Techniques for the Quantification Density of Microplankton Populations
275
cross stand (8). In its upper part it has a ring (9) made of soft rubber, rising
for 0.5 mm up the surface, which provides for hermetization of the chamber.
The cup (B) is supplied with crossing stainless steel wires (11) which support
the filtering membrane. The body has one, and the cup two connections for
the passing of water (1,3) and one for avoiding air bubbles during the filling
of the chamber (2). The same connection (2) serves for the discharge uf CUllcentrated phytoplankton from the chamber. The filtration system is combined
as shown in Fig. 6.2.
The Nucleopore filtering membranes of 0.8-1.2-llm pore size are cut into
88-cm squares and soaked in a weak Trilon B solution. The membranes can be
used several times. For this, after the filtration procedure is finished, the used
membranes are collected and washed in a hot detergent solution. After thorough rinsing with hot water, they are dried and can be used again.
To start the filtration procedure, the freshly taken sample is poured into
the bottle A (Fig. 6.2), having 1-1 marks on its wall. The exit tube is attached
to the connection 3 of the combined funnel (Fig. 6.1). The funnel is turned on
its side the connection 2 placed upwards and the clamp on the tube attached
to the connection 2 is opened. Then by opening the clamp on the tube the
chamber is completely filled with water, which is passed through the filter and
also fills the upper chamber. The funnel is returned to its normal position,
being filled with no air bubbles inside, and filtration begins. When a needed
volume of water is thus passed through the funnel, all clamps are closed. Both
tubes are disconnected from the funnel, the clamp on connection 3 is opened,
and approximately one third of the water is discharged into 50-ml serum bottle
by opening clamp on connection 1. Then both clamps are closed again, and the
contents of the chamber is shaken by circular movements to wash out the algae
A
c
B
Fig. 6.2. A stand for inverse filtration funnel. A
Sample; B funnel; C sink for filtrate
275
cross stand (8). In its upper part it has a ring (9) made of soft rubber, rising
for 0.5 mm up the surface, which provides for hermetization of the chamber.
The cup (B) is supplied with crossing stainless steel wires (11) which support
the filtering membrane. The body has one, and the cup two connections for
the passing of water (1,3) and one for avoiding air bubbles during the filling
of the chamber (2). The same connection (2) serves for the discharge uf CUllcentrated phytoplankton from the chamber. The filtration system is combined
as shown in Fig. 6.2.
The Nucleopore filtering membranes of 0.8-1.2-llm pore size are cut into
88-cm squares and soaked in a weak Trilon B solution. The membranes can be
used several times. For this, after the filtration procedure is finished, the used
membranes are collected and washed in a hot detergent solution. After thorough rinsing with hot water, they are dried and can be used again.
To start the filtration procedure, the freshly taken sample is poured into
the bottle A (Fig. 6.2), having 1-1 marks on its wall. The exit tube is attached
to the connection 3 of the combined funnel (Fig. 6.1). The funnel is turned on
its side the connection 2 placed upwards and the clamp on the tube attached
to the connection 2 is opened. Then by opening the clamp on the tube the
chamber is completely filled with water, which is passed through the filter and
also fills the upper chamber. The funnel is returned to its normal position,
being filled with no air bubbles inside, and filtration begins. When a needed
volume of water is thus passed through the funnel, all clamps are closed. Both
tubes are disconnected from the funnel, the clamp on connection 3 is opened,
and approximately one third of the water is discharged into 50-ml serum bottle
by opening clamp on connection 1. Then both clamps are closed again, and the
contents of the chamber is shaken by circular movements to wash out the algae
A
c
B
Fig. 6.2. A stand for inverse filtration funnel. A
Sample; B funnel; C sink for filtrate