Sampling techniques Flashcards
What is essential to define before collecting zooplankton samples?
The scientific question being asked
This shapes the sampling strategy.
What are key considerations when defining the scientific aims of zooplankton sampling?
- Biodiversity
- Abundance
- Biomass
- Species composition
- Behaviour
What are the process scales that should be considered in zooplankton sampling?
- Short-term local scales
- Long-term climatic scales
What approaches can be taken in zooplankton studies?
- Theoretical
- Experimental
- Observational
What elements are included in the work plan for zooplankton sampling?
- Sampling locations
- Frequency
- Resolution
- Sample size
- Pooling strategies
- Abiotic factors
- Analysis techniques
What is the main challenge in sampling zooplankton?
No single piece of equipment works equally well for all species and sizes
What factors influence the choice of sampling gear for zooplankton?
- The scientific question
- Where, when, and how the sampling is done
- Literature reviews
What does the Western Channel Observatory (WCO) track?
Biodiversity and oceanographic changes off Plymouth
What method does the CMarZ (Census of Marine Zooplankton) use?
Multi-net systems to capture zooplankton at various depths
What type of sampling does the Atlantic Zone Monitoring Programme conduct?
Regular sampling at fixed sites and across transects
What is the focus of the Atlantic Meridional Transect (AMT)?
Compares productivity between upwelling zones and subtropical gyres
What types of water sampling bottles are mentioned for zooplankton collection?
- Niskin
- Go-Flow
What is a problem associated with using water sampling bottles for zooplankton?
Patchiness; one bottle may hit a plankton patch while another misses
How do plankton pumps operate?
Water is pumped through a mesh net and measured with a flowmeter
What is the maximum depth for deck-operated plankton pumps?
~80m
What are the three main components of nets used in zooplankton sampling?
- Weighted frame
- Mesh fabric
- Cod-end (collection bottle)
What does Filtration Efficiency (FE) measure?
How much water actually flows through the net mesh compared to the theoretical volume
What does Open Area Ratio (OAR) compare?
The open filtering area to the net mouth area
What effect does mesh size have in zooplankton nets?
Controls the size of zooplankton captured
What happens if the towing speed of a net is too fast?
Water backs up and bypasses the net
What are mouth cones used for in net design?
Reduce turbulence at the net opening
What do rigid body nets (Gulf Sampler) protect?
Delicate species at higher tow speeds
What do jet nets reduce in terms of flow speeds?
Internal flow speeds to protect fragile plankton
What are Bongo Nets?
Twin nets with different mesh sizes for comparative sampling. They can be closed to isolate depth layers.
