Oceanography 4

Siliceous ooze is particularly abundant on the seafloor at __________ and at __________.

high latitudes; equatorial upwelling zones

Two common types of chemical compounds found in biogenous sediments are __________ and __________.

calcium carbonate; silica

What is calcareous ooze?

a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes

Carbon dioxide (CO2) combines with water (H2O) to form __________.

Carbonic acid (H2CO3)

The depth at which calcite dissolves rapidly in the ocean is called the __________.

calcite compensation depth or CCD

What would happen if the depth of the CCD were above the top of the mid-ocean ridge?

Calcareous ooze would not be found below the CCD.

How does siliceous ooze accumulate on the seafloor if silica-based residues are dissolved slowly at all depths?

Silica tests accumulate faster than seawater can dissolve them.

As a whole, the pH of surface waters of the ocean is slightly __________.

alkaline

Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.

biogenous

Calcite-secreting organisms such as __________ and __________ live in the ocean's sunlit surface waters and form the basis of most marine food webs.

coccolithophores; foraminifers

What three steps are required for calcareous ooze to exist below the CCD?

deposition of calcite shells above the CCD, cover of these shells by a non-calcareous material, and movement of the sea floor over millions of years

The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.

diatoms; radiolarians

The pH scale is a measure of the __________ ion concentration of a solution.

hydrogen

What is the calcite compensation depth, or CCD?

the ocean depth below which calcite is unstable and will dissolve quickly