Halmos Faculty Studies Oceanographic Structures and Light Levels

In February, Halmos College biology faculty members Matthew Johnston, Ph.D. and Tracey Sutton, Ph.D. were two of the authors for a Frontiers in Marine Science article, “Oceanographic Structure and Light Levels Drive Patterns of Sound Scattering Layers in a Low-Latitude Oceanic System”.

The oceanic biome is approximately 71% of the planet’s area and much more of the planet’s living space by volume, yet it remains vastly understudied. This paper discusses the research looking at one of the most conspicuous features of this biome: the persistent and ubiquitous sound scattering layers formed by zooplankton and micronekton.

These organisms are responsible for the Earth’s largest animal migration, a process known as diel vertical migration. This paper looks at several factors have been reported to structure the spatial and temporal patterns of sound scattering layers, including temperature, oxygen, salinity, light, and physical oceanographic conditions. Results indicate correlations in the vertical position and acoustic backscatter intensity of sound scattering layers with oceanographic conditions and light intensity. The importance of biotic (primary productivity) and abiotic (sea surface temperature, salinity) factors varied across oceanographic conditions and depth intervals, suggesting that the patterns in distribution and behavior of mesopelagic assemblages in low-latitude, oligotrophic ecosystems can be highly dynamic.