aquatic ecosystems monday, august 22nd reminder: hw3 part ii due wednesday! midterm thursday
TRANSCRIPT
Aquatic EcosystemsAquatic Ecosystems
Monday, August 22nd
Reminder: HW3 Part II due Wednesday!Midterm Thursday
Ecotone: the transition zone between two diverse communities
Ecotone: the transition zone between two diverse communities
WHAT DID YOU FIND??????WHAT DID YOU FIND??????
Kelp forest ecosystemKelp forest ecosystem
Kelp provides otter habitat Sea urchins eat kelp
Otters eat sea urchins
Impact of Kelp on Low Productivity Terrestrial Env’ts
Impact of Kelp on Low Productivity Terrestrial Env’ts
Example: Channel Islands
•Kelp detritus = nutrient input to intertidal communities
•Marine bird and mammals feed on intertidal organisms
•Feces/guano provide nutrients to terrestrial organisms
•Biggest impact where ratio of shoreline to area is high
Kelp forest ecosystemKelp forest ecosystem
•30-40 m water depth
•Determined by light availability
•Require high concentrations of nutrients
•Occur mostly in areas of upwelling
•Provide primary production (food) and habitat!
Rocky Intertidal ZonationRocky Intertidal Zonation
Where to snorkel, rocky shore or sandy beach? Why?
Aquatic EcosystemsAquatic Ecosystems
• Oceans • Lakes
• Streams and Rivers• Estuaries
• Freshwater wetlands
Some General Questions:Some General Questions:
Where does the energy to support aquatic life come from?
How productive are each of the aquatic environments?
What is the limiting factor in each aquatic environments?How are nutrients cycled?
How have humans changed these environments?
The open ocean is most like…The open ocean is most like…A) a tropical rain forestB) the boreal forestC) the desertD) chaparral
…with regard to productivity.
Where is the ocean most productive?Where is the ocean most productive?
Where nutrients are available:
near the coastFrom upwelling
• rivers bring nutrients Polar upwelling
– Short, intense productivity
Where sunlight is available:Top 100 meters (euphotic zone)
Coastal UpwellingCoastal Upwelling
•Most upwelling occurs in responseto longshore winds.
•Upwelling: increased nutrients, increased primary production good fishing!
•El Nino brings warm water, shuts downupwelling, bad for fisheries
Is Primary Production always good for upper trophic levels?
Is Primary Production always good for upper trophic levels?
Harmful algal blooms: toxicity or increase in BOD suffocation, starvation
Red tide
The open ocean is most like…The open ocean is most like…A) a tropical rain forestB) the boreal forestC) the desertD) chaparral
…with regard to productivity.
Coral reefsCoral reefs
Coral reefs are extremely productive Visibility is great! But we know that nutrient-rich water is murky
How is this possible?Where are the nutrients?What terrestrial biome does this remind you of?
Coral reefsCoral reefs
Efficient cycling of nutrients Complex relationships between
organisms• Corals: plants or animals?• zooxanthellae in coral• intricate food webs
Light Penetration in LakesLight Penetration in Lakes
Secchi disk
Euphotic zone
Aphotic zone
Sediment
eu: well or good a:
without
Thermal Stratification of LakesThermal Stratification of Lakes
Epilimnion
HypolimnionSediment
Summer
Thermocline
Thermal Stratification of LakesThermal Stratification of Lakes
Thermocline
Epilimnion
HypolimnionSediment
(wind)
Summer Fall
Well-mixed profileSediment
Thermal Stratification of LakesThermal Stratification of Lakes
Hypolimnion
Thermocline
Well-mixed profileSediment
Epilimnion
HypolimnionSediment
(wind)
SummerFall
WinterFrozen
Warmer
Well-mixed
Well-mixed profileSediment
Cooling
Cooling
Thermal Stratification of LakesThermal Stratification of Lakes
Hypolimnion
Thermocline
Well-mixed profileSediment
Well-mixed profileSediment
Epilimnion
HypolimnionSediment
(wind)
SummerFall
WinterSpring Frozen
(4°C)
Well-mixed profileSediment
Cooling
Cooling
Warming
Warming
SummarySummary Aquatic Ecosystems
Limiting factors (light, nutrients, dissolved oxygen) and Temperature Rocky Intertidal
Zonation and adaptations Oceans
Productivity: euphotic zone/thermocline/nutrients/BOD/algal bloomsOpen ocean vs. coast
– Nutrients: upwelling and coastal inputs
Coral Reefs (zooanthellae, coral bleaching, ocean acidification, dynamite fishing) Lakes… seasonality of:
Light penetration (euphotic vs. aphotic zones)Temperature (epilimnion vs. hypolimnion)Oxygen (aerobic vs. anaerobic/anoxic)Nutrients (oligotrophic vs. eutrophic)