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OCN 201 Biology Lecture 3Professor Grieg Steward
Classification of Marine Life & Habitats
C
H
H
H
S
carbon dioxide
sugars
nucleotides
lipidsamino acids
Autotrophs can make the organic building blocks of life starting from carbon dioxde
Heterotrophs have to eat organics
• Autotrophs - use CO2 to make organics
• Who: All plants, some protista and bacteria
• Can use sunlight (photo-) or chemical (chemo-) energy
• Heterotrophs - Need to consume organic compounds• Who: everything that is not autotrophic
• Mixotrophs - They can do both!
Classifying Marine Organisms by Nutrition
Autotrophic Cell
CO2 H2O+
Sugar
O2+
Energy
C6H12O66 6 6
Cells are more than sugar. Other compounds are built from simple sugars plus nutrients (Nitrogen, Phosphorous) & trace metals)
Autotrophy(photosynthesis or chemosynthesis)
Autotrophic Cell
CO2 H2O+ O2+C6H12O66 6 6
RespirationReversing the reaction yields energy the cell can use
Energy
Heterotroph
CO2 H2O+ O2+C6H12O66 6 6
HeterotrophyHeterotrophs consume organics. Much is respired to get energy and some is used as building
blocks to grow.
Energy & growth
Mixotrophy
Very common among marine planktonMany Protists in the ocean are both
phytoplankton AND predators!
Photosynthesis &predation
Mixotrophs can do this
Carbon Dioxide
Sugar
Water
But when nutrients are scarce
So they EAT other cells to get their nutrients
They can’t make all the necessary building blocks
especially nitrogen (N) and phosphorus (P)
> 3.5 billion
700 million
500 million
2 billion
Photosynthesis (Cyanobacteria) Photoautotrophs Chemoautotrophs
Heterotrophs Mixotrophs
Heterotrophs
ANIMALSFUNGI
Photoautotrophs
PLANTS
Multicellular Life
Eukaryotes (Protists)
Photoautotrophs Heterotrophs
Mixotrophs
Bacteria and Archaea
Venus Fly TrapSea Slug
Eastern Emerald Elysia
“Mixotrophic” Animals Truly Mixotrophic Plants
Upside-down Jelly Cassiopea
Photo: Patrick J. Krug
Photo: Linda & Jason
Pitcher PlantLaurence Gaume, Yoel Forterre
thisiswhyimbroke.com
EXCEPTIONS
• Benthic (benthos = bottom)
• Pelagic (pelagius = of the sea)
Classifying Marine Organisms by Habitat
Ocean Habitats
PELAGICBENTHIC
Intertidal (littoral)
zone
• Benthic (benthos = bottom)• Infauna• Epifauna
• Pelagic (pelagius = of the sea)• Plankton (Drifters, weak swimmers)
• Nekton (Swimmers)
Classifying Marine Organisms by Lifestyle
Infauna
Epifauna
35 mm
5 mm
PelagicOrganisms
Nekton(all are animals)
Planktonphytoplanktonzooplanktonbacterioplankton
Physical Divisions of the Marine Environment
4000 m
Bathyal
Abyssal
6000 mHadal
Littoral (intertidal)
200 mSublittoral
Supralittoral (splash zone)
NERITIC OCEANIC
EpipelagicMesopelagic
Bathypelagic
Abyssopelagic
Hadalpelagic
1000 m
• Temperature & Light DECREASE with Depth & Latitude
• Pressure INCREASES with Depth
• Salinity more variable near shore
• Air exposure in the littoral zone
Physical & Chemical Factors Affecting Life
Pressure Increases with Depth
Photo courtesy Kate Achilles
Deep-diving marine mammals have collapsible lungs
Temperature VariationsTemperature Decreases with Depth
POLAR
POLAR
TROPICAL
TEMPERATE
TEMPERATE
Temperature Decreases with Latitude
Light Variations
SunlightPressure
Light energy
Light intensity decreases with latitude and with depth
Pressure
TOTAL light and COLOR Spectrum Vary with depth
UVRed BlueYellow Green
about 600 m
20 to 100 m20 to 100 m“Good” Light
about 600 m
Twilight
No Light
Euphotic zone= where photosynthesis is possible!
Disphotic zone= there is light but not enough for photosynthesis!
No light from the sun penetrates
Euphotic
Disphotic
Aphotic
Photosynthesis Feeds The Ocean
Energy
Food
The Pelagic Divisions (By Light)
about 600 m
TwilightDISPHOTIC ZONE
20 to 100 m“Good” LightEUPHOTIC ZONE
APHOTIC ZONE No Light
Photosynthesis can only happen up here!