Stream Eco Final

A great deal of studies during the early days of stream ecology were focused on aquatic insect distribution. What was a major factor contributing to this focus?

An interest in fish and fisheries management

What is an example of a metric of water quality?

Concentration of industrial pollution and concentration of sewage pollution

A historical motivation for studies in stream ecology was management of fisheries. Identify benefits or a benefit of a well-managed fishery and water quality?

Economic, recreation, cultural, food

The field of stream ecology historically had a strong focus on what biological component of aquatic insects compared to terrestrial ecosystems?

Life-history of aquatic insects was historically studied more strongly than that of terrestrial insects

What are the differences or difference between applied and basic research?

Applied research, as the name implies, can be useful to solving existing problems

What is a similarity or similarities between basic and applied research?

Applied research can be based on discoveries made using basic research and doing applied research to solve existing problems can help us learn basic principles

Ecological systems including stream ecosystems can be thought of as a hierarchy, what does the term hierarchy mean in this case?

Higher levels contain the prior levels making the system increasingly more complex as you increase in level

Let’s imagine this hierarchical stream ecosystem further. Identify the pairing or pairings below that has a lower level paired with a higher level

organisms-community, sand grain- dune, stram-valley

The discipline of stream ecology can be broadly defined as

The study of the relationships between organisms, and their physical environments in flowing waters

Trees are a largely terrestrial organisms, not aquatic. Despite this, trees play important roles in stream sturcture and function. Identify an important role or roles trees play in streams.

Trees provide shade for the stream channel lowering temperature and light levels

Identigy an example of detritus in streams and its ecological importance

Dead leaf as an important food for mivrobes and insects

What chemical properties of water molecules contribute to their unique physical nature?

Hydrogen bonding and polarity

Without hydrogen bonding water would be in what state under normal atmospheric conditions?

Gaseous

Water is often considered a universal solvent. What is an example of the ecological relevance of this?

Water dissolves, delivers, and holds biologically essential nutrients

What is the difference betwen laminar and turbulent flow?

Turbulent is chaotic and laminar is smooth

Which has the smallest Rynolds number

Microscopic zooplankton

At very low Reynolds numbers what kind of forces dominate?

Viscous

Why does water temperature matter to aquatic dwelling animals like fish?

Temperature impacts how much gas can be in solution and temperature impacts metabolic rates of animals like fish

Compared to atmospheric air, oxygen diffusion into water is

extremely slow

What term can be used to describe a specilized role or habitat of an organism withing its ecosystem

niche

Let’s imagine your friend is taking a geomorphology field course over the summer. What do you think will be the overarching focus of this class?

Earth surface forms and the process that create them

You see a job posting or a fluvil geomorphologist. What might be some items listed in the desired skills section of the job add?

Understanding of sedient processes, understanding of hydrologic processes, ability to model and clculate river discharge, evaluate watershed features and characterize channel form

Identify the term that fits this definition. The volume of water passing through a river at a given time.

Discharge

The physical template of a stream is inherently abiotic or non living. However, what might serve as an example of biota or living things playing a role in the physical templte of a stream?

A tree altering bank characteristics and huans building dams

What two geomorphic aspects are in equilibrium on Lanes scale?

Sediment load and discharge

What positively contributes to water energy and movement in a stream channel?

Slope

Hyporheic exchange

Continuous bi-directional exchange of water between a river channel and underlying sediments

What kind of assumptions are made when aquatic insects are used to asses the water quality of a stream or river?

The absence of a species implies that it cannot live there due to pollution

According to Strahler stream order a first order stream would most commonly occur where in the watershed?

headwaters

What is challenging about restoring or engineering the physical template of a stream?

It requires a great undrstanding of highly dynamic and unique flow and sedimentary patterns. I

Watershed

A land area that cannels or collects rainfall and snowmelt to streams and rivers

True or False: Stream ecology is a relatively old field or discipline compared to physics

False

What is unique about stream ecosystems compared to terrestrial ecosystems?

Streams have directional flow

What are the five components of the natural flow regime presented by Poff an colleagues?

magnitue, frequency, duration, timing, and rate of change

The size of a stream channel plays important roles and can tell a lot about its ecological characteristics. Identify what a stream channel size can tell us or govern.

Stream channel size can govern the amount of water it can hold, the relative effect of riparian vegetation input and shading, and it can indicate where in a watershed a stream is occurring.

Freshwater ecosystems contain relatively high numbrs of species diversity compared to terrestrial and marine ecosystems per a given area. From a conservation perspective what other metric of biodiversity do freshwaters show the highest values in?

Imperiled species per given area

Scale dependence

Patterns or processes that change depending on the resolution over space or time at which they are observed

Heterogeneity

The quality or state of dissimilar or diverse elements

You are standing at the edge of Yellow Dog River Falls and you notice changes in water velocity and turbulence and you look from upstream to downstream. What dimension of the stream are you comparing along?

Logitudinal

What dimensions can be used to examine or describe ecological scale?

Temporal and spatial

Select an example of the ecological relevance of heterogeneity

heterogeneity can support coexistence of a greater diversity of speces; in a physical habitat can provide refugia promoting population stability; tends to affect dominance of community members

You are a fish bilogist and have been monitoring the two fish species population with your own field work and long term data going vack to the 1970s on the West Branch of the Escanaba River. During this time frame there have been several severe hydrological disturbances via flooding in the watershed. One species, the Big Lebowski Bass, remains unchanged despite these disturbances, while a different species, the Walter Shad, experiences large declines in abundance but has the ability to quickly return to prior levels following the distrubance. Pick the option below that best fits how you would describe these two fish species.

Big Lebowski Bass is Resistant and the Walter Shad is Resilient

Many species of aquatic insects synchronize their emergence or transition into their terrestrial adult life stage with seasonal disturbances events such as yearly flooding and high flows. Identify a specific stressor associated with high flows that these insects might be trying to avoid

Dislodgment, scouring, burial in sediment

Many species of aquatic insects passively move downstream in search of other habitat. Identify a specific stressor that can initiate this movement behaivor.

Predation

What is the term used to describe the passive downstram movement of an insect in a stream or river?

Drifting

Many prey species avoid predation using senses other than sight. How else are predators detected by their prey?

Smelling chemical cues or their predator its self or smelling allarm cues or chemicals from injured conspecifics

Flow disturbances are often associated with high flows. However,, very low flows or drying disturbances can also be an important fow related stressor for stream biota. Identigy biological stressors associated with these ow flow disturbances.

Desication, reduced habitat volume, hypoxia

Exclustion experiments where a particular group of species or a single species is excluded from an area of a stream can be used to scientifically test for what?

The effects of biological interactions

What are some ways that researchers have executed exclusion of a particular group of species or a single species from an area of a stream

Electricity, stones or bricks at various heights in the water column, cages or mesh, pesticides

Why might understanding competition between two stream species be important?

Competiton between species may promote coexistence and stability of the community and may control population cycles of certain species

What is the dominant primary producer in streams and what is it comprised of?

Periphyton which is a combination of algae, fungi, and bacteria

Lamprey can be considered parasites of trout and other fish. What king of parasites are lampreys in these instances? Why do they have this classification?

Lampreys are ectoparasitic because they live on the external surface of the host

What are or is a tradeoff associated with endoparsitism and ectoparasitism?

Endoparasites are more sensitie to the hosts behavior while ectoparasites are more sensitive to environmental conditions

You have designed an experiment to test for the competition between two caddisfly species. Upon analyzing and interpreting the data you find both species had positive effects on the other species fitness. How would you characterize this type of biotic interaction outcome?

Mutualism

In the above scenario, you found that interaction of two species of caddisflies improved fitness for both involved. What might be a mechanism for this?

Reduction of stress, Resources or food acqusition, creation of new or novel habitat

How might the grazing of algae counterintuitvely increase or accelerate its productivity?

Grazing can accelerate stream productivity by reducing light and nutrient limitaions

Identify a factor or factors that helps to keep dominant and competitvely superior species in check.

Physical disturbances, herogeneity in habitat over space and time, heterogeneity in resources oveer space and time

You conduct an experiment with two species of snails and discovered that both species of snails had a reduction in fitness at the end of the experiment. What species interaction did you likely observe between these two species?

None of the above (Facilitation, ecosystem engineering, commensalism, parasitism)

You are building a food web and are doing gut content analysis for an armored catfish. You find that the majority of stoach contents include plants and algae. What would you categorize this fish as?

Grazer

In the same food web that you were building above, what limitations will you have to confront by using diet data alone?

Taxonomic resolution, availability in the environment with will change across space and time, and you might not see certain things that were digested

The functional feeding group of collector gatherers eat what food source primarily?

Deposited fine particulate organic matter

The functional feeding group of scrapers or grazers eat what food source primarily and what part of this food source are they addimilating most efficiently?

Epilithic algfae and biofilms and assimilating the associated bacterial and fungal communities more efficiently

The addition of predator into a stream food web can sometimes affect other parts of the community and food web. What components can top predators impact, how do they impact these other parts, and what is this called?

Top predators can incrase primary producers by diminishing the abundance or effects of primary consumers via trophic cascade

In a conventional food web, what is the direction of the arrow indicating between nodes?

The direction of energy flow

In a quantitative food web what can arrow direction and size indicate?

The amount and direction of energy flow

What happens when leaves fall into streams that make them nutritious for animal consumers?

Leave are covered in microbial bacterial and fungal communities

Heterotroph

The formation of heterotrophic biomass through time

Which of the following is an example of a keystone spcies and why?

Beaver because it builds dams that create habitats for a multitude of other species

Identify a stream ecologist that we have covered in class and what they are known for

Bobbi Peckarsky- biotic interactions in streams and Mary Powere- stream food webs

What role do many invertebrates play in food webs?

Conduits of energy from lower trophic levels to higher levels

Identify the accurately described fate or fates of organic matter in streams from the list below:

Downstream transporation and deposition, transformation into other forms of organic matter including animal biomasss, mineralization into inorganic compounds

What term best describes organic matter originating from outside of the stream channel?

Allochthonous

What term describes organic matter originating from inside of the stream channel?

Autochthonous

Select the option below that best describes the peanut butter cracker analogy of leaves in streams

Leaves are unnutritious on their own but are colonized by more nutritioous bacteria and fungi serving as the peanut butter in this analogy

You are conucting a study and find that different tree species have leaves with variable nutritional quality which you find relates to how quickly they are brocken down by insects in streams. Which broadeer stateent is supported by your work?

Riparian tree species assemblage affect decomposition rates within streams and nutritional quality of allochthonous material can determine decomposition in streams

Why and how do nutrients tend to affect rates of decompostion within streams?

Nutrients fuel the production and growth of bacteria and fungi which lead to increased breackdown of organic matter

What is the main difference between CPOM and FPOM and how do detritivorous insects sometimes play a role in connecting the two?

CPOM and FPOM are different sizes or organic matter and insects directly alter organic matter size in streams by eating it and egsting is as feces.

You conduct a broad study on the effects of scale on decompostion rates across a range in latitude from the Puerto Rico to Alaska. You expect to find that decomposition rates changed with temperature driven variation across latitiude. However, you fail to find support for this hypothesis. What might explain this surprising result?

Vegetation communitites change across this broad latitiudinal gradient, detritivorous insects are locally adapted to local temperatures thus variation in temperature across the study is not affecting within site patterns in decomposition, and insect communities change across these broad latitudinal gradients.

You are interested in measuring the contribution of insects to decompostion of leaves in streams and you want to account for the effects of microbial breakdown as well. To do so you place two different types of leaf bags in the streams. One type of bag has a very fine mesh wich excludes insects but allows microbes, and one bag has a coarser mesh wich allows for insects and microbes. How would you estimate the contribution of insects to litter mass loss in this design?

Litter mass loss attributable to insects will be the difference in the losses between the course and the fine mesh bags.

You hae hired as an ecologist by a secret government organization to explore life and ecosystems of other planets. As part of your mission, you land on the planet of Dagobah and find a lifeform. You determine that the predominant energy source for this lifeform is organic compounds the predominant carbon source of this life form is derived from organic compounds. How would you classify this organism?

Heterotroph

The total rate of organic matter production or oxygen produced by autotrophs at an ecosystem level can be summarized with wich term?

Gross Primary Production or GGP

Select the option that best describes how light and dark bottles or chambers can be used to estimate primary production

Light bottles containing primary producers represent Net Primary Production and dark bottles represent Ecosystem Respiration and you take the difference between the two

Fill in the end of this statement: When estimating primary production, you must to take into account that autotrophs BLANK

Respire and produce oxygen

In the light and dark bottle question what is actually being measured to determine production in the bottles or chambers?

dissolved oxygen

The ratio of production to respiration can provide a perspective on the energetics of an ecosystem where:

A production to respiration ratio greater than 1 indicates an autotrophic ecosystem and a production to respiration ratio less than 1 indicates a heterotrophic ecosystem

Law of conservation of mass

Using what Law can you base the movement of materials through and ecosystem

Fill in the two blanks from the options below: Headwater streams tend to have a BLANK Edge to Volume ratio which is thought to be correlated with a proportionally BLANK amount of imput fro the surrounding terrestrial landscape

High and High

Measuring primary production and other ecosystem processes is difficult in rivers because large amounts of biomass can be removed through flood disturbances. What assumption of ecosystem concept does this violate and how is this remedieed?

Steady state assumption is violated but overcome by accoounting for temporal variation

How do you measure sprialing length for organic carbon

Average distance traveled downstream by organic carbon before being respired as CO2

What nutrient comprises the majority of Earths atmosphere

Nitrogen

What law below concern the role of limiting nutrients and what does this law state?

Liebigs law of the minimum, growth is dictated not by total resources but thhe scarcest most limiting nutrient

Fill in the blank: Proteins, amino acids, and nucleic acids are examples of

nitrogen assimilation into organisms and organic nitrogen

Fill in the blank: The sum of nitrate, nitrite, and ammonium is referred to as

dissolved inorganic nitrogen

Why is the term nutrient spiraling used in the study of nutrient cycles within streams?

Nutrients cycle as they move downstream

Historically rivers were thought of more as pipes in terms of nutrient cycling. Pick the answer that best articulates this false view of rivers and nutrients

Rivers receive and transport nutrients from terrestrial landscapes

Nitrogen Fixation

The bacterial assimilation of atmospheric nitrogen

Ammonification

Microbially mediated decompostition of dead organic matter into inorganic nitrogen

Excretion is an important component of the nitrogen cycle. What components of the stream ecosystem are responsible for excretion of nitrogen and what form is it often in?

Organisms are responsible for excretion in the form of ammonium

Why does excretion occur?

When more N than needed is ingested the rest must be excreted to maintain elemental balance

Indentify the dominant form of inorganic phosphorus

phosphate