The historical roots of plankton sampling go back to the first 19th century when Thomson invented a net to sample crab and barnacle larvae. Plankton nets could also be a specific tool commonly used for this study.A plankton net is used to collect plankton samples in stagnant water. It consists of a towing line and harness, a nylon mesh net, and a cod-end. Plankton nets are said to be one of the oldest, simplest, and least expensive methods of sampling plankton.
Well, this is where I used a word called “planktons,”…. So let us know as well…
What Are Planktons?
So let me explain it to you briefly; the diverse collections of organisms found in water that cannot propel themselves against a current are named planktons. They provide an essential food source for many small and massive aquatic organisms such as mussels, fish, and whales in the ocean.
Plankton includes plants and animals at the mercy of the tides and currents of the sea. Her name comes from Greek and means “drifter” or “wanderer.”
They exist in both freshwater and marine environments. There are two different types of plankton – phytoplankton, the vegetable plankton that makes its food, and zooplankton, the animal plankton that grazes on the phytoplankton.
Now let’s go back to the actual topic. The plankton nets are commonly used for both vertical and horizontal sampling. It enables researchers to analyze plankton quantitatively (cell density, cell colony, or biomass) and qualitatively (e.g., chlorophyll-a as the primary production of phytoplankton) in water samples from the environment.
Structure Of The Plankton Network
The upper part of a plankton net consists of a dragline connected to a three-point harness, with a nylon net in the middle responsible for holding the plankton net. There is a cod-end – and exhaust valve with a collection cylinder.
First, let’s briefly mention the top part. The dragline and harness are the upper part of a plankton net and usually hold it. The tow lines associated with Triangulum harnesses are made of nylon rope and can be adjusted to level A that suits the user.
Then we have The nylon mesh, which is also the middle part of the plankton net and is used to filter out the plankton in the water sample according to the dimensions of the mesh. In addition, its funnel allows you to catch plankton of different sizes effectively.
Last but not least, The codend is located at the bottom of the plankton net at the top of the funnel. It is a collecting cylinder and an opening and closing valve.
Who Uses These Plankton Nets?
Usually, a plankton net is used by scientists (mostly Aquatic Scientists). It is made of very fine meshes to collect plankton easily. Scientists generally tow a plankton net behind a boat for collection. The mesh used in a plankton net has holes that allow water to pass through but are small enough for plankton not to pass through.
A standard method of collecting a plankton sample is to pull the net horizontally with a slow boat. Someone should rinse the net with the sample water before collecting the plankton.
Here the user should ensure that the codend is fully closed by turning the valve to a vertical position. Then the plankton net is lowered horizontally to the water surface on the side of the slow-moving boat. The sampling takes place for 1.5 minutes. After the time is over, the plankton sample is collected in a sample bottle by opening the codend above by turning the valve horizontally.
When the sample is collected, analyze it with a microscope to identify the species of zooplankton or phytoplankton or a cell count, which can be performed to determine the plankton cell density of the water source.
What Do Scientists Think Of This?
Oceans, rivers, lakes, and streams play an essential role in the world and the environment. Scientists can assess the health of our ocean ecosystems by taking samples of zooplankton and ichthyoplankton (fish eggs and larvae) from both the surface and the depths.
Observations of this plankton can tell us much about the productivity at the bottom of the food chain, the spawning location and adult stock size, the dispersal of fish larvae and crabs from the nursery grounds, and the transport of ocean currents.
Worth Knowing Facts About Plankton Nets
Two types of plankton nets come in handy when sampling plankton; the Neuston Net and the Bongo Net.
A poorly chosen mesh can prove fatal to a plankton study. In practice, unsuitable nets result in inefficient use of time and space on ships, crew exhaustion, clogging, extrusion, flight or avoidance of target species, etc.
That’s all the necessary information about plankton and plankton nets. I hope this content was helpful to you!!!