Micro 350-Ecosystems/Ecology

From the aquatic systems below, where are heterotrophic Bacteria the most abundant?

Marine coastal waters

The physiochemical conditions of a microenvironment, by definition, remain static.

false

Upwelling increases ________________ which can result in red tides (algae blooms).

nutrient availability

________ are the main primary producers in freshwater environments.

phototrophic microorganisms

Ecological theory states that for every organism there is at LEAST one ________, and the microenvironment where the organism is most successful is called the ________.

niche / prime niche

Limiting nutrients in soils are generally organic compounds.

False

Ocean acidification decreases the precipitation of calcium carbonate and thus will probably affect the cycling of Ca and other nutrients in the ocean.

False

The Calvin cycle provides autotrophs the ability to convert inorganic carbon into biomass and generate energy during this process.

False

Human activities have disrupted the carbon cycle by

burning carbon stored as fossil fuels or biomass, thus increasing the amount of carbon dioxide in the atmosphere.

The calcium cycle is tightly coupled to the

carbon cycle through calcium carbonate formation in ocean waters.

________ use inorganic electron donors released from deep-sea hydrothermal vents.

chemolithotrophs

Sudden nutrient perturbations in an environment initially ________ the overall prokaryotic diversity.

decrease

The ocean has mitigated the impact of anthropogenic carbon dioxide production by

absorbing 500 billion tons of atmospheric carbon dioxide and over 80% of the trapped heat energy.

According to bacterial abundance studies done so far on soils, the ________ represent the most abundant phylum.

Proteobacteria

Which of the following processes does denitrification contribute to?

acid rain, ozone depletion, and global warming

Nitrogen fixation results in the

addition of biologically available N to an ecosystem.

Anammox is an anaerobic process that generates energy from ________ and forms N2.

ammonia and nitrite

The metabolic process of denitrification

reduces NO3-

What is the largest carbon reservoir on Earth?

rocks and sediments

The generation time of Escherichia coli in the human intestine is ________ in laboratory culture.

slower than

The number of Roseobacter in the ocean describes

species abundance

Some nitrifying prokaryotes carry out metabolic cooperation by a process known as

syntrophy

One important difference between the C, N, and S cycles and the P, Ca, and Si cycles is that

the P, Ca, and Si cycles do NOT involve gaseous forms that can alter Earthʹs atmospheric chemistry.

In the soil, oxygen concentrations are highly variable even within a soil particle. The center of the particle may be anoxic even if the outer portions are oxygen-rich. In this context, facultative anaerobes could be found

throughout the particle

The largest reservoir of methane is found

trapped in volcanic rocks in tropical environments around the world.

Arid soils are among the most extreme environments on earth.

true

Many microbial habitats are unsuitable for plants and animals.

true

Alternative autotrophic routes to the Calvin cycle such as the reverse citric acid cycle and the hydroxypropionate pathway are unified in their requirement for

CO2

What is the major reservoir of stable nitrogen?

N2

How does the concentration of prokaryotic cells at the surface of pelagic water compare with the concentrations at depths below 1000 m?

There is a decrease in concentration with increasing depths

In the natural carbon cycle, carbon dioxide is returned to the atmosphere by the respiration of animals and chemoorganotrophic microorganisms.

True

More carbon is present in dead organic material on Earth than in living organisms.

True

The addition of excess nutrients in aquatic habitats can result in

eutrophication

Carbon dioxide is the only greenhouse gas produced by anthropogenic activities.

false

Chemoheterotrophic bacteria are primary producers.

false

Functional differences can be observed by using 16S rRNA gene phylogenetics of a microbial community.

false

A population of metabolically related microorganisms is called a(n)

guild

Agricultural application of nitrogen fertilizer

increases global warming by increasing the production of nitrous oxide (N2O) by denitrification in agricultural soils.

Human interactions with the environment are

increasing the rate of infectious disease

Epsilonproteobacteria are most dominant in hydrothermal vents because they

oxidize sulfur as electron donors

Microenvironments of soil exist where ________ concentrations greatly vary.

oxygen, nitrate, and sulfur

Which organisms form the foundation of the carbon cycle?

phototrophs

Which of the following represents increasing microbial diversity? population-guild-community community-guild-population cell-community-population guild-community-population

population-guild-community

Nitrous oxide (N2O) is a

potent greenhouse gas that is a product of denitrification.

Two major environmental extremes of the deep sea are high ________ and low ________.

pressure/nutrient levels

The metabolic process of ammonification ________ ammonia.

produces