Download pdf - Scientific work related to water

Scientific work

related to water

, May 2012 Augusta

How we did the workWe studied two rivers (Belelle and Mandeo) and two

intertidal zones (Ortigueira’s ria and Cobas beach).

Dates: November and March

Students involved: 1st ESO (12-13 year-olds), 2nd ESO(12-13 year-olds), 3rd ESO (14-15 year-olds), 4th ESO(15-16 year-olds) and 1st Bach (16-17 year-olds)

Subjects: Biology, Chemistry and Science for theContemporary World

We worked on the field, in the lab and in class.

We organised some conferences about these subjects.

Belelle and Mandeo river

Ortigueira’s ria:situation

Ortigueira’s ria

Cobas beach:situation

Cobas beach

Rivers

Aspects observed:

Parts of the course

Flora and fauna

Chemical data

Anthropogenicaction Pollution

Uses: energy, agriculture,recreation

Parts of the rivers’ course

High course

- The river has more inclination and carries little water.

- Due to the inclination the water is very oxygenated.

Middle course

- Higher flow; affluents; riparian forest.

Low course

- Forms part of the estuary.

The course of the rivers is divided in three parts:

Parts of the rivers studiedWe only observed and collected data in the middle course and

the low course of the rivers.

In the middle course the water is more dynamic and has moredisolved oxygen, so it is cleaner. This is the part where thewater for human supply (consumption) comes from.

The middle course of the river

The low course of the river• The low course is less dynamic and the quantity of disolved oxygen

is lower.

• The low course may be under the influence of tides.

Flora: the riparian forest

The riparian forest is one of the most outstandingfeatures of the river bank.

It follows the river course.It’s important for the conservation of the river course.Common trees: European alder, sycamore plane,

hazelnut tree, bay laurel and oak.


Sycamore plane Acer pseudoplatanus

Hazelnut treeCorilus avellana


In spring In autumn

FloraWild saffron

Royal fernOsmunda Regalis

FAUNA

Calopterix virgo Salamander

Erithacus rubeculaEuropean robin

Lutra lutraEuropean otter

Gerris lacustris

Chemical data

We measured temperature, pH, conductivity anddissolved oxygen in the middle course and the lowcourse of the river.

Chemical data

Part of the river

Temperature pH Conductivity Dissolved oxygen

Belelle river Middle course

9.6 ºC 6.64 190 S/cm 8.5 ppm

Low course 10.1 ºC 7.15 251 s /cm 8.3 ppm

Conclusions:

The highest pH and conductivity

are found in the low course due to

the influence of tides.

Chemical data: low course

Chemical data: middle course

Anthropogenic action

It’s noticeable all along the course ofthe riverIt has been present for a long timebecause water is very useful andnecessary, as some constructions wefound on the way bear witness to.Nowadays, there is still pressure dueto the same reasons

Some constructions in the river bank

ANTHROPOGENIC ACTION

POLLUTION We found some sporadic spots in the low course

UsesThe uses that we could observe were: householdconsumption, irrigation, farming usage, powergeneration, recreational uses

Waterwheel

Irrigation

Recreation

Uses

Hydroelectrical plant

Public washing place

Detour for consumption

Recreational uses

Intertidal zones

We studied two zones:

Ortigueira’s ria

Cobas beach

Intertidal zone

Zone of coast that is under water at high tide and above water at low

tide

Intertidal zone: substrate type

Intertidal zone: substrate type

Soft: sandy-muddy

High tide line: supralittoral zoneThe high tide line features species like:

Armeria flowers

Xantoria and Crythmun maritimun

Crythmun marking the high tide line

High tide line

Yellow Xantoria Zone

Green Seaweed Zone

Dun Seaweed Zone

Red Seaweed Zone

FLORA: seeweed

Dun seaweed

Green seaweed

Red seaweed

FLORA

Salicornia sp.Limonium sp.

Examples of plants that aren’t seaweed

Specific fauna

Limpet

AnemoneBalanus sp.

Monodonta sp. Litorina litoralis

Pollicipes cornucopia

Clams / Cardium edule

Holoturia

Intertidal zone:

occasional fauna

Cormoran

Purple sandpiper

Anas platyrhynchos

Larus argentatus

Dolphin family -Calderon

In the lab: seawater study

The aim of the study was:

To separate the seaweed’s pigmentsby paper chromatography.

To extract iodine from seaweed.

To measure the density of seawater.

A sample of seawater and seaweed was taken to the lab.

Seaweed chlorophyll

Extracting the pigments

Seaweed pigments

Filtering the extract

Seaweed pigments

Separating the green, red and brown pigments bypaper chromatography

Density of seawater

Finding out the density of seawater by weighting

Density of sea water. Results

Mass

(g)

Volume(cm3)

Density

(g/cm3)

25,51 25 1.020

25,49 25 1.019

25,47 25 1.019

Density (g/cm3) 1.019

The density of sea water in Cobas beach is 1019 kg/m3

Uses– Fishing

– Recreation

– Energy: waterwheel

– Gathering seaweed for different uses

Changes and pollution

Private property, law isn’t respected. No public walking path

Rats: waste waters