Limnology Final Exam

What are the 3 types of bonds?

Covalent, polar covalent, hydrogen bonds

How does cohesion differ from adhesion?

Cohesion = attraction between like particles; Adhesion = attraction between unlike particles

How do oligo vs eutrophic lakes differ?

Eutrophic = highly productive, very turbid, light absorbed; Oligotrophic = low productivity, very clear, blue/green light penetrates deeper

What are the 4 phases of thermal stratification in lakes?

Spring turnover, summer stratification, fall turnover, winter stratification

What are the 3 layers in a lake?

Epilimnion, metalimnion (thermocline), hypolimnion

What are the sources & sinks of O2 in a lake?

Sources = gas exchange, groundwater, photosynthesis; Sinks = respiration, decomposition, precipitation of calcium/magnesium carbonate

What are the limiting nutrients in freshwater systems?

Nitrogen and phosphorus

How does a wetland differ from a lake?

Wetland = saturated soils + vegetation; Lake = open water body

What are the 3 main types of stream habitats?

Riffle = fast, rocky; Run = moderate flow; Pool = deep, slow, fine sediments

Define a watershed.

Land area draining water to a common point

Define discharge.

Volume of water moving past a point per time

What are the ways a lake can form?

Glacial, tectonic, volcanic, river processes, landslides, erosion, human activity

Why is a reservoir a hybrid of a river & lake?

Upper = river-like; lower = lake-like

Biotic

Living components of an ecosystem

What color does each photosynthetic pigment reflect?

Reflects certain wavelengths and absorbs others for photosynthesis

What is periphyton?

Algae and microbes attached to submerged surfaces

What are the types of periphyton?

Epilithic (rocks), epiphytic (plants), epipelic (sediment), epipsammic (sand)

What are the 3 adaptations of aquatic macrophytes?

Reduced support, gas exchange adaptations, dissected leaves

What is the ecological role of macrophytes?

Habitat, water quality improvement, sediment stabilization

What is the ecological importance of crayfish?

Predator and prey; transfers energy in food webs

What reasons are mussels impaired in North America?

Poor water quality, habitat loss, dams, sedimentation, pollution, invasive species

What are the 2 suborders of Odonata, and how do they differ?

Zygoptera = wings together; Anisoptera = wings spread

Provide examples of major aquatic insect orders

Mayfly, stonefly, dobsonfly/fishfly, caddisfly, beetle, true bug, fly

How does a community differ from an assemblage?

Community = all organisms; Assemblage = subset of organisms

Define a food web

Feeding relationships diagram

Define biodiversity

Variety and number of organisms

What are types of diversity?

Species, genetic, functional

Why are biotic indicators used?

Assess environmental quality

What are 2 drawbacks of direct approaches?

Healthy conditions unclear; only shows present

Define species richness

Number of species

What does species evenness measure?

Distribution equality of individuals

Why use tolerance-based indicators?

Identify pollution tolerance

Define alien vs invasive species

Alien = non-native; Invasive = harmful spread

What are characteristics of invasive species?

Fast reproduction, high dispersal, adaptable, outcompete natives

What are 4 control methods for invasive species?

Mechanical, chemical, biological, ecological

Ecosystem Processes

Energy flow and interactions

Shredders

Feed on leaves/organic matter

Collector-gatherers

Collect detritus

Scrapers

Graze algae/biofilm

Predators

Eat other organisms

What is the river continuum concept?

Gradual changes from headwaters to mouth

Major feeding groups in headwaters

Shredders, collectors, predators

Major feeding groups in medium streams

Collectors, scrapers, predators

Major feeding groups in large rivers

Collectors, filter feeders, predators

Define channelization

Altering stream channel

Impacts of channelization

Erosion, sedimentation, reduced habitat, altered water quality

Benefits of large woody debris

Habitat, food source, nutrient trapping

Abiotic effects of dams

Sediment changes, water quality, habitat alteration

Biotic effects of dams

Fish migration disruption, ecosystem changes

Define eutrophication

Nutrient enrichment causing change

Stages of eutrophication

Nutrients → plant growth → decay → oxygen loss

Natural vs cultural eutrophication

Natural = slow; Cultural = rapid, human-caused

Nutrient management techniques

Reduce inflow, disrupt cycles, increase outflow

What are the 3 laws used to conserve streams?

Clean Water Act, Endangered Species Act, Safe Drinking Water Act

Stream restoration methods

Re-engineering, buffers, channel repositioning, floodplain management, erosion control