Housekeeping

1) Please take a copy of the syllabus.

2) Updated email address: mguannel@mdc.edu

Please use this email address for all communications.

3) Website for posting lecture slides, etc: in progress.

4) In-class activities: Most will count as credit/no-credit.

There will be a total of 11 activities

(you can miss 1 without penalty to your grade).

5) Attendance: will be taken at the end of class today.

Extra Credit Assignment #1

What are 50 ways that the ocean influences life on land?

Carrageenan comes from red algae.

Due April 8

Learning Goals: Chapter 1

- Read Chapter 1, “The Origin of the Ocean”

- Key Points and Questions:

- How does the process of science work?

(observations, hypotheses, theory…)

- How did the ocean form on our planet?

- How old is the ocean?

- How big is the ocean?

- Why do we wonder whether there is water on other planets

or moons?

Scientific Method

Theory

Hypothesis

“Scientists like to be shown why an idea is correct, rather than being told.”

Pseudo-nitzschia forms Harmful Algal Blooms (HABs).

razor clams,

other

shellfish

humans:

Amnesic Shellfish

Poisoning (ASP)

WDFW

Seattle Times

anchovies,

sardinesNOAA

“the birds”sea lions

Marine Mammal Center

USFWS

Some species are

believed to produce the

highest levels of toxin.

Scientific Method

Theory

Hypothesis

“Scientists like to be shown why an idea is correct, rather than being told.”

~180 ng /L

Domoic acid (DA) was detected off the coast of southern Africa.

• ~200 ng / L maximum

• Potentially harmful to

organisms like sea lions

• Which types of

phytoplankton were there?

(which species?)

“Whodunnit”?

P. galaxiae:

P. cuspidata:

P. subpacifica:

P. micropora:

P. caciantha:

P. pungens:

Toxin levels in the lab (max pg DA/cell*):

0.00036

0.031

0

0

0

0.47

Toxin in the field:

3.0 pg DA / cell

considered to be

“non-toxic”

species

Scientific Method

Theory

Hypothesis

“Scientists like to be shown why an idea is correct, rather than being told.”

“How inappropriate to call this planet Earth

when it is quite clearly Ocean.”

- Arthur C. Clarke

• 71% of Earth’s surface is ocean.

• 97% of the Earth’s water is in the ocean.

• The ocean is much deeper than the land is high:

Average depth = 3682 meters (12,081 feet = 1.7 miles)

vs average elevation (840 meters or 2772 feet)

• Average temperature is 3.9 degrees C (39 degrees F) – why?

• About half of all people live within 150 miles of a coastline

How did the ocean form?

Stage 1: Protostar

• A spinning nebula begins

to shrink and heat.

• Once it is hot enough,

fusion happens – hydrogen

atoms form helium.

Stage 2: Star

• The star changes hydrogen

and helium to other atoms

(carbon, oxygen).

Stage 3: Red Giant

• Dying star uses up carbon,

oxygen, hydrogen

• Temperatures increase

• Core collapses and it

grows hotter

Stage 4: Supernova

• A large explosion creates

other heavier elements

(iron, gold, etc).Images of protostars from the Hubble Space Telescope.

“Stars Form Seas”

Elements are created by growing,

heating, and dying stars.

Our own solar system

begin to form

~4.55 billion years ago.

Nebula: a large, diffuse cloud of dust and gas

“Accretion” = planet building

Small particles stick together

into large masses.

This process lasted about

30-50 million years.

Heat by gravitational collapse, radioactivity

and bombardments kept Earth semi-liquid.

Lighter

matter and

silicates

Iron

Density stratification - As Earth cooled and solidified, denser

materials sank to center, less dense material remained at surface.

As Earth continued to cool,

volcanic activity caused “outgassing”

of many substances, especially

water vapor.

Outgassed water vapor eventually

condensed to liquid.

The first oceans were born …

about 4.5 billion years ago.

Comet impacts may have also added water and organic compounds to ocean.

http://htwins.net/scale2/?bordercolor=white

The Scale of the Universe

How/where did life begin?

Life on Earth originated about

3.5 billion years ago.

The first life forms were likely

anaerobic – they survived without

oxygen (and perhaps in the dark).

Cyanobacteria:

Early life forms

(Later) produced oxygen

Now dominate the ocean

Microbial mats

(living)

formed

stromatolites

(fossils)

Did life originate at

hydrothermal vents?

• All life depends on salty

water within its cells to

dissolve and transport

chemicals.

• Water holds heat.

• Water moderates

temperatures.

• Water suspends

nutrients and wastes.

We believe that life began in the oceans.

Earth’s atmosphere responded to this life.

Oxygen revolution (~2bya)

Oxygen makes ozone (O3).

With protection from ozone, life likely

moved to land (800 mya).

Geological Time

First

life form

Bacteria began to

produce oxygen

“Oxygen revolution”

“Is there life on Mars?”

(from an artist’s imagination)

Valleys believed to be

caused by flowing water

“Is there life on

Mars?”

Photo in text from Mars

Curiosity rover:

smoothed “streambed” rock

Liquid water beneath ice very likely on Europa (moon of Jupiter).

Fountains of ice shoot from the surface of Saturn’s moon.

Are there other Earth-like planets?

Habitable zone – water in all 3 phases