Cycles and Environments

I. Food Chain

A. Phytoplankton produce 95% of all the marine productivity

1. Phytoplankton go through photosynthesis- production of energy from the sun

2. Phytoplankton are called autotrophs – “self –feed”,

make their own food

B. 5% of marine productivity comes from:

1. other plants – seaweed, kelp, seaoats, and

2. Bacteria; bacteria go through chemosynthesis – production of energy from organic matter

C. Important parts of the food chain1. Heterotrophs – feed only on

“plants”; zooplankton are the heterotrophs of the ocean;

2. Carnivores – feed only on “meat”; usually predators – an organism that hunts and kills its food

3. Decomposers – feeds on decaying matter; very important in keeping nutrients in the environment; Ex. bacteria

D. The food chain must be in a pyramid shape

1. There must be more autotrophs than any other organism

2. Carnivores can NEVER exceed the heterotrophs

3. Heterotrophs can NEVER exceed the autotrophs

II. Important Nutrients in the Ocean

A. Carbon Dioxide

1. Phytoplankton must have CO2 to go through photosynthesis

2. Stays a cycle because all other organisms release CO2, plus plenty in atmosphere

3. The Cycle

CO2Atmosphere

Plants

Photosynthesis

Sugar and O2

Animals

Respiration

B. Nitrates

1. Needed by all organisms for building proteins

2. But Nitrates (NO3) aren’t found in the environment naturally like CO2

3. However, Nitrogen (N2) makes up 78% of our atmosphere

4. So bacteria is needed to take N2 and make NO3 (nitrates);

this bacteria is called nitrogen-fixing bacteria – very important

5. Decomposers also help keep nitrates in the cycle

6. But must have BACTERIA to get nitrates

N2

7. The CycleAtmosphere

Nitrogen fixing bateria

NO2 - Nitrite Nitrogen fixing

bacteria

Nitrate NO3

plantsanimals

Die and waste

NH4

Nitrogen sinks

upwelling

C. Other important “cycles”

1. Water - … it’s the ocean – without no life

2. Phosphates – needed for DNA, RNA, and Fats

3. Minerals – a variety needed, kept in cycle through food chain &

the decomposers

III. Environments of the OceanA. Estuaries1. Most important environment in

the world!2. Acts as a breeding ground and a nursery for much of the marine life3. Estuary – where freshwater and

saltwater mix Ex. Mississippi Delta4. Lower salinity levels because of

freshwater = safe for the “babies”

5. No life in ocean without estuaries (WaterWorld)

6. Estuaries highly endangered – see a major decline in marine life

7. Problems: a) Pollution – from both rivers and

oceanb) development – fill them in, build

on topc) overfishing

8. Most are now protected because they are soooo important

B. Sand dunes

1. create a habitat for some marine life

2. Ghost crabs, sea oats, snails are some examples

3. Very important:

a) Sand dunes prevent beaches from eroding

b) protect land mass from hurricanes

4. Very fragile environment even if reaches up to 50 feet5. Basically made of sand and plants;

if plants die, sand dune erodes6. Can be very dangerous = cave ins

(yes people have died)7. Found only on beaches that have lots of sand, long and flat8. STAY OFF THE SAND DUNES

C. Intertidal Zone

1. Zone between high and low tide marks = intertidal zone

2. ONLY marine environment exposed to air

3. #1 worry for intertidal organisms is desiccation = drying out

4. The harshest marine environment – such drastic changesa. exposed t air, up to 12 hoursb. heavy influx of freshwater,

especially during rainc. most forceful wave actiond. Drastic changes in salinity and

T (within minutes)

5. Intertidal zone easy to study:

a. A wide variety of life

b. exposed to air (no scuba equipment needed)

c. It’s Right There!

6. Types of intertidal zones is based on the substrate (ground)a. Sandy Intertidal

1) Substrate always in constant motion

2) So animals have to move quickly

3) Examples: bivalves (clams), mole crabs, ghost shrimp

4) Will not find barnacles, plants – no place to

anchor

b. Muddy Intertidal1) Very fine sediments – muddy;

helps “collect” stuff2) Have a very rich supply of

nutrients and life3) But have low oxygen levels,

because nutrients begin to decay and all the organism “suck” up the O2

4) A very noticeable smell – rotten eggs (decaying matter)

5) Very little wave action - so little movement of mud, O2, etc

6) Examples of organisms: sea grasses, worms, diatoms, snails

c. Rocky Intertidal

1) Organisms have to be able to “stick” to rock or will be “washed” away

2) Most rock intertidal organisms are sessile

3) Examples: barnacles, snails, algae, sea anemones = have great “stick ‘um” powers

4) Because of the morphology (shape) and color of organisms, rocky intertidal has distinct zone

5) Have certain adaptations to avoid desiccation = mostly close up tightly or produce mucus