Production & Life in the Ocean
Life and Energy

• Question:
– Where does the energy that one can observe in marine communities (which allows for movement, reproduction, etc.) ultimately come from?
Life and Energy
• Energy in Living systems
– Source = Sun
– Producers
– Consumers
Primary Production
• Phytoplankton
– Photosynthesis
– GPP
– Respiration
– NPP
– Biomass
Controls on Primary Production
• Light
– Euphotic zone
– Production of sugars > consumption
– Break even point = compensation depth
• Variations - latitude
• Seasonal variations and lag time
Controls on Primary Production
• Biogeochemical cycles
– Major Component = carbon
– Conservative element
• The carbon cycle
• Consumption
– Incorporated
– Resprired
– Excreted
• Microbial loop
Controls on Primary Production
• Biogeochemical cycles
• Nonconservative = nutrients
– Limiting
• Nitrogen
– Bodies, gas, DON
– Fixed by bacteria
– denitrification
Controls on Primary Production
• Nutrients
• Phosphorous
• Dissolved = phosphate
– Depth controlled distribution
– Nutrient sinks
– Upwelling
• Other Nutrients
– iron
Global Primary Production
• Coastal Regions
• Upwelling
• Downside of coastal proximity
• Primary Productivity
– Ocean versus Land
Total Production
• Feeding (trophic) Relationships
– Primary producers = autotrophs
– Consumers = heterotrophs
• Trophic Pyramid
– Primary producers
– Primary consumers
– Secondary consumers
– Top ConsumersTotal Production
• Food Chains = misconception
• Food Webs
– Predator/prey relationships
Primary Producers
• Phytoplankton
Primary Producers
• Multicellular algae
– Kelp
Primary Producers
• Higher level plants - angiosperms
– Sea grasses
– Mangroves
Primary Producers
• Primary production on coral reefs
• Autotrophs within coral tissue
– zoosanthelae