Demonstrating oxygen evolution during photosynthesis …

But it rapidly decreases below 50-75m as photosynthesis declines whileanimals use up most oxygen.

The process of photosynthesis: carbon fixation and reduction

Any object emits a spectrum of electromagnetic radiation that depends on its temperature. In addition, atoms of each element emit and preferentially absorb characteristic frequencies of light. These spectral lines allow identification of the presence of the element, even in microscopic quantities or for remote objects, such as a star. Nuclear transitions that emit or absorb gamma radiation also have distinctive gamma ray wavelengths, a phenomenon that can be used to identify and trace specific radioactive isotopes.

The incomplete oxidation of glucose causes a build up of lactic acid and creates an oxygen debt.

Oxygen | definition of oxygen by Medical dictionary

In contrast with photosynthesis, respiration is the process through which animals convert oxygen and glucose, chemical they get from food, into energy.
The Calvin cycle, Calvin–Benson–Bassham (CBB) cycle, reductive pentose phosphate cycle or C3 cycle is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms.

Instead, you are reading the  of the naturally occurring isotopes of carbon, some of which include radioactive isotopes.

Radioactive elements that occur naturally are considered part of Background radiation comes from anything that is part of the natural world that is around Because of this, you can easily conclude that radioactivity is not bad.

Samuel Ruben and Martin Camen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water.

Energy - Royal Society of Chemistry

However, because carbon dioxide is a natural product of combustion of a fossil fuel with oxygen, the only real way to reduce the amount of carbon dioxide output is to reduce fossil fuel consumption.

Alkalize For Health - Oxygen - Cancer Alternatives

The combustion reaction of a fossil fuel with oxygen releases water, carbon dioxide, and any impurities contained in the resource into the environment.

What are the Properties of Oxygen? - InnovateUs

All gases are less soluble as temperature increases, particularly nitrogen,oxygen and carbondioxide which become about 40-50% less soluble with anincrease of 25ºC.

The Quartz Page: Physical Properties

In the ocean where a pH of around8 is found, this becomes even less at 0.01 µmol/kg, which makeshydrogen ions twenty times scarcer than oxygen and 200 times scarcer thancarbondioxide.

AQA GCSE 9-1 Biology 1 Paper 1 separate science past …

Nuclear processes, including fusion, fission, and radio-active decays of unstable nuclei, involve changes in nuclear binding energies. The total number of neutrons plus protons does not change in any nuclear process. Strong and weak nuclear interactions determine nuclear stability and processes. Spontaneous radioactive decays follow a characteristic exponential decay law. Nuclear lifetimes allow radiometric dating to be used to determine the ages of rocks and other materials from the isotope ratios present.

Composition of seawater - Seafriends

Nuclear fission and radioactive decays limit the set of stable isotopes of elements and the size of the largest stable nucleus. Spontaneous radioactive decays follow a characteristic exponential decay law, with a specific lifetime (time scale) for each such process; the lifetimes of different nuclear decay processes range from fractions of a second to thousands of years. Some unstable but long-lived isotopes are present in rocks and minerals. Knowledge of their nuclear lifetimes allows radiometric dating to be used to determine the ages of rocks and other materials from the isotope ratios present.