Diel Oxygen Measurements Lab Report Example | Topics and Well Written Essays - 750 words - 1

Diel Oxygen Measurements - Lab Report Example The water may be used in anthropogenic activity such as cooking and laundry. Measurement of diel changes in dissolved oxygen concentrations of freshwater systems is a widely accepted method of examining its productivity. It measures the dissolved oxygen concentrations twice a day (sunrise and sunset) to determine the gross productivity and respiration of the system (Van de Bogert, 2007). This is based on the carbon dioxide-acquiring and oxygen-producing photosynthesis, as well as the carbon dioxide-producing and oxygen-acquiring respiration. It is thus to be expected that the oxygen is highest during the sunset because the sunlight-requiring photosynthesis happened during the day, and lowest during the sunrise because photosynthesis does not occur to offset respiration (Hansom et al., 2003). In this light we may also expect that the surface is more productive at the bottom than at the surface, because it is more difficult for sunrays to hit deeper areas of the water. The objective of this experiment was to measure the productivity of aquatic systems in San Joaquin Marsh. Specifically, the researchers aimed to measured the dissolved oxygen concentration on the bottom and surface of the marsh, to calculate the productivity/respiratory ratio, and to assess whether the surface and bottom are autotrophic (productivity/respiratory > 1), or heterotrophic (productivity/respiratory Dissolved oxygen concentrations were measured at the surface and bottom of 8 different ponds on the site from Monday, 6:00 am sunrise and 7:45 pm sunset, to Tuesday, 6: 00 am sunrise. After data gathering, productivity/respiratory ratios were calculated as