Burkholder JoAnn M.

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Burkholder
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JoAnn M.
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  • Preprint
    Ocean urea fertilization for carbon credits poses high ecological risks
    ( 2008) Glibert, Patricia M. ; Azanza, Rhodora ; Burford, Michele ; Furuya, Ken ; Abal, Eva ; Al-Azri, Adnan ; Al-Yamani, Faiza ; Andersen, Per ; Anderson, Donald M. ; Beardall, John ; Berg, Gry M. ; Brand, Larry E. ; Bronk, Deborah ; Brookes, Justin ; Burkholder, JoAnn M. ; Cembella, Allan D. ; Cochlan, William P. ; Collier, Jackie L. ; Collos, Yves ; Diaz, Robert ; Doblin, Martina ; Drennen, Thomas ; Dyhrman, Sonya T. ; Fukuyo, Yasuwo ; Furnas, Miles ; Galloway, James ; Graneli, Edna ; Ha, Dao Viet ; Hallegraeff, Gustaaf M. ; Harrison, John A. ; Harrison, Paul J. ; Heil, Cynthia A. ; Heimann, Kirsten ; Howarth, Robert W. ; Jauzein, Cecile ; Kana, Austin A. ; Kana, Todd M. ; Kim, Hakgyoon ; Kudela, Raphael M. ; Legrand, Catherine ; Mallin, Michael ; Mulholland, Margaret R. ; Murray, Shauna A. ; O’Neil, Judith ; Pitcher, Grant C. ; Qi, Yuzao ; Rabalais, Nancy ; Raine, Robin ; Seitzinger, Sybil P. ; Salomon, Paulo S. ; Solomon, Caroline ; Stoecker, Diane K. ; Usup, Gires ; Wilson, Joanne ; Yin, Kedong ; Zhou, Mingjiang ; Zhu, Mingyuan
    The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.
  • Preprint
    Harmful algal blooms and eutrophication : examining linkages from selected coastal regions of the United States
    ( 2008-07-28) Anderson, Donald M. ; Burkholder, JoAnn M. ; Cochlan, William P. ; Glibert, Patricia M. ; Gobler, Christopher J. ; Heil, Cynthia A. ; Kudela, Raphael M. ; Parsons, Michael L. ; Rensel, J. E. Jack ; Townsend, David W. ; Trainer, Vera L. ; Vargo, Gabriel A.
    Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.
  • Article
    Defining planktonic protist functional groups on mechanisms for energy and nutrient acquisition : incorporation of diverse mixotrophic strategies
    (Elsevier, 2016-01-03) Mitra, Aditee ; Flynn, Kevin J. ; Tillmann, Urban ; Raven, John A. ; Caron, David A. ; Stoecker, Diane K. ; Not, Fabrice ; Hansen, Per J. ; Hallegraeff, Gustaaf M. ; Sanders, Robert W. ; Wilken, Susanne ; McManus, George ; Johnson, Matthew D. ; Pitta, Paraskevi ; Våge, Selina ; Berge, Terje ; Calbet, Albert ; Thingstad, Frede ; Jeong, Hae Jin ; Burkholder, JoAnn M. ; Glibert, Patricia M. ; Graneli, Edna ; Lundgren, Veronica
    Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks.