The hydrosphere is any form of water.
The hydrosphere is made up of any form of water, or H2O on the Earth, including clouds. Big parts of the hydrosphere are the oceans, which cover 75% of the Earth. Did you know that the oceans were formed about 1 billion years after the solar system was formed? The hydrosphere first formed approximately 4 billion years ago! Each zone ends with the Greek root "pelagic", meaning open sea. The depth of the ocean is measured in meters, because, if you look at the picture below, the measures on the left hand side are in meters, and are much simpler numbers. It is estimated that the deepest part of the ocean is in the Challenger Deep in the Mariana Trench at 10,994 m deep. The temperature of the ocean can get as high as 97°F (36°C) to as low as 28°F (-2°C).
The 5 Layers of the Ocean:
- The Epipelagic Zone (sunlight zone): This zone is the top most layer of the ocean. It extends from the surface to 200 m deep into the ocean. This zone temperature ranges from 97°F (36°C) to 28°F (-2°C) seasonally throughout all of the oceans.The temperature in this zone varies the most because it is most affected by the temperature of the air above it and it is the layer that receives the most sunlight energy. This layer of the ocean is called the photic zone since this is where most photosynthesis occurs. Most of the ocean plants and animals will live in this layer.
- The Mesopelagic Zone (twilight zone): This zone is directly underneath the Epipelagic Zone. It extends from 200 m to 1,000 m deep in the ocean. The temperature of this zone varies from 68°F (20°C) at the top to around 39°F (4°C) at the boundary closest to the Bathypelagic Zone. Less sunlight penetrates the water to reach this zone, so less plants and animals live in this zone. Most animals who flourish in this zone are fluorescent and semi-deep sea creatures. An example of one such animal that flourishes is the bristlemouth sea creature, whose population has grown quite a lot throughout the years.
- The Bathypelagic Zone (midnight zone): As the diagram below shows, the ocean gets darker the further down you go. The Bathypelagic Zone is 1,000 to 4,000 m deep. Just think, it extends to 13,100 ft. The average person is about 5' 8 in, so that's about 2,312 people! The temperature of this zone normally stays close to around 39 °F (4 °C). No sunlight reaches this zone, so no primary production, the production of chemical energy by living organisms (ex: photosynthesis), is possible. The lack of light means organisms cannot see, so a few species therefore do not have eyes because of this. Many large aquatic sea creatures such as whales live in this layer of the ocean.
- The Abyssopelagic Zone (the abyss): The abyssopelagic zone is about 37°F (3°C) at the top to around 36°F (2°C). This layer never receives any sunlight. Most dead biological materials settle in this layer, as well as the Hadalpelagic Zone. The waters are very calm here, because most turbulent water is in the upper two zones. Shells of zooplankton and phytoplankton are found in this layer, as well as anglerfish, giant squid, and tripod fish.
- The Hadalpelagic Zone (the trenches): The pressure of the water and how dark it is in this layer of the ocean cause the temperature of this layer to stay at an average of 32°F (0°C). Similarly to the Abyssopelagic Zone, this layer of the ocean never receives any sunlight. Not many creatures can survive here. Known creatures include jellyfish, viperfish, and sea cucumbers.
The Cryosphere
The cryosphere is made up of any frozen water, whether it be on land or in the water. The cryosphere actually only takes up 2% of the water on Earth. The temperature of the cryosphere is always at 32°F (0°C) or lower, since ice, to stay frozen, must stay at freezing temperature. The word cryosphere is derived from the Greek root "krios", meaning cold. This part of the hydrosphere is very important to the Earth's climate. The cold of the snow and ice negate the heat of the sun to help regulate Earth's temperature. Polar regions are very sensitive to climate changes, so the cryosphere can help scientists identify global climate changes.
- Ice and snow on land are one part of the cryosphere. 95% of the cryosphere is made up of the continental ice sheets found in Greenland and Antarctica. Other land parts of the cryosphere includeice caps, glaciers, and areas of snow and permafrost. When areas of continental ice flow onto the sea ice, shelf ice is formed.
- The other part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic. It also includes frozen rivers and lakes, which mainly occur in polar areas. If all the ice in the ocean melted, the ocean would actually rise up approximately 60 m.