FW Lecture #1

Accessible Runoff

Water available for human use is accessible runoff, calculated as rainfall minus evaporation, which equals surface runoff plus groundwater.

Fresh Lakes

Fresh lakes have a volume of 91,000 km³, accounting for 0.007% of the total water on Earth, with an average residence time of 1-500 years.

Rivers/Streams

Rivers and streams have a volume of 2,120 km³, representing 0.0002% of total water on Earth, with an average residence time of 1 week to 1 month.

Glacial Lakes

Most of North America's lakes were formed during the last glacial cycle (approx. 10,000 to 20,000 years ago), shaped by the glacier's weight and movement or by glacial debris forming dams.

Water Chemistry

Water chemistry includes aspects such as pH and carbonate equilibria, with phosphorus typically being a limiting nutrient, though nitrogen can also occasionally be limiting.

Oligotrophic Lake

An oligotrophic lake is characterized by low nutrient levels, good light penetration, high dissolved oxygen, deep waters, and supports species like smallmouth bass, lake trout, pike, sturgeon, and whitefish.

Eutrophic Lake

A eutrophic lake has high nutrient levels, poor light penetration, low dissolved oxygen, shallow waters, and experiences high algal growth. Common species include carp, bullhead, and catfish.

Types of Organic Matter Sources

Organic matter sources can be divided into autochthonous (produced within the ecosystem, e.g., algae) and allochthonous (originating outside the ecosystem, e.g., dead leaves).

Differences Between Streams and Lakes

Streams have continuously moving water that influences sediment and organisms, disturbances are more frequent, detritus is a major energy source, and they lack distinct habitats.

Mountain Stream Zone 1

Headwaters where streams flow down steep mountain slopes, creating deep, V-shaped valleys, and often featuring waterfalls and rapids.

Mountain Stream Zone 2

The transfer zone where lower-elevation streams merge, flowing down gentler slopes and broadening river valleys.

Mountain Stream Zone 3

The depositional zone where the river meanders across a broad, flat valley and may form deltas.

Mountain vs Lowland Stream Segments

Mountain streams are sensitive to rainfall, influenced by hillslope movement, and characterized by downcutting channels, whereas lowland streams are less sensitive and channel movement is primarily lateral.

Riffles

Riffles are relatively shallow, fast-moving sections of a stream characterized by a steep water surface slope.

Runs

Runs are deeper sections of the stream that follow riffles, with a less turbulent water surface.

Pools

Pools have a near-flat water surface, are significantly deeper than the stream's average depth, and allow fine sediments to deposit.

Glide

The glide is the section of the stream transitioning from the pool to shallower water before the next riffle.

Cascade

A cascade is a steep, stepped slope featuring whitewater and boulders.

Coarse Particulate Organic Matter (CPOM)

CPOM includes larger organic materials such as leaves, woody debris, and plant parts, which contribute to the organic matter pool.

Fine Particulate Organic Matter (FPOM)

FPOM consists of smaller particles resulting from the breakdown of CPOM and includes feces and detrital particles.

Dissolved Organic Matter (DOM)

DOM refers to organic particles found in a dissolved state in water, originating from various biological and chemical processes.

Trophic or Functional Feeding Groups for Macroinvertebrates

Macroinvertebrates are grouped based on the size and source of organic matter they consume, with adaptations in mouthparts and feeding behavior.

Shredders

Shredders are macroinvertebrates that consume CPOM, such as decomposing vascular plants or wood.

Filtering Collectors

Filtering collectors are organisms that filter FPOM and suspended particles from the water column.

Gathering Collectors

Gathering collectors ingest sediments or loose organic particles found in decompositional areas.

Scrapers

Scrapers graze periphyton attached to surfaces in the aquatic environment.

Predators

Predators capture and ingest prey or tissue, feeding on living animals.

Dye Release

Dye passage through the system indicates less hydrologic retention, resulting in reduced time for microbes to process nutrients and DOM.

Riparian Zone

The riparian zone is the functional interface between terrestrial and aquatic environments, influencing light, organic matter, and nutrients.