Discuss why marine phytoplankton are generally smaller and more ...

[luminitza]

Discuss why marine phytoplankton are generally smaller and more ornate than their freshwater counterparts.
 
  What will be an ideal response?

Question 2

Variations in Earth's orbit that influence long-term climate changes include ________.
 
  A) the shape of Earth's orbit (eccentricity)
  B) the tilt of Earth's axis of rotation (obliquity)
  C) the wobbling of Earth's axis of rotation (precession)
  D) eccentricity, obliquity and precession

[Christopher]

Answer to Question 1

The photic zone is the upper portion of the ocean in which light levels are sufficient to support photosynthesis. In the open ocean, this layer is 100-200 meters deep. If autotrophic planktonic organisms sink below 200 meters, then they die. Marine diatoms are much smaller than freshwater diatoms; their increased surface area to volume ratio keeps them afloat. Additionally, marine diatoms have ornate spines that increase surface area. Many freshwater diatoms live in habitats where light penetrates to the bottom so sinking is not problematic. Freshwater diatoms lack the ornate spines frequently observed in marine diatoms because light penetrates to the bottom of the pond, stream, or puddle where they live.

Answer to Question 2

D

[luminitza]

Both answers were spot on, thank you once again

[Christopher]

Great! Please up vote