Plankton and Their Importance in
the Marine Ecosystem
Video
Types of Plankton
Phytoplankton
Phytoplankton
Zooplankton
Bacterioplankton
Phytoplankton Importance
• Make up most of Earth’s biomass
– Biomass = the mass of living organisms
• Phytoplankton produce about half of Earth’s
oxygen through primary production
• Phytoplankton remove carbon dioxide from
atmosphere
• Support the rest of the food web
Phytoplankton
Adaptations for Phytoplankton Success
•
SIZE – Small is better! The smaller the cell is the
easier diffusion takes place.
•
Delay Sinking – Due to heavy cell walls,
phytoplankton tend to sink away from the light
they need. If the rate at which they sink is
decreased there is a chance they may get pushed
back to surface (upwelling).
Viscosity and Size
• Surface Area to Volume Ratio
Viscosity and Size
• Larger surface area to volume ratio = large
surface area for frictional resistance to sinking
– Good for plankton to be small
• Larger SA/V ratio also increases efficiency of
nutrient uptake and waste disposal
– Cube a would take up nutrients and dispose of
waste 3 times more efficiently than cube c
Decreasing the Sinking Rate
• Increase friction with
horns, wings, and
other cellular
projections.
• Zig Zag or spiral down
the water column.
https://web.duke.edu/nicholas/bio217/jrc25/
impacts.html
• Some have gas filled
floats.
Phytoplankton’s Preferences
• “Cold” water (species dependent)
– More nutrients
– More gases
– Slower sinking rate
– Maintain a position near surface for light
• BUT!!! Earth’s waters are warming…
http://www.giss.nasa.gov/research/news/20060925/
http://www.giss.nasa.gov/research/news/20060925/
Effects of Climate Change thus far…
• Average global temperature increase of about
1°F (0.6°C) over the past century
• Average ocean temperature increase in that
time of 0.18°F (0.1°C).
– Warming has occurred from the surface to a depth
of 2,300 ft (700 meters)
– Majority of most marine life lives here
Cold vs. Warm Water Species
Cold Water Species
• Higher viscosity waters
• Floating organisms
larger
• Few appendages
• Slower growing – lower
rate of biological
activity
• More total biomass
Warm Water Species
• Lower viscosity waters
• Floating organisms
smaller
• Often have ornate
plumage
• Faster growing – higher
rate of biological
activity
• More total species
Will warming waters affect
phytoplankton?
• Design a plankton and test the sinking rate in
both cold and warm waters
• Write your hypothesis on data sheet
How will increasing temperatures affect
phytoplankton specifically?
• Decrease in viscosity of water = increase in
sinking rate
• Removal of plankton from sunlight waters
• Implications in carbon cycle (land and ocean)
and oxygen production
• Can plankton adapt quickly enough??