Download 8.E.1.1 NOTES

Understand the hydrosphere and the impact of humans on local systems
and the effects of the hydrosphere on humans.
WATER……..
1. Water is one of the most common substances on Earth, and is circulated on Earth by a process
known as the water cycle.
2. Water is known as the universal solvent because so many things will dissolve in it.
3. Most of the Earth’s water is found in the oceans (97%).
4. The majority of fresh water exists in ice caps, glaciers, and aquifers (77%).
5. Salinity refers to the amount of salt in a given substance. Ocean salinity is determined by the
amount of dissolved minerals from erosion from the Earth’s crust, ejections from volcanoes,
dissolved materials from sediment deposited on the ocean floor and hydrothermal vents.
6. Hydrothermal vents are features on the crest of oceanic ridges that release dissolved
minerals into the oceans. These vents are the exit point on the ocean floor from which
seawater that has seeped into the rocks of the oceanic crust flows back into the ocean. This
super-heated water brings large amounts of dissolved minerals with it.
7. The water cycle is the continuous movement of water in an around Earth. The sun is the
source of energy that drives the water cycle. When the sun heats the surface of water, it
evaporates and rises into the atmosphere as a gas known as water vapor. As the water rises
it cools, forming clouds, and condenses into water droplets (condensation). The water will
then precipitates as rain, sleet, hail or snow.
8. Some of this precipitation is captured by tree canopies and evaporates again into the
atmosphere in a process called transpiration.
9. The precipitation that falls to the ground becomes runoff, which courses over the surface of
the earth in streams. It can seep into the ground and accumulate which becomes
groundwater.
10. Permeability is a measure of the ability of a rock or sediment to transmit water or other
liquids. Water does not pass through impermeable materials.
11. An aquifer is a large deposit of groundwater that can be extracted and used.
12. Surface water moves into river basins from areas called watersheds. Watersheds are the
areas of land that water drains in to when the ground is saturated or impermeable.
13. A river basin is the portion of land that water travels across or under on its way to a river.
The final destination of the water drained by a river basin is an estuary or an ocean.
14. Everyone lives on a river basin. There are 17 river basins in NC.
15. Estuaries are places where fresh and salt waters meet, producing variations in salinity and
high biological activity.
16. Estuaries are partially enclosed bodies where seawater is diluted by fresh water that drains
from the land, making the water in an estuary brackish, which means slightly salty.
17. Estuaries trap nutrients and sediment that are carried from the land by rivers and from the
ocean by tides. These conditions create an extremely fertile area for plant and animal life.
Estuaries are one of the most productive ecosystems on earth.
18. Estuaries waters are shallow, so sunlight penetrates to the bottom, which promotes plant
growth.
19. There is a great biological diversity in estuaries. The rivers that feed estuaries deposit
sediments rich in nutrients, which settle to the sand and mud at the bottom of the estuary
floor. Fish, shrimp, crabs, clams and oysters are some of the species that are able to adapt to
the brackish conditions.
20. Estuaries are good nurseries, as they provide a protected habitat for species to hatch and grow
in before they migrate to the sea.
21. Estuaries help control erosion and reduce flooding of the mainland. Sandbars buffer the
impact of waves, while plants and shellfish beds anchor the shore against tides.
22. Estuaries are a type of environmental filter in that the plants and animals in estuaries filter
pollutants out of the water. Ex: Salt marsh plants trap some of the chemicals and pathogens
carried by rivers and move them into soils where they can be neutralized and oysters filter
impurities out of water.
23. Bacteria eat organic matter found in the sediment and in turn release carbon dioxide,
hydrogen sulfate and methane into the atmosphere. This prevents gases from being
excessively stored up in the estuary. HOWEVER…toxins can accumulate in estuaries causing
many environmental and health problems.
24. Chemical pollution and sedimentation are great threats to the well being of estuaries and
oceans.
25. The largest NC estuary is the Pamlico Sound.