Getting intimate with aquatic sediments

Getting intimate with aquatic sediments

The Unisense profiler’s microsensors can measure a range of variables. (Photo: Lee Bryant, Virginia Polytechnic Institute)

NIWA’s new micro-profiler enables us to study biogeochemical processes in aquatic sediments at a remarkably fine scale.

The profiler can take measurements on the seabed (or lake floor) in up to 100 m water depth. Several microsensors automatically probe into the sediment at increments of as little as 50 micrometres (about the width of a human hair). These can capture such things as chemical gradients that result from production, consumption, and transport of dissolved matter within the sediment and in the overlying water.

Future marine applications include:

  • monitoring the breakdown of organic matter beneath marine farms,
  • determining the condition of the seafloor environment in estuaries to develop indicators of estuarine health,
  • studying nutrient cycling in subtidal ecosystems in support of resource management decisions.

The profiler’s first outing, however, is to the perennially ice-covered lakes Hoare and Fryxel in Antarctica, where it’s being used to study mat-forming microbes.

Research subject: Oceans