1. BACTERIOPLANKTON: DISTRIBUTION AND ECOLOGY

2. Role of bacteria in the carbon cycle

3. Recall

4. How to determine numbers of cells and biomass Direct count Culture Fluorescence microscopy ATP Identify environmental microbes by PCR, RFLP, and sequencing

5. SEM micrograph of bacterioplanktonFluorescence micrograph of bacterioplankton

6. ASSUMPTIONS Growth of bacteria substrate-limited Thus, bacterioplankton most common in layers where primary production highest (epilimnion) Low biomass in metalimnion A second maximum in the hypolimnion Numbers lowest in winter

7. Thus, bacterioplankton should vary according to season and depth

8. Co-occurrence of phytoplankton and bacterioplankton

9. Numbers and relative occurrence of bacterioplankton in a Michigan Lake from October to July

10. Numbers and production rates of bacterioplankton through the seasons

11. Lake Hancza, the deepest lake in Poland

12. Gotkowska-Płachta A., Niewolak S., Korzeniewska E. 2003. VERTICAL DISTRIBUTION AND SEASONAL CHANGES IN THE NUMBER OF BACTERIOPLANKTON IN THE WATER OF LAKE HAŃCZA, PARTICULARLY IN THE PERIOD OF RESERVOIR SUMMER STRATIFICATION. EJPAU 6(2), #10. Figure 2. Vertical changes of temperature, oxygen saturation and number of planktonic bacteria (thousands of cells/ 1 cm 3 of water) in the water of Lake Hańcza (at station 1) during summer stratification of the lake in 1997 and 1998. A temperature, B oxygen, C planktonic bacteria

13. Gotkowska-Płachta A., Niewolak S., Korzeniewska E. 2003. VERTICAL DISTRIBUTION AND SEASONAL CHANGES IN THE NUMBER OF BACTERIOPLANKTON IN THE WATER OF LAKE HAŃCZA, PARTICULARLY IN THE PERIOD OF RESERVOIR SUMMER STRATIFICATION. EJPAU 6(2), #10. Figure 3. Vertical changes of temperature, oxygen saturation and number of planktonic bacteria (thousands of cells/ 1 cm 3 of water) in the water of Lake Hańcza (at station 1) during summer stratification of the lake in the years 1999 and 2000. A temperature, B oxygen, C planktonic bacteria

14. Also controlled by Temperature (as you have seen, usually highest in warm months) pH (grow best in circumneutral pH) Often restricted by nutrient availability, especially phosphate

15. Model of seasonal control of bacterioplankton

16. DOC: Amino Acids and Carbohydrates Concentrations low Assimilated faster in aerobic water than in anaerobic water Assimilation faster in warmer water than in cooler water Humic acids degrade very slowly and may be linked to other organics

17. Uptake of DOC As cells die, 5-35% released as DOC Extracellular release of DOC by primary producers a major source Most DOC released by primary producers in the euphotic zone Bacterial assimilation peaks after peak release of DOC by phytoplankton

19. Distribution of carbon fractions versus rates of uptake

20. The microbial loop

21. Idealized daily fluctuations of various parameters that impact bacterial uptake

22. Organic content of suspended particulate matter (POC) through the seasons

23. Phytoplankton production relative to rates of sedimentation of POC

24. Rates of turnover by large and small bacterioplankton

25. Bacterioplankton in riverine and lacustrine systems De Araujo, M.F.F. and M.J.L. Godinho. 2008. Seasonal and spatial distribution of Bacterioplankton in a fluvial- lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation. Brazilian Archives of Biology and Technology. 51(1): doi: 10.1590/S1516- 89132008000100024

26. Bacteria in Rivers and Lakes, a Study De Araujo, M.F.F. and M.J.L. Godinho. 2008. Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation. Brazilian Archives of Biology and Technology. 51(1): doi: 10.1590/S1516-89132008000100024

27. Summary for bacterioplankton. See Table 17-16 (p. 523) RIVERSRESERVOIRSLAKES Bacterioplankton abundance High to very highModerate to highLow Bacterioplankton production Low but increasing with stream order Low to moderateLow Bacterioplankton respiration HighModerateLow Bacterioplankton Mortality HighModerateHigh