Environmental science test 1

Environment

where an organism lives both biotic and abiotic stuff

decomposers

break down organic matter

trophic level

the level occupied in the food web

What two conditions for an ecosystem tend to have the most NPP?

warm and wet

What two conditions for an ecosystem tend to have the worst NPP?

cold and dry

Ecosystem productivity from high to low

tropical forests, temperate forests, scrublands, desert grasslands, tundra

What does primary productivity in the oceans?

Phytoplankton (microscopic algae)

Two factors that control productivity in the ocean

light and nutrients

Flux

the movement between sources and sinks

Three main reservoirs of carbon storage

atmosphere, land, and ocean

What are fossil fuels considered in the carbon cycle?

a 4th reservoir, but it is not cycled back

Where is the most carbon stored?

ocean sediments

Change in atmospheric CO2 during last century

It went from 280 to 400ppm

Why is the ocean/forests a net sink for carbon?

More CO2 enters it than leaves

Why is nitrogen needed?

An essential part of protein, DNA, RNA, and chlorophyll

What percent of the atmosphere is CO2?

0.035%

What percent of the atmosphere is nitrogen?

78%

What is the problem with nitrogen?

It is in the atmosphere, but not in a usable form

What is the first step of the nitrogen cycle?

Biological nitrogen fixation by microbes into ammonia (NH3)

What happens to ammonia (NH3) if in soil, hydrogen is added?

NH4+ ammonium ion, which can be absorbed by plants and enter the food chain

What happens to ammonia (NH3) if in soil, oxygen is added?

NO3 nitrate, which can be absorbed by plants and enter the food chain

Denitrification

bacteria converts nitrate (NO3) to atmospheric nitrogen (N2)

One way humans add nitrogen to the soil

fertilizer use

Population

a group of similar organisms in the same place at the same time

Community

a group of interacting populations in the same place at the same time

4 factors that influence population size

Resource availability, competition, Interspecific interactions, conditions of the environment

Density-dependent fluctuation

when a population size fluctuates in response to the density of another population; example:  predator/prey relationships

Density-independent fluctuation

when a population size fluctuates in response to something in the environment like climate or fire

Carrying capacity (K)/density-dependent equilibrium

the point at which there is a stable population (births = deaths)

Why does density-dependent equilibrium/carrying capacity (K) happen?

The resources in the environment can only support a certain number of individuals

Life history strategy

two different strategies for growing, surviving, reproducing

What are r-selected species?

devote a lot of time to reproduction and little to growth

Where do r-selected species live and why? 

They typically live in harsh environments where large pop sizes are an advantage

What are characteristics of r-selected species?

rapid development, early maturity, small body size, short life, early birth, large number of offspring, minimal parental care

Example of r-selected species

american toad

K-selected species

devote a lot of time to growth and little to reproduction

Where do k-selected species live and why?

They typically live in stable environments where survival is largely determined by competition for resources

What are characteristics for k-selected species?

slow development, delayed reproduction, large body size, long life, repeated reproduction, few offspring, good parental care

Example of a k-selected species

Bear

Energy flow

the flow of energy (calories) through an ecosystem begins with photosynthesis (PS)

Photosynthesis equation

6CO2 + 6H2O with solar energy = C6H12O6 + 6O2

What is the interface between atmosphere and biosphere?

Leaf

What does photosynthesis do to carbon?

transfers it from the atmosphere to the biosphere

What happens to the carbon from CO2?

gets incorporated into plant and animal tissue (biomass)

Cellular respiration equation

O2 + H2O+ C6H12O6 equals CO2 + H2O + energy

What is the byproduct of cellular respiration?

CO2

Gross Primary Production (GPP)

the total PS in the system

Net Primary Production (NPP)

PS-Respiration  (units are typically g of carbon/m²/year)

autotroph (primary producer)

the photosythesizers

heterotroph

consumer

herbivores (primary consumers)

plant eaters

Ecology

the study of the relationships of living things to one another and the environment

Commenalism

One species benefits, the other is not affected

Mutualism

Both species benefit

Source of Hudson River

Lake Tear of the Clouds on Mount Marcy (5344 feet elv) in the Adirondack Mountains

Mouth of Hudson River

The Battery (NY Harbor)

What happens at the Upper Hudson River?

The river flows down from Lake Tear of the Clouds and has lots of changes in elevation

What happens at the Lower Hudson River?

Starts at Federal Dam at Troy and has very little change in elevation

Estuaries

bodies of water where rivers meet the sea

Two things estuary waters are like

tidal and brackish (because of the mix of fresh and seawater)

Watershed

All the land that drains to a body of water

What contributes to the Hudson River?

Numerous small rivers

Four factor that affect climate

elevation, presence of mountains, latitude, and proximity to ocean

How does elevation affect climate?

lower pressure at higher altitudes causes lower temperature

How does latitude affect climate?

warmer at equator because solar energy is more intense at the equator and diminishes toward the poles, because of earth’s tilt and rotation

How does proximity to ocean affect climate?

less diurnal (daily) and seasonal temp variation due to moist air; and increased precip due to more moisture avail from nearby ocean = maritime

What does moist air do to climate and why?

Moist air gains and loses heat more slowly that dry air and therefore land near water has a more moderate climate

Specific heat capacity

the amount of heat per unit mass required to raise the temperature by one degree Celsius2

Water’s specific heat

4.18 J/g^oC (high)

Dry air’s specific heat

1 J/g^oC (high)

Water vapor/moist air’s specific heat

2 J/g^oC (high)

Which way does the Hudson River flow?

Both ways

Flood

ocean water flows up the river (N)

Ebb

ocean water flows back out to sea (S)

Slack

the point when the current is switching between flood and ebb

Knot

unit used to measure the speed of the current

How much is one knot?

1.15 miles

When do high tides occur?

at a given location when that location is lined up with the moon, because of Earth’s rotation

Why do low tides occur?

when the location is perpendicular to the moon, because of Earth’s rotation

Spring tides

Sun pulls parallel w/moon; higher than normal tides during full and new moons

Neap tides

Sun pulls perpendicular to moon; lower than normal tides during quarter moons

What is the Hudson’s salinity?

varies from about 2 to 20 g/L

Two things that control density of water

salinity and temp

Salt stratification/salt wedge

the saltwater would become the bottom layer, as it is more dense, and the freshwater would be the top layer

How does the Hudson stratify?

By salinity

thermal stratification

If cold water meets warm water, the cold water would be the bottom layer as it more dense

Salt front

the leading edge of the salt when the tide comes in and floods up the river (100 mg/L)

Range of DO in the Hudson

ranges from 8 – 14 mg/L

Percentage of oxygen in atmosphere

21%

Oxygen content of water in the Hudson is largely controlled by which two things

photosynthesis and respiration, and exchange with the atmospher

What were the old DO levels in the Hudson?

4 mg/L

What fixed the Hudson’s dissolved oxygen?

the Clean Water Act of 1972

Which water holds more oxygen and why?

Cold water, because warm water molecules are more active and push out gases

Three places DOM (dissolved organic matter) comes from

watershed soils, decomposition in the river, pollution

Three roles of DOM (dissolved organic matter)

food for bacteria, can support food chain, can carry/transport non-water soluble pollutants

Where does pollution to an estuary come from?

the water coming off the watershed also often brings with it all of the pollutants that were applied to the lands in the watershed (ex: pesticides)

The Clean Water Act (CWA)

establishes the basic structure for regulating discharges of pollutants into the waters of the United States, created sewage treatment plants, and regulating quality standards for surface waters

Point source

direct pollution sources (ex: pipes) (you cannot use this without a permit under the CWA)

Two standards set up the CWA

setting wastewater standards and water quality standards for all contaminants

What do estuaries do to water?

water flows through a salt marsh, marsh grasses and peat (a spongy matrix of live roots, decomposing organic material, and soil) filter pollutants