Curiously Polar

Some of the volatile man-made chemicals that are produced and used in temperate areas are transported to the polar areas by the natural circulation of water and air. Among these we have the Persistent Organic Pollutants abbreviated as POP's. Once arrived in the colder zones in the Arctic or the Antarctic these substances condense and are absorbed in the environment. On the ground or in the water these molecules often enter the food chain and bioaccumulate in the body or organisms throughout their life cycle as well as they are passed on to the next level through the food chain increasing in concentration: a phenomenon called biomagnification. Among these substances there are some which are directly poisonous in higher concentrations, but there are also others which are mimicking natural hormones. By taking the place of the original body molecules, and disrupting thus physiological functions, these endocrine disruptors can modify organ functionality like the reproductive cycle or body growth with dire consequences for the organism and the population.

In Svalbard there are few inhabited places and Ny Ålesund is one of them. The settlement which originally was a coal mining town has now become the main field hub for polar reseach.

Aquaculture is a very lucrative business and salmon farming is definitely one of its most prominent sectors. In this episode we discuss salmon farming as it is practiced in Norway.

Marine mammals face considerable challenges to reproduce. Pinnipeds have the possibility to exit the water and most of them reproduce on the dry while cetaceans and sirenians never exit the water and must copulate and give birth in the liquid medium facing problems like hydrodynamics, the absence of a stable support and no limbs to help keeping the partner close to oneself. Strategies differ among the species and the variety of solutions is amazing.

In a previous episode we have mentioned that the magnetic field of the Earth through goelogical time has undergone variations in intensity and even reversals with the north magnetic pole migrating to close to the south pole and vice versa for the south magnetic pole. How do we know this and what consequences for life on the planet could it have had?

What kind of ship is adapted for polar voyages? The early voyages of discovery have been made using wooden ships and the technology evolved up to Nansen's Fram. Nowadays metal hulls are the norm and the vessels are classified in a system of "ice classes". Icebreakers are a world apart and they have their own classification. Some of them are very large and have considerable engine power that allows them to navigate through the polar ice at all seasons . With the opening of the northern routes more commercial ships will be built to an ice class and some are already in service

..and why is Iceland called Iceland?

The European name of Greenland is most probably due to a marketing maneuver to encourage settlement, even if during the Viking settlement the climatic conditions of the island were at an optimum and therefore it was probably greener than what we observe presently. Iceland though had several names before a permanent Viking settlement and was a victim of a similar but negative marketing strategy.

Auroras, Northern or Southern Lights are a spectacular phenomenon that attract a large number of tourists to the polar areas. They were known since antiquity but the phenomenon was attibuted to supernatural powers. In fact they form in a circle around the magnetic poles when the charged elementary particles in the solar wind are captured byt the magnetic field of the earth and are directed towards the upper levels of the atmosphere and ionize elementary gasses like hydrogen and oxygen. The probability of Auroras apperaring in the sky can be predicted by analyzing the variations in the solar wind and in the magnetic field of the Earth. Auroras have been observed also on other planets. in the solar system. Real time aurora on video. Chris' Aurora photo from the ship.

The magnetic compass has been the most important instrument used for navigation since the beginning of the European voyages of discovery and until satellite positioning was introduced. The principle of functioning is dependent on the magnetic field of the Earth. It is not a recent invention and a form was used for divination in China since 200 BCE. It was used for navigation first in the 11th century in China and probably it was introduced from there to Europe in the 12th century through trade routes. The of the compass for navigation is testified by the effort put by nations to measure the magnetic field of the planet, to determine the position of the magnetic north pole and to investigate its yearly movement. One of the famous expeditions to pursue such investigations was the Franklin voyage in search of the Northwest Passage. The Vikings who navigated areas close to the magnetic pole, which makes the magnetic compass unusable, most probably used a sun-based compass, that could also be used to determine variations in latitude during a voyage, and they might even have been able to use this system in conditions of bad visibility usign a crystal of calcite as polarizing filter. The next revolution for polar navigation came with the invention of the gyrocompass. Nowadays navigation is greatly symplified and made accessible to private and professional users through satellite systems like GPS, GLONASS and GALILEO and BeiDou which can be accessed using dedicated receivers or apps on mobile devices.

Dog power has been used for thousands of years and, in the Arctic, it has survived practically unchallenged until the present, whereas in temperate and tropical areas other animals have taken the place of dogs in helping humans move about. Nowadays dogs are still used for transportation in several areas, but there is also a boom in the recreational use of dogs as tractors, and not only for pulling sleds. Wikipedia links: Dog sled, Sled dog, Sirius Dog Sled Patrol, Will Steger (homepage). Help make this podcast sound better with a donation to the MARIO MICROPHONE FUND.