Chaoborus larva

These are free-swimming larvae of so called phantom midges or lake flies and inhabit the area between the bottom and the surface of ditches. They are hunters of small crustaceans such as daphnia and cyclops. These animals are practically transparent, and are therefore also called glass larvae. (For the sake of clarity, the preparation has been stained)

With the help of air bubbles in the fore and abdomen, they remain in balance with the water and float unseen through ditches, swimming with leaping movements. They grow to about 1 cm to 1.5 cm long. When two larvae meet each other, a tumble around each other occurs.

Multipurpose symbiosis

The black alder - Alnus glutinosa - lives in symbiosis with bacteria from the actinomycetes group. These are capable of withdrawing nitrogen from the atmosphere. Through this partnership, the alder, despite its relatively high nutritional requirements, can colonize nitrogen-poor locations.

Algae Bloom

 

These beautiful golden spheres are single colonies of the golden algae synura. Like all other organisms, synura is able to reproduce and one colony eventually turns into two. But when conditions are right, reproduction happens a lot more frequently and what used to be a few colonies can quickly turn into an enormous algae bloom. Even though each synura colony is microscopic and only measures around 20-30 microns in diameter. Their large numbers in an algae bloom are able to turn the water in their freshwater habitats a yellowish brown color. A bloom of synura like the one in the image usually happens in spring and fall when the water is cold. But not all algae will bloom in cold water.

Trypanosoma cruzi

Trypanosoma cruzi is a single-celled parasite, first described in 1909 by the Brazilian physician Carlos Chagas, and the causative agent of Chagas disease. It is a tropical vector disease that occurs in humans, among others, and mainly in South America.

Zeolites from La Crosa de Sant Dalmai volcano

La Crosa volcano, also called “La Crosa de Sant Dalmai”, shares the space between the Catalan municipality of Vilobí d’Onyar (in the lands of Sant Dalmai) and those of Bescanó and Aiguaviva. Located in the NE of Catalonia, in Girona.

It is a wide volcanic maar or crater (over 1.200 m, one of the largest in Europe) and low altitude (156 meters above sea level) formed by a phreatomagmatic eruption, produced by an explosion caused by groundwater in contact with ascending magma from the main chamber. The violent explosions have formed a ring of pyroclastic projections, formed both by juvenile materials (of basaltic composition, chalk, tuff and some volcanic bombs) and by fragments of subterranean rocks (igneous and metamorphic fragments). The phreatomagmatic origin of the Crosa maar differentiates it from the rest of the volcanoes in the area, in which strombolian eruptions predominate. It must be said, however, that within this phreatomagmatic volcano we find a smaller cone of the Strombolian type.

The eruptive period of La Crosa is between 7.9 and 1.7 million years (My), characteristic of the volcanic processes of the La Selva depression. The oldest in the Empordà region date from 12 to 8 My and the most recent, from La Garrotxa, are between 500,000 and 10,000 years old.

Figure 1. View of La Crosa de Sant Dalmai volcano, from the Can Guilloteres viewpoint.

Luminous wood

On the images you can see a cross section of a thin stem of Tilia showing the annual rings which are composed of Xylem in botanical terms or wood in daily language.

At the beginning of the growing season in a temperate climate, the Cambium will produce larger Xylem cells with thinner walls. These large cells (earlywood) are formed because the tree needs a lot of sap after winter. The earlywood is lighter and more porous. At the end of the growing season, the Cambium will produce narrower cells with thicker walls (latewood). Thus latewood contains more matter and is less porous, so it will look darker. Earlywood and latewood, which are formed during the same growing season, make up one annual ring. The most recent growth rings are situated at the tree's periphery, under the Cambium which is between the wood and the bark.