19 Apr

Global Scholar’s continue their research around the world



Fearless Curiosity, Fulbright scholar Phoebe Oldach ’13’s bold path to success by MaryAlice Bitts-Jackson

Phoebe Oldach ’13 doesn’t just talk with her hands. She talks with her pen—accompanying every in-depth explanation with a brisk doodle or scrawl that visualizes her point.  By the end of our hour together, she’s filled a once-pristine sheet of computer paper with illustrations of chemical chains, fish fins and toxic-waste dump sites—a visual guide to a conversational path that takes several small detours, but in the end, progresses to one destination: a Fulbright award.  For more of this article about Phoebe and her research as a Dickinson Global Scholar see: http://www.dickinson.edu/news-and-events/news/2012-13/Phoebe-Oldach–13/

18 Apr

Findings confirmed!

Ischia, ItalyAt the recent Mediterranean Seagrass Workshop in Morocco a group led by Professor Maria Buia showed that the seagrass P. oceanica also suffers reduced phenolic contents in high CO2 / low pH waters near Ischia, Italy, confirming our findings on C. nodosa from Italy and our more recent work on aquatic plants in the Chesapeake Bay.  Their group documented changes in total reactive phenolics that were similar to those we observed at the volcanic vent sites on Vulcano in May 2011.  Last year other researchers found that P. oceanica patches can be the longest-living organisms on Earth, each surviving up to 100,000 years or more.


16 Apr

Vulcano volcano fieldsite

Vulcano volcanoThe main crater of the volcano on the island of Vulcano, Itlay, showing our fieldsite in the foreground.  This underwater vent sites emit carbon dioxide, simulating the conditions of ocean acidification and is one of the study sites for the Europena MedSeA program.

08 Apr

Global Scholars and the Forum for Education Abroad

Presentation1Forum for Education Abroad’s annual conference in Chicago where we had the opportunity to share the results of our first Dickinson Global Scholars program.  The 2012  program was a combination of intensive student-faculty research and global education and a collaborative effort to study the impacts of climate change on Moreton Bay, Australia.  Thanks to all of those who supported our new model of student research and study abroad, including Dickinson’s own Centers for Global Studies and Engagement and Sustainability Education as well as the Smithsonian Institution, NASA, and NSF!

07 Mar

New article on plant resource transport and metabolism

Book CoverNew article on plant carbohydrate and nitrogen metabolism published with colleagues from the University of Missouri’s Bond Life Science Center.  The article describes our work with poplar seedlings and older trees, showing that wound responses include the rapid import of sugars but not extra nitrogen-based resources to wound sites such as grazed leaves.  The response is faciliated by jasmonic-acid induction for the activity of extracellular invertases and sugar importing proteins.  See the article here: http://www.landesbioscience.com/journals/psb/article/21900/

01 Mar

Linking science and culture: the art of bonsai


Students from Biology 325 Plant Physiology joined with students and faculty from the the East Asian Studies department and those involved in the College’s new LUCE grant to learn the art of bonsai from local expert Jim Doyle.  This event was the first held in the Inge Stafford Greenhouse facility, which opened a few weeks ago.  For more information, and all the photos find your way to: http://blogs.dickinson.edu/luce-asian-studies/event-feb-28th/



Seismic-Japan-and-Bonsai-events-096-150x150 Seismic-Japan-and-Bonsai-events-045-150x150 2013-02-28_17-01-32_842 2013-02-28_16-42-12_914


24 Jan

Three new articles about chemical ecology

OLYMPUS DIGITAL CAMERAIt’s been a busy year and we’re pleased to have contributed to the following studies, each focusing on different aspects of plant chemical ecology.

Schultz JC, HM Appel, Ferrieri A, Arnold TM (in review) Flexible resource allocation during plant defense response.  Invited review, submitted May 2013 to Frontiers in Plant Science.

Witter A, Arnold TM (2013) Nature’s Medicine Cabinet: An Interdisciplinary Course Designed To Enhance Student Learning by Investigating the Ecological Roles of Natural Products.   ACS Books “Teaching Bioanalytical Chemistry” Symposium Series volume “Teaching Bioanalytical Chemistry.”

Arnold TM, Appel H, and Schultz JC (2012) Is polyphenol induction simply a result of altered carbon and nitrogen accumulation?  Plant Signaling & Behavior 7:11, 1-3.

16 Jan

Stafford Greenhouse Facility – Open for classes!

A sneak peek at the new Inge P. Stafford Greenhouse for Teaching and Research which has been under construction this winter.  We’re very excited and ready to start teaching in the facility next week, even as construction continues outside.  The facility, with it’s three climate-controlled research modules and common classroom space, will revolutionize our teaching and research capabilities.  In the first few weeks we’ve initiated projects on climate change, grape chemistry, salamander life cycles, and conservation of an endangered butterfly.





08 Jan

Carbon dioxide information is beautiful (and scary)


Ideas, issues, knowledge, data — visualized!

This clever illustration from the “Information is Beautiful” is from the website of David McCandless, a London-based author, writer and designer.  It makes it easier to imagine the relative amounts of carbon dioxide emitted to the atmosphere and marks the predicted dates of some consequences of climate change.  Check it out at:


Personally, I’m a big fan of clever and easy-to-follow illustrations because they are part art and part teaching genius.  They also appeal to my tendency to think in abstract shapes and patterns.  What do you think of this illustration?

There are numerous other examples of illustrated data sets worth exploring on this website, such as:


By the way, that beautiful photo is from © David Liittschwager / National Geographic Stock.

20 Dec

Seagrasses sequester carbon dioxide

slide1There are about 20 billion tons of carbon sequenstered in living seagrasses.  About 10% of this, or 2 billion tons, are contained in (poly)phenolic substances.  These substances are likely to influence the fate of the other 90% of the stored carbon as they influence rates of decomposition, grazing, and pathogen infection.  We discussed some of this in our short presentation on the impacts of climate change on seagrass natural products this week.

03 Dec

Seeing Red: the future of seagrasses?

Red Leaf SeagrassWe’re into red leaves.  Why?  Because often the red substances are anthocyanins.  These colorful compounds can shield plants from the harmful effects of too much light, especially dangerous UV light, and heat.  In Australia researchers have observed reddened seagrass leaves for quite a while (think ozone hole – lots of UV light).  Now researchers are finding that it is a common response in these plants, and that it protects them.  Similar respones have been observed on land, where immature leaves are often redish.  Could this answer the oft-asked question: Why are young leaves red?

The nice thing about proposal writing is that we’re forced to re-read the literature and uncover gems like the recent papers by Alyssa Novak and Fred Short.  Here’s one:

Leaf reddening in the seagrass Thalassia testudinum in relation to anthocyanins, seagrass physiology and morphology, and plant protection Author(s): Novak, Alyssa B.; Short, Frederick T.  Source: MARINE BIOLOGY  Volume: 158   Issue: 6  Pages: 1403-1416

And what happens when seagrass leaves turn red?  It is possible that they will be less palatable and nutritious to grazers (sorry waterfowl, manatee, and turtles) and more resistant to decay.  But that depends on which phenolic subtances might be accumulating with the anthocyanins and a host of other factors.  Our recent study of ocean acidification showed that high CO2 levels caused a decrease in many phenolic substances.  But we didn’t measure anthocyanins.  It will be interesting to dive back into the freezer an analyze those tissues!

26 Nov

Trees worldwide a sip away from dehydration

Plumbing systems operate on a razor’s edge, leaving forests vulnerable.  This by Susan Milius in ScienceNews. “Trees in most forests, even wet ones, live perilously close to the limits of their inner plumbing systems, a global survey of forests finds.  Seventy percent of the 226 tree species in forests around the world routinely function near the point where a serious drought would stop water transport from their roots to their leaves, says plant physiologist Brendan Choat of the University of Western Sydney in Richmond, Australia. Trees even in moist, lush places operate with only a slim safety margin between them and a thirsty death.  Reference: B. Choat et al. Global convergence in the vulnerability of forests to drought. Nature. doi: 10.1038/nature11688
15 Nov

Reef Rumble! Corals attacked by seaweeds use chemical cues to call in grazing fish

CoralsOk, I’ll be honest.  As plant biochemists we usually cheer for the guys in green (in this case, the seaweeds).  But even we can make an exception when fleshy seaweeds attack corals, which are already in serious decline from coral bleaching, warming sea temperatures, and other aspects of climate change.  In a recent article in Science magazine, Dixson and Hay describe one way corals fight back against seaweeds that threaten to overgrow them.  In short, some corals can call in grazing fish – in this case gobbies – to remove the invaders.  The communication is chemical, involving waterborne signals.  Here’s the reference:

D.L. Dixson and M.E. Hay. Corals chemically cue mutualistic fishes to remove competing seaweeds. Science, Vol. 338, November 9, 2012, p. 804. doi:10.1126/science.1225748.

and a summary from Scientific American:


05 Nov

Ocean fertilization debate goes private

school of fish in coral

Ocean fertilization is a type of geoenginerring involving the addition of limiting nutrients to ocena surfaces with the goal of increasing phytoplankton productivity, which may take up and store some of the excess carbon dioxide building in the atmosphere.  While it has the potenital to help mitigate climate change it also risks damaging ocean ecosystems.  The US Ocean Carbon and Biogeochemistry Program recently released it’s report of the un-regulated ocean fertilization experiment conducted by a private company off the Pacific coast of Canada this summer, which dumped 100 metric tons of iron-rich dust into the ocean in an attempt to earn carbon credit funds.  The report summary is available here: http://www.whoi.edu/fileserver.do?id=136984&pt=10&p=39295


05 Nov

1500 and counting……


Our recent PLoS ONE paper, coauthored by Dickinson students Hannah Leahey, Chris Mealey, and Kelly Maers, passed the 1,500 download milestone this month.  Not bad for a study on seagrasses and marine grazers.  To celebrate we’re reposting a summary of the work  (with some never before seen photos) below:

Tom ArnoldThe world’s oceans absorb carbon dioxide (CO2) and slow the pace of climate change.  At the same time the absorbed CO2 lowers the pH of ocean waters, changing seawater chemistry in the process called ocean acidification.  This can have devastating impacts on corals and shellfish, disrupting the process of calcification essential for the construction of coral reefs and the cultivation of oysters and clams in aquaculture.  However, the added CO2 could boost the photosynthesis and growth of coastal seagrasses, according to recent studies suggesting that seagrasses will be “winners” in future acidified seas (1).  This is a critical question for those hoping to manage or restore coastal waterways because seagrass meadows reduce coastal erosion and serve as nursery grounds for fish and shellfish, but have been in steep decline world-wide.

The results of a recent study published in the journal PLoS ONE challenge the assumption that seagrasses would necessarily be “winners” in a future high CO2/ low pH world (2).   The team, led by Dr. Tom Arnold from Dickinson College, examined the effects of ocean acidification on seagrasses, particularly their ability to produce a range of protective chemicals called phenolics.

Students Eating“Like most plants,” explained Arnold, “seagrasses produce phenolic substances that can act as structural and chemical defenses, inhibiting the growth of disease organisms and deterring fish and other grazers from consuming the leaves.”  Indeed ecologists have long understood that plant phenolics can have numerous roles in plants.  Slight changes to their chemical structure give them useful properties as antimicrobials, antioxidants, sunscreens for harmful UV radiation, bitter-tasting deterrents, digestion reducers, and flower pigments, as well as making them the building blocks for forming wood.  “On land, more CO2 often means more phenolic substances in plants,” Arnold explained “and this too could be beneficial if it helps protect them from insects or disease”.

Scuba DiverTo test this a team of researchers, including Dr. Whitman Miller from the Smithsonian Environmental Research Center and three undergraduate students from Dickinson College1, simulated ocean acidification using an instrument called a F.O.C.E., which stands for Free Ocean Carbon Enrichment.  The instrument generates high CO2 / low pH seawater and releases it into experimental areas of seagrass meadows.  By dialing in the correct settings on the F.O.C.E. they mimicked conditions predicted to occur within the next 100 years in several meadows of aquatic plants, including widgeon grass Ruppia maritima and redhead grass Potamogeton perfoliatus, in the Chesapeake Bay.  In each of their experiments they found that high CO2 conditions led to a dramatic loss of the phenolic protective substances in these plants.  “We were quite surprised.” said Arnold “This was different than what has been observed on land.”

According to the authors, the surprising observation may be caused by something else that plagues many coastal waterways – nutrient pollution.  On land, plants often struggle to acquire nutrients such as nitrogen and phosphorous for growth and, thus, excess CO2 is diverted to the production of phenolics.  This might protect plants from grazers at a time when they would find it most difficult to regrow lost tissues (3).  However, coastal plants may respond differently because they are often bathed in nutrient-rich waters, the result of nutrient pollution (called “eutrophication”).  In this scenario excess CO2 can be combined with nutrients to fuel rapid plant growth instead of phenolic synthesis (4).

Group of StudentsTo confirm the discovery, Arnold traveled to the Island of Vulcano in the Mediterranean Sea, where CO2 is emitted not only from volcanic craters on land but also from underwater volcanic seeps, creating a natural laboratory for the study of ocean acidification.  Here a short swim towards the underwater seep provides a glimpse of the future.  As CO2 levels increase closer to the seeps the ecosystem changes visibly – seagrasses and some seaweeds thrive, while creatures such as sea urchins and molluscs disappear (5).  On Vulcano Arnold joined forces with Dr. Jason Hall-Spencer from the University of Plymouth and Dr. Marco Milazzo from the Dipartimento di Scienze della Terra e del Mare at the University of Palermo.  Together they compared populations of the seagrass Cymodocea nodosa growing near the seeps.  They analyzed populations growing at control sites, where the average pH was 8.1 and concentrations of CO2 were 422 ppm – well within the “normal” range for ocean waters.  Closer to the seeps, however, the average pH was as low as 7.3 and CO2 levels were nearly ten times higher.  They once again found the surprising decrease in concentrations of the phenolic protective substances near the vents, confirming the work done thousands of miles away in the Chesapeake Bay.

“What this means for seagrasses and the creatures that depend upon them isn’t clear yet”, says Arnold.  “It is something we are working to understand.”

Students with a netRecently, he traveled to the world’s second largest sand island, North Stradebroke Island in Australia, to study unusual underground springs flow through mangrove forests to acidify coastal areas.  There the team is working to determine if high CO2 causes seagrasses growing there to become more vulnerable to grazing by local rabbitfishes2.  Other groups are studying CO2 impacts on seagrass pathogens, such as the slime-mold like microbe that triggers outbreaks of the infamous wasting disease, which is believed to have contributed to a world-wide die-off of eelgrass in the 1930s.  “We wonder, will seagrasses really be ‘winners’ in future acidified seas?  If ocean acidification stimulates the growth of seagrasses but at the same time reduces their natural defense mechanisms, what does this mean for grazers such as fishes, turtles and dugongs and microbes that cause disease?” he explains.  “We just don’t know.  We really need this information before we can predict how seagrasses, and therefore coastal communities, will respond.”