Imaging plankton to understand Gulf of Mexico ecology and potential interactions with oil

Adam T. Greer

Assistant Research Professor

adam.greer@usm.edu

Deepwater Horizon (April 20, 2010) – 11 lives lost

Below the surface

https://www.whoi.edu/oceanus/feature/where-did-deepwater-horizon-oil-go

?

What is plankton?

Holoplankton

Meroplankton

Phytoplankton(O2 production)

Zooplankton Marine Snow

Planktos – “wanderer” or “drifter”

Why do we care about plankton?• Critical link in the food web

• Early life stages of many animals (meroplankton)

• “Canaries in the coal mine”

• Marine snow exports carbon and can entrain other materials (e.g., oil)

CONCORDE – nGOM river-dominated shelf ecosystem

Critical area for:1) Fisheries2) Transport

processes (river plumes, fronts, winds, etc.)

Plankton ecology links these two topics!

Greer et al. 2018 Oceanography 31(3)

Conventional plankton sampling methods

• Bongo nets

• Multiple Opening and Closing nets• Better vertical resolution

• Minimum vertical scale is at least 10 m, horizontal scales of 100’s of meters

• Biases in organism detection

New Optical Systems• High resolution (cm to m scale)

• (Semi or fully) automated data processing

• Fewer biases among different organisms (sample gelatinous plankton well)

• Sample volumes & imaging techniques

• Most are towed or profiled

Images from Benfield et al. 2007

Video Plankton Recorder (Davis et al. 2004)

Underwater Video Profiler (Gorsky et al. 2001)

Large Area Plankton Imaging System (Madin et al. 2006)

• Line-scan camera

• Motor actuated wings

• 16-17 images per second (12 cm * 12 cm * 50 cm)

• 2 TB of image data every 3.5 hours

In Situ Ichthyoplankton Imaging System

Sample plankton and water properties to describe…

• Physical structure• Temp, salinity, light, oxygen

• Fronts, eddies, internal waves

• Currents

• Biological structure• Patterns produced by

feeding and predation

• Competition

• Social interactions

Both relevant to ocean ecology and oil/pollutant exposure rates

Chiaverano et al. in prep

Plankton thin layers

• Common in many coastal areas – not well-studied in the GOM

• Ecological significance: concentrated feeding zones (community composition matters)

• Affect predicted oil exposure rates

GOM thin layer during summer (July 24, 2016)

4.3 cm

Zooplankton around the thin layer

Take Home Message(s)

• Imaging data revealing key relationships between planktonic organism abundance and oceanographic properties.

• This information is needed to determine which organisms will be exposed to oil in the event of a spill.

The ISIIS data are complex.

Behavioral interactions Size and orientation information

Thank You!adam.greer@usm.edu

Marine snow • Abundance and distribution • Shapes (indicate sinking)