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Field of Specialization: Physiology and Biogeochemistry
Most of my work involves metals and microbes, either trace metals essential for the nutrition of marine phytoplankton, or the microbially-mediated mobilization and cycling of contaminant metals.
Phytoplankton Trace Metal Physiology and Biogeochemistry
Microscopic marine algae (phytoplankton) are responsible for about 40% of the carbon dioxide removed from the atmosphere annually (while land plants are responsible for the remainder). Despite the near equal significance of phytoplankton and land plants, a lot less is known about how phytoplankton grow, what limits their growth, and what chemical and physical factors favor one group of phytoplankton over another. It is also compelling that, within one litre of seawater, many hundreds of species can be found. How do all these species co-exist and what makes each different from the others?
Our research focuses on two goals:
To understand what factors influence the relative success of one phytoplankton group over another, and
to achieve a quantitative and mechanistic understanding of how one group of phytoplankton can “economize” on a limiting nutrient. They can either be better at acquiring the nutrient, use it more efficiently in the cell, or a combination of both.
Most of my work to date has involved various aspects of the micronutrient iron – how phytoplankton acquire iron and how much they need to fuel Fe-intensive processes such as N2 fixation (see my CV). A hallmark of my work has been the use of interdisciplinary approaches rooted in phytoplankton ecology, physiology, field-based oceanography, aquatic and analytical chemistry and modern molecular techniques.
Two currently funded projects are described below:
1. Investigating mechanisms of iron storage in diatoms and N2 fixing cyanobacteria. Despite the importance of Fe in marine ecosystems, and that lab cultures reveal a high and variable capacity to store Fe (for future use when Fe in the surrounding seawater is depleted), nothing is known about the mechanisms of Fe storage. We’ve proposed that one diatom and the cyanobacterium Trichodesmium store iron in ferritin-like “protein cages”, similar to the mechanisms used in mammals. It seems another diatom has an altogether different mechanism, involving storing iron in intracellular vacuoles. We are investigating this in cultures using a combination of techniques. We have field opportunities in the summers of 2008 and 2009 to the tropical Atlantic Ocean aboard US research vessels (Cape Verde Islands, Barbados).
2. Investigate the ways two diatom species recover from Fe stress in the ocean. The relative speed at which two species can recover from Fe limitation after an episodic iron input probably influences which species will “win” and make up the bulk of the bloom population. We are developing whole genome microarrays for two diatom species, and will look at the transcription of “recovery” proteins, the production of metabolites (via GC-MS) and metal quotas (using high resolution ICPMS http://marine.rutgers.edu/LAICPMSintro/Index.htm ). Then we will follow up with novel findings (ie unique genes that may be involved in Fe metabolism) using genetic transformation protocols.
Microbially-mediated mobilization and cycling of contaminant metals
These projects, involving microbial cycling of cadmium and chromium, are under development. Contact me for further information.
Graduate Program in Oceanography
Institute of Marine & Coastal Sciences
Rutgers University, New Brunswick, NJ 08901
2004-present American Society for Microbiology.
1999-present Phycological Society of America.
1997-present American Society of Limnology and Oceanography.
1999-present American Geophysical Union.
Ph.D. in Coastal Oceanography, State University of New York at Stony Brook, Stony Brook, New York; August 2002 (Co-advisors: Sergio Sañudo-Wilhelmy & Edward J. Carpenter).
B.S. in Natural Resources Management (Fisheries Science), Cook College, Rutgers University; May 1993.
2008. Thamatrakoln, K., and A.B. Kustka. When to say when: can excessive drinking satisfy the silicon requirements of diatoms?. (submitted to Bioessays).
2008. Bellenger, J.P, T.D. Wichard, A.B. Kustka, and A.M. Krapiel. Catechol siderophores mediate molybdate and vanadate oxyanion acquisition in the nitrogen fixing bacterium, Azotobacter vinelandii (Nature Geosciences 1: 243-246).
2008. Subramaniam, A., P.L. Yager, E. J. Carpenter, C. Mahaffey, K. Björkman, S. Cooley, A.B. Kustka, J.P. Montoya, S. A. Sañudo-Wilhelmy, R. Shipe, and D.G. Capone. Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean (Proc. Natl. Acad. Sci. 105:10460-10465).
2008 Morel, F.M.M., A.B. Kustka, and Y. Shaked. The role of unchelated Fe in the Fe nutrition of phytoplankton. Limnol. Oceanogr. 53: 400-404.
2007 Kustka, A.B., A. Allen, and F.M.M. Morel. Sequence analysis and regulation of iron acquisition genes in two marine diatoms. J. Phycol. 43: 715-729.
2006 Burns, J., J.P. Zehr, J.P. Montoya, A.B. Kustka, and D.G. Capone. Effects of EDTA additions on natural populations of Trichodesmium (Cyanophyta). J. Phycol. 42:900-904.
2006 Tovar-Sanchez, A., S. Sañudo-Wilhelmy, A.B. Kustka, S. Agusti, J. Dachs, D. Hutchins, C. Duarte. Impact of dust deposition and river discharges on trace metal composition of Trichodesmium spp. in the Tropical and Subtropical North Atlantic Ocean. Limnol. Oceanogr. 51: 1755-1761.
2005 Campbell, L., E.J. Carpenter, J.P. Montoya, A.B. Kustka, and D.G. Capone. Picoplankton community structure within and outside a Trichodesmium bloom in the southwestern Pacific Ocean. Vie et Milieu Special Edition on Picoplankton.
2005 Kustka, A.B., Y. Shaked, A.J. Milligan, D.W. King, and F.M.M. Morel. Extracellular production of superoxide by marine diatoms: Contrasting effects on iron redox cycling and availability. Limnol. Oceanogr. 50: 1172-1180.
2005 Shaked, Y., A.B. Kustka, F.M.M. Morel. A general kinetic model for iron acquisition by eukaryotic phytoplankton. Limnol. Oceanogr. 50: 872-882.
2004 Shaked, Y., A.B. Kustka, Y. Erel and F.M.M. Morel. Simultaneous determination of iron reduction and uptake by phytoplankton. Limnol. Oceanogr. Methods 2:137-145.
2003 Kustka, A.B., E.J. Carpenter, S. Sañudo-Wilhelmy, J. Burns, D. Capone, and W.G. Sunda. Iron requirements for N2 and NH4+ supported growth in cultures of Trichodesmium (IMS 101): comparison with nitrogen fixation rates and Fe: C ratios of field populations. Limnol. Oceanogr. 48: 1869-1884.
2003 Kustka, A.B,. S. Sañudo-Wilhelmy, E.J. Carpenter, D.G. Capone, and J.A. Raven. A revised iron use efficiency model of nitrogen fixation, with special reference to the marine N2 fixing cyanobacterium, Trichodesmium spp. (Cyanophyta). J. Phycol. 39: 12-25.
2002 Kustka, A. B., and S. Sañudo-Wilhelmy. Iron and marine nitrogen fixation: progress and future directions. Res. Microbiol. 153: 255-262.
2001 Sañudo-Wilhelmy, S.A., A.B. Kustka, C.J. Gobler, D.A. Hutchins, M. Yang, K. Lwiza, J. Burns, D.G. Capone, J.A. Raven, and E.J. Carpenter. Phosphorus limitation of nitrogen fixation by Trichodesmium in the central Atlantic Ocean. Nature 411: 86-89.
1997 Stefano, G., B. Salzet, C.M. Rialas, M. Pope, A. Kustka, K. Neenan, S. Pryor, M. Salzet. Morphine and anandamine stimulated nitric oxide production inhibits presynaptic dopamine release. Brain Research 763 (1): 63-68.
Invited Presentations (last 12 months)
April 20, 2007: University of South Carolina, Marine Sciences and Chemistry.
May 10, 2007: Drexel University, Biosciences and Biotechnology.
October 5, 2007: Frontiers in Geobiology Workshop. Gottingen, Germany (funded by Deutsche Forschungsgemeinschaft).
October 26, 2007: Lamont Doherty Earth Observatory, Biology and Paleo Environment.
November 16, 2007: University of North Carolina Wilmington, Biology and Marine Biology.
December 4, 2007: University of Southern California, Marine and Environmental Biology.
January 23, 2008: Earth and Environmental Sciences, Rutgers-Newark.
March 4, 2008: Committee’s Choice Session, Ocean Sciences, Orlando, FL
March 27, 2008: Old Dominion University, Ocean, Earth and Atmospheric Sciences.
In preparation manuscripts
Kustka, A.B. Iron availability in the oceans: consensus, controversy and the promises of the post-genomic era. (Biogeosciences, Special Issue, Proceedings of Geobiology Conference, Göttingen, Germany).
Kustka, A.B., A.J. Milligan, K.D. Bidle, and J.Reinfelder. Molecular evidence for C4-type C fixation in marine diatoms. (Plant Physiology).
Knapp, A.N., A.B. Kustka, F. Lipschultz, and D.M. Sigman. The relationships among dinitrogen fixation and dissolved organic nitrogen concentration and isotopic composition in the oligotrophic ocean. (Global Biogeochem. Cycles).
Knapp, A.N., A.B. Kustka, and D. Sigman. Isotopic composition of size-fractionated dissolved organic nitrogen from the oligotrophic ocean. (Limnol. Oceanogr.)
Some of these lab facilities are currently under construction. Contact me for further details.
Lab equipment & facilities in our or neighboring labs
A “class 100” clean lab, for aqueous and biological sample preparation for ultra-trace element determination, supplied with 0.12 micron filtered air and Milli-Q 18.2 m water.
Culturing facilities for marine and freshwater plankton.
Beckman Coulter Particle Size Analyzer.
Tangential Ultrafiltration System for separation / concentration of biomolecules.
High Performance Liquid Chromatography for radiolabeled (14C, 32P, 59Fe) substrates.
Culturing and clean facilities for radiotracer work (currently including 55Fe, 59Fe, 14C, possibly 75Se, 109Cd, 51Cr).
UV oxidizer for production of organic-free water.
Waterville Analytical FeLume Fe(II) Chemiluminescence Flow Injection Analytical System.
Nucleic acid and protein separation tools (thermal cyclers, western blotting apparatus, centrifuges, etcetra).
Spectramax M2 96-well plate reader (fluorescence and spectroscopy).
Turner AU-10 fluorometer.
We also enjoy fruitful collaborations with the Rutgers Inorganic Analytical Laboratory and the Environmental Biophysics and Molecular Ecology groups, at IMCS. This provides invaluable cross-fertilization and access to several research tools not housed in my lab (for example, fluorescence activated cell sorting flow cytometry, ICP-MS, biolistics gene gun).
2007. Frontiers in Geobiology Workshop, Göttingen, Germany.
2003. Dissertation Initiatives for the Advancement of Limnology and Oceanography Award Recipient, Bermuda.
2001. Research Fellow, Swedish Foundation for International Cooperation in Research and Education, University of Stockholm, Sweden.
1992. NOAA Undergraduate Research Fellow. Rutgers University Marine Field Station, Rutgers University.