Marine Biology - Lectures 4 - 6

Why is water so good at interacting with other substances?

It is the universal solvent and is a polar molecule

What is the physical state of water at a temperature of 4°C ?

Liquid

Why does ice float?

It is less dense than water

Which ions comprise about 85% of the solutes in seawater?

Sodium and Chloride

What unit of measurement is salinity of water generally expressed in?

grams

Define the Rule of Constant Proportions.

Elements are always in a fixed proportion by mass

Why is the rule of constant proportions important for marine organisms?

It provides a stable environment

What are the sources of ions commonly found in seawater?

Sodium - landmasses

Chloride - volcanic activity

Phosphorus - rock

Nitrogen - atmosphere

Sulfur - volcanic activity

What nutrient is most limited in marine systems?

Fluoride

What is a Hadley Cell?

a large-scale, tropical atmospheric circulation driven by the rising of warm, moist air at the equator and its subsequent descent in the subtropics

Generate trade winds

Describe how atmospheric circulation by Hadley Cells works in relation to solar radiation and precipitation.

Solar radiation is strongest at the equator, driving rising warm moist air that produces heavy rainfall. That air moves poleward, cools, and sinks in the subtropics, causing dry conditions. The surface winds then return to the equator, completing the Hadley Cell circulation.

How are latitudinal winds formed?

Hadley cells create zones of rising and sinking air. As the air flows north or south, the rotation of the Earth deflects its path. This curving of air creates the latitudinal winds

Define/Describe the Coriolis Effect.

Deflection of moving objects caused by the rotation of the Earth.
Curving right in the N hemisphere and left in the S hemisphere

What causes the Coriolis Effect?

Rotation of the Earth

How does the Coriolis Effect influence ocean circulation?

Winds created by hadley cells push the surface of the ocean, causing gyres

What is a gyre? Where are gyres located?

A gyre is a large system of rotation ocean currents.
5 major gyres.
North atlantic, south atlantic, north pacific, south pacific, and indian

What factors determine ocean currents?

Solar energy, wind, and Coriolis effect

What is an Ekman spiral?

the pattern by which a current in the layer above creates a current in the layer below

What is Ekman transport?

When the ekman layer moves off at. 90° from initiating wind

Does a current move water across the sea’s surface?

Yes

Define thermohaline circulation.

deep ocean currents due to the rise and sink of water based on density

How do the “thermo" and the “haline” aspects interact to produce circulation?

Temperature and salinity work together to change water’s density

Describe how thermohaline circulation moves around the world.

Dense water sinks and flows deeply. It then rises slowly and returns as warm surface currents.

How does thermohaline circulation regulate the Earth’

By redistributing heat, storing and cycling carbon, bringing nutrients to the surface, and stabilizing climate patterns

How does thermohaline circulation interact with Coriolis Effect to produce a gyre?

thermohaline circulation moving water and the coriolis effect bending the moving water. They trap currents into gyres.

What is the highest point in a wave called?

Crest

What is the lowest point in a wave called?

Trough

What is the distance between the highest and lowest points in a wave called?

Height

What is the distance between two wave crests called?

Wavelength

How does water circulate in a wave? Does a wave move water across the sea’s surface?

Water circulates by moving in an up and down in a circular motion in a wave but it is not transported. Waves do NOT move water across the sea’s surface

What does the height of a wave depend on?

Wind

What is a swell?

Waves in the absence of wind, rounded crests and troughs

What is a sea?

Waves in which wind pushes crests into sharp peaks and stretch out through troughs

What is a surf?

near shore, high and steep waves that fall forward and break

What is a rogue wave?

Usually tall waves that come out of nowhere due to wave reinforcement

What is wave cancellation?

Crests of one wave meet troughs of another producing an intermediate wave height

What is wave reinforcement?

Crests of 2 waves collide, additive effect produces higher wave

Why do waves break on the beach? (i.e., what physically happens to water as it approaches shore?)

Waves become closer together and eventually pile up high and fall forward and break

Define a tide.

Rhythmic rise and fall of sea-surface levels

What causes the tide?

Gravitational pull of the moon on ocean water

What produces low tide?

Water on far side of earth pushes away from the moon

What produces high tide?

Water on closer side to the moon being pulled towards the moon

What is a neap tide? What produces a neap tide?

When the sun is opposing the moon - weaker tides
In waxing and waning moon phases
Produced by the moon being further from the sun

What is a spring tide? What produces a spring tide?

When sun is in line with the moon - stronger tides
In new and full moon phases
Produced by the moon being closer and in line to the sun

What is the difference between diurnal, semidiurnal, and mixed semidiurnal tide patterns?

Diurnal - 1 time a day
Semidiurnal - 2 times a day
Mixed - varies

What are estimated to be the most diverse aquatic inhabitants?

How are viruses and other micoorganisms transported by accident by humans around the world?

How can marine viruses be potentially useful?

Which micro-organisms are often be extremophiles and as such are commonly found everywhere?

Which micro-organism is important in several ocean processes including nutrient cycling, decomposition, and energy flow through food webs?

What is the method scientists are developing to rapidly identify the biodiversity of bacteria in marine ecosystems?

What group is the only photosynthetic bacteria?

Certain cyanobacteria can cause toxic substances, an event that is called what?

Are marine protists phylogenetically closely related?