This data represents the average data of one hundred experimental measurements of a laboratory "microecosystem" that was constructed to mimic the flora and fauna of the San Marcos River in Texas, U.S.A. The light was carefully controlled so that the ecosystem experienced a "perfect" 12 hour day.
At dawn, there were 2.600 mmol of CO2 per liter of water.
Time (hrs past dawn) Rate at which CO2 enters/leaves (mmol/liter/hr) -------------------- ------------------------------- 0 0.0 1 -0.042 2 -0.044 3 -0.041 4 -0.039 5 -0.038 6 -0.035 7 -0.030 8 -0.026 9 -0.023 10 -0.020 11 -0.008 12 0.0 13 0.054 14 0.045 15 0.040 16 0.035 17 0.030 18 0.027 19 0.023 20 0.020 21 0.015 22 0.012 23 0.005