Salinity

These flashcards cover key concepts from the lecture on marine salinity, ocean features, and circulation patterns.

What are the four major oceans and their respective surface area percentages?

Pacific: 50.1%, Atlantic: 26.0%, Indian: 20.5%, Arctic: 3.4%.

What is the average depth of the Pacific Ocean?

3940 m.

What characterizes the aphotic zone in marine environments?

Insufficient light for photosynthesis.

What is the average depth of the sea floor?

3 – 6 km.

What is an abyssal plain?

A flat area of the ocean floor making up 70% of it, mostly composed of mud.

What is a seamount?

An underwater volcano that has not reached the surface.

Define salinity in seawater.

The concentration of solutes in seawater, typically around 35‰.

What does thermohaline circulation refer to?

Circulation driven by variations in density due to temperature and salinity.

What is the primary driver of deep water currents according to recent models?

Wind.

What are polynyas?

Areas of the ocean that are ice-free, important for ice formation and global circulation.

What do we call the mixing of seawater and freshwater in estuaries?

Saltwater intrusion.

How are estuaries classified based on their formation?

Fjord, Ria, Coastal plain, Bar-built, Blind, Delta front, Tectonic.

What impacts the salinity and biological environment in intertidal zones?

Evaporation, precipitation, tides, and seasonality.

What factors contribute to the variability of seawater density across latitudes?

Temperature and rainfall.

What are the three main types of water masses in thermohaline circulation?

Surface (0-550 m), Intermediate (550-1500 m), Deep/Bottom (greater than 1500 m).

What is the photic (euphotic) zone?

The upper layer of the ocean where there is sufficient light for photosynthesis to occur.

What is the Southern Ocean?

The fourth-largest major ocean, surrounding Antarctica, often delineated by the Antarctic Circumpolar Current.

What is the Challenger Deep?

The deepest known point in the Earth's seabed, located in the Mariana Trench at approximately 10,935 m.

What is the pycnocline?

A layer in the ocean where water density increases rapidly with depth.

What is the 'Global Conveyor Belt'?

A constantly moving system of deep-ocean circulation driven by temperature and salinity (thermohaline circulation).

Define an estuary.

A partially enclosed coastal body of brackish water where freshwater from rivers mixes with saltwater from the open sea.

What is a Fjord?

A long, narrow, deep inlet of the sea between high cliffs, typically formed by the submergence of a glaciated valley.

What is an ocean trench?

Long, narrow depressions on the seafloor that are the deepest parts of the ocean, typically formed by tectonic subduction.

What characterizes the mixed layer in the ocean?

The uppermost layer where winds and waves mix the water, resulting in relatively uniform temperature and salinity.

What are the two main types of polynyas?

Sensible heat polynyas (driven by warm water upwelling) and latent heat polynyas (driven by persistent winds).