It is mostly utilized by living organisms, especially man and animals in respiration. 0 0 1. Phytoplankton produce oxygen through photosynthesis. 0 0 0. What are Natural sources of oxygen on earth? The main source of this atmospheric water was volcanic eruptions and outgassing. In fact, the abundance of oxygen was toxic to some autotrophs and they became extinct. The hydrogen molecule is light, and has a quick thermal velocity,so it can escape Earth's atmosphere leaving behind the free oxygen to form a diatomic oxygen molecule. what is the source of oxygen on earth ? Relevance. The exact figure is difficult to calculate because scientists do not know how much phytoplankton exists on Earth. The answer is tiny organisms known as cyanobacteria, or blue-green algae. A number of people would agree that trees and the entire vegetation are one of the primary sources of oxygen on Earth. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. There are many sources of oxygen, but a few are the breathing of plants and animals and the decomposition of dead plant and animal material.The main source of atmospheric free oxygen is photosynthesis, which produces sugars and free oxygen from carbon dioxide and water. A sea water. What is a major source of oxygen for the Earth's atmosphere? 20.95% oxygen by volume (Source - dry air value, I am ignoring water vapor) 70.8% of the Earth's surface is covered by water, 29.2% by land ; The mean radius of the Earth … Oxygen occurs freely in the air, trapped in the earth crust as chemical compounds, or dissolved in water. this is a section quiz..help? This is the type of oxygen that humans and other animals breathe. What Produces Most of the World's Oxygen? Favorite Answer. Until about two billion years ago free oxygen was a scarce commodity in the Earth's atmosphere. Amazon forest is … Login to reply the answers Post; OhHelloThurr. We need to collect a few facts before we start our analysis. Oceanographers probe the impact of deep swirling vortices on phytoplankton. Plants take in carbon dioxide and emit oxygen in the form of the molecule O2. They also act as a carbon sink. The molecule is broken down into one diatomic hydrogen molecule and one free oxygen. If phytoplankton provides 50% of the earth's oxygen, what's the other half? 6 Answers. C plants, It's the O2, to CO2 exchange we have with plants. caleb. Answer Save. 9 years ago. Answer to: What is the primary source of the Earth's oxygen? The primary source of Earth's oxygen is plant life. B the sun. Lv 4. Oxygen is one of the most important elements on Earth to life, and it comprises a fifth of our atmosphere. Lawrence C. Lv 6. Atmospheric oxygen levels have declined over the past 1 million years, although not nearly enough to trigger any major problems for life on Earth, a new study finds. I suppose the largest source of oxygen on Earth is the Amazon forest in South America. The rise of oxygen on early Earth may have been caused by a microbial changing of the guard between methane-producers and oxygen-producers. Plants photosynthesise to produce oxygen. A new study shows Earth's oxygen levels continue to decline, a phenomena that has puzzled scientists. Plant life essentially produces oxygen as a byproduct of photosynthesis and respiration. 8 years ago. we give off CO2 plant with photosynthesis give off oxygen. The oxygen cycle elaborates how oxygen circulates in various forms through nature. Plants, they turn CO2 into oxygen. It is hypothesized that no living thing on Earth at that time had a use for oxygen. World’s Biggest Oxygen Producers Living in Swirling Ocean Waters . Question Date: 2003-05-06: Answer 1: Phytoplankton provide a lot of oxygen to the air. After many plants evolved on Earth, there was an abundance of oxygen floating freely in the atmosphere.