Aquatic Ecology Lecture Exam 2

Ekman Dredge

Secchi Disk

LaMotte water sampler

What is an Ekman Dredge used for?

To collect a benthic sample

What is a Secchi Disk used for?

To measure water quality and determine trophic state.

What is a LaMotte water sampler used for?

To collect a water sample at different depths to measure water chemistry.

Do lentic systems have standing or flowing water?

Standing

Do lotic systems have standing or flowing water?

Flowing

What type of flow do lentic systems have?

Laminar flow

What type of flow do lotic systems have?

Turbulent flow

What type of system has organic material within the water?

Lentic

What type of system has organic material outside the water?

Lotic

What type of processes are predominant in lentic systems?

Depositional processes

What type of processes are predominant in lotic systems?

Erosional processes

What type of algae do lentic systems have?

Planktonic

What type of algae do lotic systems have?

Periphyton

What type of macrophytes do lentic systems have?

Rootless and floating

What type of macrophytes do lotic ecosystems have?

Rooted

What is a reservoir?

An artificial pond or lake made by a dam in a valley or depression.

What is the formation process and characteristics of a TECTONIC lake origin?

A basin formed by movement of Earth’s crust, very old and deep. Ex: Lake Baikal

What is the formation process and characteristics of a POTHOLE/KETTLE lake origin?

Formed when ice left from a retreating glacier is buried in till, then melts. Includes small lakes/wetlands. Ex: Prairie Pothole Region in Alberta

What is the formation process and characteristics of a MORAINE lake origin?

Glacial activity deposits a dam of rock and debris, narrow valley

What is the formation process and characteristics of a VOLCANIC/CALDERA lake origin?

Volcanic explosion causes a hole that is filled with water, often round and deep. Ex: Crater Lake

What is the formation process and characteristics of a OXBOW lake origin?

River bend pinches off, leaving a lake behind, shallow and narrow

What is monomictic stratification?

Water mixes once a year- tropical

What is amictic stratification?

Water never mixes- saline and polar

What is polymictic stratification?

Water mixes several times a year- shallow

What is dimictic stratification?

Water mixes twice a year

Describe the littoral zone

Shallow water near the shore

Describe the limnetic zone

Open water

Describe the profundal zone

Deep and plantless

Describe the benthic zone

Bottom

Define lake area

Measure of lake size

Define lake volume

Area x depth

Define bathymetry

Depth profile used to find lake volume

Define hydraulic retention time/ residence time

Time required for a lake to fill/empty

Define shoreline development

Irregularity of the shore/shape

Define fetch

The amount of open water in a lake

What are the 3 sources of dissolved oxygen in lakes?

Atmosphere, Photosynthesis, and inflows from tributaries and groundwater

What are the 3 sinks of dissolved oxygen in lakes?

Respiration, outflow, and diffusion

How does high water temperature affect DO concentration?

Decreases DO

How does decomposition affect DO concentration?

Decreased DO

How does photosynthesis affect DO concentration?

Increased DO

How does respiration affect DO concentration?

Decreased DO

Describe an orthograde DO profile

75-100% saturation at all depths, straight line

Describe a clinograde DO profile

High saturation in epilimnion and low saturation in hypolimnion

Organisms that go where water takes them

Plankton

Organisms that go where they choose

Nekton

Organisms that live on the lake bottom

Benthos

Define zooplankton

Animal-like plankton

Define phytoplankton

Plant-like plankton

Define bacterioplankton

Bacteria-like plankton

What are planktivores?

Organisms that eat zooplankton

What are benthivores?

Organisms that eat benthos

What are piscivores?

Organisms that consume fish

What are detritivores?

Organisms that eat organisms that live on detritus/mud

What is an estuary?

A bay where the river empties into the sea, mixing freshwater and saltwater