Investigating the Relationship Between Dissolved Oxygen and Nitrate Concentration as a Proxy for Marine Ecosystem Health

Coastal environments such as seagrass meadows span a wide range of spatial scales and can experience disturbances that cause rapid shifts to ecosystem dynamics. Increased pressure to the coastal zone has highlighted the need for constant, real-time monitoring to monitor current ecosystem status. A custom, low cost, high resolution, in situ sensor network was designed and tested in the Lower Laguna Madre, Texas to characterize primary productivity in seagrass meadows through gradient patterns of dissolved oxygen concentration, with the purpose of determining whether seagrass or phytoplankton were the more dominant primary producer. There was a distinct vertical and horizontal gradient of dissolved oxygen concentration over a clear diel cycle within densely vegetated seagrass patch sites. The pattern indicated that seagrasses were the dominant primary producers in the system, which has implications for other ecosystem dynamics such as the locations of hyperoxia or thermal refugia for marine species