Question

lungs of the planet continued
plants on land are not the only organisms that photosynthesize. phytoplankton
in the oceans could also be a big part of global oxygen production. to compare
the amount of oxygen that might be produced by different ecosystems, we want to
be able to measure not just npp, but the total amount of photosynthesis and the
total amount of cellular respiration within the ecosystem. this value of total
respiration and decomposition accounts for all organisms - including animals.
gross primary productivity is measured by the total amount of carbon (from
carbon dioxide) that is taken up by photosynthesis. (a negative number means
carbon is being taken out of the atmosphere.)
if we subtract the total amount of carbon that is released into the atmosphere from
decomposition and cellular respiration, we can figure out how much carbon is
being taken up in oceans and on land.
table 5 below presents data on the amount of photosynthesis, cellular respiration,
and decomposition that occurs on land and in the oceans. remember, the more
carbon dioxide that is taken up, the more oxygen that is produced. table 5 shows
total global carbon uptake and release typical in the 1990s. the abbreviation gt
stands for gigatonne, which is equivalent to one billion metric tons (tonnes). one
major source of carbon that is not represented in this table is release from the
burning of fossil fuels (approximately 6.3 gt/year).
table 5. worldwide primary productivity, cellular respiration, and carbon
uptake in the 1990s. negative numbers indicate that carbon dioxide is being taken
up and positive numbers indicate that carbon dioxide is being released into the
atmosphere.

1. data analysis based on the data in table 5, compare the amount of oxygen

that is being released (accounting for the amount used) by producers in the
oceans versus producers on land.

Explanation:

The problem involves comparing oxygen production (related to carbon uptake as more carbon dioxide uptake means more oxygen production) by producers in oceans and on land. The data in the table shows gross primary production (related to carbon uptake) and net production of carbon. The ocean has a lower (more negative in terms of carbon uptake which correlates to more oxygen release considering the relationship) net production of carbon (-1.7 Gt C/yr) compared to land (-1.4 Gt C/yr). Since more carbon uptake (as per the context where negative numbers for carbon uptake imply more oxygen - as carbon dioxide uptake is part of photosynthesis which produces oxygen) is associated with more oxygen release (accounting for usage as per the problem statement), the ocean producers release more oxygen.

Answer:

The ocean producers release more oxygen than the terrestrial producers.