Earth Science Part 3 MSL Study Guide
How is water an energy agent (currents and heat transfer)?
The biggest influence on the coastal system is solar energy, which differentially heats the earth’s atmosphere, ocean,
and land surfaces. Differential heating drives the great heat pump operating between the air, sea, and land and
produces storms and winds that result in wind tides, waves, and currents. Solar energy heats the water’s surface and
then converts liquid water into water vapor that enters the atmosphere. As the vapor cools, heat is released into the
atmosphere, and the vapor forms droplets that gravity then pulls back to the earth as rain; it can then repeat the
process. The process of heat absorption by water in one area and heat release by vapor miles away regulates the
temperature of our atmosphere. Water falls as precipitation to the earth’s surface under the influence of gravity.
What happens to it next? Energy transfers occur throughout the water cycle. Shorelines are affected when the work
of wind and waves moves sediment from one place to another — eroding some, building others, but always moving
sediment.
How do ground water and surface water interact? Nearly all surface-water features (streams, lakes, reservoirs,
wetlands, and estuaries) interact with ground water. These interactions take many forms. In many situations, surfacewater bodies gain water and solutes from ground-water systems and in others the surface-water body is a source of
ground-water recharge and causes changes in ground-water quality. As a result, withdrawal of water from streams
can deplete ground water or conversely, pumpage of ground water can deplete water in streams, lakes, or wetlands.
Pollution of surface water can cause degradation of ground-water quality and conversely pollution of ground water
can degrade surface water. Thus, effective land and water management requires a clear understanding of the
linkages between ground water and surface water as it applies to any given hydrologic setting.
How is the density of ocean water affected by temperature? How does this result in major ocean currents
distributing heat away from the equator toward the poles?
Temperature and density share an inverse relationship so when the surface currents (i.e. the Gulf Stream) flow
towards the poles from the equatorial Atlantic Ocean, they are cooled and flow downhill into deep water basins
forming the North Atlantic Deep Water. These currents resurface in the northeast Pacific Ocean 1,200 years later.
Ocean water from all of the ocean basins mixes thoroughly, carrying heat energy and matter in the form of solids
and gases, making Earth's ocean a global system. The state of this thermohaline circulation, sometimes called the
global conveyor belt, can have an enormous impact on the climate of our planet.
The difference in density of cold water versus density of warmer water is responsible for ocean currents and
upwelling. Warm seawater floats and cold (4°C), dense (1 g/cm3), seawater sinks. Ocean temperatures also
vary across the surface and into the depths. The highest salinity possible (saturation) for seawater is 35 ppt and
at 4°C the salinity causes the density to actually be 1.0278 g/cm3. This slightly heavier density is another
contributing factor to upwelling as it causes the water molecules to roll over each other.
How are coastal climates moderated by water (due to its high specific heat capacity) compared to inland
climates?
Liquid water at the surface plays a significant role in climate moderation. Water takes much longer than air to heat
up, and also longer to cool, because it has much higher specific heat (its ability to conduct heat or cold compared to
dry air). On hot days, water absorbs heat, keeping the air somewhat cooler. When the air gets cool, however, water
slowly releases heat to the atmosphere, raising air temperatures. This is why temperatures along coastlines are cooler
in summer and warmer in winter relative to inland areas . Temperatures vary more the farther inland you travel.
There is some moderation of climate because condensation is an exothermic process, and warms the atmosphere,
particularly in wet coastal areas (i.e., downwind from the ocean).
What is a river basins?
A river basin is the portion of land drained by a river and its tributaries (streams that flows into a larger stream or
other body of water). It encompasses all of the land surface drained by many streams and creeks that flow downhill
into one another, and eventually into one river. The final destination is an estuary or an ocean. Just like a bathtub
catches all the water that falls within its sides, a river basin sends all the water falling on the surrounding land into a
central river and out to the sea. Everyone lives in a river basin. Even if we don't live near the water, we live on land
that drains to a river or estuary or lake, and our actions on that land affect water quality and quantity far
downstream.
Just like an artery connects the parts of a body to one another, a river threads together the creeks and streams,
valleys and hills, lakes and underground springs that share a common assembly of water. Whatever happens to
surface or groundwater in one part of the river basin will find its way to other parts. A river basin meets the
definition of an ecosystem, in which all things are connected and interdependent.
What is the difference between a river basin and a watershed?
Both river basins and watersheds are areas of land that drain to a particular water body, such as a lake, stream, river
or estuary. In a river basin, all the water drains to a large river. The term watershed is used to describe a smaller area
of land that drains to a smaller stream, lake or wetland. There are many smaller watersheds within a river basin.
The Office of EE, in partnership with other DENR divisions including the Division of Water Quality and the
Wildlife Resources Commission, has created informative river basin education materials.
What is an aquifer? An aquifer is an underground layer of water-bearing rock. Water-bearing rocks are permeable,
meaning that they have openings that liquids and gases can pass through.
How do flood events affect groundwater? Groundwater flooding is a result of geological, hydrogeological,
topographic and recharge phenomena. Groundwater flooding occurs as a result of water rising up from the
underlying rocks or from water flowing from abnormal springs. This tends to occur after much longer periods of
sustained high rainfall. Higher rainfall means more water will infiltrate into the ground and cause the water table to
rise above normal levels. Groundwater tends to flow from areas where the ground level is high, to areas where the
ground level is low. In low-lying areas the water table is usually at shallower depths anyway, but during very wet
periods, with all the additional groundwater flowing towards these areas, the water table can rise up to the surface
causing groundwater flooding.
Groundwater flooding is most likely to occur in low-lying areas underlain by permeable rocks (aquifers). These may
be extensive, regional aquifers, such as Chalk or sandstone, or may be localized sands or river gravels in valley
bottoms underlain by less permeable rocks. Groundwater flooding takes longer to dissipate because groundwater
moves much more slowly than surface water and will take time to flow away underground.
Water Vocabulary
Aquifer - A permeable geological layer or formation that is capable of storing and transmitting water in significant
amounts
Groundwater- the water contained within an aquifer
Water Table - The natural level of underground water
Porosity - The volume of pore space available in a rock
Permeability - The ability of a porous material to transmit fluid
Artesian Well - Water that naturally flows due to the pressure of the ground pushing on the aquifer from above