Aquatic Habitat Lakes and Oceans

Lecture 15

Factors Influencing Lake Dynamics

• Hydrology• Geology• Morphometry• Base chemistry• Biology (food chain)• Human activity

Human Impacts on Lakes

•Alter hydrology•Increase nutrients•Increase sediment•Alter vegetation

Water Quality Determined by:

Combinations of:• Alkalinity• Phosphorous• Dissolved Oxgyen• Nitrogen• Temperature• Dissolved &

suspended solids

• chlorophyll• iron• calcium• algae• macrophytes• Morphometry• fish

Water Quality Classifications Measured by Phosphorous in parts

per billion

Lake Productivity Through Time

Eutrophic Conditions

Natural Eutrophication

• geologic time (thousands of years)• natural sedimentation delivered by

streams• the lake gradually shallows• phosphorous is in the sediments - taken

up by macrophytes• the lake turns into a marsh, and

eventually a forest • To set back the successional clock, the

lake must be dredged

Cultural Eutrophication

• Human generation• P in water• Increased algae & macrophytes• No change in depth• Improved only by decreasing

nutrient input

Seasonal Changes in Habitat

Water is the most dense at 4 degrees C

Habitat Scale

• Macrohabitat: Temperature, DO

• Mesohabitat: estuaries, littoral zones

• Microhabitat: fish occupied location

Habitat Management in Ponds & Lakes

(video of plant control)

Habitat Management in Ponds & Lakes

• Nuisance plant control

• Water level manipulations

• Artificial spawning structures

• Cover• aeration

Ocean Habitat and Fish

Zones of Habitat in Ocean

• Benthic realm: all those areas in direct contact with the bottom.(shelf, upper slope, lower slope, abbysal, hadal zones)

• Pelagic realm: independent of the ocean bottom, open water habitats. (epipelagic, mesopelagic,bathypelagic, hadopelagic)

Habitat Management in Oceans

•Decrease pollutants

•Prevent shoreline development

•Add artificial reefs

Nutrient Source?