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Stoichiometry of the Microbial Loop: J. Matthew Haggerty

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Stoichiometry of the Microbial Loop: J. Matthew Haggerty

  1. 1. Stoichiometry  of  the  Microbial   Loop   J.  Ma5hew  Haggerty   SDSU/UC  Davis   Dinsdale/Eisen  Lab  
  2. 2. What  is  the  Microbial  Loop?  
  3. 3. Complicated  By  Diversity  Diverse  Nutrient  Regimes     SelecJve  Grazing  from  a  Diverse   Protozoan  Community   Diverse  ProkaryoJc  Community  
  4. 4. Complicated  By  Diversity  Diverse  Nutrient  Regimes     SelecJve  Grazing  from  a  Diverse   Protozoan  Community   Diverse  ProkaryoJc  Community  
  5. 5. Nutrients  in  the  Ocean   Deep-Sea Research II 49 (2002) 463–507Iron cycling and nutrient-limitation patterns in surface waters of the World Ocean J. Keith Moorea,*, Scott C. Doney, David M. Gloverb, Inez Y. Fungc a National Center for Atmospheric Research NCAR, P.O. Box 3000, Boulder, CO 80307, USA b Woods Hole Oceanographic Institution, 573 Woods Hole Road, Woods Hole, MA 02543, USA c University of California Berkeley, 301 McCone Hall, Berkeley, CA 94720, USA Accepted 17 June 2001 •  Comprehensive  nutrient  compilaJon  of  nutrients   (N,C,P,Fe,Si,CaCO3,Chl)  Abstract •  global surface waters of the world ocean. The f  nutrient  lhas acyclingphytoplankton size class A Analysis  predicts  regions  o is used to study ironpatterns in marine ecosystem mixed-layer model ecosystem model imitaJon  fnutrient-limitation small and or  whose growth can be funcJonal  groups.   a diatom class which can also be Si-limited, and a different   limited by N, P, Fe, and/or light,diazotroph phytoplankton class whose growth rates can be limited by P, Fe, and/or light levels. The modelalso includes a parameterization of calcification by phytoplankton and is described in detail by Moore et al.(Deep-Sea Res. II, 2002). The model reproduces the observed high nitrate, low chlorophyll (HNLC) conditions in the SouthernOcean, subarctic Northeast Pacific, and equatorial Pacific, and realistic global patterns of primaryproduction, biogenic silica production, nitrogen fixation, particulate organic carbon export, calciumcarbonate export, and surface chlorophyll concentrations. Phytoplankton cellular Fe/C ratios and surfacelayer dissolved iron concentrations are also in general agreement with the limited field data. Primaryproduction, community structure, and the sinking carbon flux are quite sensitive to large variations in the
  6. 6. Diatom  LimitaJon  J.K. Moore et al. / Deep-Sea Research II 49 (2002) 463–507 Deep-Sea Research II 49 (2002) 463–507 Iron cycling and nutrient-limitation patterns in surface waters of the World Ocean J. Keith Moorea,*, Scott C. Doney, David M. Gloverb, Inez Y. Fungc a National Center for Atmospheric Research NCAR, P.O. Box 3000, Boulder, CO 80307, USA b Woods Hole Oceanographic Institution, 573 Woods Hole Road, Woods Hole, MA 02543, USA c University of California Berkeley, 301 McCone Hall, Berkeley, CA 94720, USA Accepted 17 June 2001
  7. 7. Small  Phytoplankton  LimitaJon   Deep-Sea Research II 49 (2002) 463–507 Iron cycling and nutrient-limitation patterns in surface waters of the World Ocean J. Keith Moorea,*, Scott C. Doney, David M. Gloverb, Inez Y. Fungc a National Center for Atmospheric Research NCAR, P.O. Box 3000, Boulder, CO 80307, USA b Woods Hole Oceanographic Institution, 573 Woods Hole Road, Woods Hole, MA 02543, USA c University of California Berkeley, 301 McCone Hall, Berkeley, CA 94720, USA Accepted 17 June 2001
  8. 8. Diazotroph  LimitaJon   Deep-Sea Research II 49 (2002) 463–507 Nutrient-limitation patterns for the diatoms (A), the small phytoplankton (B), and the diazo Iron cycling and nutrient-limitation patterns in surface waters r months. Areas where all nutrient cell quotas are of the World Ocean >97% of the maximum cell quota valud as nutrient-replete. Also shown is the percentage of total ocean area where each nutrient is a, b c J. Keith Moore *, Scott C. Doney, David M. Glover , Inez Y. Fung a National Center for Atmospheric Research NCAR, P.O. Box 3000, Boulder, CO 80307, USA b Woods Hole Oceanographic Institution, 573 Woods Hole Road, Woods Hole, MA 02543, USA c University of California Berkeley, 301 McCone Hall, Berkeley, CA 94720, USA Accepted 17 June 2001onutrients and the initially high iron concentrations in this region
  9. 9. 60° S What  about  co-­‐limiJng  nutrients   75° W 25° W 25° E 0.30 b 50° N 0.25 25° N Surface P* (µmol kg¬1) 0.20 0° 0.15 0.10 25° S 0.05 50° S 0 LETTERS 0° 40° W 80° W PUBLISHED ONLINE: 1 NOVEMBER 2009 | DOI: 10.1038/NGEO667Large-scale distribution of Atlantic nitrogenfixation controlled by iron availabilityc 50° NC. Mark Moore1,2 *, Matthew M. Mills3 , Eric P. Achterberg2 , Richard J. Geider1 , Julie LaRoche4 , 1Mike I. Lucas , Elaine L. McDonagh , Xi Pan , Alex J. Poulton , Micha J. A. Rijkenberg2 , 5 2 2 2David J. Suggett1 , Simon J. Ussher6 and E. Malcolm S. Woodward7 0 N*
  10. 10. The  ComplicaJons  Diverse  Nutrient  Regimes     SelecJve  Grazing  from  a  Diverse   Protozoan  Community   Diverse  ProkaryoJc  Community  
  11. 11. DeviaJon  in  Microbial  Redfield  RaJo   Discussion Paper Arendal Jomfruland BGD Arendal Jomfruland 10 8 8, 6227–6263, 2011 8 6 6 Seasonal variability CN CN 4 4 in seston | 2 stoichiometry Discussion Paper 2 0 0 H. Frigstad et al. Non-autotrophs (atomic ratios) Live autotrophs (atomic ratios) 120 200 100 Title Page 150 Lines 80 Lines Redfield Redfield CP Abstract Introduction 60 CP 100 Annual Mean Annual Mean | 40 50 Conclusions References Discussion Paper 20 0 Tables Figures 0 35 15 30 J I 25 J I 10 20 Biogeosciences Discuss., 8, 6227–6263, 2011 Biogeosciences NP NP 15 www.biogeosciences-discuss.net/8/6227/2011/ Back Close Discussions | 5 10 doi:10.5194/bgd-8-6227-2011 Discussion Paper © Author(s) 2011. CC/Attribution 3.0 License. Full Screen Esc 5 0 0 This discussionSummer is/has beenWinter review for the journal Biogeosciences (BG). paper Fall Winter Printer-friendly Version Spring under Spring Summer Fall Winter Spring Summer Fall Winter Spring Summer Fall Please refer to the corresponding final paper in BG if available. Fig. 11. Interactive DiscussionFig. 10. Calculated N:P, C:P and C:N of live autotrophs for Arendal and Jomfruland with lines Calculated N:P, C:P and C:N of non-autotrophic fraction for Arendal and Jomfrushowing annual mean ratio and the Redfield ratios. Error bars show the SE. with lines showing annual mean ratio and the Redfield ratios. Error bars show the SE. Seasonal variation in marine C:N:P 6262 stoichiometry: can the composition of 6263 | seston explain stable Redfield ratios? H. Frigstad1,2 , T. Andersen3 , D. O. Hessen3 , L.-J. Naustvoll4 , T. M. Johnsen5 , and R. G. J. Bellerby6,2,1
  12. 12. Quick  Rundown  on  Cyanobacteria  •  Known  for  their  role  as  nitrogen  fixers  •  Spurred  iron  ferJlizaJon  experiments  •  The  primary  nitrogen  fixer  is  Trichodesmium    •  Prochlorococcus  and  Synechococcus  are  not   nitrogen  fixers  but  primary  producers  •  Ber1lsson  highlighted  the  role  of  C:P  ra1os   limi1ng  carbon  sequestra1on    
  13. 13. Trichodesmium   American Society of Limnology and Oceanography http://www.jstor.org/stable/2670974 . •  Nitrogen  fixaJon  is  iron  limited  in  75%  of  the  worlds   oceans     .Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at •  Iron  limitaJon  results  in  loss  of  photosyntheJc  pigments  http://www.jstor.org/page/info/about/policies/terms.jsp.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org..     American Society of Limnology and Oceanography •  Use  five  Jmes  as  much  iron   http://www.jstor.org/stable/3597553 . •  20-­‐50%  iron  used  as  nitrogenase   . Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at •  Phosphate  limitaJon  seen  at  N:P  raJo  >  40   http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.
  14. 14. Flexible elemental stoichiometry in Trichodesmiumspp. and its ecological implicationsAngelicque E. White1 and Yvette H. SpitzCollege of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503David M. KarlSchool of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822Ricardo M. LetelierCollege of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503 Abstract 1788 White et al. We conducted laboratoryexperimentsto assess the bioelementalplasticity of cultures of Trichodesmium IMS101underphosphorus (P)-replete, and . . . . conditions.The resultsreveala high degree P-restricted,20 light-limited •  Highlight  the  extreme   Specifically,Trichodesmium J- is capableof growthwith carbon(C) : nitrogen of stoichiometric flexibility. IMS101 n= 73 (N) : P ratios of C585_56: een  in   approximately times higherthan would be predictedby the Redfield six deviaJons  that  can  N16:N90o+10 signifyinglow cellularP quotasrelativeto C andN. Luxuryconsumptionof ratio(C106 be  sPI), thus P1, , reference Trichodesmium    after periods:  PprolongedP restriction,........ both light and dark conditions,resultingin P occurs rapidly C :  N of 1000 -:. under - substantial increases in P 125 891 1   quotas and reductions of C:N:P a ratios (C96__8 :N16-1: 0 o P1). Comparisons of laboratory culturedata to our field observations -- the NorthwestAtlanticand the North Pacificindicatethat, from I II /- •  Low  demand  for  P   the of Trichodesmium P andpersistently low P content relative to C and N while natural populations and lowest C: exhibit N: /P ratios recordedin the laboratoryare rarely (C290_15: N53+-3: P1), highest u, - - observedin nature. We have also performedlaboratoryexperiments- 600 -- 0 - intendedtoQsimulatethe energeticand .600 - nutritionalextremesthat would occur as naturallymigratingpopulationsof Trichodesmium out of the sink •  Highlights  zone into P-richregionsof the upperdisphoticzone. The durationof darksurvivalfor this isolateis on euphotic the  strong   0 0 . . . . . differences  son d,n  lab   scale of cells are unable to recoverfrom light deprivation.This finding provides the order of een  i after which time 0 3-6 O - O - a constraint the temporal verticalmigration. extremes  and  field:  Believes   200- : : 200 , ---------- -- PC:PP = 106 --- --.PC:PP= 106----. --. extreme  stoichometric   0 ~...l. i..... 0 a 50 100 150 0 30 60 - Species of the is  limited  by   marine cyanobacterial fieldPacific - gyres, frequencythe process of biological N2 fixation variaJon   colony-forming 0 50 100 150 0 1020 0 where lab samples - PN:PP frequency samples PN:PPgenus colimitaJon   have been well described as promi- PN: PP versusPC: PP for field and laboratorydata sets from this study. Dotted net Trichodesmium Fig. 10. has been documented to seasonally enhance thenent dinitrogen (N2) fixing organisms (diazotrophs) linesthe RedfieldPC: PP (106), PN: PP (16)(C) and nitrogen (N) out ratio the in show transport of carbon stoichiometry,and the criticalPN: PP of = (PN: PPcritical 50). Histogramsfor each axis are also shown. Field data conformto a normal global [p euphotic zone (Karl et al.and Lillieforstestsfor et al. 2005). Givenoligotrophic tropical and subtropical regions of the distribution valuesfor the Kolomogorov-Smirnov 1997; Capone normality(Zar 1999) that Trichodesmium-based productivity is by nature sto-ocean (Capone 2001; Karl et al. 2002). The notoriety of not significantat the 0.05 level].Laboratorydata adhereto a log normaldistribution. are this
  15. 15. Limnol. Oceanogr., 48(5), 2003, 1721-1731 1723 ? 2003. by the American Society of Limnology and Oceanography,Inc. Despite the apparent morphological similanties and close l ooo Elemental composition of marinerelationships, pigmentation is very different in phylogenetic Prochlorococcus and Synechococcus: Implications for the three the ecological stoichiometry ofstrains; for example, Prochlorococcus lack phyco- the sea biliproteins but instead synthesize divinyl-chlorophyll a and b (Partenskyet al. 1999) and the Synechococcmsstrains dif- S. Bertilsson and 0. Berglund2 100 fer in their relative content of phycouribilin and phycoery- ¢ Department of Civil and Environmental (Rocap 2002). Massachusetts Synechococcus WH8103 thrin Engineering, Furthermore,Institute of Technology, - Cambridge, Massachusetts 02139 is motile, whereas the other two strains lack any form of c) swimming motility (Waterbury1986; Rocap 2002). ce D. M. Karl o All cultures were maintained at 22°C in constant light at 10 School of Ocean and Earth Science and Technology, University Cool-white Honolulu, Hawaii 96822 5 30-40 ,umol quanta m 2 S-l. of Hawaii, fluorescent lamps C:N: P in Prochlorococcus and Synechococcus were used for all incubations. Batch cultures were grown in o 1727 S. W. Chisholm 25 ml Sargasso Sea-based medium added to 50-ml borosil- ._ Department of Civil and Environmental glass tubes with 25 mm inner diameter (Moore et al. icate Engineering, Massachusetts Institute of Technology, Massachusetts 02139 2002). Filter-sterilized and autoclaved seawater was amend- Cambridge, Elemental Table 3. ratios (molarC:N, C:P, and N:P) for marinephytoplankton cultures,bacteria,and particulate organicmatter.ArithmeticAbstract presented, ed with filter-sterilized stock solution of NH4Cl to a final meansare with standard deviation betweenbrackets. 1.000 concentration of 800 jumol L-, and a stock solution of The elemental composition of marine cyanobacteriais an importantdeterminantof the ecological stoichiometry NaH2PO4was added to either 50 or 1 ,umol L-l toN: P C:N C:P obtain in low-latitude marine biomes. We analyzed the cellular carbon (C), nitrogen (N), and phosphorus (P) contents of Reference Sample o Prochlorococcus (MED4)media with molar N: P ratios of WH8012) under nutrient-repleteand P-starved con- and Synechococcus (WH8103 and 16 and 800 respectively. AProchlorococcus Med4 nutrient-repleteconditions, C, N, and P quotas (femtogram cell-) of the three strains were 46 ? 4, ditions. Under filter-sterilized trace-metal stock solution was added to the / ;) 100 P-replete9.4 ? 0.9, and 1.0 + 0.2 following 5.7 (0.7) 20 + 3, and 1.17 ,umol L-1 ethylene dia- + 7, 50 + 2, 3.3 + for MED4; final concentrations: 1.8(17) for WH8012; and 213 92 + 13. 121 ? 0.1 21.2 (4.5) - t This study minetetraaceticacid, nmol 464?(28) nmol ? 62.3 (14.1) P-limited0.5 for WH8103. In P-limited cultures, they were861 + 2,L-l zinc, 5 and 0.3L-l 0.1 for MED4; 132 ? 6, 21 + 2, 7.4 (0.2) 9.6 0.1, cobalt, 90 c and 0.5 ? 0.2 for WH8012; and 244 ? 21, 40 +34, and L- + 0.01 for WH8103. P limitation had no effect on nmol L-l manganese, nmol 0.8 molybdenum, lO nmol L-lSynechococcus WH8012 of MED4 and WH8012 nmol L- nickel, content of WH8103. The cellular C quota was consis- the N cell quota selenium 10 but reduced the N and 1.17 gmol L-l iron. o P-replete tently higher in P-limited than in nutrient-repletecultures.130 (19) iradiance 24.0 (3.6) and N: P ratios than 5.4 (1.1) All the All cultures were acclimated tothree strains had conditions higher C: P ° 10 This study P-limitedthe Redfield ratio under both the respective growth medium (P-replete and P-limited) and nutrient-repleteand P-limited conditions. The C:N molar ratios ranged 5-5.7 in 7.5 (0.8) 723 (61) 96.9 (37) - replete cultures and 7.1-7.5 inaP-limited cultures; C:P ranged 121-165 thethe replete cultures and 464-779 under for minimum of three transfers before in start of the ex-Synechococcus WH8103N:P rangedperiment.the replete replicate cultures were set limitation. Our results suggest that P limitation; 21-33 in Eighteen cultures and 59-109 under P up for Prochlorococcus and Synechococcus5.0 have relatively low P requirementsin 33.2 each thus the particulate the field, and P-replete and (0.2)the Redfield165(8) medium differorganism combination, and the growth of(5.2) for the This study may each organic matterthey produce would 7.1 from P-limitedof new ratio (106C: 16N: IP) often assumed production particulateorganic culturein the monitored on a 779 (122) by noninvasive in matter was sea.(0.9) daily basis 109 (10.5) 1 vivo chlorophyll fluorescence using a TurnerlOAU fluorom-Exponential* Prochlorococcus (6 strains) eter (TurnerDesigns). The P-replete cultures were 15.9-24.4 8.5-9.9 156-215 harvested Heldalet al. 2003 during the midexponential ubiquitous (after euphotic zone The marine cyanobacterium Prochlorococcus is a small growth phase in the 7-9 d), and of tropical and subtropicalExponential* Synechococcus(diameter, P-limited /tm) thatwere harvested during the early sta- et al. 1988; the 0.5-0.8 cultures is oceans (40?S-40?N; Chisholm - photosynthetic prokaryote Partensky et al. WH8103 10 150 2). Nine replicate tionary growth phase (12-14 d) (Fig. Abundances in15 cul- surface waters areet al. 2003 1999). warm ¢ Heldal typically - WH7803 8.9 113 13.3 tures (three pooled samples of three tubes) were collected found as deep as 200 m below > 105 cells ml-, and cells are Corresponding author (Stebe@ebc.uu.se). Present address: De- cS on combusted Whatman GF/F filters (2 h (Campbellfor al. 1994; the surface at 450QC) et the of SynechococcusExponential Evolutionary Biology/Limnology, Uppsala University, N, and six single cultures were partment Partensky et al. 1999). c) analysis of particulateC and These features make Prochlorococcus the n SE-75236 Uppsala, Sweden. numerically dom- WH7803 2 Present address: harvested in 7 similar way inant a 115 16.4 CuhelandWaterbury Departmentof Ecology/Limnology, Lund Uni- for the analysis ofphototroph in the oceans. Its close relative, particulate P. o 1984 oxygenicMarine SE-223 62 Lund, Sweden. All filtrations were done under low vacuum (<10 kPa) in in subtropicalecosystems. phytoplankton versity, culturest Synechococcus, is also important - o an acid-washed and rinsed filtration funnel made of glass. 7.7 (2.6) 75 (31) 10.1 (3.9) Geider and La Roche 2002 Average Acknowledgments Although concentrationsare typically an order of magnitude Additional filtrations with We thank John Waterburyfor kindly making the axenic Syne- 25-75 mlthan those of Prochlorococcus (Campbell et al. 1994; 4-17 lower of 0.2-,um-filteredme- 27-135 5-19 Range dia from the harvested cultures were et al. as controls for chococcus strains available to us, Tom Gregory for skillful analysis DuRand done 2001), their larger average cell size (diametersMarine particulatemattert of total P using the MRP method, Crystal Shih forof dissolved nutrients to the Whatman GF/Fet al. 2001) makes them approxi- adsorption laboratorywork of 0.6-2.1 /xm; Herdman fil- ters. All filters were dried 114 (1-2 in a preliminary study of C:N:P in Prochlorococcus, and Lisa at 60°C(45) d) and stored in the 7.3 (1.7) 16.4 global Geider and La Roche 2002 20 Average mately equal in terms of(6.2) Moore and Stephanie Shaw for initialdark in a desiccator until analysis. The three remaining cul- photosynthetic discussions on experimental biomass. Sy- Time (days) 15 3.8-12.5 35-221 5-34
  16. 16. Limnol. Oceanogr., 48(5), 2003, 1721-1731? 2003. by the American Society of Limnology and Oceanography,Inc.Elemental composition of marine Prochlorococcus and Synechococcus: Implications forthe ecological stoichiometry of the seaS. Bertilsson and 0. Berglund2Department of Civil and Environmental Engineering, Massachusetts Institute of Technology,Cambridge, Massachusetts 02139D. M. KarlSchool of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822S. W. ChisholmDepartment of Civil and Environmental Engineering, Massachusetts Institute of Technology,Cambridge, Massachusetts 02139 Abstract The elemental composition of marine cyanobacteriais an importantdeterminantof the ecological stoichiometry•  Over  half  the  phosphate  is  Jed  up  in  the  DNA   in low-latitude marine biomes. We analyzed the cellular carbon (C), nitrogen (N), and phosphorus (P) contents of Prochlorococcus (MED4) and Synechococcus (WH8103 and WH8012) under nutrient-repleteand P-starved con- ditions. Under nutrient-repleteconditions, C, N, and P quotas (femtogram cell-) of the three strains were 46 ? 4, 9.4 ? 0.9, and 1.0 + 0.2 for MED4; 92 + 13. 20 + 3, and 1.8 ? 0.1 for WH8012; and 213 + 7, 50 + 2, 3.3 +•  P  replete  cultures  are  dividing  quickly  and  operaJng   0.5 for WH8103. In P-limited cultures, they were 61 + 2, 9.6 ? 0.1, and 0.3 ? 0.1 for MED4; 132 ? 6, 21 + 2, and 0.5 ? 0.2 for WH8012; and 244 ? 21, 40 + 4, and 0.8 + 0.01 for WH8103. P limitation had no effect on the N cell quota of MED4 and WH8012 but reduced the N content of WH8103. The cellular C quota was consis- with  low  levels  of  carbon   tently higher in P-limited than in nutrient-repletecultures. All three strains had higher C: P and N: P ratios than the Redfield ratio under both nutrient-repleteand P-limited conditions. The C:N molar ratios ranged 5-5.7 in replete cultures and 7.1-7.5 in P-limited cultures; C:P ranged 121-165 in the replete cultures and 464-779 under•  P  limited  cultures  much  more  carbon  and  nitrogen   P limitation; N:P ranged 21-33 in the replete cultures and 59-109 under P limitation. Our results suggest that Prochlorococcus and Synechococcus may have relatively low P requirementsin the field, and thus the particulate organic matterthey produce would differ from the Redfield ratio (106C: 16N: IP) often assumed for the production dense   of new particulateorganic matter in the sea. The marine cyanobacterium Prochlorococcus is a small ubiquitous in the euphotic zone of tropical and subtropical•  Discusses  the  value  of  slow  growth  and  low  photosynthetic prokaryote (diameter, 0.5-0.8 /tm) that is oceans (40?S-40?N; Chisholm et al. 1988; Partensky et al. 1999). Abundances in warm surface waters are typically proporJons  of  geneJc  machinery  to  surviving   > 105 cells ml-, and cells are found as deep as 200 m below Corresponding author (Stebe@ebc.uu.se). Present address: De-partment of Evolutionary Biology/Limnology, Uppsala University, the surface (Campbell et al. 1994; Partensky et al. 1999).SE-75236 Uppsala, Sweden. These features make Prochlorococcus the numerically dom- oligotrophic  condiJons  and  phage   2 Present address: Departmentof Ecology/Limnology, Lund Uni- inant oxygenic phototroph in the oceans. Its close relative,versity, SE-223 62 Lund, Sweden. Synechococcus, is also importantin subtropicalecosystems.Acknowledgments Although concentrationsare typically an order of magnitude We thank John Waterburyfor kindly making the axenic Syne- lower than those of Prochlorococcus (Campbell et al. 1994;chococcus strains available to us, Tom Gregory for skillful analysis DuRand et al. 2001), their larger average cell size (diametersof total P using the MRP method, Crystal Shih for laboratorywork of 0.6-2.1 /xm; Herdman et al. 2001) makes them approxi-in a preliminary study of C:N:P in Prochlorococcus, and LisaMoore and Stephanie Shaw for initial discussions on experimental mately equal in terms of global photosynthetic biomass. Sy-
  17. 17. Limnol. Oceanogr., 48(5), 2003, 1721-1731? 2003. by the American Society of Limnology and Oceanography,Inc.Elemental composition of marine Prochlorococcus and Synechococcus: Implications forthe ecological stoichiometry of the seaS. Bertilsson and 0. Berglund2Department of Civil and Environmental Engineering, Massachusetts Institute of Technology,Cambridge, Massachusetts 02139D. M. KarlSchool of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822S. W. ChisholmDepartment of Civil and Environmental Engineering, Massachusetts Institute of Technology,Cambridge, Massachusetts 02139 Abstract Arendal Jomfruland •  Cyanobacteria  seem  to   The elemental composition of marine cyanobacteriais an importantdeterminantof the ecological stoichiometry 10 in low-latitude marine biomes. We analyzed the cellular carbon (C), nitrogen (N), and phosphorus (P) contents of Prochlorococcus (MED4) and Synechococcus (WH8103 and WH8012) under nutrient-repleteand P-starved con- 8 have  a  disJnct  low   ditions. Under nutrient-repleteconditions, C, N, and P quotas (femtogram cell-) of the three strains were 46 ? 4, 6 9.4 ? 0.9, and 1.0 + 0.2 for MED4; 92 + 13. 20 + 3, and 1.8 ? 0.1 for WH8012; and 213 + 7, 50 + 2, 3.3 + CN 0.5 for WH8103. In P-limited cultures, they were 61 + 2, 9.6 ? 0.1, and 0.3 ? 0.1 for MED4; 132 ? 6, 21 + 2, phosphate  signature   4 and 0.5 ? 0.2 for WH8012; and 244 ? 21, 40 + 4, and 0.8 + 0.01 for WH8103. P limitation had no effect on the N cell quota of MED4 and WH8012 but reduced the N content of WH8103. 2The cellular C quota was consis- tently higher in P-limited than in nutrient-repletecultures. All three strains had higher C: P and N: P ratios than •  Findings  conflict  with   the Redfield ratio under both nutrient-repleteand P-limited conditions. The C:N molar ratios ranged 5-5.7 in 0 Live autotrophs (atomic ratios) replete cultures and 7.1-7.5 in P-limited cultures; C:P ranged 121-165 in the 120replete cultures and 464-779 under P limitation; N:P ranged 21-33 in the replete cultures and 59-109 under P limitation. Our results suggest that marine  parJculate   Prochlorococcus and Synechococcus may have relatively low P requirementsin the field, and thus the particulate 100 organic matterthey produce would differ from the Redfield ratio (106C: 16N: IP) often assumed for the production 80 Lines ma5er  studies   of new particulateorganic matter in the sea. Redfield CP 60 Annual Mean 40 •  BerJlsson  refers  to   The marine cyanobacterium Prochlorococcus is a small ubiquitous in the euphotic zone of tropical and subtropical 20photosynthetic prokaryote (diameter, 0.5-0.8 /tm) that is oceans (40?S-40?N; Chisholm et al. 1988; Partensky et al. 0 1999). Abundances in warm surface waters are typically Copin-­‐Montegut  1983   Corresponding author (Stebe@ebc.uu.se). Present address: De-partment of Evolutionary Biology/Limnology, Uppsala University, > 105 cells ml-, and cells are found as deep as 200 m below the surface (Campbell et al. 1994; Partensky et al. 1999). 15 but  also  seen  in  Frigstad  SE-75236 Uppsala, Sweden. These features make Prochlorococcus the numerically dom- 2 Present address: Departmentof Ecology/Limnology, Lund Uni- inant oxygenic phototroph in the oceans. Its close relative, 10versity, SE-223 62 Lund, Sweden. NP Synechococcus, is also importantin subtropicalecosystems.Acknowledgments Although concentrationsare typically an order of magnitude We thank John Waterburyfor kindly making the axenic Syne- lower than those of5Prochlorococcus (Campbell et al. 1994;chococcus strains available to us, Tom Gregory for skillful analysis DuRand et al. 2001), their larger average cell size (diametersof total P using the MRP method, Crystal Shih for laboratorywork of 0.6-2.1 /xm; Herdman et al. 2001) makes them approxi- 0in a preliminary study of C:N:P in Prochlorococcus, and LisaMoore and Stephanie Shaw for initial discussions on experimental mately equal in terms of global photosynthetic biomass. Sy- Winter Spring Summer Fall Winter Spring Summer Fall
  18. 18. Divergence  in  the  Picoplankton  •  Stoichiometric  variability  exists  across  the  microbial   community  •  Includes  funcJonal  differences  (auto  and   heterotrophs)  •  Within  classificaJons  of  autotrophic  cyanobacteria  •  And  even  within  a  genus  as  a  result  of  nutrient   limitaJon  
  19. 19. Moving  Microbial  Stoichiometry  Up   the  Food  Chain  Diverse  Nutrient  Regimes     SelecJve  Grazing  from  a  Diverse   Protozoan  Community   Diverse  ProkaryoJc  Community  
  20. 20. J. Eukaryot. Microbiol., 56(5), 2009 pp. 466–471r 2009 The Author(s)Journal compilation r 2009 by the International Society of ProtistologistsDOI: 10.1111/j.1550-7408.2009.00428.x Growth Phase and Elemental Stoichiometry of Bacterial Prey Influences Ciliate Grazing Selectivity DAVID F. GRUBER,a,b STEVEN TUORTOa and GARY L. TAGHONaa Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 71 Dudley Road, New Brunswick, New Jersey 08901, and b Department of Natural Sciences, City University of New York, Baruch College, P. O. Box A-0506, 17 Lexington Avenue, New York, New York 10010 ABSTRACT. Protozoa are known to selectively graze bacteria and can differentiate prey based on size and viability, but less is known about the effects of prey cellular composition on predator selectivity. We measured the effect of growth phase and elemental stoichiometry of Escherichia coli on grazing by two ciliates, Euplotes vannus and Cyclidium glaucoma. Bacterial cells of a single strain were trans- formed with green and red fluorescent protein and harvested from culture at differing growth stages. Cells in exponential growth phase had low carbon:phosphorus (39) and nitrogen:phosphorus (9) ratios, while cells from stationary phase had high carbon:phosphorus of 104 and nitrogen:phosphorus of 26. When offered an equal mixture of both types of bacteria, Cyclidium grazed stationary phase, high car- bon:phosphorus, high nitrogen:phosphorus cells to 22% of initial abundance within 135 min, while Euplotes reduced these cells to 33%. Neither ciliate species decreased the abundance of the exponential phase cells, lower carbon:phosphorus and nitrogen:phosphorus, relative to control treatments. Because protozoa have higher nitrogen:phosphorus and carbon:phosphorus ratios than their prokaryotic prey, this study raises the possibility that it may be advantageous for protozoa to preferentially consume more slowly growing bacteria. Key Words. Bacteria growth phase, microbial loop protozoa grazing, selective grazing.P •  Grazers:  Euplotes  and  Cyclidium   ROTOZOA play a major ecological role in aquatic environ- ments due to their effectiveness in consuming a wide range of such as length heterogeneity analysis by PCR (Suzuki 1999), have also been used to assess protistan bacterivory of filtered and non- •  Grazed:  Fluorescently  labeled  E.  coli  prey size classes and types, which include other protozoa, phyto-plankton, and bacteria (Azam et al. 1983; Fenchel 1980a; Porter et filtered seawater samples. There are multiple factors that can influence grazing. Growthal. 1985; Sherr and Sherr 2002; Sherr, Sherr, and Pedros-Alio rates of both ciliates (Taylor and Berger 1976) and flagellates –  Glowing  Green  8  and  72  hours    Glowing  Red  72  and  72  hours  1989). Grazing by bacterivorous protozoa is of considerable im-portance given that protozoa not only constitute a major source of (Sherr, Sherr, and Berman 1983) have been demonstrated to vary depending on the species of bacteria grazed. Different bacterial –  8:    39:9:1    72:  104:26:1  mortality to both heterotrophic and autotrophic bacteria (Cole1999; Pace 1986), but they are also food for other zooplankton, species are grazed at varying efficiencies (Mitchell, Baker, and Sleigh 1988). In addition, protozoa actively select bacteria basedserving an important link in the microbial web (Kiorboe 1998; on various prey attributes, such as cell size and cell surface prop-Sherr and Sherr 2002, 2007; Stoecker and Capuzzo 1990). Bac- erties (Gurijala and Alexander 1990; Monger, Landry, and Brownterivory has been demonstrated to strongly influence prokaryotic 1999; Sanders 1988; Tso and Taghon 1999).
  21. 21. r 2009 The Author(s)Journal compilation r 2009 by the International Society of ProtistologistsDOI: 10.1111/j.1550-7408.2009.00428.x Growth Phase and Elemental Stoichiometry of Bacterial Prey Influences Ciliate Grazing Selectivity DAVID F. GRUBER,a,b STEVEN TUORTOa and GARY L. TAGHONaa Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 71 Dudley Road, New Brunswick, New Jersey 08901, and b Department of Natural Sciences, City University of New York, Baruch College, P. O. Box A-0506, 17 Lexington Avenue, New York, New York 10010468 J. EUKARYOT. MICROBIOL., 56, NO. 5, SEPTEMBER–OCTOBER 2009 ABSTRACT. Protozoa are known to selectively graze bacteria and can differentiate prey based on size and viability, but less is known about the effects of prey cellular composition on predator selectivity. We measured the effect of growth phase and elemental stoichiometry of Escherichia coli on grazing by two ciliates, Euplotes vannus and Cyclidium glaucoma. Bacterial cells of a single strain were trans- formed with green and red fluorescent protein and harvested from culture at differing growth stages. Cells in exponential growth phase had low carbon:phosphorus (39) and nitrogen:phosphorus (9) ratios, while cells from stationary phase had high carbon:phosphorus of 104 and nitrogen:phosphorus of 26. When offered an equal mixture of both types of bacteria, Cyclidium grazed stationary phase, high car- bon:phosphorus, high nitrogen:phosphorus cells to 22% of initial abundance within 135 min, while Euplotes reduced these cells to 33%. Neither ciliate species decreased the abundance of the exponential phase cells, lower carbon:phosphorus and nitrogen:phosphorus, relative to control treatments. Because protozoa have higher nitrogen:phosphorus and carbon:phosphorus ratios than their prokaryotic prey, this 72  hr   study raises the possibility that it may be advantageous for protozoa to preferentially consume more slowly growing bacteria. 8  hr   Key Words. Bacteria growth phase, microbial loop protozoa grazing, selective grazing.P ROTOZOA play a major ecological role in aquatic environ- ments due to their effectiveness in consuming a wide range of such as length heterogeneity analysis by PCR (Suzuki 1999), have also been used to assess protistan bacterivory of filtered and non-prey size classes and types, which include other protozoa, phyto-plankton, and bacteria (Azam et al. 1983; Fenchel 1980a; Porter et filtered seawater samples. 72  hr   There are multiple factors that can influence grazing. Growth 72  hr  al. 1985; Sherr and Sherr 2002; Sherr, Sherr, and Pedros-Alio rates of both ciliates (Taylor and Berger 1976) and flagellates Fig. 2. Change in bacterial abundance in the grazing experiment1989). Grazing by bacterivorous protozoa is of considerable im- where both Escherichia coli-GFP and E. coli-RFP were harvested afterto vary (Sherr, Sherr, and Berman 1983) have been demonstratedportance given that protozoa not only constitute a major source of 72 h. Symbols areon the species of treatment, grazed. Different bacterial depending the average for each bacteria error bars are 95% con- Fig. 1. Change in bacterial abundance in the grazing experimentmortality to both heterotrophic and after 8 h and E.bacteria af- fidence levels.are grazed at line denotes no change in(Mitchell, GFP, andwhere Escherichia coli-GFP was harvested autotrophic coli-RFP (Cole species Vertical dashed varying efficiencies abundance. Baker,1999;h.Pace 1986), the averageare each treatment, error bars are 95% green fluorescent protein; RFP, red protozoa actively select bacteria basedter 72 Symbols are but they for also food for other zooplankton, Sleigh 1988). In addition, fluorescent protein.serving an important link in line denotes no change (Kiorboe 1998;confidence levels. Vertical dashed the microbial web in abundance. on various prey attributes, such as cell size and cell surface prop-Sherrgreen fluorescent protein; RFP, red fluorescent protein. 1990). Bac-GFP, and Sherr 2002, 2007; Stoecker and Capuzzo erties (Gurijala and Alexander 1990; Monger, Landry, and Brownterivory has been demonstrated to strongly influence prokaryotic tent1999; Sanders two atTso h (PTaghon 1999). protein was between the 1988; 72 and 5 0.51), whilediversity and alter genotypic, phenotypic, and metabolic compo- significantly higher for E. coli-GFP than for E. coli-RFP at 8 h role in The physical and chemical properties of prey and theirsition of significantly in the Euplotes treatment (t9.5 5 5.36, (P 5 0.0097). grazing have been extensively studied in phytoplanktondeclined bacterial communities (Hahn and Hofle 2001; Hahn, selectiveP 5 0.0004), to 33% of initial abundance (Table 1).Moore, and Hofle 1999; Jurgens and Matz 2002; Matz and Jurgens and metazoan zooplankton (DeMott 1995), but less so in bacteria2003; Matz et al. 2002b; Simek et al. 1997); viruses also were an In the experiment where both E. coli-GFP and E. coli-RFP play and protozoa (Matz,DISCUSSION Jurgens 2002a). Protozoan se- Deines, andharvested role in the C:N:P (mean Æ 95% confidence (Fuhrmanimportantafter 72 h, bacterial community compositionlevel) of lective feeding appears to be an important mechanism determin-1999; Fuhrman 114 (Æ 13):28 (Æ 3.1):1 (Æ 0.2), not significantly we Iting well documented that of planktonic food webs and influencingE. coli-GFP was and Noble 1995; Herndl et al. 2005). While is community structure bacterivorous protozoa selectivelydifferentaddressthat of E. coli-RFP, 104 (Æ 2.3):25 (Æ 0.6): the graze based organic size of remineralization and nutrient cycling. Thedo not than viruses in this study, an understanding of rates of on cell matter bacteria (Gonzalez, Sherr, and Sherr À1
  22. 22. •  Marine  nutrients  •  Controls  on  nutrient  cycling  •  Role  of  microbial  taxa    maybe  something  on   parJculate  Red  field  raJos  •  PredaJon  on  microbial  communiJes  •  Cyanobacteria  and  how  there  red  field  raJo  is   different  •  Difference  influences  predaJon  •  Ecological  role    •  Control  on  nutrient  cycling  
  23. 23. Iron and growth in Trichodesmium spp. 1881 Table 2. Fe: C: N: P for Trichodesmiumfrom the north coast of Australia. All samples collected in November 1999; date indicates dayof month. Paired samples for Fe:P and C:N were collected (see text) in duplicate in most cases, except on 17 November 1999 (n = 3)andwhereno standard deviation reported = 1). is (n Latitude Fe:C (SD) Fe:P (SD) C:P (SD) N: P (SD) Date collections Longitude (/,mol:mol) (mmol:mol) (mol:mol) (mol:mol)Zodiac 1 11?12.75S 139?19.47E 67.5 (5.0) 1.06 (0.09) 158 (25) 21(7) 2 10?32.73S 136?34.15E 29.6 (2.1) 0.69 (0.07) 235 (7) 33 (1) 5 11?49.82S 128?42.64E 28 (11) 0.51 253 38 6 12?49.22S 125?53.54E 78 (13) 1.58 (0.19) 203 (8) 31.6 (0.5) 8 14?06.22S 123?09.46E 21.4 0.23 105 14 12 14?47.22S 122?10.31E 27.9 0.32 115 20 13 13?33.57S 124?31.13E 18.5 0.14 79 17 14 12?43.43S 127?33.64E 18.0 (3.4) 0.29 (0.06) 159 (2) 28 (1) 17 12?04.65S 128?56.72E 24.0 (4.1) 0.74 (0.13) 310 (20) 52 (7) 19 9049.60S 130?06.69E 40.0 (8.5) 0.79 232 36 Mean (SE) 35 (21) 0.64 (0.44) 185 (74) 29 (12)R/V Ewingcollections 2 10?32.73S 136?34.15E 143 82) 6 12?49.22S 125053.54E 222quantities of cellular iron in excess of that needed to support uptake and growth, and, thus, populations can achieve highmaximum growth (Figs. 2B, 3A). This ability for luxury Fe: C ratios during periods of low specific growth rate dueuptake may be an important adaptive strategy for Tricho- to other limiting factors. This additional iron can then bedesmium in near-surface oceanic waters, where iron inputs used to support diazotrophy once other limitations subside.are often sporadic. The majority of the Fe flux to the open Alternately, the extracellular contributions of Fe toward theocean can be supplied by aeolian dust deposition (i.e., cal- field Fe: C contents are unknown, suggesting that there mayculated as 95% at a station in the N. Pacific Gyre; Martin be physiological limitation despite the apparent excess ofand Gordon 1988), which is highly seasonal in the North measured Fe.Pacific and North Atlantic Oceans. Superposed on this broad The Fe: C ratios in Trichodesmiumreportedhere are con-seasonality are episodic dust deposition events. For example, siderably lower than previous reports for this region (Ber-at Midway Island, about 50% of the annual deposition of man-Franket al. 2001). Although we cannot offer a conclu-iron to the mixed layer occurred during a 3-week period sive explanation for these differences, the higher previously(Uematsu et al. 1985). In contrast, the flux of iron due to measured values may have resulted from iron contamination,upwelling in high nutrient low chlorophyll (HNLC) areas is a potential problem in any iron analyses of natural marine
  24. 24. •  Also  saw  how  low  P  abundance  was  different   from  other  autotrophic  communiJes   C:N: P in Prochlorococcus and Synechococcus 1727 Table 3. Elementalratios (molarC:N, C:P, and N:P) for marinephytoplankton cultures,bacteria,and particulate organicmatter. Arithmetic meansarepresented, with standard deviationbetweenbrackets. Sample C:N C:P N: P Reference Prochlorococcus Med4 P-replete 5.7 (0.7) 121(17) 21.2 (4.5) This study P-limited 7.4 (0.2) 464 (28) 62.3 (14.1) Synechococcus WH8012 P-replete 5.4 (1.1) 130 (19) 24.0 (3.6) This study P-limited 7.5 (0.8) 723 (61) 96.9 (37) Synechococcus WH8103 P-replete 5.0 (0.2) 165(8) 33.2 (5.2) This study P-limited 7.1 (0.9) 779 (122) 109 (10.5) Exponential* Prochlorococcus (6 strains) 8.5-9.9 156-215 15.9-24.4 Heldalet al. 2003 Exponential* Synechococcus WH8103 10 150 15 Heldalet al. 2003 WH7803 8.9 113 13.3 Exponential Synechococcus WH7803 7 115 16.4 CuhelandWaterbury 1984 Marine culturest phytoplankton Average 7.7 (2.6) 75 (31) 10.1 (3.9) Geider and La Roche 2002 Range 4-17 27-135 5-19 Marine particulatemattert Average 7.3 (1.7) 114 (45) 16.4 (6.2) Geider and La Roche 2002 Range 3.8-12.5 35-221 5-34 Marine bacterial cultures Exponential 3.8-6.3 26-50 5.5-7.9 Vrede et al. 2002 P-limited 7.7-12 176-180 16-19 * Cells cultured in PCR-S11 medium (Partenskyet al. 1999), sampled in exponential phase. t Meta-analysis of nutrient-repleteeukaryotic marine phytoplanktoncultures. t Meta-analysis of marine particulatematter.

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