Nutrient Limitations of Phytoplankton in the Global Ocean

Stoichiometry
of
the
Microbial

Loop

J.
Ma5hew
Haggerty

SDSU/UC
Davis

Dinsdale/Eisen
Lab

What
is
the
Microbial
Loop?

Complicated
By
Diversity

Diverse
Nutrient
Regimes

SelecJve
Grazing
from
a
Diverse

Protozoan
Community

Diverse
ProkaryoJc
Community

Nutrients
in
the
Ocean

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

•  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 iron
patterns 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 model
also 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 Southern
Ocean, subarctic Northeast Pacific, and equatorial Pacific, and realistic global patterns of primary
production, biogenic silica production, nitrogen fixation, particulate organic carbon export, calcium
carbonate export, and surface chlorophyll concentrations. Phytoplankton cellular Fe/C ratios and surface
layer dissolved iron concentrations are also in general agreement with the limited field data. Primary
production, community structure, and the sinking carbon flux are quite sensitive to large variations in the

Diatom
LimitaJon

J.K. Moore et al. / Deep-Sea Research II 49 (2002) 463–507


of the World Ocean
a
b
c

Small
Phytoplankton
LimitaJon


of the World Ocean
a
b
c

Diazotroph
LimitaJon


Nutrient-limitation patterns for the diatoms (A), the small phytoplankton (B), and the diazo
r months. Areas where all nutrient cell quotas are of the World Ocean
>97% of the maximum cell quota valu
d 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
b
c
onutrients and the initially high iron concentrations in this region

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/NGEO667

Large-scale distribution of Atlantic nitrogen
ﬁxation controlled by iron availabilityc
50° N
C. Mark Moore1,2 *, Matthew M. Mills3 , Eric P. Achterberg2 , Richard J. Geider1 , Julie LaRoche4 , 1
Mike I. Lucas , Elaine L. McDonagh , Xi Pan , Alex J. Poulton , Micha J. A. Rijkenberg2 ,
5 2 2 2

David J. Suggett1 , Simon J. Ussher6 and E. Malcolm S. Woodward7
0

N*

The
ComplicaJons

Diverse
Nutrient
Regimes

SelecJve
Grazing
from
a
Diverse

Protozoan
Community

Diverse
ProkaryoJc
Community

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 Discussion
Fig. 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 Jomfru
showing 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

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

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 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.

.

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.

Flexible elemental stoichiometry in Trichodesmiumspp. and its ecological implications

Angelicque E. White1 and Yvette H. Spitz
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503

David M. Karl
School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822

Ricardo M. Letelier
College 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:PP
genus 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 the
nent 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). Given
oligotrophic 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

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. A
Prochlorococcus 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-l
Synechococcus 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 subtropical
Exponential* 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 Synechococcus
Exponential 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
oxygenic
Marine 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 (diameters
Marine 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

Limnol. Oceanogr., 48(5), 2003, 1721-1731

Elemental composition of marine Prochlorococcus and Synechococcus: Implications for
the ecological stoichiometry of the sea
S. Bertilsson' and 0. Berglund2
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology,
Cambridge, Massachusetts 02139

D. M. Karl

S. W. Chisholm
Abstract

•  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
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.
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 (diameters
of 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 Lisa
Moore and Stephanie Shaw for initial discussions on experimental
mately equal in terms of global photosynthetic biomass. Sy-

Limnol. Oceanogr., 48(5), 2003, 1721-1731

Elemental composition of marine Prochlorococcus and Synechococcus: Implications for
the ecological stoichiometry of the sea
S. Bertilsson' and 0. Berglund2

D. M. Karl

S. W. Chisholm
Abstract Arendal Jomfruland

•  Cyanobacteria
seem
to

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
20
photosynthetic 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

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,
10
versity, SE-223 62 Lund, Sweden.

NP
Synechococcus, is also importantin subtropicalecosystems.
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 (diameters
of total P using the MRP method, Crystal Shih for laboratorywork of 0.6-2.1 /xm; Herdman et al. 2001) makes them approxi-
0
in a preliminary study of C:N:P in Prochlorococcus, and Lisa
Moore 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

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

Moving
Microbial
Stoichiometry
Up

the
Food
Chain

Diverse
Nutrient
Regimes

SelecJve
Grazing
from
a
Diverse

Protozoan
Community

Diverse
ProkaryoJc
Community

J. Eukaryot. Microbiol., 56(5), 2009 pp. 466–471
r 2009 The Author(s)
Journal compilation r 2009 by the International Society of Protistologists
DOI: 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. TAGHONa
a
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. Growth
al. 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 (Cole
1999; 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 based
serving 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 Brown
terivory has been demonstrated to strongly influence prokaryotic 1999; Sanders 1988; Tso and Taghon 1999).

r 2009 The Author(s)
Journal compilation r 2009 by the International Society of Protistologists
DOI: 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. TAGHONa
a
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
468 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 experiment
1989). 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 demonstrated
portance 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 experiment
mortality to both heterotrophic and after 8 h and E.bacteria af- fidence levels.are grazed at line denotes no change in(Mitchell, GFP, and
where 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 based
ter 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 Brown
terivory has been demonstrated to strongly influence prokaryotic tent1999; Sanders two atTso h (PTaghon 1999). protein was
between the 1988; 72 and 5 0.51), while
diversity 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 their
sition of significantly in the Euplotes treatment (t9.5 5 5.36, (P 5 0.0097). grazing have been extensively studied in phytoplankton
declined bacterial communities (Hahn and Hofle 2001; Hahn, selective
P 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 bacteria
2003; 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, and
harvested role in the C:N:P (mean Æ 95% confidence (Fuhrman
importantafter 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 influencing
E. coli-GFP was and Noble 1995; Herndl et al. 2005). While is community structure bacterivorous protozoa selectively
differentaddressthat of E. coli-RFP, 104 (Æ 2.3):25 (Æ 0.6): the graze based organic size of remineralization and nutrient cycling. The
do not than viruses in this study, an understanding of rates of
on cell
matter
bacteria (Gonzalez, Sherr, and Sherr
À1

•  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

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 day
of 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?12.75'S 139?19.47'E 67.5 (5.0) 1.06 (0.09) 158 (25) 21(7)
2 10?32.73'S 136?34.15'E 29.6 (2.1) 0.69 (0.07) 235 (7) 33 (1)
5 11?49.82'S 128?42.64'E 28 (11) 0.51 253 38
6 12?49.22'S 125?53.54'E 78 (13) 1.58 (0.19) 203 (8) 31.6 (0.5)
8 14?06.22'S 123?09.46'E 21.4 0.23 105 14
12 14?47.22'S 122?10.31'E 27.9 0.32 115 20
13 13?33.57'S 124?31.13'E 18.5 0.14 79 17
14 12?43.43'S 127?33.64'E 18.0 (3.4) 0.29 (0.06) 159 (2) 28 (1)
17 12?04.65'S 128?56.72'E 24.0 (4.1) 0.74 (0.13) 310 (20) 52 (7)
19 9049.60'S 130?06.69'E 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?32.73'S 136?34.15'E 143 82)
6 12?49.22'S 125053.54'E 222

quantities of cellular iron in excess of that needed to support uptake and growth, and, thus, populations can achieve high
maximum growth (Figs. 2B, 3A). This ability for luxury Fe: C ratios during periods of low specific growth rate due
uptake may be an important adaptive strategy for Tricho- to other limiting factors. This additional iron can then be
desmium 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 the
ocean can be supplied by aeolian dust deposition (i.e., cal- field Fe: C contents are unknown, suggesting that there may
culated as 95% at a station in the N. Pacific Gyre; Martin be physiological limitation despite the apparent excess of
and 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

•  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.

Nutrient Limitations of Phytoplankton in the Global Ocean

Recommended

Recommended

More Related Content

What's hot

What's hot (15)

Viewers also liked

Viewers also liked (14)

Similar to Nutrient Limitations of Phytoplankton in the Global Ocean

Similar to Nutrient Limitations of Phytoplankton in the Global Ocean (20)

Recently uploaded

Recently uploaded (20)

Nutrient Limitations of Phytoplankton in the Global Ocean