• Microscopic image of harmful algal bloom phytoplankton


Rapid in-situ phytoplankton monitoring to support marine aquaculture and long term climate change

Phytoplankton form the base of the marine food web. Through their primary production they are crucial to carbon cycling. Some species that form "harmful algal blooms (HABs) are harmful to human health and/or finfish and shellfish aquaculture operations.

There are many thousands of species of phytoplankton. The diversity in responses of these to changing environmental conditions means that long term time series are required to understand the role of environment/climate in driving the productivity and biodiversity of our oceans. 

Phytoplankton increases (blooms) can occur over short timescales (days). Should blooming species be harmful, rapid early warning is required for the aquaculture industry and its regulators to protect human health (from HAB generated toxins that are vectored to humans by shellfish) and minimise mortalities, as a consequence of other HAB genera, of farmed fish.

At present, the time and cost to analyse phytoplankton samples by microscopy or molecular methods prevents the high resolution monitoring required to a) understand climate effects and b) provide rapid early warning to the aquaculture industry and its regulators of HAB events.

A solution to this problem is the Imaging FlowCytobot (IFCB). This is an in-situ automated submersible imaging flow cytometer that also generates images of phytoplankton in-flow.

The IFCB allow real time (every 20 minutes) monitoring of phytoplankton including HAB events.  Once the instrument is "trained", images can be automatically classified to genus or even species level with accuracy comparable to that of human experts. Data are therefore comparabe in quality with traditional microscope counts but are obtained at a much higher temporal resolution.  

Data collection is achieved through a novel combination of flow cytometric and video technology to capture high resolution images of suspended particles. Laser induced fluorescence and light scattering from individual particles are measured and used to trigger targeted image acquisition; the optical and image data are then transmitted to shore in real time.

Images collected during this continuous monitoring are processed with automated image classification software.

The IFCB can be deployed from a raft or pier to track the progression of annual phytoplankton cycles or HAB events. It can also be configured to sample from shipboard underway seawater systems, allowing phytoplankton communities to be monitored continuously along cruise routes.

IFCBs have been used to collect data in a range of environments ranging from Florida to the Arctic with, e.g., the first harmful bloom so the shellfish biotoxin producing dinoflagellate Dinophysis being revealed by use of an IFCB (Campbell et al. 2010 J Phycol 46:60-75). IFCBs are now also being utilised for harmful algal bloom detection in Scandinavia and New Zealand.

At present, there is no IFCB or similar capability in the UK. This instrument will therefore provide a step change in the capability of UK environmental science to monitor phytoplankton and provide early warning of the HABs that impact aquaculture.

In this project we propose to purchase, train and deploy at IFCB in UK coastal waters allowing, for the first time, the production of the long term, temporally resolved data sets we require to understand the environmental control of phytoplankton and HABs in UK waters.

The instrument will ordinarily be located at the Marine Scotland Coastal Observatory in Shetland close (a major site of aquaculture). IFCB data will be made freely available in real time via our web portal (www.HABreports.org) in a similar manner to an instrument in the Gulf of Mexico. Our own expert data interpretation will enhance its benefit for aquaculture practitioners.  The IFCB will therefore provide a long term data resource for scientists, policy makers the aquaculture industry and its regulators.