Scientific work related to water

, May 2012 Augusta

How we did the work We 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 the Contemporary 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 Anthropogenic

action 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 studied We 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 more

disolved oxygen, so it is cleaner. This is the part where the water 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 outstanding

features 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.

Flora: the riparian forest

Sycamore plane Acer pseudoplatanus

Hazelnut treeCorilus avellana

Alder Alnus glutinosa

Flora: the riparian forest

Bay laurel

Laurus nobilis

Oak

Quercus robur

In spring In autumn

FloraWild saffron

Royal fernOsmunda Regalis

Willow - Salix sp.

Celery - Apium graveolens

FAUNA

Chysomela menthastri

on mint leaf

Mint beetleTemporary frog

Calopterix virgo Salamander

Erithacus rubeculaEuropean robin

Lutra lutraEuropean otter

Gerris lacustris

Chemical data We measured temperature, pH, conductivity and

dissolved oxygen in the middle course and the low course of the river.

Chemical dataPart of the river

Temperature pH Conductivity Dissolved oxygen

Belelle river Middle course

9.6 ºC 6.64 190 µS/cm 8.5 ppm

Low course 10.1 ºC 7.15 251µs /cm 8.3 ppm

Conclusions: The highest pH and conductivity are found in the low course due to the influence of tides.

Portable digital Multiline P3 WTW

Chemical data: low course

Chemical data: middle course

Anthropogenic action

It’s noticeable all along the course of the riverIt has been present for a long time because water is very useful and necessary, as some constructions we found on the way bear witness to. Nowadays, there is still pressure due to the same reasons

Some constructions in the river bank

ANTHROPOGENIC ACTION

The riparian forest has diminished due to the invasion of pastures

POLLUTION We found some sporadic spots in the low course

UsesThe uses that we could observe were: household consumption, irrigation, farming usage, power generation, recreational uses

Waterwheel

Irrigation

Recreation

Uses

Hydroelectrical plant

Public washing place

Detour for consumption

Recreational uses

Agriculture and livestock

Intertidal zones

We studied two zones: Ortigueira’s ria Cobas beach

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

Intertidal zone: substrate type

Hard: rocky

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

LimpetAnemone

Balanus sp.

Monodonta sp. Litorina litoralis

Carcinus maenas

Pollicipes cornucopia

Clams / Cardium edule

Martesterias glaciaris

Holoturia

Intertidal zone: occasional fauna

Cormoran

Seagull colony

Purple sandpiper

Rat

Anas platyrhynchos

Larus argentatus

Dolphin family - Calderon

In the lab: seawater study

The aim of the study was:

To separate the seaweed’s pigments by 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 by paper 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

Discarded fishing gear

THANK YOU VERY MUCH FOR YOUR ATTENTION