The ocean contains 97% if the water in the biosphere. Approx. 2% is bound in glaciers and polar ice caps which the remaining 1% is in lakes, rivers, and groundwater.
The main processes in the water cycle are evaporation, condensation, and precipitation.
Photosynthesis removes substantial amounts of atmospheric CO2 each year. This quantity is approx. equaled by CO2 added to the atmosphere through cellular respiration by producers and consumers. The burning of fossil fuels is adding significant amounts of additional CO2 to the atmosphere.