Dale A. Holen
Associate professor of Biology
PSU Worthington-Scranton
“Animals” that Photosynthesize
and “Plants” that Eat
Aquatic Food Web
Primary
Producers
(phytoplankton)
Primary
consumers
(zooplankton)
Secondary
consumers
Tertiary
consumers
Terrestrial food chain Aquatic food chain
Classification of Living Things
Viruses, Prions, Viroids
Prokaryotes
Eukaryotes
- protists
- fungi
- plants (autotrophic/phototrophic)
- animals (heterotrophic/phagotrophic)
Elysia chlorotica
Vaucheria litoria
Bacterial Grazing by Planktonic Lake Algae
David F. Bird and Jacob Kalff
Science 31 January 1986: 493-495.
Ecological Significance of Mixotrophy
chloroplasts
beads
Flynn KJ, Stoecker DK, Mitra A, Raven JA, GlibertPM, Hansen PJ, Granéli E,
Burkholder JM (2013) Misuse of the phytoplankton–zooplankton dichotomy: the need to assign organisms as mixotrophs within plankton functional types. Journal of Plankton Research 35, 3–11
Classical misrepresentation of the functional classification of planktonic protists
Functional classification of planktonic protists contributing to primary and/or secondary production
Spectrum of nutritional capabilities for representative
Chrysophytes
Strict phototrophy Mallamonas, Synura
Mixotrophy:
Obligate phototrophy and facultative Dinobyron divergens
phagotrophy Dinobryon cylindricum
Obligate phototrophy and obligate Uroglena americana
phagotrophy Ochromonas spp.
Chrysamoeba
Facultative phototrophy and facultative Ochromonas danica
phagotrophy Poterioochromonas
malhamensis
Strict phagotrophy Spumella
Paraphysomonas
Ochromonas vallesciaca
Holen, 1995. Chrysophyte Algae, Cambridge Univ. Press
Paramecium bursaria photosynthetic animal
http://protist.i.hosei.ac.jp/PDB/images/Ciliophora/Paramecium/bursaria/sample_4.jpg
http://content8.eol.org/content/2008/12/10/21/98465_large.jpg
With Chlorella Without Chlorella
Endosymbiotic
Chlorella
Mesodinium (Myrionecta) rubrum photosynthetic animal
http://www.smhi.se/oceanografi/oce_info_data/plankton_
checklist/others/mesodinium_rubrum.gif
Crytptomonad endosymbionts
Obligate phototroph
Strombidium viride photosynthetic animal
http://protist.i.hosei.ac.jp/PDB/Images/Ciliophora/Strombidium/sp_4.jpg
http://www.dr-ralfwagner.de/Bilder/Strombidium_viride-15.jpg
Kleptoplastidy
Ochromonas (Chrysophyte) Phagotrophic algae
• single-celled, naked
• 4-12 mm diameter
• two unequal flagella (one w/mastigonemes)
• 1-2 chloroplasts
• raptorial feeders
• nutritionally diverse
• statospores (species-specific)
• 80 species?
http://4.bp.blogspot.com/_VA6LePZ6KNY/R60qdxEFAoI/AAAAAAAAAYE/h6UTegWfhZs/s320/Ochromonas.jpg
Which came first, photosynthesis
or phagotrophy?
Traditional grazing chain
Mixotrophs in the Microbial Food Web
≈30% What is the fate of all this OM?
Chrysolepidomonas dendrolepidota
• strict phototroph?
• ≈ 6 µm diameter
• cells solitary and free swimming
• heterokont, longer flagellum with
mastigonemes
• single parietal chloroplast and distinct
stigma
• unique scales cover cell body
• stomatocyst
• distribution?
Peters, M. C. and Andresen, R. A. (1993), THE FINE STRUCTURE AND SCALE FORMATION OF CHRYSOLEPIDOMONAS DENDROLEPIDOTA
GEN. ET. SP. NOV.(CHRYSOLEPIDOMONADACEAE FAM. NOV., CHRYSOPHYCEAE). Journal of Phycology, 29: 469–475.
Collecting a water sample
Time (h)
0 20 40 60 80 100 120 140
FLB ingestion f
lagellate
-1
0.0
0.2
0.4
0.6
0.8
1.0
Mean FLB ingested vs. time for Chrysolepidomonas cultured at 20 µE m-2 s-2. Each data point is the mean of 3 replicate samples with 100 flagellates counted / sample. Mean ingestion rate = 0.72 bacteria flagellate-1 h-1.
r2 = 0.78 y = 0.003x + 0.30
What is the bacterial ingestion rate of Chrysolepidomonas?
Beads or FLB?
Time (h)
0 50 100 150 200 250 300 350
Fla
gellate
concentr
ation (
ml-1
)
0
50x103
100x103
150x103
200x103
250x103
300x103
Without added bacteria
With added bacteria
µ = 0.027, dt = 26.1 h
µ = 0.019, dt = 36.1h
Growth of Chrysolepidomonas on DYV inorganic medium at 20o
C at a light intensity of 240 µE m-2 s-1 on a 12:12 light/dark cycle.
How does phototrophic growth compare to mixotrophic growth?
Time (h)
0 20 40 60 80 100 120 140 160
Fla
gellate
Concentr
ation (
ml-1
)
0
20x103
40x103
60x103
80x103
100x103
120x103
140x103
Without added bacteria
With added bacteria
Growth of Chrysolepidomonas on DYV inorganic medium minus N & P at 20o C at a light intensity of 240 µE m-2 s -1 on a 12:12 light/ dark cycle.
Can Chrysolepidomonas use bacteria as a source of mineral (N and P) nutrients?
µ = 0.017, dt = 40.5 h
µ = 0.009, dt = 73.7 h
Bacterial concentration (ml-1
)
0 5x106 10x106 15x106 20x106 25x106 30x106
Chry
sole
pid
om
onas
(h
-1)
0.010
0.015
0.020
0.025
0.030
Growth rate of Chrysolepidomonas as a function of initial bacterial concentration. All cultures were incubated on DYV inorganic medium at 20o C and 240 µE m-2 s-1 on a 12:12 light/dark cycle. P. aeruginosa was used as the particulate food source.
Time (h)
0 20 40 60 80 100 120 140 160
Fla
gellate
Concentr
ation (
ml-1
)
0
2000
4000
6000
8000
10000
12000
Growth of Chrysolepidomonas on a small (≈ 2 µm) green alga at 200 C and a light intensity of 240 µE m-2 s-1.
How flexible is Chrysolepidomonas relative to the food it consumes? (Is there food selectivity/discrimination?)
The effects on Chl a (cell-specific and total)
in P. malhamensis during growth on bacteria
in the light and the dark.
Dissolved Oxygen (mg L-1
)
0 2 4 6 8 10D
ep
th (
M)
0
2
4
6
8
10
12
Temp ( oC)
0 5 10 15 20 25 30
Dep
th (
M)
0
2
4
6
8
10
12
Illumintion ( E m -2
s -1
)
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Dep
th (
M)
0
2
4
6
8
10
12
Prorodon
Van Dorn Bottle
YSI DO and temp.
meter
Light sensor
and meter
Thermocline
Prorodon concentration (ciliates L-1
)
0 2000 4000 6000 8000 10000 12000 14000
Depth
(M
)
0
2
4
6
8
10
12
Prorodon concentration (ciliates L-1
)
0 2000 4000 6000 8000 10000 12000 14000
Depth
(M
)
0
2
4
6
8
10
12
Dissolved Oxygen (mg L-1
)
0 2 4 6 8 10D
ep
th (
M)
0
2
4
6
8
10
12
Temp ( oC)
0 5 10 15 20 25 30
Dep
th (
M)
0
2
4
6
8
10
12
Illumintion ( E m -2
s -1
)
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Dep
th (
M)
0
2
4
6
8
10
12
D.O. ≈ 1.0 mg L -1
Light = 6 µE m-2 s-1
Homo sapiens chlorotica