UARK Earth Science Exam 2 Study Guide (Stahle)

The ____ ____ aka Hoplostethus atlanticus fish, is at the depth of 750-1200m, red and blue and turns orange on catch. Weighs 1 kg, the record is 3.2 kg's. Longevity: 100 - 150 years (before industrial revolution!)

Orange Roughy

The Orange Roughy has a mercury content of ___-___ (vs. 0.08 for most fish).

0.30-0.86 ppm

The status of the Orange Roughy fish are ____ and ____ ("no such thing as a sustainable deep-water fishery" MSC).

Overfished and threatened

____ ____ warm eyed predators of the cold sea,

hunt in cooperative parabolic formations with 15 individuals.

Bluefin Tuna

The Bluefin Tuna are being driven to extinction by _____

overexploitation

Bluefin Tuna are known as our modern "____ __ __ ____"

buffalo of the sea

North Atlantic table fish

- From 1850-1960 the amount of fish that was caught gradually increased from 100,000 tons to 300,000 tons through the 100 or so years

- From 1960-1970 there was a huge spike in the amount of fish that was caught (800,000 tons)

- From 1970-1980 there was a major decrease in the amount of fish caught (800,000 tons to about 150,000 tons)

- From 1992 to about 1997 zero tons of fish were caught. From 1997 to 2002 about 10,000 tons were caught.

Global primary productivity

The rate of biomass production by photosynthesis.

Where is global primary productivity the highest and why?

In upwelling zones which is where rising waters rich in dissolved nutrients reach the surface ocean

pollution, nutrient overload, fishing (demersal and pelagic), shipping, invasive species, climate change, ocean acidification, habitat modification, garbage accumulation in mid-ocean gyres, etc. are examples of..?

Human impacts on marine ecosystems

___% of global marine ecosystems have 'medium high' to 'very high' impact by human activities.

41%

Where are our largest impacts on marine ecosystems globally?

The North Sea, Norwegian Sea, East China Sea, The Gulf of Thailand

The ____ ____ is 3-dimensional closed system (no water enters or leaves the system it's all the same water) - balance between pools and fluxes - mostly characterized by residence times

Hydrologic Cycle

A pool in the hydrologic cycle is a ____

Reservoir

The flux of the hydrologic cycle refers to the ?

inflow and outflow of the water

What are the largest fluxes of water movement on this planet?

From the ocean to the atmosphere, through evaporation and precipitation.

In the map of global water vapor concentrations, the most global water vapor is located where? Why?

The highest amount of water vapor is along the equator because that is where the most evaporation takes place due to the heat of the sun

In the map of the precipitation averages around the globe, the most precipitation occurs where? Why?

The most precipitation occurs along the equator because that is where most water evaporation takes place, which is the reason for heavy rainfall

The present drainage of the ____ river is 11 million years old

Amazon river

The Ancestral River flowed ____ off Africa

West

The Andean orogeny of the Amazon blocked the ____ outlet

Western

The Amazon created massive ____ ____ in western Basin

freshwater lake

The Amazon spilled & cut north to the ____ Sea via the Orinoco

Caribbean

The Amazon eventually cut through the Guianan & Guaporé Shields to reach the ____ Sea.

Atlantic

Did the Amazon river always flow west-to-east?

No, it used to flow east-to-west eons ago, due to the Purus Arch that divided the Amazon's flow, sending one side of the river eastward toward the Atlantic Ocean and the other side westward toward the still-growing Andes Mountains.

The freshwater plume of the Amazon River sends the most amount of freshwater discharge into the Atlantic Ocean; its discharge is ___% of freshwater supply to global oceans

~17%

The freshwater plume of the Amazon River is important because?

They have a significant effect on water salinity, pollution, carbon and nutrient levels, and sea surface temperature. Which has an overall effect of the marine ecosystem

An area drained by a single river, includes the main river and its tributaries

Drainage Basin

Types of rivers are:

The classic dendritic drainage system, Trellis drainage, and radial drainage

Dendritic drainage system

Trellis drainage

Streams moving through areas of hard and soft rock

Radial drainage

The stream types based on seasonal water flow:

Perennial, Periodic, and Episodic

Type of stream that has continuous flow in parts of its stream bed all year round during years of normal rainfall.

Perennial Stream

Type of stream that flows during certain times of the year when smaller upstream waters are flowing and when surface water provides enough water for stream flow.

Periodic stream

(picture is true if the stream experiences rainfall)

Type of stream that occurs in in drylands landscapes after heavy rainfall, transports many sediments and debris

Episodic stream

Names of the greatest floods in history?

Zanclean flood and Noah's flood

What flood?

When the Atlantic Ocean breached the sill at the Strait of Gibraltar and poured into the great Mediterranean depression, 5 MILLION YEARS AGO.

Zanclean flood

What flood?

Flood that happened 7,600 YEARS AGO when the sill at the Bosporus Strait (at Istanbul, Turkey) was breached by rising sea level following the end of the Ice Age.

Noah's flood

____ can act as natural dams holding water back.

Glaciers

A glacial ____ is the result of glaciers melting into a valley and it being filled with glacial water

lake

When glaciers rapidly melt, it can result in a release of that held-back water, causing dangerous ____.

floods

The glacial dam that holds back the water breaks, creating some of the most ____ floods on the planet

destructive

Many landscapes are scabbed and scarred due to glacier ____ ____.

outburst floods

Ice dam fails at Glacial Lake _____, Montana

Missoula

The ice dam failed at Glacial Lake Missoula in Montana ____ years ago

12,000

Lake _____ was 2000' deep, 500 miles^3 of water (half the size of Lake Michigan)

Lake Missoula

At lake Missoula the ice dam bursts and floods at rate of the combined flow of all ____ on earth

rivers

Stupendous flood, from Glacial Lake Missoula, scours the Columbia River basin and creates the ____ ____

Channeled Scablands

The melting of the Laurentide ice sheet because of warming temperatures during the last ice age created ____ lakes

proglacial

____ lakes are massive lakes that formed on the outer edges of the ice sheets

proglacial

With the rapid retreat of the ____ ____, these lakes flooded frequently (in some cases flooding half of North America).

ice sheets

When the three major lakes, ____, ____ and ____ flooded, they carved out potential channels that are used by major rivers today (including the Mississippi!).

Agassiz, McConnell, and Ojibway

Retreating glaciers also acted to flood glacial water northward into ____ Bay and the ____ Ocean

Hudson Bay and the Arctic Ocean

Runoff is a function of what variables?

Precipitation, infiltration, interception, evaporation

rainfall or snowfall

precipitation

When water soaks into subsurface soils and moves into rocks through cracks and pore spaces.

infiltration

Process that refers to precipitation that does not reach the soil, and is blocked by the leaves, branches of plants and the forest floor.

interception

The process by which water changes from a liquid to a gas or vapor

evaporation

Urbanization would affect infiltration negatively due to the lack of ____. Concrete, asphalt, building, etc. is not permeable.

soil

Urbanization would increase ____, which would increase the likelihood of flooding.

runoff

What are the 2 types of flooding?

Upland and Lowland flooding

____ flooding develops rapidly given the drainage basin is typically smaller and that the land is at a higher elevation.

Upland

____ floods affect larger drainage basins. These floods are typically much longer in duration, sometimes lasting weeks.

Lowland

The relationship between a heavy precipitation event and subsequent peak in river discharge is the?

Lead-lag relationship

What can be predicted in the lead-lag relationship?

Flood timing, magnitude, and duration

What influences the lead-lag relationship? Which would have affects the flood timing, magnitude, and duration predictions?

- intensity and duration of the precipitation

- the size of drainage basin

- stream gradient

- vegetation cover

- human alteration of the land surface

Return time analysis

to calculate the flooding recurrence interval (R)

Equation for "return time" or "recurrence interval"

1. Identify largest flood each year (level or discharge)

2. Rank years by flood magnitude [large (#1) to small]

3. Calculate R (return time):

R = (n + 1) / m

R = (n + 1) / m

What do the letters stand for?

R = return time (in years) for a particular flood magnitude

n = number of years of runoff data

m = the rank order of each flood (magnitude)

The calculations for a ____ ____ analysis of a river gives us the estimated time in years when the same magnitude flood will happen again as it did in the past

return time analysis

Return time analysis is ____ accurate

NOT

Why is return time analysis not accurate?

- short flood records

- it's purely statistical

- human modifications

What is the purpose of dams? What are the good impacts of dams?

- Water supply and storage

- Navigation Hydroelectricity

- Flood control

- Irrigation for agriculture

What are the negative impacts of dams?

- Alteration of flow (often slower) sediment, nutrients, and even freshwater species can no longer move downstream.

- unpredictability of flooding downstream (flood pulses are disrupted)

- important habitat is often lost, species diversity declines

The process of dredging or straightening of a stream

River channelization

Why do we channelize streams? What are the good impacts of channelization?

- Easier navigation

- Reduces flood risk - maybe?

- Allows for development on floodplain

- Erosion control

What are the negative effects of channelization?

- Riparian reduction from channelization increases runoff

- Decrease in riparian vegetation

- Channelized stream increases velocity

- Species reduction in streams and increased flooding downstream of channelized region

Structures that are built alongside streams to increase stage height

Artificial levees

What are the positive impacts of artificial levees?

- Reduce FREQUENCY of flooding

- Allow for development along the floodplain

If a river system has been channelized and artificial levees have been built along its banks, what can happen to the river system?

Too much water can enter the levied and channelized portion of the river and cause extreme flooding which can be very destructive. The amount of money spent on urbanization, that would be destroyed by the flooding, would cost more than to channelize rivers and build levees

To increase the elevation of a stream gage's flood stage with levee systems. This would cause more damage when the elevated stream floods due to the water level already being higher than the floodplain. The flooding water gains more velocity when traveling downward toward the floodplains

Stream channel aggradation VS. avulsion

(Geomorphology of Old River) 1st

The Red River and Mississippi River were parallel rivers each flowing south to the Gulf of Mexico during the ____ ____

Prior millenium

(Geomorphology of Old River) 2nd

Westwardly meander belt of the Mississippi intercepts the Red. The upper Red becomes a tributary, the lower Red becomes a distributary, named the ____ during the 15th century.

Atchafalaya

(Geomorphology of Old River) 3rd

____ cuts off Turnbull's bend in 1831

Shreve's cut

(Geomorphology of Old River) 4th

Upper Old River channel gets abandoned, ____ ____ River links the three rivers, log jam in Atchafalaya is removed. Atchafalaya becomes deeper and wider carrying more and more Mississippi flow in 1950

Lower Old River

(Geomorphology of Old River) 5th

New Orleans District completes construction of Overbank Structure and Low Sill structure in ___. Completes Navigation Lock and Old River Closure in ___.

1964 and 1963

(Geomorphology of Old River) 6th

Auxiliary structure completed in ___. Hydropower plant completed in ___.

1986 and 1990

What would happen if Mississippi floods into the Atchafalaya?

There would be a saltwater intrusion and drinking water crisis. This would effect ~2 million people

____ leads to increased channel aggradation and/or degradation and bank erosion

Deforestation

____ often leads to higher stream flow variability

Urbanization

More water enters streams in shorter periods of time

(because of surface conditions). Which will increase ____ ____.

erosion rates

Urban development can result in ____ to stream habitat either directly, such as from modifications to channel and riparian areas, or indirectly, such as from higher streamflows that reshape the channel

alterations

Deforestation in the Amazon has taken place near Manaus and more populated areas. This land is being replaced with grass and ____ land.

Agricultural

What have been the effects of stream flow hydrology after the deforestation in the Amazon?

There has been an increase in stream flow velocity and drought.

The American River basin abruptly rises above Sacramento underlain by crystalline bedrock, creating a hazardous setup for catastrophic flooding from atmospheric rivers.

Reason why Sacramento is a flood prone city

River flood magnitudes have ____ in the southwest

Decreased

River flood magnitudes have ____ in the Eastern Great Plains, parts of the Midwest, and from the Northern Appalachians into New England

Increased

Lowlands with shallow and sometimes intermittent water. They form a gradient between permanently dry uplands and always-wet open water systems. They are often recognized by surface water, unique soil conditions, and specialized vegetation cover.

Wetlands

Wetlands clean water, prevent floods, recharge aquifers, protect shorelines, and provide vital habitat for marine and freshwater animals.

Functions of wetlands and why they are important