Plankton Sampling: The Chelsea Plankton Sampler provides a modern replacement for traditional sampling mechanisms such as that used in the Continuous Plankton Recorder (CPR) programme of the Sir Alister Hardy Foundation for Ocean Science (SAHFOS).
Plankton sampling provides invaluable insights into numerous aspects of plankton dynamics and ecology including: climate change, biodiversity and biogeography, eutrophication, harmful algal blooms, fisheries investigations, plankton ecology, taxonomy, regime shipts and non-indigenous species.
The Plankton Samplier is ideally suited for use in undulating bodies such as the NuShuttle, to enable discrimination of zooplankton variability with depth. It is designed to operate autonomously, collecting zooplankton samples within a user programmable index advanced filter mesh, for post mission laboratory analysis. It can also be fitted to onboard flow-through systems (such a FerryBox type systems).
- Applications and Features
- Fisheries research
- Plankton studies
- Fixed depth and undulating towed vehicles
- Pumped systems
- Onboard batteries and microcontroller
- Hydrodynamics closely matched to the Hardy sampler
- Integral flow meter
- Integral 6 channel data logger
- Uses standard 270 mm mesh silk or 80 mm nylon gauze
- Pre-programmed or commanded sampling
The Autonomous Plankton Sampler is the result of a collaborative venture between the Centre for Coastal Marine Science and Chelsea Technologies Group to design and develop a new versatile, low-cost plankton sampler mechanism. The Autonomous Plankton Sampler is intended for use in Chelsea’s NuShuttle and AquaShuttle towed vehicles as well as ship-borne and mooring pumped deployments. It also provides a modern replacement for traditional sampling mechanisms such as that used in the Continuous Plankton Recorder (CPR) programme of the Sir Alister Hardy Foundation for Ocean Science (SAHFOS).
The Autonomous Plankton Sampler incorporates an internal programmable data logger controller and battery pack coupled with state of the art electric motor technology to drive the gauze advance mechanism. Gauze advance, battery low and memory full flags are logged after every gauze advance. The Autonomous Plankton Sampler provides data logging for six external environmental sensors along with the capability to trigger the gauze advance protocol from an external source such as MINIpack or other CTDs. Provision has been made for the inclusion of a flow meter if required. The system is intended to meet the requirements of sampling programmes for the 21st Century, whilst maintaining backward data compatibility with the 60-year time series of the CPR and other long-term monitoring programmes. The sampler sensor suite is optimised to meet the requirements of programmes such as GOOS, EuroGOOS, the Large Marine Ecosystems (LME) programme and the US National Marine Fisheries Service.
Instrument Software: The Graphical User Interface (GUI) is a 32-bit Windows application used to programme the controller. Error detection is used on all data transfers. The plankton sampler screen allows the operator to set the frame advance rate based on either time, chlorophyll-a or flow.
- Mechanism Design
The Autonomous Plankton Sampler is constructed in stainless steel with two spools of either silk or nylon gauze, integral microcontroller, motor, batteries and flow meter. On towing, or pumping, the water passes through the intake aperture. The zooplankton are captured upon a filtration gauze which is then covered by a second gauze and wound on to a collection spool immersed in preservative. Post-deployment analysis is undertaken either on gauze or wash off.
- The hydrodynamics of the water intake into the sampling mechanism closely matches that of the existing Hardy mechanism. This is intended to maintain continuity between the samples collected during the last 60 years by the CPR programme and those that will be collected using the new system.
- The electric motor permits the use of an electronic controller, and the ability to programme a complete tow in terms of sampling duration before each gauze advance. External advance on demand is also available.
- The onboard microprocessor also enables such features as early gauze advance to be incorporated, for example by high chlorophyll levels. The option of sensing the pressure differential across the gauze permits advance when the onset of clogging is indicated.
- Measurement of flow through the device can be incorporated in the mechanism exhaust. The controller/logger system permits logging of gauze advance, flow rate, together with output from external sensors, all date and time stamped.
- Standard silk gauze (270mm mesh) is used (the spool being capable of holding up to 6 metres). Nylon gauze may also be used, permitting sample wash-off and allowing the use of mesh sizes down to 80mm for quantitative sampling of juvenile stages and smaller copepods.
- All gauze is provided in lengths of 6 metres.
- The mechanism can be used in undulating bodies such as the Chelsea Technologies Group NνShuttle, to enable discrimination of zooplankton variability with depth.
- The mechanism has been simplified to obviate the need for skilled operators to set up prior to deployment.
Size: 140mm x 235mm x 291mm Weight: 12.75Kg Depth Rating: 200 metres Operational duration: 2 to 4 weeks Batteries: 6 x 1.2V primary cells Time between gauze advances: 15 secs to 1 year Switch on: Internally programmable or external trigger Preservation: Formalin tank Gauze size: 80 to 400 µm range Filtration area: 50 x 100 mm Inlet port: 25 x 100 mm Maximum tow speed: 25 knots
Video shows the Plankton Sampler being deployed from a NvShuttle towed oceanographic vehicle while on trial in China