Final Exam -- Freshwater Systems

Collector

Organisms that are designated by their use of adaptive features to filter and catch organic matter

Grazer

Organisms that feed off of periphyton that accumulates on larger structures such as stones, wood, or large aquatic plants

Shredder

Organisms that feed off of coarse particulate organic matter such as small sections of leaves. They ingest the organic matter along with volunteer organisms (fungi, microorganisms) attached to the source; shredders break it up into a finer particulate matter.

Periphyton

Complex mixture of algae, cyanobacteria, heterotrophic microbes, fungi, and detritus, that are attached to submerged surfaces in most aquatic environments

Discuss the importance of the River Continuum Concept—include stream order, BMI assemblage [from a functional feeding standpoint], role of the riparian based on stream size

RCC describes how rivers change as they flow from headwaters to end waters. As stream size increases, the assemblage of BMI shifts from shredders and collectors in headwaters to collectors and predators in larger river systems. The riparian zone is important to headwater systems because much of the food consumed by shredders and collectors is from fallen leaves.

Stream order and size affect temperature in streams. True/ False 

True

How does the riparian zone affect BMI?  

In order for a healthy stream flow, different BMIs have different functions. In a riparian zone, many shredders and collectors are needed to break down nutrients for predators and collectors in larger river systems.

The riparian zone also provides protection/shelter for BMIs from predators.

Explain nutrient spiraling [include an illustration in your response].

S = Sw + Sp

Sw = uptake length; average distance a nutrient molecule travels downstream in dissolved form

Sp = turnover length; average distance a nutrient molecule travels downstream in particulate form

What are the three ways benthic macroinvertebrates feed off organic material and why is this important for the RCC?

Shredders feed on small sections of leaves, in which they break up the leaf into a finer particulate matter.

Collectors use adaptive features to filter and catch organic matter.

Grazers feed off of periphyton that accumulates on large structures.

This is important for the RCC because each BMI has a specific task that helps the stream flow be healthy.

Describe the leaf processing sequence after it enters the streambed as litterfall. 

What is a functional feeding group and how are individuals in this group categorized? 

Functional feeding groups are a classification approach that is based on behavioral mechanisms of food acquisition rather than taxonomic group. Individuals are categorized based on their mechanisms for obtaining food and the particle size of the food, and not specifically on what they are eating.

Define the relationships between light, algae, polysaccharide matrix, substratum. 

Light exposure triggers physiological processes in the algae cells.

Discuss and define DOM/POM/COM/CPOM [provide the relative particle size of each group].

Dissolved organic matter (DOM) is transported from the watershed into aquatic systems.

Particulate Organic Material (POM)

Coarse Organic Material (COM)

Course Particulate Organic Material (CPOM) are small sections of leaves (1 mm-10 cm)

ISC

Impervious Surface Cover

CSO [include effects on urbanization on water quality]

Combined Sewer Overflows

Chemical effects depend on:

• extent and type of urbanization

• presence of wastewater treatment plant effluent

Geomorphology

A branch of geology that is concerned with the structure, origin, and development of the topographical features of the earth’s surface

With ISC, how does it affect the water penetrating into the ground?

Water penetrates into the ground faster when ISC is present

Floods peak faster and are shorter in duration with more ISC. True/False

True

The water table declines and groundwater recharge is increased with ISC. True/False

False, groundwater recharge is reduced and water table declines

Know how the different percentages of imperviousness affect evapotranspiration and runoff.

How does ISC affect discharge and baseflow from a pre-development and post-development standpoint? 

As ISC increases:

• Culverts, canals, and pipes alter the distribution of water

• Floods peak faster and are shorter duration

• Flood peaks increase

  • A 2-year flood in an urban stream is equivalent to a 10-year flood in a forested stream

What are some geomorphic effects of urbanization?  

• Alters drainage density

  • decreases natural channel densities

  • Increases overall drainage density

• It affects sediment supply and discharge

• Stream widening and incision - begins between 2-6% ISC

• Decreased channel stability

• Loss of pool-riffle structure

• Alters sediment texture - less fines, more coarse substrate

• Less large woody debris

What effects does land aggregation and removal of trees have on streambeds?

• Increased stream temperature

• Decreased groundwater recharge

• “Heat island” effect

Briefly describe how wastewater systems work/where the water comes from and travels to.

Wastewater systems work by collecting wastewater from homes, businesses, and industries. The water then travels through pipes to a septic tank or a wastewater-treatment plant. The treatment plants clean the wastewater for discharge into streams or other receiving waters, or for reuse.

What is a stormwater hotspot? Provide examples.  

An area of land that produces higher concentrations of pollutants; normally found in urban runoff

• Commercial parking lots

• Fleet storage areas

• Industrial areas

• Gas stations/vehicle service areas

• Landscape nurseries

What is the ecological role of microbes and algae in a body of water?

Microbes

• Bacterial densities increased in urban streams

• Increased antibiotic resistance

Algae

• Reduced species diversity

• Reduced biomass

How does urbanization impact benthic macroinvertebrate populations?

• Decreased diversity

• Decreased abundance (toxins) or increased abundance (nutrients)

• Shifts in species composition

  • Relative increase of tolerant species

• Community “health” declines

Increased suspended solids in water (turbidity) heightens the effects of erosion. True/False

True

Provide 4 ways that urbanization impacts the fish community. 

• Fish diversity declines

• Fish abundance declines

• Tolerant taxa increase

• Increased % of contaminated fishes'

• Sensitive taxa decline

• Increased abundance of exotics

• Overall community “health” declines

What percent ISC can you generally find a degradation threshold?

10-20%

What do endocrine-disrupting chemicals (EDCs) do to aquatic organisms?

Mimic or block natural hormones

What type of land use is most impactful on FW systems?  

Urban land use

What components may increase levels of effluent in aquatic systems?

• Sewage - pharmaceuticals

• Industry - pulp and paper chemicals

Diel

involving a period of 24 hours

DVM

(Diel vertical migration) of zooplankton to potentially avoided fish predation

DHM

(Diel horizontal migration) zooplankton aggregate in macrophytes beds during daylight hours and migrate to the pelagic zone to avoid predators

YOY fishes

Young-of-the-year fishes (defined as larval/juvenile fish produced in the current year’s spawn)

Infochemicals

Organisms who live in an “odor world”; they depend strongly on chemical stimuli to learn about the biotic and abiotic environment

Cyclomorphomsis

A phenomenon in cladocerans that involves a regular seasonal and/or induced change in body allometry… evidence is equivocal if temperature, predation, or a combination of these factors induces morphological changes

How does size selective grazing affect the size and composition of the zooplankton community? 

Predation (fish) influenced the size and composition of the zooplankton community— large-bodied zooplankton were rapidly consumed, resulting in zooplankters which tend to be smaller in size

How does zooplankton biomass correlate to total phosphorus levels?

Zooplankton biomass is higher when total phosphorus levels are higher

The interaction between larval fishes and cladocerean abundance is typically a _______ relationship. 

Negative

In tropical systems, zooplankton still exhibit the same vertical migration as they do in stratified lakes. True/False 

True

Typically, during day light hours, where are Daphnia found? 

In the sediments or in the aphotic zone

What is the most abiotic factor in transparent lakes that is most consequential in regulating Daphnia survivorship?

Seasonal phosphorus availability

Lakes where zooplankton tend to show very limited vertical migration are typically eutrophic and/or minimal populations of zooplanktivorous fish.  True/False

False, typically oligotrophic

Baseflow

Streamflow which results from precipitation that infiltrates into the soil and eventually moves through the soil to the stream channel

Riparian zone

Pertaining to, situated or dwelling on the margin of a river… including banks on water bodies where sufficient soil moisture supports the growth of vegetation

Delta

Flat plane of alluvial deposits between the branches at the mouth of a river, stream, or creek

Incised channel

A stream that, through degradation, cut its channel into the bed of a valley

Backwater

A pool formed by water backing upstream from an obstruction or a secondary channel that is connected to the active main channel

Lotic

Aquatic system with rapidly flowing water (e.g. brook, stream, or river) where net flow of water from headwaters to the mouth is unidirectional

Glide

A shallow stream reach with a maximum depth that is ~ 5% or less than average stream width and velocity < 20 cm/sec

Alliuvium

Deposits resulting from sediment transport that is deposited in streambeds, floodplains, lakes, and/or estuaries

Battureland

Strip of land between low water and the edge of a levee

Headwaters

The source of a stream

Meander

A curved portion of a sinuous winding stream— consisting of two consecutive loops; one clockwise, one counterclockwise

Suspended load

Sediment moved by a stream in suspension

Percolation

The movement of water through the soil (influenced by gravity)

Epilithic/Epipelic/Epiphytic/Epizootic

Epilithic - algae on rock or stones

Epipelic - algae growing on sediments

Epiphytic - algae on plants

Epizootic - algae growing on animals

Sublimation

Transition of a substance from the solid phase to the gas phase without passing through an intermediate liquid phase

Evapotransporation

Describes the sum of evaporation and plant transporation from the Earth’s land surface to the atmosphere

Explain how a headcut is generated—include an illustration in your response. 

A headcut is upstream migration or deepening of a stream channel created by erosion

Contrast and draw a cutbank vs. a point bar. 

Cutbank - streambank that has been eroded and has a steep face

Point bar - located on the inside of meander bends

Draw a braided, straight, meandering and anatomizing channels. 

Headwaters typically have coarse sand and laminar flow. True/False 

False, they have coarse gravel and turbulent flow

Explain and draw the global hydrological cycle. 

The global hydrologic cycle is a continuous exchange of moisture between the oceans, the atmosphere, and the land.

Explain ENSO—include the movement of water in the southern ocean, location of various land masses, turnover, planktonic productivity, wind direction, location of various oceanic water masses, and the overall effects of both El Nino and La Nina on worldwide precipitation---especially as it pertains to North America. 

• Relatively predictable oscillations in the Southern Pacific Ocean influence global rainfall/snowfall

• Upwelling off the Peruvian coast brings cold, nutrient-rich waters to the surface —> triggering elevated primary production that sustains robust marine systems (usually water temps are ~ 8 degrees C warmer in the west) … water is about 0.5 m higher in Indonesia than Ecuador

• However, ~ every 5-7 years westward trade winds dissipate allowing warmer central/west waters to shift towards the east; this disrupts the intensity of near-continent upwelling

• As El Nino sets in, climatological conditions then depart from “normal”— specifically southwest U.S. receives increased precipitation and colder winters conversely the AK, Canada, and much of the northern U.S. states have warmer winters

• El Nino is “climatologically counterbalanced” by La Nina in the southern Pacific Ocean

• Following the El Nino period—that regulates the movement of warm water—trade winds reverse and blow west (with higher-than-normal intensity and duration) resulting in a pronounced increase in upwelling off the South American coast that usually extends far out from the coast along the equator

• Elevated trade wind activity in La Nina results in conditions then depart from “normal”—specifically southwest U.S. receives almost no precipitation; conversely the AK and Canada are extremely cold and flooding plaques southeast Asia