Lecture 3 Flashcards
Viscosity
“internal” friction
Measured in centipose (CP), 1 CP in pure water
Water Properties
- At bigger scales, water seems more tubulent
- At smaller scales, water seems more viscous, water molecules stronger (honey like)
- If zooplankton stop swimming, they don’t drift
- Small organisms are surrounded by a boundary layer of water, makes it hard to filter, absorb or move
Zooplankton filter adaptions
Cladoceras use their carapace as an enclosed high pressure chamber that forces water through their filter. Select for large algae
Copepods use filter like paddles to create currents into their mouth. Select for smaller algae
Aquatic microbes
- When algae are N or P limited, they excrete DOC which is food for bacteria also detritus
- Bacteria are feed on by Protozoa and them by zooplankton. This is the microbial loop
- Viruses attack bacteria and algae, releaseing more algae (viral shunt)
Anoxic conditions
When respiration exceeds photosynthesis in deep water, oxygen can’t diffuse from surface leading to oxygen depletion
Anoxic bacteria pairs
Suplur metabolisms and Methane metabolisms
Purple and green sulphur bacteria
- Sulphur metabolisms
- Phototrophs ( anoxygenic)
- Fix CO2 but use H2S and produce SO4
- Different wavelengths to algae
Sulphate reducing bacteria
- Sulphur metabolisms
- Anerobic sulphate respiration
- USes SO4 and produce H2S
- Causes rotten egg smell
Methanogenic archae
- Methan metabolisms
- Anerarobic methanogic respiration
- Use CO2 and produce CH4
- Aqautic habitats and animal digestion systems
Methantrophic bacteria
- Methan metabolisms
- Methan as a carbon source
- Still require oxygen
- Live where Oxygen and methane overlap
Aqautic consumers are what-limited?
gape-limited as they can’t easily tear food
Ontogenetic diet shifts
- Organisms eat different things at different life stages as mouth grows
- Juvililes usually eat algae or zooplankton
Algae overturn
- Grow and repoduce very fast
- Biomass is higher in high trophic levels due to high algal turnover
