The study of ocean – atmosphere interactions

29 07 2014

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





DNA in the Clouds

25 07 2014

As a third year graduate student in a biochemistry lab, I don’t often get experiences like this. A giant wave-generating tank is novel to me and quite a bit different than the pipet-land I usually live in. Walking into the transformed hydraulics lab always leaves an impression on me. The facility has come alive. It is crammed full with buzzing whirring equipment, and buzzing, whirring people. Scientists and students from all over the country all pointed at a common goal. Every time I walk in there, I step back and really understand what I am a part of. I’m proud. This experience hasn’t always been easy, but it has been rewarding. Certainly, the unwavering dedication of everyone down at the waveflume day to day is truly inspiring.

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Author Jennifer Michaud in the lab extracting DNA


I am not the only biochemist/biologist involved in IMPACT, but definitely my work stands apart from what others are doing. The name of my game is DNA. My efforts are to collect cells from the waveflume and extract their DNA, which will then be used to identify all the species present.   I would like to characterize not only what microbes are there, but also how they change across a bloom and relate to a natural ocean phytoplankton bloom. More specifically, I am interested to learn which species transfer from bulk to the sea surface to aerosols (airborne particles) and how this changes in conjunction with the growth of phytoplankton and correspondingly bacteria. My highest hope is that certain phenomenon, like ice nuclei, particle types, and interesting organic molecules, might be able to be connected to the predominance of a species or group at the time of their occurrence.

To do this I collect water samples. Harvesting cells is done by vacuum filtration under sterile conditions serially with different sized filters to fractionate the samples into phytoplankton, bacteria, and viruses and vesicles. The major hurdle to my sampling is having enough. Cells are not overly abundant in the marine environment and many liters of water are generally required for DNA analysis. Here we are trying to optimize our methods so that that we get as much DNA from minimal sample amounts so that other analyses are not disrupted. Additionally, sampling cells from aerosols poses its separate challenges. We are using a SpinCon PAS 450-10A Wet Cyclone Portable Air Samplers (Sceptor Industries, Kansas City, MO) to concentrate cells in the aerosols. This instrument has previously been used to sample air above a NY city high-rise and other sites for microbes. The instrument pumps aerosols into a glass chamber containing buffer creating a vortex in which cells are trapped which then are collected by our standard methods. DNA is isolated using an optimized phenol chloroform extraction. Then our precious samples will be sent away for sequencing to identify species.

Yesterday was big sample collection day for me. Lots of filtration. Today, I am extracting DNA from the aerosol samples. I hope they have lots!

Jennifer Michaud, Graduate Student, Burkart Group, Department of Chemistry and Biochemistry, UC San Diego





Approaching the Finish Line…

25 07 2014

Although it was a ton of hard work, I have enjoyed being part of the CAICE (Center for Aerosol Impacts on Climate and the Environment) IMPACTS (Investigation into Marine Particle Chemistry and Transfer Science) 2014 intensive. Professors and students from all over the country are gathered here to better understand the link between ocean biology and the composition and physical properties of particles emitted from sea spray.

10457561_692410517491553_292097329586178028_n[2]I am a 3rd year graduate student in Chris Cappa’s group at UC Davis. I came to UC San Diego to investigate how much these particles grow as a result of humidification using a cavity ring-down spectrometer (CRD). The larger these particles grow, the more light they scatter. By scattering solar radiation, these particles cool the planet and are therefore important for understanding the Earth’s climate. Particles emitted from sea spray take up a lot of water because they are mostly composed of salt. However, the biology of the ocean impacts what these particles are made of and, by making the particle less “salty,” can decrease the how much water they take up.

The "beach" area of the wave flume in the Hydraulic Lab at SIO

The “beach” area of the wave flume in the Hydraulic Lab at SIO

My goal is to quantify how changes in particle composition due to biological processes in seawater influence how much these particles grow due to humidification.
During this unique, once-in-a-lifetime experiment, everyone I have worked with has been incredibly positive and fun to be around. At the end of IMPACTS, I will leave with both exciting data and many new friends.

 

Sara Forestieri, Graduate Student, Cappa Group, Department of Civil and Environmental Engineering at UC Davis





Collaboration and teamwork are a key to great discoveries

23 07 2014

Dozens of instruments from many universities, this is what it takes to do real science! Nowadays, great discoveries are not possible within one laboratory working in isolation. Collaborations of research teams that have various techniques, approaches, and backgrounds from multiple scientific disciplines are necessary for innovations and advances. This summer professors, graduate and undergraduate students from all over the country came to Scripps Institution of Oceanography at University of California, San Diego to participate in 2014 NSF Center for Aerosol Impacts on Climate and the Environment (CAICE) IMPACTS (Investigation into Marine PArticle Chemistry and Transfer Science) campaign.

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The author, Olga, and her group mate Jon preparing for particle collection on MOUDI


I came from the University of Iowa where I just started my fifth year of graduate school in Dr. Vicki Grassian research group. My area of interest is phase, composition and hygroscopicity of individual sea spray aerosol particles. We collect particles generated during wave breaking and then take them back to Iowa for detailed micro-structural analysis with a variety of microscopic and spectroscopic techniques. Atomic force microscopy is a tool to image the surface of particles at the nanoscale and it is exceptionally noteworthy that it can reveal 3D shape of particles. Scanning electron microscopy and transmission electron microscopy can image particles down to 1 nm resolution and when used with energy-dispersive X-ray spectroscopy can reveal spatial elemental composition of particles. Raman microspectroscopy gives information about vibrations of functional groups thus revealing chemical composition of particles as small as several hundred nanometers. Elemental and molecular composition derived from these techniques can be combined with on-line measurements such as aerosol time-of-flight mass spectrometry to get the most complete information about particles’ composition. All microscopy techniques can be performed in chambers where relative humidity is be controlled and size of particles is monitored using microscope. Therefore, we can detect how particles grow in humid environment. Raman microspectrometer can detect the water in particles spectroscopically and thus can be additionally used to monitor water content of particles as relative humidity changes. It is very important to know how particles interact with water as it determines how particles will interact with light, form clouds and react with trace gases in the atmosphere (which can be fairly humid). Finally, as we learn about the dependence of particles’ properties on their detailed chemical composition we can understand and more importantly predict their properties in the environment better!

As I have already mentioned collaboration is a key for breakthrough research discoveries. Collaboration and teamwork! This picture illustrates teamwork in action where Jon and Olga (author) are putting together stages to collect sea spray aerosol particles. This is a great campaign that unites many research groups and I look forward to analyzing our particles and working with other participating groups to shade more light on marine atmosphere.

Olga Laskina, Research Assistant, Grassian Research Group, Department of Chemistry at University of Iowa





CAICE Enriches and Challenges Intellectual Capacity

21 07 2014

Growing up in a developing country, Rwanda, located in East Africa, who would have thought we could be part of this huge and positively worldwide contributing project?

Authors Grace de Dieu Irumva and Hosiana Abewe with UCSD Chancellor Pradeep Khosla in front of the wave flume

Thanks to CAICE, for opening the doors and providing us the opportunity to profoundly learn about the impact of sea spray aerosols on the climate and environment.

As determined undergraduates, we were intellectually challenged by the change in climate and environment. We longed to know and understand different perspectives and hypotheses on this global issue. One of the hypotheses was to detect if different primary biological seawater particles, such as bacteria, have an impact in chemical and biological composition of the sea spray aerosols released from seawater.

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The authors preparing substrates for MOUDI ( MicroOrifice Uniform Deposit Impactor), an off-site apparatus that collects the aerosols particles on different stages for further microscopical analysis.


To test the above-mentioned hypothesis, different experiments have been designed: two different bacteria strains are pre-cultured on separate medium, thereafter transferred into flasks containing filtered- autoclaved seawater and allowed to grow under the same environmental conditions.

In the meantime, aerosols are collected through bubbling and ultimately analyzed by different analytical instruments, including ATOFMS and WIBS. From these analyses, the data collected will help us detect the chemical and biological composition of the aerosols released, respectively.

Thus far, we have been learning from prestigious scientist researchers, while enriching and challenging both our intellectual and professional capacity. We are certain that this project will nourish and aspire us further to tackle the global environmental problems.

 

Hosiana Abewe and Grace De Dieu Irumva, undergraduate students, Prather Group, Department of Chemistry and Biochemistry.





Another world record…?

19 07 2014
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Jon Trueblood, University of Iowa graduate student, working with one of the MOUDI impactors

I arrived here in San Diego on July 15, 2014 just in time to see everything working!!! This includes phytoplankton blooms occurring in multiple MART systems and of course the 33 m wave flume. I am so impressed with the students and postdocs who were able to get this first time every experiment going – the largest indoor phytoplankton bloom – a world record.   I see many happy (and some tired) faces. What is clear is that everyone is now excited as we are starting to collect very significant data and many new chemistry findings are starting to be realized. These studies will focus on the molecular speciation and chemical complexity of the sea surface microlayer and of sea spray aerosol. A number of off-line and on-line analyses will be done to determine what molecular species are present in order to better understand the transfer of molecules from sea water, and the sea surface microlayer, into sea spray aerosol. This will give us more detailed information on the chemistry of sea spray aerosol. For off-line analysis of sea spray aerosol, a wide range of substrates are being used to collect particles for single particle analysis using a MOUDI impactor to get size resolved composition. Overall, CAICE investigators aim to analyze the chemical composition, structure, phase, hygroscopicity, and reactive properties of as many particles as possible. By the end of the experiment it is estimated that nearly one billion sea spray aerosol particles will be collected. That is right – one billion particles!!! (Another world record???) I can’t wait to see what we learn from these samples in the next few months.

In addition to the great science we continue to give tours to everyone who wants to see what we are doing. Saturday morning a group of high school and undergraduate students came by to view the wave flume here in the hydraulics lab at SIO. It was fun to see how they were excited to see the experiment and to talk to them about it. We discussed the importance of chemistry and the molecular fundamental knowledge needed to understand sea spray aerosol. We then all went out to the pier to see where the sea water came from and to take look at the other experiments there. We also enjoyed the beautiful view – what a great way to spend a Saturday morning!

 

Vicki Grassian, F. Wendell Miller Professor of Chemistry at the University of Iowa and CAICE, Co-Director

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CAICE IMPACTS a UCSD Undergrad

18 07 2014

After finishing my second year of undergrad at UCSD, I am thrilled to already be a part of the CAICE IMPACTS experiments. My interests revolve around understanding the surface chemistry of seawater and its impact on the selective transfer of species from the bulk seawater to the surface seawater and ultimately to the sea spray aerosols during the phytoplankton bloom in the wave-flume.

A Tensiometer measuring the surface tension of surface seawater via a Platinum plate

A Tensiometer measuring the surface tension of surface seawater via a Platinum plate

To get a sense of the changes occurring in the surface of the seawater, I have been measuring the surface tension in the sea-surface microlayer (upper most millimeter of the surface) and the bulk seawater (the water beneath the surface) using a tensiometer shown in the image on the right. Surface tension can be thought of as the force that causes a liquid’s surface to pull closely together for minimal surface area, and the tensiometer uses a platinum plate to measure the force the liquid exerts on it. I am looking for changes in the surface tension day-by-day in the wave-flume as the phytoplankton bloom progresses to see how this surface property changes and how it impacts the chemical properties of the surface water and sea spray aerosols.

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A preliminary infrared spectrum of dehydrated bulk seawater

To determine the changing chemical and biological composition of bulk seawater, sea-surface microlayer, and sea spray aerosols, I am using infrared (IR) spectroscopy, which essentially uses light in the infrared region to cause molecules to vibrate. These vibrations can be seen as peaks in the IR spectrum shown on the right, and each peak corresponds to a certain chemical group. It should be interesting to see if changes in functional groups are apparent to better understand the transfer of molecules from the surface of the ocean to sea spray aerosols.

While learning all of the chemistry behind CAICE is exciting, the true nature of its impact on my undergrad experience comes from the diversity and perseverance of everyone I have met. From biologists to oceanographers, I am so grateful to be around this atmosphere of scientists coming together to work on the impact sea spray aerosols have on our climate and environment. I have met numerous PIs, postdocs, and grad students, and they have all given me insight into what I want to do in the future. I want to continue to explore and help determine the true impact the changing environment has on our lives and how we can all make the effort to improve our understanding of the world’s scientific complexity.

Joshua L. Cox, Undergraduate Researcher, Prather Group, Dept. of Chemistry and Biochemistry, UCSD