Photosynthesis and Carbon Cycle Review

Reference Lesson 13 in text

Photosynthesis

Photo – Greek meaning “pertaining to light”Synthesis – Greek meaning “putting together”Autotrophs combine light and substances to

create sugar (food) for themselves

Microbes

Microbes are any microscopic organismBase of marine food websVery fast growth rate and life cyclesMore oxygen is produced in the ocean than on

continents

Ozone

Phytoplankton – plant like microbesPhotosynthetic bacteria – Cyanobacteria

Oldest fossil found on Earth – 3.5 billion years ago

Before this – no oxygen existed on EarthProduced Ozone - a compound found in the upper atmosphere

Before this, no organisms could survive on land due to UV light damage

People are nuts

Oldest fossils on Earth

Cyanobacteria

Photosynthetic Microbes

Diatoms Contain chloroplasts

Sunlight can penetrate their clear, silica shells

DinoflagellatesContain chloroplasts

Can also ingest food (animal –like)

Photosynthesis

Occurs in an organelle chloroplast

Converts light energy chemical energy

6CO2 + 6H2O C6H12O6 + 6O2

Seasonal Photosynthesis

The tilt of the Earth and its revolution around the Sun result in seasonal differences in light availability.

Therefore, there are seasonal differences in photosynthesis—both on land and in the ocean.

Nearly 50% of sun entering our atmosphere is absorbed by oceans

Photic Zone

Sunlight penetrates only about 200 meters (~650 feet)

Photosynthesis can only occur in this top layer, called the photic zone.

What else besides light is necessary for photosynthesis?

Carbon Dioxide

One major source of carbon dioxide (CO2) in the ocean is from marine organisms.

Living things release CO2 as a byproduct of respiration.

CO2 is released from decomposers feeding on dead organisms.

Nutrients

Necessary nutrients include: Nitrogen

Phosphorus

Potassium

Iron

Phytoplankton absorb these directly through their cell membranes

2 sources: Released when living matter decomposes

Runoff from land

Chlorophyll and Enzymes

Pigments – light absorbing molecules in autotrophs

Chlorophyll – primary pigment in chloroplasts Reflects green

Absorbs red and blue wavelengths of light

Enzymes are proteins found in the membranes of organisms Speed up chemical reactions

Especially in Photosynthesis

Carbon Cycle

Ocean holds >90% of Earth’s Carbon Dioxide

In addition to Photosynthesis, also used by molluscs to build their CaCo3 shells

Plants take in CO2 to make carbohydrates

Carbs get passed through food chain

Carbon Cycle

Buried remains of carbon-rich organisms become incorporated into rocks

Eventually remains are compressed into fossil fuelsBurning fossil fuels release CO2 into atmosphere

Ocean absorbs ~50% released into atmosphere

Carbon Cycle Sources

CO2 also released by underwater and land volcanoes

CO2 and CH4 (methane) released through mining and agriculture

Carbon released through deforestation

Summarize Photosynthesis Sources

Ingredients Sources

Light

Carbon Dioxide

Nutrients

Chlorophyll

Enzymes

Summarize Photosynthesis Sources

Ingredients Sources

Light Sun

Carbon Dioxide Respiration, Decomposition, Undersea Vents and Volcanoes, Breakdown of rocks/shells

Nutrients DecompositionRunoff

Chlorophyll Contained within the phytoplankton

Enzymes Contained within the phytoplankton

Carbon Cycle