30 Apr

Seagrass responses to ocean acidification: Chris M earns departmental honors

 

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Biology Honors Presentations.  Wednesday, May 1, 4:30 p.m.Stafford Auditorium.  Christopher Mealey presents “Climate Change Effects on Marine Ecosystems” 

Chris Mealey will present his honors thesis research, including work from the Chesapeake Bay (USA) and Moreton Bay (Australia) this week.  Chris arrived in our lab four years ago and also conducted research at the School for Field Studies – Turks and Caicos site on invasive lionfish and at the University of Queensland as a part of our Global Scholars Program.  Some of his work was published in the journal PLoS ONE in 2012 and he will be attending the graduate program in marine biology at the University of Charleston in the fall.  Come hear about his work on Wendesday!

NEW UPDATE: Chris was awarded departmental honors for his thesis “Impacts of Ocean Acidification on the Polyphenolics of Seagrasses” on May 14, 2013.  Congratulations Chris!

Abstract

Atmospheric carbon dioxide (CO2) has increased by about 40% since the Industrial Revolution, with current levels residing around 395ppm. A portion of this excess CO2 is absorbed by the oceans resulting in the increase of H+ and carbonic acid concentrations, as well as a corresponding reduction in mean pH. This phenomenon is termed ‘ocean acidification’ (OA). Multiple studies demonstrate a decline in calcification of many marine organisms as a result of OA, but greater photosynthetic productivity in algae and seagrasses has also been reported. However, little is known regarding the effects of OA on the chemical defenses produced by these marine angiosperms. Three forms of CO2 enrichment were utilized in this study to observe the effects OA may have on secondary metabolite accumulation in four species of seagrass. These include a Free Ocean Carbon Enrichment (F.O.C.E.) system – Severn River, MD (USA), a natural volcanic vent – Vulcano (Italy), and the naturally acidified Myora Springs – North Stradbroke Island (AUS). Additionally, herbivory tests examined preferences of juvenile black rabbitfish on eelgrass grown in low and normal pH regions near the naturally acidified Myora Spring (AUS). Phenolic acids, the main chemical defenses of these species, were identified and measured via HPLC, whereas more complex tannin concentrations were measured by colorimetry. The results of this experiment observed a significant decrease, about 60% in some instances, in the production of these secondary metabolites corresponding to a decrease in average oceanic pH and an increase in pCO2 concentrations. The reduction in the accumulation of these chemical defenses within the observed seagrasses implies a greater susceptibility to herbivory and harmful pathogens, which reveals location dependent impacts of OA on marine plants.

19 Apr

Global Scholar’s continue their research around the world

 

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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

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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/

 

 

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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.

 

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08 Jan

Carbon dioxide information is beautiful (and scary)

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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:

http://www.informationisbeautiful.net/visualizations/how-many-gigatons-of-co2/

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:

http://www.informationisbeautiful.net/play/snake-oil-supplements/

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:

http://blogs.scientificamerican.com/science-sushi/2012/11/08/coral-recruits-goby-bodyguards-against-seaweed-assasins/

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