Planktology seminars

Distinguishing diatom and dinoflagellate blooms in Chesapeake Bay is difficult because its waters are optically complex and field observations rarely coincide with satellite measurements. This project combines historical phytoplankton observations, NOAA satellite bloom products, geospatial processing and ecological information in a reproducible workflow. Quality control addresses mixed pixels, land contamination, cloud, missing observations, saturation and inconsistent coordinates. Of 31,531 field-to-satellite records, 860 initially pass validation; neighbouring pixels offer further recoverable data. A preliminary Mini U-Net illustrates segmentation feasibility but exposes weak automatic labels, motivating interactive expert validation and masking. Seasonal phenology and environmental variables are evaluated as features for future multimodal models. The NOAA NERTO project was mentored by Michelle Tomlinson and Sachidananda Mishra at NCCOS.

I shall present two recent piece of work investigating how shape effects the transport of active particles in shear. Firstly we will consider the sedimentation of particles in 2D laminar flow fields of increasing complexity; and how insights from this can help explain why turbulence can enhance the sedimentation of negatively buoyant diatoms [1]. Secondly, we will consider the 3D transport of elongated active particles under the action of an aligning force (e.g. gyrotactic swimmers) in some simple flow fields; and will see how shape can influence the vertical distribution, for example changing the structure of thin layers [2]. [1] Enhanced sedimentation of elongated plankton in simple flows (2018). IMA Journal of Applied Mathematics W Clifton, RN Bearon, & MA Bees. [2] Elongation enhances migration through hydrodynamic shear (in Prep), RN Bearon & WM Durham.