EMES 103 - Exam 1

Percentage of Earth’s area covered in water

~71%

Percentage of Earth’s water that is seawater

~97%

Average depth of the oceans

~3

Typical thickness of the atmosphere

~100 km

Two dominant gases in atmosphere

Nitrogen and Oxygen

Percentage of air that is nitrogen

~78%

Percentage of air that is oxygen

~21%

Percentage of atmosphere that is carbon dioxide

~0.04%

Present-day concentration of CO2

~420 ppm (parts per million)

CO2 concentration before industrial revolution

~280 ppm

Why and how are maps of Earth’s surface distorted

Because a 3D sphere is projected onto a 2D surface

Definition of latitude

Angular distance north or south of the equator

Definition of longitude

Angular distance east or west of the prime meridian

Kilometers in a degree of latitude

~111 km

Definition of contour map

Map showing lines of equal elevation/depth

Definition of vertical exaggeration

Stretching the vertical scale relative to the horizontal

Why vertical exaggeration is used

To make subtle depth/elevation changes visible in oceanography

Definition of scientific notation

Expressing numbers as a power of 10 times a coefficient between 1 and 10

How long ago Earth formed

~4.6 billion years ago

Conditions on early Earth

Hot

How long ago life appeared on Earth

~3.5–4 billion years ago

First life forms

Chemosynthetic

Role of photosynthetic organisms in atmosphere

Produced oxygen

Most recent ice age

~20

Temperature difference during ice age

~5°C cooler on average

Typical CO2 concentration during ice age

~180 ppm

How we know past atmospheric conditions

Ice cores showing trapped gas bubbles

Why studying the ocean is difficult

Humans can’t breathe underwater

How people overcome not breathing underwater

SCUBA

Ocean surface difficulties

High waves

Why we can’t see well in water

Light and EM radiation are absorbed/scattered quickly

How pressure varies

Pressure increases with depth in both atmosphere and ocean

Thickness of water equivalent to 1 atmosphere

~10 meters

What it means that ocean is corrosive

Seawater causes rusting and breakdown of materials

Definition of fouling

Organisms growing on submerged equipment

4 primary subdisciplines of oceanography

Biological,physical,chemical,geological

Most common way to measure bathymetry

Echo sounding (sonar)

Simple technique for collecting sediment

Grab sampler

Complicated technique for collecting sediment

Core sampling

Definition of water column

Vertical section of water from surface to seafloor

Definition of CTD

Conductivity

Why CTD used before sampling

To know water properties before collecting samples

Device used to collect water samples

Niskin bottles or rosette sampler

Why sampling ocean biology is difficult

Organisms are small

Why volume filtered matters in net tow

To calculate density/abundance of organisms

Similarity of submersible and ROV

Both allow underwater exploration

Difference between submersible and ROV

Submersible carries humans; ROV is tethered and unmanned

Difference between AUV and ROV

AUVs are untethered and autonomous

Definition of ARGO program

Global network of drifting floats measuring ocean temperature and salinity

Techniques to measure currents

Drifters

Principal layers of Earth

Crust (rigid)

Definition of lithosphere

Crust + upper rigid mantle

Definition of lithospheric plates

Fragments of lithosphere moving on asthenosphere

Two types of crust

Continental and oceanic

Thickness and density of continental crust

~35 km thick

Thickness and density of oceanic crust

~7 km thick

Definition of isostasy

Balance of crust floating on mantle depending on thickness/density

3 types of relative plate motion

Divergent,convergent,tranform

Typical features at divergent boundary

Mid-ocean ridges

Typical features at convergent boundary

Trenches

Typical features at transform boundary

Fracture zones

Definition of spreading cycles

Cycles of opening/closing oceans as plates move

Name of last supercontinent

Pangaea

When Pangaea existed

~200–250 million years ago

Definition of convection

Heat-driven circulation in mantle

Role of convection in plates

Drives plate motion

Definition of hot spots

Stationary mantle plumes creating volcanoes

Examples of hot spots

Hawaii

Definition of active margin

Plate boundary with tectonic activity (trenches

Definition of passive margin

Transition from continent to ocean with no boundary (Atlantic coast)

Sea level difference during last ice age

~120 meters lower

Definition of isostatic sea level change

Local change from crust rising/sinking

Definition of eustatic sea level change

Global change from ice volume or ocean volume shifts

Two types of bonds in molecules

Ionic and covalent

Stronger bond type

Covalent

Bond holding water together

Covalent bond

Meaning of polar molecule

Molecule with uneven charge distribution (positive and negative ends)

Two types of intermolecular bonds

Hydrogen bonds and van der Waals forces

Stronger intermolecular bond

Hydrogen bonds

Bond binding water molecules together

Hydrogen bonds

Definition of heat capacity

Energy required to change temperature

Definition of latent heat

Energy required to change state (fusion/vaporization)

Water’s heat capacity compared to other molecules

Higher than most

Importance of high heat capacity

Moderates Earth’s climate

Why water dissolves substances

Its polarity breaks apart ions/molecules

Major ions in seawater

Na+

How salinity is measured

CTD conductivity sensors

Approximate salinity of seawater

~35 ppt (parts per thousand)

Effect of temperature on gas solubility

Colder water holds more gas

Effect of pressure on seawater density

Increases density

Effect of salinity on seawater density

Increases density

Effect of temperature on seawater density

Decrease in temp increases density

Effect of salinity on freezing point

More salinity lowers freezing point

Colors transmitted best through water

Blue and green wavelengths

Effect of CO2 on seawater acidity

Increasing CO2 lowers pH (more acidic)

Basic classes of sediment grain size

Gravel

Smallest sediment size

Clay (

Definition of sorting

Range of grain sizes in a sample

Origin of lithogenous sediments

From rocks on land

Mechanisms transporting lithogenous sediment

Rivers