[ Study of meso and microhabitat ofMargaritifera auricularia on the river Ebro in Burgos ]

The production of microalgae and other microscopic photosynthetic organisms (such as cyanobacteria) is an important parameter for the survival of pearl-mussels, as they are a main source of food through filtration in their gills of river water. In order to know the level of this primary production along the altitude profile of the studied section of the river Ebro, a campaign was carried out in July to measure the levels of photosynthetic pigments (chlorophyll “a” and phycocyanins) in the water.

Phycocyanins are ficobilinic pigments (a blue metal-free chromoprotein) that are typical of cyanobacteria (formerly called cyanophycean or blue-green algae). They function as light-absorbing substances to perform photosynthetic function, together with chlorophylls: particularly about 500 nm (absorbs orange and red light) and fluoresce about 700 nm.

For this work objective, classical techniques have been used for the extraction, after filtering 1 L of river water, of chlorophyll “a” using acetone and measuring its selective absorption of light at 4 wavelengths (spectrophotometry); and also using a field fluorometer (MatrixFlu VIS).

Fluorescence chlorophylls measurements

These portable optical sensors make it possible to calculate the concentration in real time and at the foot of the river of these photosynthetic pigments and also of the dissolved coloured fraction (CDOM) in water, coming from humic substances.

MatrixFlu VIS allows the visualization of your measurements through a proprietary interface that can also be consulted in the field using a G2-Interface Boxconnection (©TriOS) on a portable device such as a tablet or telephone.. You can also connect to a Tribox3 controller (©TriOS) and program warning alarms.

” Study for the improvement of the knowledge of the population situation of Margaritifera auricularia in Castilla y León. EN04-19 ”