EVS test 2 Hydrosphere

Hydrosphere

All water on Earth — oceans, ice, groundwater, rivers, lakes, and atmosphere.

Stream discharge

Volume of water flowing past a point per time (m³/s); depends on stream speed and cross-sectional area.

stream load

Material carried by a stream: dissolved load, suspended load, and bed load.

water table

The upper surface of the zone of saturation

zone of aeration

Region above the water table where pores contain air and some water.

zone of saturation

Region where pores are completely filled with water.

porosity

The percentage of a rock’s volume that is open space.

permeability

The ability of a rock to transmit water through its pores.

aquifer

A permeable rock layer that stores and transmits groundwater

cryosphere

Frozen water on Earth — glaciers, ice caps, snow, sea ice, permafrost.

snow line

Lowest elevation where snow persists year-round; affected by temperature, latitude, and precipitation.

accumulation

Addition of snow/ice to a glacier.

ablation

loss of glacier ice through melting, sublimation, or calving.

mass balance

Net gain or loss of glacier ice; positive = glacier grows, negative = retreats.

salinity

The total dissolved salt content in water, usually measured in parts per thousand (‰).

thermohaline circulation

Deep-ocean circulation driven by density differences from temperature (thermo) and salinity (haline).

What happens to stream discharge after heavy rainfall?

It increases due to greater runoff feeding into streams.

How do oxbow lakes form?

A meander loop is cut off from the main river channel as sediment seals off its ends.

Why do deltas form at river mouths?

River velocity decreases, causing sediment to deposit.

What happens to the water table during drought?

It lowers as groundwater is used faster than recharge.

How do humans affect aquifers?

Overuse, pollution, and impermeable surfaces reduce recharge and contaminate water.

Which melting ice raises sea level — glaciers or sea ice?

glaciers and ice sheets; sea ice melting does not raise sea level (it’s already floating)

Why is ocean salinity higher in areas with more evaporation

Water leaves as vapor, but salts remain, concentrating salinity.

Why are deserts often near cold ocean currents?

Cold currents cool the air, reducing its ability to hold moisture → dry coastal climates.

What drives surface ocean currents?

Prevailing winds, modified by the Coriolis effect, forming gyres.

Direction of gyres:

Clockwise in Northern Hemisphere, counterclockwise in Southern Hemisphere.

When sea ice forms, what happens to salinity of nearby seawater?

When sea ice forms, what happens to salinity of nearby seawater?

Why does upwelling increase productivity?

It brings nutrient-rich deep water to the surface, supporting plankton growth.

How can melting of Greenland ice affect global circulation?

How can melting of Greenland ice affect global circulation?