The twilight zone is a section of water extending from the euphotic zone down to 1000m. A new study demonstrates that this region acts like a gate and that little makes it to the seafloor.
…carbon dioxide –taken up by photosynthesizing marine plants in the sunlit ocean surface layer–does not necessarily sink to the depths, where it is stored and prevented from re-entering the atmosphere as a greenhouse gas.
Instead, organisms in the twilight zone consume the material (50-80%) long before it reaches the murky depths. Understanding these processes are important for predicting the role of the deep ocean in sequestering carbon for long geological times.
“Unless the carbon that gets into the ocean goes all the way down into the deep ocean and is stored there, the carbon can still make its way back into the atmosphere. Without this long-term storage, there is little influence on atmospheric levels of carbon dioxide, a greenhouse gas that impacts the earth’s climate.”
image from Science Daily