Oceanography Chapter 4

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 Sediments

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

Calcite compensation depth or CCD

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

Calcium carbonate and silica

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

Carbonic Acid (Very brief period of time until it converts to bicarbonate ions.)

You take a sediment sample from the ocean floor at a depth of 5500 m. The area has low biological productivity and the CCD is at 4500 m depth. Your sample will probably consist of __________.

Clay

From smallest to largest, which list of sediment particle sizes is in the correct order?

Clay, Silt, Sand, Pebbles

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

Salt beds of the U.S. Gulf Coast are __________.

Hydrogenous sediments

Oozes are uncommon on continental margins because __________.

The biogenous component tends to be overwhelmed by the amount of lithogenous material derived from the nearby continent .

Sediments with all grains of about the same size are classified as __________.

Well-sorted

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

high latitudes; equatorial upwelling regions

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

Coccolithophores and foraminifers

You add sand, silt, and clay to a jar of water, shake the jar vigorously, and allow the sediment to settle. The resulting sediment will most closely resemble that of a(n) __________.

Continental Rise

Marine sediment with more than 30% biogenous material is called __________.

Ooze

The most abundant mineral in lithogenous sediments is __________

Quartz

Sediment samples from deep beneath the ocean floor are recovered by

Rotary drilling.

Neritic sediments are most likely to be composed of __________.

Sand, silt, gravel

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.