• UCSBgauchos twitter avatar
    Gilbertson Earns Big West Player of the Week Honor https://t.co/P0wmPtDjNT
    1 hour 31 min ago
  • ucsantabarbara twitter avatar
    When secrets are exposed, can life ever be the same? That question is at the heart of @ucsbTD's “Lydia." https://t.co/r1KKTmmB5N
    7 hours 8 min ago
  • ArtsandLectures twitter avatar
    RT @KCRWinSB: Extreme sports, mountain culture & exotic locations are a few highlights of the @BanffMtnFest. Don't miss it! https://t.co/sR…
    7 hours 9 min ago
  • ArtsandLectures twitter avatar
    .@DrSidMukherjee on the powerful documentary Cancer: The Emperor of All Maladies with @kenburns & @katiecouric https://t.co/p7pRHUrhGr
    7 hours 19 min ago
  • ArtsandLectures twitter avatar
    Fearless foodies, we're prepping for @AltonBrownLive with a giveaway! Find out how you can win #AltonBrown swag!… https://t.co/7xWh29cuct
    7 hours 35 min ago
  • UCSBgauchos twitter avatar
    WWP: Gauchos Begin Barbara Kalbus Invitational Against No. 8 Michigan https://t.co/p3U6s9Pswr
    7 hours 48 min ago
  • UCSB_GradPost twitter avatar
    Maria Vazquez on seeing the big picture and grad school life lessons https://t.co/8ghZtxLgvN #UCSB #ucsbgradpost
    8 hours 54 min ago
  • UCSBgauchos twitter avatar
    Gauchos Host Riverside in Final Home Game Thursday https://t.co/FPzQSdg2Ae
    9 hours 15 min ago
  • UCSBengineering twitter avatar
    Cryptographer Stefano Tessaro receives early career recognition from the Alfred P. Sloan Foundation https://t.co/iQi8qUA6uS
    9 hours 38 min ago
  • AS_UCSB twitter avatar
    Eager to make your mark on campus? Pop into our winter recruitment fair to learn how to get involved with your A.S.… https://t.co/Cp0VIE7bEq
    9 hours 59 min ago
  • brenucsb twitter avatar
    RT @CoraKammeyer: So cool to hear @GlobalEcoGuy speak at @brenucsb about the work @calacademy is doing to explore+explain+sustain our awe-i…
    11 hours 27 min ago
  • ArtsandLectures twitter avatar
    @mrjoshz @benshapiro oops, not an A&L event. Daily Nexus says it was put on by UCSB College Republicans: https://t.co/z8KDFjpXTv
    12 hours 7 min ago
  • brenucsb twitter avatar
    .@GlobalEcoGuy: Museums are the most trusted institutions in the nation w/ high approval ratings from Dems & Republicans alike #BrenTalks
    13 hours 4 min ago
  • ArtsandLectures twitter avatar
    Looking forward to another collaboration #theemperorofallmaladies #thegene https://t.co/BEzznCTSdN
    13 hours 6 min ago
  • brenucsb twitter avatar
    @GlobalEcoGuy: Museums serve ~ 1 billion visitors a year, more than all the sports stadiums & theme parks in the nation combined #BrenTalks
    13 hours 7 min ago

Scientist Probes Marine Iron Particles Uptake Puzzle

Tuesday, September 21, 1999 - 17:00
Santa Barbara, CA

Studying the different mechanisms marine plants and bacteria use to acquire traces of iron from sea water may help explain variations in phytoplankton productivity and increase understanding of the process by which the oceans absorb or release carbon into the atmosphere, a primary

factor in global warming.

This is the focus of work performed by UC Santa Barbara chemist Alison Butler and her research colleagues from the University of Delaware that was described in a paper published late last month in Nature magazine. The article, titled

"Competition among marine phytoplankton for different chelated iron species," outlines possible ways bacteria and other prokaryotes (cells without internal organelles) bind iron in comparison to diatoms and other eukaryotic (cells with organelles) phytoplankton.

"Since iron availability plays a critical role in phytoplankton growth, as well as in many other marine microorganisms---maybe even the entire global carbon cycle---we wanted to know what molecular mechanisms control iron uptake," said Butler. As a bioinorganic chemist, her role was to isolate the iron-carrying molecules from the bacteria, known as siderophores, and determine their structures. This had never been done before for open-ocean bacteria, though siderophores from bacteria living in fish guts and deep-sea mud had been described.

The researchers asked themselves, was there a difference in the type of iron complex used by eukaryotic plankton when compared to that used by prokaryotic bacteria? They analyzed a variety of compounds, including iron pyrrole (porphyrin) complexes. Overall, they found plankton much more efficient at acquiring iron from the porphyrin complexes than was bacteria.

"That was not so surprising," said Butler, "but we still do not know the details of how the plankton got the iron."

Bacteria acquired iron from a variety of siderophoric compounds, some of which they do not produce themselves. "That was surprising," Butler said. "The dogma has been that bacteria can only use their own siderophores, which have a specific uptake process, to capture and assimilate the iron. We are just beginning to understand the molecular basis of these very interesting differences."

Butler, who came to UCSB in 1986, and her research group have explored the discrepancy between iron availability in surface ocean waters and iron requirements of marine bacteria since 1990. By recently joining a National Science Foundation-funded consortium of 22 other scientists from other disciplines---the Princeton-based Center for Environmental BioInorganic Chemistry---she expects to extend her exploration many more years.