Spotlight Series: Keiran Swart

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science party on the research expedition.

Keiran Swart

Keiran Swart on the deck of the Endeavor.  He is cleaning his net following one of the tows (how he collects organisms).

Keiran Swart on the deck of the Endeavor. He is cleaning his net following one of the tows (how he collects organisms).

Keiran Swart was born and raised in Miami.

Educational background: My undergraduate degree is from the University of Miami, where I studied geosciences, and my program had an emphasis on carbonate geology and sedimentology (for example, reef systems).  I am currently a graduate student in geosciences at Princeton.

 

How did you become interested in science?  A youth of Carl Sagan.  Actually, my parents are both geologists – my dad is also a geochemist, like me, my mom is more of a classical geologist, core-work and the like.  I grew up in it and always assumed I’d be a scientist.

 

Research Interests:

My main research interest is foraminifera – small (200µm) Protista that exist everywhere in the ocean.  They are like little microcosms of coral reefs because they host symbiotic life.  They are also calcareous – they contain calcium carbonate in their shells and have been a focus of geochemical study for over fifty years.  The oxygen isotopic ratio in their shells has been used to make judgments about atmospheric conditions, from temperature changes and other properties, a relationship discovered by Cesare Emiliani (incidentally, he’s also from Miami).

Foraminifera serve as geochemical proxies because they are representative across the ocean, are abundant, and are continuous (meaning they are everywhere and always present).  We can’t directly measure what the Earth was like a long time ago, but we can look at foraminifera to give us an idea.   My work is looking at the reconstruction of the past environment with foraminifera.

With foraminifera, there’s almost an endless amount of stuff you can do with it.  For example, inside a fossil, all that’s left is the shell, but the shell isn’t just calcium carbonate – it’s built on a web of protein that is an almost inconsequential component of the total mass (less than a percent).  Looking at this tiny organic component can help determine many different things such as degree of nutrient consumption or water mass movement.  My group tries to unify different parts of the field, including  modeling and studying modern analogs, to look at how the foraminifera population tracks environmental changes on a glacial interglacial timescales.

 

Research aboard the R/V Endeavor:

I want to look at the carbon isotopic composition of foraminifera, which is partly based on the trophic enrichment of isotopes (essentially, you are what you eat),  Original photoautotrophic bacteria create new organic matter (carbon) that represents the conditions the bacteria come from and the nutrients available – for nitrogen, this means nitrate or ammonium, and for carbon, carbon dioxide or bicarbonate.  The photoautotrophs are the bottom of the food web.  They are eaten by something else, which undergoes metabolism and excretes waste (this goes on all the way up the food web).  As we go up the food web though, the lighter isotopes (14N and 12C) tend to be excreted more than the heavier ones (15N and 13C).

I’m interested in what controls this variability. To analyze, I pick out the species of interest, then incinerate them to produce carbon dioxide and nitrogen gases.  The gases are then put through a GC (gas chromatograph – this separates the gases) and a mass spec to look at the mass profiles.  From these, I can look at both the carbon and nitrogen isotope ratios and correlate with different environmental permutations.

 I am interested in the isotopic composition of foraminifera.  Because they are heterotrophs and eat everything, and have a symbiotic relationship with organisms that fix new carbon and trap it, there exist a complicated mesh of processes that affect the signal.  Therefore, I need to get a good grasp on how the carbon isotopic composition varies across the food web and from different environmental conditions (including temperature, CO2 content in water, and pH, among others).

Basically, I collect water samples for alkalinity and carbon testing, and filter for organic matter.  At the process stations, I do plankton and zooplankton tows to collect those organisms.

The phytoplankton and zooplankton get crushed up and combusted in silver foil, and then undergo a series of redox reactions to trap gases.  This allows me to get the isotopic composition of the gas and see how it varies.  In the future, I hope to incorporate species levels and distinctions as well.

With my water samples, I do titration alkalinity (add acid until there is a rapid pH change) and measure the change in carbon.  Carbon is very complex but, essentially, CO2 is in equilibrium with H2O in various forms: carbonic acid (H2CO3), bicarbonate (HCO3), or, carbonate (CO32–), and is constantly re-equilibrating.  To look at what is biologically accessible to the foraminifera, I record a bunch of different conditions, like those I mentioned earlier – temperature, pH, etc.

 

Plans for the future: I want to stay in academia, though I have given thought to doing work for a nuclear regulatory agency (enforcing test ban treaties works by measuring the decay of radioactive isotopes) or work for the and environmental NGO or Greenpeace, but I do think I want to end up in academic doing research.

Back to Ms. B:

Mr. Swart is extremely passionate about his research and I hope that came across in his responses – having a sincere passion for what you are studying is essential!

Until next time,

Ms. B.

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Spotlight Series: Qixing Ji

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science team on the research expedition.  Each scientist and his/her research will be featured – I provided the prompts and the scientists added their own information (my comments will be in brackets: [ ]).

Qixing Ji

Qixing Ji

Qixing Ji

Qixing Ji is from Shenzhen, China, a high-tech city of 14 million people and home to one of China’s two stock exchanges.  He recently received his Masters degree and is working on his PhD from Princeton University.

How did you become interested in science? I like solving problems and get a lot of satisfaction from solving a problem.  Science is all about discovering a problem and solving it.  Princeton is a great place to study science and Dr. Ward is an excellent advisor.

 

Educational background:  My undergraduate degree is in environment engineering from Zhe Jiang University.  I am currently completing my PhD in geosciences at Princeton.

 

Research interests:  Broadly, my general interest is chemical oceanography – chemical reactions related to biology in the ocean.  Specifically, my interest is in biogeochemistry.  I like chemistry because it’s an amazing subject.  It has a good combination of concepts, observations/experiments, and math.

I mainly study nitrous oxide, N2O, (laughing gas) and its distribution and biological production by bacteria and archaea in the ocean.  Nitrous oxide is an extremely important gas for the climate.  N2O is a greenhouse gas so it traps heat in the atmosphere by absorbing infrared radiation.  It’s actually 300x more powerful than carbon dioxide, meaning for the same mass of each gas, N2O will trap 300x more heat than CO2.

N2O also depletes ozone (which, among other things, protects us from skin cancer) and is currently the most important depletion agent, not CFCs (chlorofluorocarbons).

Human activity has produced more N2O the atmosphere and we need to figure out what processes contribute to this and why.  By studying the amount of naturally-produced N2O by the ocean’s bacteria, we can find the background concentration.  This allows us to then determine how much of the atmospheric N2O comes from humans.

Phytoplankton (magnified).  These are the organisms being studied by Qixing Ji and the other scientists aboard the Endeavor. (photo courtesy of Q. Ji)

Phytoplankton (magnified). These are the organisms being studied by Qixing Ji and the other scientists aboard the Endeavor. (photo courtesy of Q. Ji)

Research aboard the R/V Endeavor: I perform two experiments: the first looks at nitrous oxide concentration and isotopes, and for the second, I do incubation experiments.

For nitrous oxide concentration and isotopes, I look at the natural abundance of both nitrogen isotopes (14Nand 15N) and oxygen isotopes (16O and 18O).  N2O in the ocean exists in an equilibrium with atmospheric N2O.  This is important because biological activities and processes that produce N2O (for example, nitrification) or utilize N2O (ex. denitrification) alter the 15N2O / 14N2O ratio compared to the atmosphere.

In my incubation experiments, I am looking at how organisms produce N2O and the mechanisms by which this occurs.  To do this, I add labeled nitrogen isotopes to ammonium and nitrite [labeled isotopes are 15N], which causes the ammonium and nitrite to become 15NH4+ and 15NO2.  I then introduce these labeled compounds one-at-a-time to my seawater samples and leave them in incubators for 12-24 hours so the organisms can continue to increase their biomass (so 12-24 hours after adding labeled ammonium, I take samples then add the labeled nitrite).  Once that is complete, I will look at the composition of the N2O they have produced – if I added 15NH4+ and there is 15N2O, then ammonium is a source compound.  If the 15N2O came from labeled nitrite (15NO2) then nitrite is a source compound.

Plans for the future: My current goal is to complete my PhD!  Eventually, I think I would like to stay in academia and be a professor.  It’s a very respectful profession and academia is a great environment for scientists.

 

Back to Ms. B:

Climate change is one of the most serious problems the world is currently facing and has an enormous impact on the environment.  Researchers like Mr. Ji are essential to understanding how humans are impacting climate so we can figure out how to minimize that impact.

Until next time,

Ms. B.

Spotlight Series: Dr. Nicolas Van Oostende

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science team on the research expedition.  Each scientist and his/her research will be featured – I provided the prompts and the scientists added their own information (my comments will be in brackets: [ ]).  Feel free to ask questions about what they are studying and how they became interested in science!

Dr. Nicolas Van Oostende

Dr. Van Oostende aboard the R/V Endeavor

Dr. Van Oostende aboard the R/V Endeavor

Dr. Van Oostende is from Ghent, Belgium and is a post-doctoral researcher at Princeton.

What is your field of study? I consider myself a microbiological oceanographer.  My field is a subset of biological oceanography but specifically focuses on microscopic organisms (the main biomass of the ocean) and their distribution.

What research are you studying on the Endeavor? I study the community structure of phytoplankton, or the relative abundance of the components in the ecological community.  Using flow cytometry [this was discussed yesterday in the McLane Pump post], I divide microorganisms by various properties – size and pigment composition are two examples.

In relation to biogeochemistry (the chemical cycles), I look at the interaction between microorganisms’ identity and function (e.g. do they produce biominerals, are they large or small, slow or fast-growing), and how that relates to what they’re doing in the ocean.

I am performing various analyses during the expedition – primary production measurements using flow cytometry to characterize the community, and nutrient  and carbon isotope uptake experiments to quantify rates of activity.

 

Previously, I studied carbon isotopes to look at calcification (like the remains of algae that created the cliffs of Dover).

The cliffs of Dover (photo from Wikipedia).  The white is essentially the skeletons of dead algae over thousands of years.

The cliffs of Dover (photo from Wikipedia). The white is essentially the skeletons of dead algae over thousands of years.

 

How did you become interested in science? I have always been interested in science.  I always did experiments when I was little and I liked blowing stuff up.  My grandmother gave me a chemistry kit when I was younger.  I find biology the most interesting of the sciences because it is much more diverse and alive than the others.

Plans for the future:  I am not sure I want to stay in academia [college-level education], and am considering a job in the private sector.  I would like something in which I can utilize my microbiology and biological modeling skills in a research-based environment.

 Educational background: My education has been at Ghent University.  I was in an international program and collaborated with other scientists in Germany, Holland, France.  The educational system is different than in the United States – a bachelors degree takes two years, then another three years for a masters degree.  Once that is complete, you can begin your doctoral work for three-four years.

I had a difficult time choosing what I wanted to study.  I very much like plants, but zoology [in a nutshell, the study of animals] was more fun.  I did my masters thesis on pollination of bees using artificial flowers.

Back to Ms. B:

There are so many scientific fields and exciting topics to research – a career in the sciences is full of possibilities!

Until next time,

Ms. B.

Spotlight Series: Jeff Hoffman

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science team on the research expedition.  Each scientist and his/her research will be featured – I provided the prompts and the scientists added their own information.  Feel free to ask questions about what they are studying and how they became interested in science!

Jeff Hoffman

Jeff Hoffman

Jeff Hoffman

Jeff Hoffman works for the J. Craig Venter Institute (www.jcvi.org) and travels the world sampling water and extracting microbial DNA.  He is originally from New Orleans.

What is your field of study?  The samples I take are for extracting DNA – I take water from wherever we are and extract DNA, looking at different organisms around the world.  The information goes into a piblic database that is accessible by everyone and is used for various research purposes, for example, alternative energy, cancer research, and synthetic biology.  I mainly look at microbial diversity in waters around the world.  The DNA is extracted from the water samples then goes to the sequencing facility, where different scientists look at it.

 

Where have you been sampling?  It’s easier to list where I haven’t been.  From 2004-2006, we did a circumnavigation around the world on Craig Venter’s boat, Sorcerer II.  We mostly stayed on the equator and went around the world – including the Panama Canal, French Polynesia, Vanuatu, Australia, South Africa, and the Caribbean.

From 2006-2009, I traveled up and down the East and West Coasts of the US.  On the East Coast, we went as far north at Nantucket, and on the West, up to Juneau, Alaska.

After 2009, we did a couple summers in Europe, in the Baltic and Mediterranean.  I’ve also been to Antarctica 5 times and, in February, I went to the Amazon River.

 

How did you become interested in science?  I never wanted to wear a suit and tie, and science was the way to go.  It’s always interested me in high school and college.  I was pre-med but preferred to be in the lab.

 

Educational background:  I did my undergraduate degree at LSU (Louisiana State University) in microbiology with a minor in psychology.  I also completed my masters at LSU in microbiology.

 

Plans for the future:  I have another trip planned to the Amazon River in September and Antarctica in December.

Back to Ms. B:

How cool is Mr. Hoffman’s job?

Mr. Hoffman’s work with the J. Craig Venter Institute becomes public knowledge – demonstrating that scientific achievement and knowledge should always be shared.  It doesn’t do much good to keep scientific information a secret!

Until next time,

Ms. B.

Spotlight Series: Dr. Sarah Fawcett

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science team on the research expedition.  Each scientist and his/her research will be featured – I provided the prompts and the scientists added their own information (my comments will be in brackets: [ ]).  Feel free to ask questions about what they are studying and how they became interested in science!

Dr. Sarah Fawcett

Dr. Fawcett

Dr. Fawcett, born and raised in South Africa, is currently completing her post-doctoral research at Princeton University.

What is your field of study? I consider myself a marine biogeochemist.  Interested in using various chemical tracer to understand biological processes – basically, how are the microscopic plants (phytoplankton) that live in the global surface ocean affected by ocean chemistry, and how do they in turn change ocean chemistry. I work on the nitrogen cycle because nitrogen is essential for life and also determines how much photosynthesis happens in the ocean (plants need N to grow).  Photosynthesis is what takes CO2 out of the atmosphere and puts it into the ocean, which ties nitrogen directly to carbon and climate.  This is true of all climate – the past, present, and future.  We can use the nitrogen tracer to tell us about climate throughout history.

What information do you hope to find on the expedition? I’m collecting phytoplankton by filtering huge volumes of seawater and concentrating the phytoplankton that live in it onto a filter .

Back in the lab, I measure the Nitrogen isotope ratio (i.e. N-15:N-14) of different phytoplankton groups, which tells me about the form of nitrogen (nitrate or ammonium) that they have been consuming. If they rely mainly on nitrate, which is mixed up into sunlit surface waters from the deep ocean, they act as a net remover of atmospheric carbon dioxide, and are therefore important for the C-cycle and climate. Ammonium, on the other hand, is recycled over and over in surface waters so that its consumption by phytoplankton has no net effect on carbon dioxide.

[go back and look at the picture of Dr. Fawcett – next to her you can see the setup of her lab.  The large jugs of water on the left are the samples collected from the ocean.  Each jug is connected to a clear, round yo-yo looking device .  These contain the filters that collect the phytoplankton.  Once all the water is filtered through, she removes and freezes the filters so she can study them further]

How did you become interested in science?  I have always been interested in marine science because it was such a big part of my life growing up.  South Africa is a beautiful country geologically and I’ve always been interested in how things work.  I do what I do because I’m really interested in feedback cycles and the balance the Earth has – there’s no better way to think about the world than to think about the biogeochemistry.  It’s truly fascinating.

Educational background: I received my undergraduate degree in Earth and Planetary Science from Harvard and my PhD from Princeton in geosciences.  I’m currently a post-doctoral research associate.

Plans for the future: I would like to be a professor in Cape Town, South Africa because I’d have access to the South Atlantic, Indian, and Southern Ocean (the ocean around Antarctica). There are so many intriguing questions directly related to how our planet works and why it’s habitable that have to do directly with these oceans (particularly the Southern Ocean, which is the largest). We have no idea how to answer some of these questions, and I think that’s really exciting. We can also learn a lot about past climate: by drilling into the ocean floor and measuring the chemical composition of the shells of microfossils that died and sank to the bottom of the ocean thousands of years ago, we can actually reconstruct what climate was like in the past, and begin to understand, for example, why the Earth has ice ages.

Back to Ms. B:

Dr. Fawcett’s research is truly fascinating and will be hugely beneficial to our understanding of the Earth.  I hope she has inspired some ideas of your own!

I will be featuring the other scientists as the voyage continues so you’ll be exposed to lots of different research ideas.

Don’t forget to comment on the posts! You can always use Edmodo to ask a question/comment if you prefer.

Until next time,

Ms. B.

Spotlight Series: Andrew R. Babbin

“Spotlight Series” is a group of posts designed to introduce you to the other members of the science team on the research expedition.  Each scientist and his/her research will be featured – I provided the prompts and the scientists added their own information (my comments will be in brackets: [ ]).  Feel free to ask questions about what they are studying and how they became interested in science!

Andrew R. Babbin

Andrew R. Babbin, twin brother extraordinaire, relaxing on the ship

Andrew R. Babbin, twin brother extraordinaire and brilliant scientist

I’m starting the Spotlight Series with my twin brother, Andrew Babbin.  He’s the main reason I was able to join the expedition and I work with him to study nutrients in seawater.

What is your field of study? I consider myself a marine biogeochemist – I study the intersection of marine microorganisms with the chemistry around them; in other words, how (mostly) bacteria respond to and shape the chemical background of the ocean. [He also uses stoichiometry in a lot of his analyses – so he’s proof that people do use it!!]

What information do you hope to find on the expedition? This cruise is a cruise of opportunity for me actually, not directly related to my own research. I am measuring concentrations of different dissolved inorganic nitrogen species – ammonium, nitrite, and nitrate – in the seawater we collect. This is necessary in order to locate certain chemical features that relate back to biology. We also need this information to better inform experiments we will be performing later where we have to add nutrients with the heavier isotope of nitrogen (15 mass) to the samples, but do not want to add a lot compared to the background concentrations. I also hope to find out exactly how my sister handles being at sea for a month. [So far, so good :-)]

How did you become interested in science? Growing up, I always had an innate desire to understand the world around me, but I have to completely credit my parents for exposing me to the natural world – whether the Jersey shore or a museum – and providing an outlet where I could explore Earth’s wonders. This desire only deepened as I grew up and began to understand exactly what a career in science meant. In high school, my math and science teachers were exemplary and I truly began to immerse myself in the scientific world.

Educational background: I graduated undergrad from Columbia University in Earth & Environmental Engineering and Applied Math. I’m now pursuing a Ph.D. at Princeton (and will be done in a few short months!).

Plans for the future: I will be a postdoctoral researcher (fancy terminology for a scientist who recently finished his Ph.D.) at MIT with Dr. Roman Stocker. I will be studying the nuances of how marine microorganisms sense differences in chemical concentrations. I am particularly interested in certain microbial groups that thrive at very, very low (as in zero) dissolved oxygen concentrations. I will be performing experiments to try to understand different phenomena that we see in the low oxygen parts of ocean. We see a variety of features (like maximum peaks in dissolved nitrite and nitrous oxide concentrations) but do not fundamentally understand why they exist. This involves probing the microbial world down to the microscopic scale that these organisms operate on using cool techniques known as microfluidics.

Back to Ms. B:

I hope you enjoyed learning a bit about what my brother studies and that his research has inspired some ideas of your own! I will be featuring the other scientists as the voyage continues so you’ll be exposed to lots of different research ideas.

Don’t forget to comment on the posts! You can always use Edmodo to ask a question/comment if you prefer.

Until next time,

Ms. B.