Zooplankton, Microbes and Predators

• why are water molecules polar?

  partial negative charge on the oxygen side and partial positive charge on the hydrogen side
• how does waters polarity create surface tension?

  hydrogen bonds are created between water molecules, allowing them to stick together and create surface tension
• what does surface tension allow small organisms to do?

  walk on water
• what can viscosity also be thought of as?

  internal friction = how much the molecules are rubbing against each other
• why do the properties of water depend on an organism's size?

  at bigger scales, water seems more turbulent and inertia is more important and vice versa for smaller scales
• what is inertia?

  tendency of moving objects to stay moving and stationary objects to stay stationary unless a force causes its speed or direction to change
• how is the balance of inertia and viscosity quantified?

  Reynolds number
• for small organisms, what is water more like?

  honey
• what are small organisms always surrounded by?

  a boundary layer
• what are cladocerans commonly known as?

  water fleas
• what is a carapace?

  Hard outer shell
• do cladocerans select what to eat?

  no, they eat everything
• do copepods select what to eat?

  yes, they can reject to eat toxic algae
• which species of zooplankton select what to eat so that they can reject toxic algae?

  copepods
• which species of zooplankton do not select what to eat and eat everything?

  cladocerans
• what do algae need to get rid of when they are nitrogen or phosphorous limited?

  excess carbon
• how do algae excrete excess carbon?

  as dissolved organic carbon
• what is dissolved organic carbon a great food for?

  heterotrophic bacteria
• what does heterotroph mean?

  that the organism cannot produce its own food
• what is heterotrophic bacteria a great food for?

  phagotrophic protozoa
• what does phagotrophic mean?

  that they are engulfing food and ingesting it in a phagocytic vacuole
• who can the protozoa be eaten by once they are big enough?

  zooplankton grazers
• what is the part of the food chain called that hangs off the side of the classic food chain?

  the microbial loop
• what does pelagic mean?

  ocean
• what are the microbial loop and viral shunt important for?

  nutrient cycling
• what happens in anoxic conditions?

  many bacteria switch to anaerobic respiration (fermentation)
• what is anoxic freshwater dominated by?

  specialist bacteria that come in pairs and use each others waste products
• what are the two pairs of specialist bacteria seen dominating anoxic freshwater?

  purple and green sulphur bacteria partnered with sulphate reducing bacteria and methanogenic Archaea paired with methanotrophic bacteria
• what is the relationship between purple and green sulphur and sulphate reducing bacteria?

  mutually beneficial
• what is the relationship between methanogenic archaea and methanotrophic bacteria?

  one way commensalism relationship
• what is the term to describe the fact that aquatic consumers can only eat things smaller than their mouths?

  gape limited
• why are aquatic consumers gape limited?

  they can only eat things smaller than their mouths
• what does aquatic species being gape limited lead to?

  aquatic species undergoing ontogenetic diet shifts
• what is an ontogenetic diet shift?

  eating different things at different life stages as their mouths grow
• why are aquatic food chains typically significantly longer than terrestrial food chains?

  aquatic primary producers are very small so a lot of the food chain levels are compressed to very small sizes