AGU: Geophysical Research Letters

 

Editors' Highlight

Aerial infrared imaging reveals nutrient-rich groundwater plumes off Hawaii's west coast

Although most freshwater entering the world's oceans comes from rivers, nutrient inputs into coastal environments via submarine groundwater discharge (SGD) are disproportionately large. Groundwaters typically contain high concentrations of dissolved chemicals, making SGD important to phytoplankton and algae growth patterns and thus critical to healthy aquatic habitats. SGD has also been suggested as stimulating harmful algal blooms and as a pathway for pollution dispersion into the ocean. Noting that human populations are increasingly reliant on resources within coastal zones, Johnson et al. (2008) conducted airborne surveys using thermal infrared (TIR) sensors to determine how much SGD is escaping into the waters off the western side of the island of Hawaii. Groundwater is the only significant source of freshwater and new nutrients to this area's coastal ocean. The authors used TIR imagery to pinpoint input locations and detail fine-scale dispersal patterns of groundwater discharging as both diffuse flow and point-source plumes into the region's coastal zone. They further showed how nutrient mixing trends can be integrated into TIR sea surface temperature to produce surface water nutrient maps.

View abstract

View full article (Subscription required)