Lichen study in the South Shetland Islands.

In English:

Scientific objectives:

-Study of nitrogen fixation in Leptogium puberulum with respect to
photosynthetic rate under natural condition;
-Microclimatic study of lichenous biotopes where the photosynthesis and
nitrogen fixation experiment was carried out;
-Comparative microclimatic study on thallus of crustacean and fruticose
lichens;
-Study on lichonometry;
-Study of lichenous vegetation on the Coppermine Peninsula, (Robert Island).

Activities carried out:

Two locations were chosen according to their degree of humidity for the study
of photosynthesis and nitrogen fixation capacity of Leptogium puberulum .
Measurements were taken during complete activity,; the temperature and hydrous
content of the thalli were evaluated and the relative humidity and amount of
photosynthetically active light in its environment were measured.In the two
localities mentioned. Microclimatic parameters were recorded of Leotogium
puberulum, Drepanocladus uncinatus and Usnea antarctica. In all, temperature
sensors, 4 relative humidity and 2 light sensors were set up, and connected to
a Grant Squirrel data-logger which recorded readings simultaneously every
minute, storing the averages every five minutes. A systematic description was
made by means of an inventory of lichenous vegetation from the intertidal area
to the summits of the rocky areas of the Coppermine Peninsula. Specimens of
numerous species were collected and prepared for experiments and laboratory
studies.

En Espanol:

Objetivos cientificos:
-Estudio de la fijacion de nitrogeno en Leptogium puberulum en relacion con
su tasa fotosintetica y bajo condiciones naturales.
-Estudio microclimatico de los biotopos liquenicos donde se realizo el
experimento de fotosintesis y fijacion de nitrogeno.
-Estudio microclimatico comparado en talos de liquenes crustaceos y
fruticulosos.
-Estudio de la vegetacion liquenica de la Peninsula Coppermine (Isla Robert).

Actividades realizadas:

Para el estudio de la fotosintesis de Leptogium puberulum en paralelo a su
capacidad de fijacion de nitrogeno se seleccionaron dos localidades, con
diferente grado de humedad. Se realizaron mediciones durante ciclos completos
de actividad, evaluandose al mismo tiempo la temperatura y contenido hidrico de
los talos, asi como la humedad relativa y la cantidad de luz fotosinteticamente
activa de su ambiente. En las dos localidades mencionadas se registraron
parametros microclimaticos en Leptogium puberulum, Drepanocladus uncinatus y
Usnea antarctica. Se instalaron un total de 8 sensores de temperatura, 4 de
humedad relativa y 2 de luz, unidos aun data-logger Grant-Squirrel que tomaba
datos simultaneamente de todos ellos cada minuto, memorizando las medias cada
cinco minutos. Se procedio a la descripcion sistematica, mediante toma de
inventarios, de la vegetacion liquenica, desde la zona intermareal a las
cumbres de los roquedos de la Peninsula Coppermine. Especimenes de numeros as
especies fueron recolectados y preparados para posteriores experimentos y
estudios de laboratorio.