Earth Sciences New Zealand is using satellite data and new strategic sampling to link sea surface sediment plumes to seafloor productivity at broad scales.
Increased erosion from land via rivers is a top threat to coastal environments. Suspended sediment limits light levels on the seafloor, which impacts photosynthesis in ecosystems that support marine flora and fauna.
To date, tracking land-to-sea sediment plumes has been limited by available technology, and no one has yet attempted to link sediment levels to what is happening on the seabed.
Plugging this knowledge gap will improve land-to-sea management efforts, leading to healthier coastal seafloor ecosystems that support vital fisheries and an array of cultural and societal uses.
Technology spanning space to sea
Earth Sciences New Zealand researchers will combine satellite imagery of the Hauraki Gulf with new strategic sampling of seafloor photosynthesis rates.
Innovative aquatic eddy covariance (AEC) instrumentation with high frequency oxygen sensors will be used to calculate rates of photosynthetic oxygen production on the seafloor and determine how this production varies with seafloor light intensity.
Twenty sites covering various habitats, depths, topographies and sediment types will be analysed at different times.
The AEC information will be coupled to a twenty-year record of seabed light derived from satellites, providing a series of maps of seabed primary production covering an 8,000km2 area of the Hauraki Gulf. Analysis of storm and non-storm periods will elucidate how sediment run-off impacts seafloor productivity—a key ecosystem function.
International collaboration
The research team including researchers from the USA, Belgium, and the University of Otago and will partner with Hauraki Māori Trust Board representatives, Auckland and Waikato Regional Council scientists, and leaders of the Revitalising the Gulf governmental response to the Tai Timu Tai Pari Hauraki Gulf Marine Spatial Plan.
