Unique Nature of Pure Water
Water is made of two hydrogen atoms and one oxygen atom.
What is H₂O?
This physical property describes the amount of dissolved salt in seawater.
What is salinity?
This dissolved ion is the most abundant negatively charged ion in seawater.
What is chloride?
This gas from the atmosphere dissolves in seawater and contributes to ocean acidification.
What is carbon dioxide (CO₂)?
This uppermost pelagic zone extends from the surface to about 200 meters and receives enough sunlight for photosynthesis.
What is the epipelagic zone?
This type of bond holds hydrogen and oxygen atoms together within a water molecule.
What is a covalent bond?
This happens to seawater pressure as ocean depth increases.
What is an increase in pressure?
This positively charged ion is the second major component of dissolved sea salt after chloride.
What is sodium?
This process uses sunlight and carbon dioxide to produce sugars in marine phytoplankton.
What is photosynthesis?
Also called the twilight zone, this layer extends from about 200 to 1,000 meters.
What is the mesopelagic zone?
Water molecules stick to each other because of this property.
What is cohesion?
When salinity stays constant, seawater generally becomes denser as this happens to its temperature.
What is decreasing temperature?
This scale measures how acidic or basic seawater is.
What is the pH scale?
When carbon dioxide dissolves in seawater, it forms this weak acid.
What is carbonic acid?
This completely dark zone extends from about 1,000 to 4,000 meters and is also called the midnight zone.
What is the bathypelagic zone?
This property allows water to absorb large amounts of heat without rapidly changing temperature.
What is high specific heat capacity?
This layer of the ocean has a rapid change in temperature with increasing depth.
What is the thermocline?
These geological features release heated, mineral-rich fluids that can alter seawater chemistry.
What are hydrothermal vents?
Ocean acidification reduces the availability of this ion, making it harder for many marine organisms to build calcium carbonate shells.
What is the carbonate ion?
This zone extends from about 4,000 to 6,000 meters and experiences extremely cold temperatures and high pressure.
What is the abyssopelagic zone?
When water freezes, hydrogen bonds arrange molecules into an open crystal structure, causing ice to have this relationship to liquid water.
What is lower density?
Two seawater samples have the same temperature but salinities of 32 and 37 parts per thousand. This sample will generally sink beneath the other.
What is the 37-parts-per-thousand sample?
A seawater sample changes from pH 8.2 to 7.2. This is how much its hydrogen ion concentration increases.
What is tenfold (10 times)?
This natural ocean process transfers carbon from surface waters to the deep ocean when organic material sinks.
What is the biological carbon pump?
A research submarine descends to 8,000 meters inside a deep ocean trench. It has entered this pelagic zone.
What is the hadalpelagic zone?