Ocean Circulation, Waves, Sediments, and Chemistry: Comprehensive Study Guide

What is the Ekman Spiral?

A concept explaining how wind drags surface water, causing it to move at an angle due to the Coriolis Effect.

How does the Coriolis Effect influence surface water movement in the Northern Hemisphere?

It deflects surface water 45° to the right of the wind direction.

What is Ekman Transport?

The net movement of the upper layer of water, which is 90° to the right of the wind direction in the Northern Hemisphere.

What are ocean gyres?

Giant circular loops of moving water in the world's oceans.

What creates the 'hill of water' in ocean gyres?

Ekman transport pushes water toward the center of the gyres, creating a 'hill' about 2 meters high.

What is geostrophic flow?

The balance between gravity pulling water down the 'hill' and the Coriolis Effect pushing it back toward the center.

What characterizes western boundary currents?

They are fast, deep, and narrow currents that move warm water toward the poles.

What characterizes eastern boundary currents?

They are slow, shallow, and wide currents that move cold water toward the equator.

What is coastal upwelling?

A process where wind pushes surface water away from the coast, allowing cold, nutrient-rich water to rise from the bottom.

What happens during coastal downwelling?

Wind pushes water toward the shore, causing it to sink.

What is El Niño?

A disruption of normal ocean-atmosphere conditions where trade winds weaken, causing warm water to move back toward South America.

What is La Niña?

An extreme normal condition where trade winds are stronger, resulting in colder eastern Pacific waters.

What drives thermohaline circulation?

Density differences caused by temperature and salinity.

What is Antarctic Bottom Water (AABW)?

The densest water mass in the world, formed in the Antarctic.

What is North Atlantic Deep Water (NADW)?

Water formed in the North Atlantic that contributes to thermohaline circulation.

What is the significance of thermohaline circulation?

It moves heat around the planet and takes about 1,000-1,600 years to complete one full loop.

What are the parts of a wave?

Crest, trough, wave height, wavelength, period, and frequency.

What defines deep-water waves?

Waves that occur when water depth is greater than half the wavelength.

What defines shallow-water waves?

Waves that occur when water depth is less than 1/20th of the wavelength.

What causes tsunamis?

Displacement of the seafloor, such as from earthquakes or landslides.

Why are tsunamis considered shallow-water waves?

Their massive wavelength is greater than the depth of the ocean.

What are tides?

Huge waves driven by the gravitational pull of the Moon and the Sun.

What forces create tidal bulges?

Gravity pulls water toward the Moon, while inertia creates a second bulge on the opposite side of the Earth.

What is the relationship between wave height and water depth in shallow-water waves?

As a wave enters shallow water, it slows down, its wavelength decreases, and its height increases until it breaks.

What is the period of a wave?

The time it takes for one full wave (one wavelength) to pass a fixed point.

How does frequency relate to wave period?

Frequency is the number of waves passing a point per second, calculated as 1 divided by the period.

Which celestial body has a greater influence on Earth's tides?

The Moon

What are Spring Tides?

Tides that occur during Full and New Moons when the Sun, Moon, and Earth are aligned, resulting in the highest high tides and lowest low tides.

What are Neap Tides?

Tides that occur during Quarter Moons when the Sun and Moon are at right angles to Earth, resulting in the smallest tidal range.

What is a Semidiurnal tide?

A tidal pattern with two high tides and two low tides of nearly equal height each day, typical of the US East Coast.

What is a Diurnal tide?

A tidal pattern with one high tide and one low tide per day, typical of the Gulf of Mexico.

What is a Mixed tide?

A tidal pattern with two high tides and two low tides of unequal heights, typical of the US West Coast.

What is sediment?

Loose particles of organic or inorganic matter that accumulate on the seafloor.

What is lithification?

The process of turning loose sediment into solid rock.

What is the energy rule regarding sediment size?

High energy environments can move larger particles like gravel and sand, while low energy environments allow only tiny particles like clay to settle.

What are Terrigenous sediments?

Sediments that come from land, resulting from erosion, rain, and wind carrying rocks and dust from continents to the sea.

What are Biogenous sediments?

Sediments that come from the remains of living organisms, such as tiny shells and skeletons.

What is an 'Ooze' in sediment classification?

A sediment sample that contains more than 30% biogenous material.

What is Siliceous Ooze?

Ooze made of silica, formed by organisms like Diatoms and Radiolarians.

What is Calcareous Ooze?

Ooze made of calcium carbonate, formed by organisms like Coccolithophores and Foraminifera.

What are Hydrogenous sediments?

Sediments formed by chemical reactions directly in the water.

What are Manganese Nodules?

Rare, potato-sized lumps of metal that grow slowly on the seafloor.

What is the Calcite Compensation Depth (CCD)?

The depth where the rate of shells falling down equals the rate of shells dissolving, below which calcareous ooze does not accumulate.

What is stratigraphy in the context of sediments?

The study of layers of sediment, where the oldest layers are at the bottom.

How do scientists use oxygen isotopes to study past ocean temperatures?

They analyze the ratio of Oxygen Isotopes (O18 vs O16) in tiny shells found in sediment cores to infer past ocean temperatures.

What is the average salinity of ocean water?

Approximately 35 parts per thousand (3.5%).

What happens to a wave's speed and height as it approaches the shore?

The speed decreases and the height increases.

During which moon phase would you expect a Spring Tide?

During the New or Full Moon.

What is the significance of sediments as a climate archive?

They provide historical records of Earth's past climate and biology, with deep-sea sediments storing information going back about 150 million years.

What are the primary components of ocean salinity?

Most of the salt is Sodium (Na⁺) and Chloride (Cl⁻).

What are the three main sources of ocean salinity?

1. Weathering of rocks on land, 2. Volcanic outgassing, 3. Hydrothermal vents.

What does the Principle of Constant Proportions state?

The ratio of major ions in the ocean remains constant, regardless of salinity variations.

What is residence time in ocean chemistry?

It measures how long an atom of an element stays in the ocean before being removed.

What is the formula for calculating residence time?

Residence Time = Total amount in the ocean / Rate at which it is added/removed.

What are conservative constituents in ocean chemistry?

Elements with long residence times, like salt, that remain in the ocean for millions of years.

What are non-conservative constituents?

Elements with short residence times, like nutrients or oxygen, that are rapidly used by biological processes.

How do gases dissolve in ocean water?

Gases dissolve better in cold water.

Which gas is the most abundant dissolved in ocean water?

Nitrogen (N₂).

What is the effect of photosynthesis on ocean chemistry?

Photosynthesis consumes CO₂ and releases O₂ in the sunlit photic zone.

What occurs during respiration in the ocean?

Respiration consumes O₂ and releases CO₂ at all depths.

What is the Oxygen Minimum Zone (OMZ)?

A depth range (500-1,000m) where O₂ levels are lowest due to bacterial consumption of organic matter.

What is the Carbonate Buffer System?

A chemical system that stabilizes ocean pH by balancing carbonic acid, bicarbonate, and carbonate.

What happens to ocean pH as CO₂ levels increase?

More CO₂ leads to more H⁺ ions, resulting in lower pH (more acidic).

What is the impact of ocean acidification on shell-building organisms?

Acidic water reduces carbonate ions needed for building shells, risking their survival.

What is the proposed solution for ocean acidification?

Adding crushed minerals to increase ocean alkalinity and neutralize acid.

Why is CO₂ low at the surface of the ocean?

Because it is consumed by photosynthesis.

What is the relationship between temperature and gas solubility in ocean water?

Colder water holds more dissolved gas than warmer water.

What is the effect of depth on CO₂ concentration in the ocean?

CO₂ concentration increases with depth due to respiration and cold water's capacity to hold more gas.

What is the significance of the term 'biogeochemistry' in ocean studies?

It refers to the interaction between biological and geological processes affecting ocean chemistry.

What happens to the pH number as water becomes more acidic?

The pH number decreases.

What is the primary effect of ocean acidification on coral reefs?

It threatens coral survival by reducing available carbonate ions for shell formation.

What is the role of photosynthesis in the ocean's oxygen levels?

Photosynthesis increases oxygen levels at the surface of the ocean.

What is the relationship between ocean temperature and dissolved oxygen levels?

Warmer waters hold less dissolved oxygen compared to colder waters.

What is the impact of human activity on ocean CO₂ levels?

Humans are increasing atmospheric CO₂, which the ocean absorbs, leading to acidification.