Ch. 21 LC

To study the impact of heavy.... Which measurement do you erect will be LOWER in the logged site than the reference site? Surface runoff soil erosion groundwater elevation soil moisture nutrient levels in runoff

groundwater elevation

Which play(s) a particularly important role in the breakdown of coarse woody detritus? scavengers fungi nutrient leaching denitrifying bacteria large detritivores

fungi

In anaerobic sediments of some wetlands, archaea use _____ for respiration. nitrate oxygen ethanol methanol octanol

methanol

Which is the process by which decomposers and detritivores break down organic nitrogen compounds into ammonia? denitrification nitrification assimilation nitrogen fixation mineralization

mineralization

As nitric oxide (NO) enters the atmosphere from combustion, it reacts with water in the air to form _____, which then falls to the ground during precipitation events. ammonia (NH3) ammonium (NH4+) nitrous oxide (N2O) nitrite (NO2-) nitrate (NO3-)

nitrate (NO3-)

In which phase of the nitrogen cycle do bacteria convert ammonium into nitrite and then into nitrate? nitrogen fixation assimilation denitrification nitrification mineralization

nitrification

You are studying nitrogen cycling in the anaerobic sediments of a deep lake. In evaluating the bacterial community, you measure a very high abundance of Psuedomonas denitrificans. You also measure the relative abundance of nitrogen species and detect 10 percent nitrate, 30 percent nitrite, and 60 percent nitric oxide. Based on this information, what end product will be formed in the reaction taking place? nitrate nitrite nitrogen gas nitric oxide ammonium

nitrogen gas

Nitrogen fixation converts _____. nitrite to nitrate nitrogen gas to ammonium ammonium to nitrate ammonia to nitrogen gas nitrogen gas to amino acids

nitrogen gas to ammonium

Fossil fuels such as oil, gas, and coal are formed over millions of years from _____. fully decomposed organic matter that is buried below the surface of Earth fully decomposed organic matter on the surface of Earth organic matter that is buried before it fully decomposes inorganic carbon contained in limestone rock inorganic carbon released during volcanic eruptions

organic matter that is buried before it fully decomposes

To help reduce the problems of cultural eutrophication and dead zones in aquatic ecosystems, in 1994, the United States banned the use of _____ in laundry detergents. sulfates ammonia phosphates nitrites nitrates

phosphates

Which is NOT a source of nitrogen fixation? precipitation cyanobacteria lightning combustion fertilizer production

precipitation

An area of land that drains into a single stream or river is called a(n) _____. watershed groundwater table bedrock aquifer estuary

watershed

You are calculating a predicted decomposition rate of a single leaf species in a tropical rainforest before you perform an experiment to measure the actual rate. You know that the leaf species has a decay rate constant of 0.023. You also know that you will place a leaf bag containing 48 g of leaf biomass in a mesh bag and come back and measure it after 100 days. Your advisor checks over your math and points out that you have not considered that your decay rate constant was determined in the absence of detritivores, which will have access to your leaf bags. The presence of detritivores generally increases the leaf decay constant by 20 percent. What leaf biomass would you now predict to be present in your bag after 100 days, taking into account the activity of the detritivores? 7.62 g 4.81 g 3.04 g 5.12 g 1.13 g

3.04 g

The concentration of CO2 in Earth's atmosphere is approximately _____ higher than the next highest measured concentration over the past 400,000 years. 24 percent 15 percent 35 percent 47 percent 6 percent

35 percent

You are examining decomposition of corn leaves following the growing season on a farm. To do this, you place 33 g of corn leaves in a mesh bag and measure decomposition over time. In a literature search, you find that the decay constant of corn leaves is typically 0.04. Given this, use the equation mt =moe-kt to predict the leaf mass remaining in the bag after 30 days. 9.94 g 14.8 g 0.009 g 23.3 g 1.7 g

9.94 g

Approximately what portion of plant matter produced in terrestrial ecosystems in a given year is not eaten by consumers? 50 percent 30 percent 90 percent 75 percent 10 percent

90 percent

Producers use photosynthesis in terrestrial and aquatic ecosystems to take _____ from the air and water and convert it to carbohydrates. The carbohydrates are used by consumers, scavengers, detritivores, and decomposers that release _____ into the air or water. O2; CO2 CO2; CO2 CO2; O2 O2; O2

CO2; CO2

Which technique might a restoration ecologist employ to reduce the amount of runoff entering a stream in a watershed? Increase impermeable surface cover to prevent more rainwater from entering the soil. Reduce terrestrial vegetation to promote rainwater infiltration through the soil. Fill in headwater stream channels with soil to make a flatter landscape in the watershed. Build drainage wetlands to collect water and facilitate soil infiltration. Increase cover of plant species with shallow roots to collect more rainwater near the soil surface.

Build drainage wetlands to collect water and facilitate soil infiltration.

What are the three products of archaea's use of methanol instead of O during anaerobic respitation leaching and runoff CO2, H2O, CH4 H2O, CH4, HCO3- COH, CH4, co3^2-

CO2, H2O, CH4

_____ is an increase in the productivity of aquatic ecosystems caused by excess nitrogen and phosphorus originating from human activities. Social nutrification Eutrophication Cultural eutrophication Nitrophosphatization Nutrification

Cultural eutrophication

True or false? Nitrogen inputs into terrestrial ecosystems primarily come from weathering of bedrock beneath the soil. True False

False

True or false? Peat decomposes more readily with cooler temperatures, so global warming has inhibited the ability of peat to break down. True False

False

Which statement regarding greenhouse gases is TRUE? The concentration of CO2, a major greenhouse gas in the atmosphere... .... Greenhouse gases in the atmosphere help keep our plant warm, but an excessive amount will cause our planet to become much warmer than it has been for a very long time.

Greenhouse gases in the atmosphere help keep our plant warm, but an excessive amount will cause our planet to become much warmer than it has been for a very long time.

Which statement is TRUE? In terrestrial and aquatic ecosystems, evaporation exceeds precipitation. In terrestrial ecosystems precipitation exceeds evaporation, but in aquatic ecosystems evaporation exceeds precipitation. In terrestrial and aquatic ecosystems, precipitation exceeds evaporation. In terrestrial and aquatic ecosystems, evaporation roughly equals precipitation. In terrestrial ecosystems evaporation exceeds precipitation, and in aquatic ecosystems precipitation exceeds evaporation.

In terrestrial ecosystems precipitation exceeds evaporation, but in aquatic ecosystems evaporation exceeds precipitation.

Which statement is TRUE? In terrestrial and aquatic ecosystems, precipitation exceeds evaporation. In terrestrial and aquatic ecosystems, evaporation exceeds precipitation. In terrestrial ecosystems evaporation exceeds precipitation, and in aquatic ecosystems precipitation exceeds evaporation. In terrestrial and aquatic ecosystems, evaporation roughly equals precipitation. In terrestrial ecosystems precipitation exceeds evaporation, but in aquatic ecosystems evaporation exceeds precipitation.

In terrestrial ecosystems precipitation exceeds evaporation, but in aquatic ecosystems evaporation exceeds precipitation.

After atmospheric CO2 diffuses into aquatic ecosystems and dissolves into solution, which process will directly occur? It will be buried in sediments and become fossil fuels. It will be broken down by decomposers. It will transform into CaCO3- and sink to form rock. It will be mineralized by bacteria into a biologically usable form. It will be transformed into methane and water.

It will transform into CaCO3- and sink to form rock.

Which equation describes nitrification? NO → NO2- → NO3- NH4+ → NO2- → NO3- NH4+ → NO3- → NO2- NO → N2O → N2 N2 → N2O → NO

NH4+ → NO2- → NO3-

Which equation describes denitrification? NO → NO2- →3- → NH4+ NH4+ → NO2- → NO3- NO3- → NO2- → NO → N2O → N2 N2 → N2O → NO → NO2- → NO3- NH4+ → NO3- → NO2- → NO → N2

NO3- → NO2- → NO → N2O → N2

Which of the following bacterial species would you most likely find in newly formed soils where nitrification has just begun (where NH4+ is just starting to be converted to NO2-)? Azobacter Nitrosomonas Nitrobacter Psuedomonas denitrificans Rhizobium

Nitrosomonas

The extraction of water from the _____ aquifer, the largest source of groundwater in the United States, has exceeded its rate of replenishment and could run out sometime during this century. Mahomet Edwards Floridan Ogallala Snake River

Ogallala

you perform an experiment... 3 mg C/g... 4:!.... 15 mg C/g... 8 mg C/g.... 1:1... 1 mg C/g..... Species C, Species D Species B, Species C Species D, Species A Species C, Species B Species A, Species C

Species B, Species C

True or false? Global warming has caused some regions of the world to become warmer than they were a century ago, while other regions of the world have become cooler. False True

True

True or false? Stratification of water does not occur in polar lakes. False True

True

True or false? Tropical forests have a much larger proportion of the total organic matter in living vegetation than in detritus. True False

True

You travel to a distant planet that is similar to Earth in every way except that the carbon cycle is reversed from the cycle on Earth. Which scenario would you expect to observe on this distant planet? Consumers would contribute CO2 to the atmosphere. Buried organic materials would become fossil fuels. Weathering of underwater rocks would release dissolved CO2. Aquatic producers would take up dissolved CO2 from the water. The ocean would contribute CO2 to the atmosphere.

Weathering of underwater rocks would release dissolved CO2.

Farmers use fertilizers containing high concentrations of inorganic nitrogen in the form of ammonium and nitrate. Which step in the nitrogen cycle are they facilitating? nitrification assimilation mineralization denitrification nitrogen fixation

assimilation

In aquatic ecosystems, nutrients that originate from terrestrial sources are called _____. allochthonous nutrients autochthonous nutrients recalcitrant nutrients cultural eutrophication point-source inputs

allochthonous nutrients

In which type of environment do bacteria turn nitrates (NO3-) into nitrogen gas (N2)? open water in aquatic habitats decomposing organic tissues consumer intestinal tracts anaerobic sediments soil containing a carbohydrate source

anaerobic sediments

In aquatic ecosystems, some dissolved CO2 undergoes chemical changes to form _____, which serves as a major component of dolomite and limestone rock. sodium carbonite iron carbonate pyrite calcium carbonate bicarbonate

calcium carbonate

Which of the following organisms, processes, or phenomena are responsible for nitrogen mineralization? decomposers primary producers sedimentation lightning combustion

decomposers

Which of the following is NOT a consequence of the rising mean temperature of Earth? decreased size of polar ice sheets altered timing of plant life histories decreased composition of peat altered length of growing seasons altered timing of animal life histories

decreased composition of peat

Which organisms play an important role in breaking down large organic matter into smaller particles with higher ratios of surface area to volume? Please choose the correct answer from the following choices, and then select the submit answer button. scavengers producers detritivores composters decomposers

detritivores

Which organisms play an important role in breaking down large organic matter into smaller particles with higher ratios of surface area to volume? decomposers producers scavengers composters detritivores

detritivores

Unlike the nitrogen cycle, the phosphorus cycle _____. is mainly restricted to terrestrial ecosystems does not contain a significant atmospheric component takes place primarily within living organisms has a fairly rapid turnover does not significantly rely on bacterial processes

does not contain a significant atmospheric component

On a global scale, the amount of evaporation is _____ to the amount of _____. equal to; transpiration equal to; precipitation more than; transpiration less than; precipitation more than; precipitation

equal to; precipitation

In an experiment in a heavily deforested watershed in North Carolina, you have one control watershed and one experimental watershed. Less than 20 percent of the land area in the control watershed contains trees, and it is drained by a single stream. You leave the control watershed alone as a reference. In the experimental watershed, you prevent further logging and plant trees until you have achieved 100 percent tree cover. The experimental watershed is drained by a different stream from that draining the control watershed. On average, what do you expect to observe over the long term in the experimental watershed compared with the control watershed? lower erosion rates on the land; higher water flow in the stream higher erosion rates on the land; lower nitrate concentrations in the stream higher nitrate concentrations in terrestrial plants and soil; lower water flow in the stream lower nitrate concentrations in terrestrial plants and soil; higher nitrate levels in the stream higher erosion rates on the land; lower water flow in the stream

higher nitrate concentrations in terrestrial plants and soil; lower water flow in the stream

Evaporation, transpiration, and precipitation are all part of the _____ cycle. hydrologic nitrogen Krebs Calvin carbon

hydrologic

In terrestrial ecosystems, the large manufacture and spread of nitrogen and phosphorus into the environment by human activities often leads to _____. increased producer productivity and species diversity reduced producer productivity and species diversity reduced producer productivity and increased species diversity increased producer productivity and reduced species diversity

increased producer productivity and reduced species diversity

You are performing an experiment to compare the decomposition rate of a single slowly decaying leaf species in two unproductive bogs (A and B) over the course of a year. You gather up exactly 180 g of leaf litter and head out to the bogs. At bog A, you submerge one mesh bag containing 90 g of leaf litter. At bog B, 13 g of your leaves spill and get blown away by the wind. You put the remaining leaves into a mesh bag and submerge them in bog B. After exactly a year, you return to collect your leaf bags. You dry and weigh the leaf biomass remaining in each bag, and you find that you have 75 g of biomass in the bag from bog A and 61 g of mass from bog B. Using the equation mt = moe-kt, what are the per year decay rate constants (i.e., k) in bog A and B, respectively? kbogA = 0.18; kbogB = 0.23 kbogA = 0.34; kbogB = 0.11 kbogA = 0.11; kbogB = 0.23 kbogA = 0.11; kbogB = 0.34 kbogA = 0.23; kbogB = 0.18

kbogA = 0.18; kbogB = 0.23

Which is a major cause of nutrient loss from most terrestrial ecosystems? weathering of rocks leaching and runoff death of plants and animals transport via evaporating water transformation into unusable forms by bacteria

leaching and runoff

Which of the following compounds would NOT leach out of decaying leaves that fall into a small forested wetland? salts lignin dissolved organic carbon sugars amino acids

lignin

The original source of most nutrients in ecosystems is _____. precipitation rock weathering bacterial fixation volcanic activity the atmosphere

rock weathering

The original source of most nutrients in ecosystems is _____. precipitation volcanic activity rock weathering bacterial fixation the atmosphere

rock weathering

The primary natural source of phosphate (PO43-) in the phosphorus cycle is _____ the atmosphere fertilizer production volcanic rock acid rain sedimentary rock

sedimentary rock

The primary natural source of phosphate (PO43-) in the phosphorus cycle is _____. acid rain sedimentary rock fertilizer production volcanic rock the atmosphere

sedimentary rock

What provides the energy for evaporation and evapotranspiration? sugars hydrostatic pressure nutrients solar irradiance water vapor

solar irradiance

Impervious surfaces increase _____. surface runoff groundwater infiltration soil stability precipitation evapotranspiration

surface runoff

Which type of ecosystem has the LOWEST ratio of decaying to living organic matter? peat bogs tundra temperate forests tropical forests grasslands

tropical forests

True or false? Human activities cause most aquatic ecosystem dead zones, although some dead zones have natural causes. false true

true

True or false? On a per-molecule basis, methane is much more effective at absorbing and radiating infrared radiation back to Earth than CO2. False True

true

Which of the following releases large amounts of carbon into the atmosphere? volcanic eruption lighting storms ocean baches

volcanic eruption

Which of the following releases large amounts of carbon into the atmosphere lightning strikes calcium carbonate formation in the ocean earthquakes volcanic eruptions floods

volcanic eruptions