particles using 2-D gas chromatography.

Being an offline sampler is an exercise in planning and delayed gratification- because my instrument is at home in Berkeley, I have no way to do preliminary checks on my samples and fine-tune my system.  All I can do is identify, mitigate, and document any potential sources of contamination, carefully design the sampling apparatus, and pay attention to any visual clues that something might be wrong. If I do everything right, the samples should, to the naked eye, be exquisitely boring.  Sea spray aerosols are generally white and so is the filter material, so they should look pretty much the same when I take them out as when I put them in. White is what I was hoping and expecting to see the first morning after the beginning of sampling- what I got was a sad and sodden grey.

The humid air coming off of the wave flume was condensing onto the insides of my metal sampling lines, collecting into droplets, and then hurtling through the sampler to soak my poor filters in a siege of tiny water balloons.  While I had anticipated that this was likely to be a problem and had built a short condenser, nothing I had tested it on prior to reaching CAICE was as humid as the wave flume and my system just wasn’t cutting it.  

In the grand scheme of things, a 47 cm water saturated filter is inconsequential.  In my world however, it spelled disaster. Wet filters do not collect aerosols in a uniform manner, and the compounds I am hoping to document can undergo reactions when they are dissolved in water.  What is more, my instrument back at Berkeley is quite sensitive (in both the scientific and, to my anthropomorphizing mind, emotional sense) and does not particularly appreciate having large amounts of salt water dumped into its internal workings. If I could not figure out a way to keep my filters dry, I would have no usable samples from the summer.   

Here I would like to take a moment to say thank you.  Thank you to my advisor Allen, our instrumentation consultant Nathan, and my mentor Lindsay for promptly answering my questions and guiding me from afar. With their advice, I swapped the 50 cm straight steel water condenser for a 3 m copper coil condenser, adjusted the slope of the collection area, added a heater to the lines, and achieved my first dry filters less than 48 hours into the campaign. Thank you to our lab manager Robin and my labmate Yutong for rushing to the rescue to overnight me the parts needed to put together the new system.  Thank you to Kathryn and Kathryn, to Jon, to Ryan, to Dan, to Brock, and to all of the others at CAICE who took time away from their own hectic schedules to offer advice, lend/look for equipment, or simply offer consolation and encouragement. When I imagined myself to be alone because I am the only CAICE student to call UC Berkeley home, I was very, very wrong.   

It would be nice to tie this anecdote up in a bow and say that with the addition of a big copper coil, all problems were solved.  However, that would be a lie. There have been a few more waterlogged filters, a few more late nights in the lab disconnecting, cleaning, drying, testing, and adjusting my setup.  As of this writing the filter collection has been successful with no water issues for nearly a week and I am cautiously confident that the current setup is ideal; then again, maybe I just jinxed myself.  What I do know for certain is that with each mishap I am learning more, panicking less, gaining confidence in myself, and deepening my appreciation for my collaborators, advisors, and H-lab friends. Most importantly, each dry filter sample collected is another tool to probe the composition of organics in sea spray aerosols in the months and years to come.

Written by: Emily Barnes, Graduate Student of Prof. Allen Goldstein at UC Berkeley

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 SeaSCAPE Experiment Featured on KPBS News

KPBS’s Erik Anderson stopped by the Hydraulics Lab to check out our SeaSCAPE Summer Experiment, which was being toured by students who are participating in UC San Diego’s COSMOS educational program. Hear the interview with CAICE Director Kimberly Prather and Managing Director Christopher Lee and learn more about what the SeaSCAPE team is up to here:


Aerosols: A Coming of Age Story

The atmosphere is a dynamic chemical reactor. In the Slade group, we are interested in the processes that control the chemical and physical state of marine aerosols as they travel out of the ocean and through the atmosphere – ending up in the clouds that control our climate and in the air we breathe. Intense sunlight and exposure to oxidants like ozone (O3) and hydroxyl radicals (•OH) can “age” gases and particles. Short term weather and long-term climate trends lead to drastically different environments with varying temperatures and relative humidities. These processes control aerosol’s chemical composition – what molecules they are made of – and physical state – how solid/liquid-like they behave. 

My focus this summer is to investigate the composition of secondary marine aerosol – particles that form in the atmosphere from gases released from the ocean. I’m working with an Extractive Electrospray Ionization Time of Flight Mass Spectrometer (EESI-TOF-MS,) a powerful instrument that can analyze molecular composition of aerosol in real time. I hope to learn more about how secondary marine aerosol evolve under different amounts of •OH exposure and at different relative humidities to simulate how they might behave in the real world and predict their environmental fate.


Like the atmosphere, the Hydraulics Laboratory is a dynamic environment. Between the mesmerizing pattern of the generated waves and the whirrs and hums of instrumentation, dozens of researchers dart around. Over the past several weeks, I’ve seen the lab transform from a near empty barn to a bustling village of researchers. Oceanographers, biologists and chemists came together with targeted missions and a wealth of information. Being a first-year graduate student with little prior atmospheric chemistry experience, I have thrived in the learning environment offered by being surrounded by such a diverse group of people. I’m excited to share my newfound understanding and learn a lot about this multidisciplinary project!

Written by: Adam Cooper, Graduate Student, UC San Diego

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).

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).