EFFECT%OFAMMONIUMADDITION%ON%THE%MICROBIAL%FOOD%WEB ... ·...
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EFFECT OF AMMONIUM ADDITION ON THE MICROBIAL FOOD WEB STRUCTURE AND COMMUNITY COMPOSITION OF THE OSMOTROPHS IN THE COMAU FJORD IN SOUTHERN CHILE Lasse Mork Olsen 1 , Klaudia Hernández 2 , Murat Van Ardelan 3 , Jose Luis Iriarte 4 , Nicolas Sanchez 3 , Humberto Gonzalez 2 , Nils Tokle 5 , CrisHna Dorador 6 , Yngvar Olsen 5 a) Nano-autotrophs 0 2 4 6 8 1012141618 g Carbon L -1 0 20 40 60 80 100 120 140 160 180 b) Micro-autotrophs 0 2 4 6 8 1012141618 g Carbon L -1 0 100 200 300 400 500 e) Micro-heterotrophs Time (days) 0 2 4 6 8 1012141618 g Carbon L -1 0 100 200 300 400 500 600 c) Nano-flagellates 0 2 4 6 8 10 12 14 16 g Carbon L -1 50 100 150 200 250 300 350 T1 T2 T3 T4 T5 T6 T7 T8 d) Pico-heterotrophs Time (days) 0 2 4 6 8 10 12 14 16 g Carbon L -1 0 50 100 150 200 250 a) Nano-autotrophs 0 1 2 3 4 g Carbon L -1 20 30 40 50 60 70 80 90 100 b) Micro-autotrophs 0 1 2 3 4 0 50 100 150 200 250 300 350 c) Nano-flagellates 0 1 2 3 4 g Carbon L -1 120 140 160 180 200 220 240 d) Micro-heterotrophs 0 1 2 3 4 0 50 100 150 200 250 300 350 e) Pico-heterotrophs L N ( mol NH 4 l -1 d -1 ) 0 1 2 3 4 g Carbon L -1 40 60 80 100 120 140 f) Copepods L N ( mol NH 4 l -1 d -1 ) 0 1 2 3 4 0 10 20 30 40 50 60 70 CONCLUSIONS • Ammonium, nitrate and silicon were depleted in all microcosms throughout the experiment, whereas phosphate was sustained at a concentra6on of 0.40.5 micro molar, indica6ng nitrogenlimita6on in general and possibly colimita6on by silicon of the diatoms. • The average biomass of phytoplankton, ciliates and copepods showed a significant linear response to the nitrogen loading rate. The biomass of heterotrophic bacteria and heterotrophic and autotrophic flagellates did not respond to the nitrogen loading gradient, indica6ng that the biomass of these were grazer controlled. • Canonical correspondence analysis (CCA) indicated that the community composi6on of both autotrophs and heterotrophic bacteria was significantly constrained by the gradient of ammonium loading rates (p<0.05). METHODS Ammonium and phosphate was added according to the molar ra6o released from salmon, and silicon according to the Redfield ra6o (N:Si:P = 28:16:1). Nutrients were added daily in a gradient of 8 loading rates (Table 1). Treatment 1 had no nutrient addi6on, whereas treatment 2 was meant to mimic natural loading (N:Si:P = 16:16:1). Treatment L N (µmol NH 4 l 1 d 1 ) L P (µmol PO 4 l 1 d 1 ) L Si (µmol Si l 1 d 1 ) 1 0.00 0.00 0.00 2 0.30 0.019 0.30 3 0.50 0.018 0.50 4 0.70 0.025 0.70 5 1.00 0.036 1.00 6 1.40 0.050 1.40 7 2.00 0.071 2.00 8 3.00 0.107 3.00 FuncHonal group DominaHng organisms QuanHficaHon Nanoautotrophs Diatoms 220 µm Microscopy counts 1 , volume calcula6ons 2 , carbon:volume 3 Microautotrophs Diatoms > 20 µm Same as above Microheterotrophs Ciliates > 10 µm Same as above Nanoflagellates Heterotrophic and autotrophic flagellates < 20 µm Fluorescence microscopy counts 4 average volume = 35 µm 3 Picohetrotrophs Heterotrophic bacteria < 2 µm Fluorescence microscopy counts 5 Carbon per cell = 25 fg Mesoplankton Copepods Microscopy and length weight 6 1 Utermöhl H (1958) Zur Vervollkommning der qua6ta6ven PhytoplanktonMethodik. Miaeilungen Interna6onal Ver einingung fur Theor und Angewandle Limnologie 9: 1–38. 2 Hillebrand H, Durselen CD, Kirschtel D, Pollingher U, Zohary T (1999) Biovolume calcula6on for pelagic and benthic microalgea. Journal of Phycology 35: 403 424. 3 MendenDeuer S, Lessard EJ (2000) Carbon to volume rela6onships for dinoflagellates, diatoms, and other pro6st plankton. Limnol. Oceanogr. 45: 569–579. 4 Hass L, 1982. Improved epifluorescence microscopy for observing planktonic microorganisms. Ann. Inst. Oceanogr. 58: 261–266. 5 Porter K, Feig Y (1980) The use of DAPI for iden6fying and coun6ng aqua6c microflora. Limnol. Oceanogr. 25: 943–948. 6 Jensen I (2012) Master thesis. NTNU, Dept. of biology. 7 Grasshoff K, Ehrhardt M and Kremling F (1983) Methods of Seawater Analysis. Verlag Chemie, Weinheim, 2nd ed. OBJECTIVES To test the impact of inorganic nutrients as they are released from aquaculture on the pelagic microbial food web in a Patagonian nord in Chile, a eutrophica6on microcosm experiment with 35 liter containers was performed with natural water in the Comau Fjord during austral summer 2010. Phosphate, nitrate and silicate was measured in an autoanalyzer, ammonium was measured by the indophenolblue method. Biomass es6mates during the experiment was based on organism counts (Table 2). The community composi6on of phytoplankton was followed by microscopy iden6fica6on, whereas that of heterotrophic bacteria by PCR DGGE 16S rDNA fingerprin6ng. From the species data matrices dissimilarity matrices were calculated, and based on these nonmetric mul6dimensional scaling (NMDS) ordina6on and canonical correspondence analysis (CCA) was performed. Figure 1: Development of carbon biomass in the microcosms during the experiment Figure 2: Average carbon biomass as a func6on of nitrogen loading rate for each func6onal plankton group Figure 3: NMDS ordina6on based on Bray Cur6s dissimilarity showing succession of the bacterial community from day 0 for treatment 4 and 6, and 6me final for the others Figure 4: BrayCur6s based NMDS showing the succession of the phytoplankton community composi6on RESULTS Table 2: Domina6ng organisms in 6 func6onal plankton groups and methods used for quan6fica6on Table 1: Gradients of nutrient loading per day in the microcosms Acknowledgements: This experiment was a part of the NTNU, Dept. of Biology project WAFOW financed by the Norwegian Research Council (project 193661). Thanks to all the hard working students and volunteers involved, and all our friends at Huinay field sta6on. Stress = 0.13 Stress = 0.08 1 Norwegian University of Science and Technology, Dept. of Sociology and Poli6cal Science, Trondheim, Norway, 2 Universidad Austral de Chile, Ins6tuto de Ciencias Marinas y Limnológicas, Valdivia, Chile, 3 Norwegian University of Science and Technology, Dept. of Chemistry, Trondheim, Norway, 4 Universidad Austral de Chile, Ins6tuto de Acuicultura, Puerto Mona, Chile, 5 Norwegian University of Science and Technology, Dept. of Biology, Trondheim, Norway, 6 Universisad de Antofagasta, Departamento de Biotecnología Email: [email protected]
Transcript of EFFECT%OFAMMONIUMADDITION%ON%THE%MICROBIAL%FOOD%WEB ... ·...
EFFECT OF AMMONIUM ADDITION ON THE MICROBIAL FOOD WEB STRUCTURE AND COMMUNITY COMPOSITION OF THE OSMOTROPHS
IN THE COMAU FJORD IN SOUTHERN CHILE
Lasse Mork Olsen1, Klaudia Hernández2, Murat Van Ardelan3, Jose Luis Iriarte4, Nicolas Sanchez3, Humberto Gonzalez2,
Nils Tokle5, CrisHna Dorador6, Yngvar Olsen5
a) Nano-autotrophs
0 2 4 6 8 1012141618
mg
Car
bon
L-1
020406080
100120140160180
b) Micro-autotrophs
0 2 4 6 8 1012141618
mg
Car
bon
L-1
0
100
200
300
400
500
e) Micro-heterotrophs
Time (days)
0 2 4 6 8 1012141618
mg
Car
bon
L-1
0
100
200
300
400
500
600
c) Nano-flagellates
0 2 4 6 8 10 12 14 16
mg
Car
bon
L-1
50
100
150
200
250
300
350
T1 T2 T3 T4 T5 T6 T7 T8
d) Pico-heterotrophs
Time (days)
0 2 4 6 8 10 12 14 16
mg
Car
bon
L-1
0
50
100
150
200
250
a) Nano-autotrophs
0 1 2 3 4
mg
Car
bon
L-1
2030405060708090
100
b) Micro-autotrophs
0 1 2 3 40
50
100
150
200
250
300
350
c) Nano-flagellates
0 1 2 3 4
mg
Car
bon
L-1
120
140
160
180
200
220
240
d) Micro-heterotrophs
0 1 2 3 40
50
100
150
200
250
300
350
e) Pico-heterotrophs
LN (mmol NH4 l-1 d-1)
0 1 2 3 4
mg
Car
bon
L-1
40
60
80
100
120
140
f) Copepods
LN (mmol NH4 l-1 d-1)
0 1 2 3 40
10
20
30
40
50
60
70
CONCLUSIONS • Ammonium, nitrate and silicon were depleted in all microcosms throughout the
experiment, whereas phosphate was sustained at a concentra6on of 0.4-‐0.5 micro-‐molar, indica6ng nitrogen-‐limita6on in general and possibly co-‐limita6on by silicon of the diatoms.
• The average biomass of phytoplankton, ciliates and copepods showed a significant linear response to the nitrogen loading rate. The biomass of heterotrophic bacteria and heterotrophic and autotrophic flagellates did not respond to the nitrogen loading gradient, indica6ng that the biomass of these were grazer controlled.
• Canonical correspondence analysis (CCA) indicated that the community composi6on of both autotrophs and heterotrophic bacteria was significantly constrained by the gradient of ammonium loading rates (p<0.05).
METHODS Ammonium and phosphate was added according to the molar ra6o released from salmon, and silicon according to the Redfield ra6o (N:Si:P = 28:16:1). Nutrients were added daily in a gradient of 8 loading rates (Table 1). Treatment 1 had no nutrient addi6on, whereas treatment 2 was meant to mimic natural loading (N:Si:P = 16:16:1).
Treatment LN (µmol NH4 l-‐1 d-‐1) LP (µmol PO4 l-‐1 d-‐1) LSi (µmol Si l-‐1 d-‐1) 1 0.00 0.00 0.00 2 0.30 0.019 0.30 3 0.50 0.018 0.50 4 0.70 0.025 0.70 5 1.00 0.036 1.00 6 1.40 0.050 1.40 7 2.00 0.071 2.00 8 3.00 0.107 3.00
FuncHonal group DominaHng organisms QuanHficaHon Nano-‐autotrophs Diatoms 2-‐20 µm Microscopy counts1, volume
calcula6ons2, carbon:volume3 Micro-‐autotrophs Diatoms > 20 µm Same as above Micro-‐heterotrophs Ciliates > 10 µm Same as above
Nano-‐flagellates Heterotrophic and autotrophic flagellates < 20 µm
Fluorescence microscopy counts4 average volume = 35 µm3
Pico-‐hetrotrophs Heterotrophic bacteria < 2 µm Fluorescence microscopy counts5 Carbon per cell = 25 fg
Meso-‐plankton Copepods Microscopy and length-‐weight6
1Utermöhl H (1958) Zur Vervollkommning der qua6ta6ven Phytoplankton-‐Methodik. Miaeilungen Interna6onal Ver-‐ einingung fur Theor und Angewandle Limnologie 9: 1–38.
2Hillebrand H, Durselen CD, Kirschtel D, Pollingher U, Zohary T (1999) Biovolume calcula6on for pelagic and benthic microalgea. Journal of Phycology 35: 403 -‐ 424.
3Menden-‐Deuer S, Lessard EJ (2000) Carbon to volume rela6onships for dinoflagellates, diatoms, and other pro6st plankton. Limnol. Oceanogr. 45: 569–579.
4Hass L, 1982. Improved epifluorescence microscopy for observing planktonic micro-‐organisms. Ann. Inst. Oceanogr. 58: 261–266.
5Porter K, Feig Y (1980) The use of DAPI for iden6fying and coun6ng aqua6c microflora. Limnol. Oceanogr. 25: 943–948.
6Jensen I (2012) Master thesis. NTNU, Dept. of biology. 7Grasshoff K, Ehrhardt M and Kremling F (1983) Methods of Seawater Analysis. Verlag Chemie, Weinheim, 2nd ed.
OBJECTIVES To test the impact of inorganic nutrients as they are released from aquaculture on the pelagic microbial food web in a Patagonian nord in Chile, a eutrophica6on microcosm experiment with 35 liter containers was performed with natural water in the Comau Fjord during austral summer 2010.
Phosphate, nitrate and silicate was measured in an autoanalyzer, ammonium was measured by the indophenol-‐blue method. Biomass es6mates during the experiment was based on organism counts (Table 2). The community composi6on of phytoplankton was followed by microscopy iden6fica6on, whereas that of heterotrophic bacteria by PCR-‐DGGE 16S rDNA fingerprin6ng. From the species data matrices dissimilarity matrices were calculated, and based on these non-‐metric mul6dimensional scaling (NMDS) ordina6on and canonical correspondence analysis (CCA) was performed.
Figure 1: Development of carbon biomass in the microcosms during the experiment
Figure 2: Average carbon biomass as a func6on of nitrogen loading rate for each func6onal plankton group
Figure 3: NMDS ordina6on based on Bray-‐Cur6s dissimilarity showing succession of the bacterial community from day 0 for treatment 4 and 6, and 6me final for the others
Figure 4: Bray-‐Cur6s based NMDS showing the succession of the phytoplankton community composi6on
RESULTS
Table 2: Domina6ng organisms in 6 func6onal plankton groups and methods used for quan6fica6on
Table 1: Gradients of nutrient loading per day in the microcosms
Acknowledgements: This experiment was a part of the NTNU, Dept. of Biology project WAFOW financed by the Norwegian Research Council (project 193661). Thanks to all the hard working students and volunteers involved, and all our friends at Huinay field sta6on.
Stress = 0.13 Stress = 0.08
1Norwegian University of Science and Technology, Dept. of Sociology and Poli6cal Science, Trondheim, Norway, 2Universidad Austral de Chile, Ins6tuto de Ciencias Marinas y Limnológicas, Valdivia, Chile, 3Norwegian University of Science and Technology, Dept. of Chemistry, Trondheim, Norway, 4Universidad Austral de Chile, Ins6tuto de Acuicultura, Puerto Mona, Chile, 5Norwegian University of Science and Technology, Dept. of Biology, Trondheim, Norway, 6Universisad de Antofagasta, Departamento de Biotecnología
Email: [email protected]
