Glossary

cleanedmapwithodenMap of Antarctica

albedo- the ability of a surface to reflect light. Snow and ice have a very high albedo, causing a lot of light to reflect back upwards. Dirty snow has a lower albedo, absorbing some of the light. This causes dirty snow to melt earlier than ‘clean’ snow, and leads to cryoconite holes on glaciers.

Antarctica- the continent at the ‘bottom of the world’ that includes the South Pole. It is the coldest, driest, and windiest continent on Earth, with the highest average elevation. Although 98% of the continent is covered by the Antarctic ice sheet (which holds 61-70% of all the freshwater on Earth in a large slab of ice on top of the continent), Antarctica is considered the world’s largest desert because it receives very little precipitation/rain. Antarctica has no native human inhabitants, although a few thousand scientists and support technicians work at the different bases on the continent during the austral summer season. Antarctica is home to many species of seals, penguins, and other birds. It is approximately twice the size of Australia, or 1.5 times the size of the United States, and is surrounded by the Southern Ocean that combines the Atlantic, Pacific, and Indian oceans south of all other continents.

Antarctic circle- the line of latitude at 66 degrees, 33 seconds south that is the lowest of the five main ‘zones’ of latitude on Earth. (The Arctic circle is the northernmost ‘circle’, while the equator is the middle and third ‘circle’.) Below the Antarctic circle, the sun is generally present 24 hours a day in austral summer, while the sun is never seen in austral winter. The opposite is true for the arctic circle; the sun is always present in boreal (Northern hemisphere) summer and never present in boreal winter. At the equator, the sun is present for 12 hours per day every day of the year, without an influence of seasonal tilts.

Antarctic plateau-the plateau is a large, flat area with a very high elevation (above 10,000ft or 3200m) that spans more than 620 miles (1000km) and includes the South Pole and a large part of Eastern Antarctica. Essentially it is the ‘tall, flat’ area of the Antarctic ice sheet, farther inland from the coast and bordered by the Transantarctic mountain range that separates East Antarctica from West Antarctica. (See map)

anthropogenic- an adjective that describes things that have been created by people rather than the natural environment. Pollution is an example of an anthropogenic compound. Some chemicals have both anthropogenic and biogenic sources, created both by people and made naturally in the environment, too.

austral summer- summer in the Southern Hemisphere; November-February. See ‘boreal’ for an explanation of hemisphere seasons.

austral winter- winter in the Southern Hemisphere; June-September. See ‘boreal’ for an explanation of hemisphere seasons.

biodegrade- to breakdown an organic substance by microorganisms

brine- while brine can refer to a few different types of super-salty seawater, in this context it refers highly concentrated seawater trapped within liquid pockets in sea ice. Fresh water freezes sooner than seawater at cold temperatures, so as ice begins to freeze, it pushes the salt ‘out’ into pockets. This concentrates the seawater into brine such that the frozen ocean is ‘fresh’ water, while the salt from the seawater is either pushed into these pockets or released into the liquid ocean underneath the floating ice.

boreal- this term describes the nature of the Northern hemisphere. Since seasons of the year are opposite in the Northern and Southern hemispheres, the Northern hemisphere has summer June-Sept, when it is pointed towards the sun, and winter November-February when the hemisphere is pointed away from the sun because Earth is tilted on its axis. This is called boreal summer and boreal winter. Comparatively, the Southern hemisphere has summer November-February because when the northern hemisphere is pointed away from the sun, the southern hemisphere is pointed towards it, making the seasons in this hemisphere opposite to those in the North. Summer in the southern hemisphere is then called austral summer, to let the observer know that it is a southern hemisphere event.

comparative altitude/ comparative elevation– This is a phenomenon most easily seen in areas near the North and South poles, also known as ‘physio-altitude’. The earth is not exactly round; it’s actually a little ‘squished’ so that it is wider around the equator. In addition, Earth spins so that the speed of rotation is 1,040 miles per hour from a point on the equator, but 0 miles per hour at the North and South poles. The higher up you climb a mountain, the lower the air pressure gets. Since Earth spins fastest at the equator, it pushes the atmosphere down in those areas, increasing the air pressure at the equator, while decreasing the air pressure at the poles. Since the poles have less air pressure, it makes it ‘feel’ like you are even higher up than you are. Concordia station’s actual elevation is 10,500ft (3230m) but when you breathe the air there, there is much less oxygen than the same elevation on the equator, so it feels like you are actually more than 12,460ft (3800m) above sea level. Since air pressure matters a lot in terms of making sure machines work correctly and people are able to breathe safely, we use ‘comparative altitude’ to describe areas in Antarctica due to the effect that this lower air pressure has.

Concordia- the station where I worked during my second season in Antarctica. Concordia is located at a place called ‘Dome C’, which is an area on the Antarctic Plateau and one of the coldest places on Earth. Temperatures range from -13F (-25C) to below -112F (-80C) during the year, and it is quite high up, with a comparative elevation of 12,460ft (3800m). It is more than 700 miles (1100km) from the coast and roughly 1000 miles (1600km) from the South Pole. Approximately 60 people work there during the austral summer season, while 15 live there for a year at a a time, overwintering until they are able to fly off the base in the following austral summer.  The closest station to Concordia is a Russian base called Vostok station, which is 350 miles (565km) away. Interestingly, this means that our closest neighbors in any direction are not North, South, East, or West, but UP, because Concordia is in such an isolated place that the next living people are the astronauts at the International Space Station when it flies overhead, 220 miles (350km) above us. No human beings are closer.

concordiaConcordia station photographed from a crane by Eric Lefebvre

conductivity- a measure of the ability of water to pass an electrical current. The conductivity of water is affected by presence of ions (charged particles and salts), temperature, and is often a measure of the total dissolved solids in water. Iin many cases, the higher the total dissolved solids in water, the higher the conductivity. Once the conductivity of a stream has been established, changes in conductivity over time can indicate changes to the chemical composition of the water in the stream.

cryoconite- a small hole (usually filled with icy water) on the surface of a glacier. Cryoconites form when dust and dirt fall onto a particular place the surface of the glacier, darkening the surface and lowering the albedo (reflectivity) of the snow. Dirty snow absorbs more heat than white snow, so dirt that the wind blows onto a particular small area causes the snow around it to melt. Once the hole has melted to 1-2ft deep, the dirt at the bottom no longer receives as much sunlight as the surrounding snow (because it is now under water), so it prevents the hole from growing any larger and you’re left with a series of small, shallow cryoconite holes of icy water that are spread out across a glacier in places where dirt once fell.

Drake Passage- the narrow channel between the bottom edge of South America at Cape Horn, Chile, and the Antarctic Peninsula and Southern Shetland Islands; the southern location where the Atlantic and Pacific Oceans meet. Because of the storms that often get caught and pass through this area, it is considered one of the most dangerous marine passages on Earth.

Drake_Passage_-_Lambert_Azimuthal_projectionDrake Passage map courtesy of Wikipedia, showing the Southern tip of South America and the Antarctic Peninsula below. Our ship, the Oden, crossed from the East side of South America, at Uruguay, to the West side of Antarctica across the Passage.

Dry Valleys- the largest ‘un-ice-covered’ region of Antarctica and part of the Transantarctic mountain range, which is also one of the most severe deserts on the planet. The Dry Valleys are an “ASPA”; an Antarctic Special Protected Area studied for the unique seasonal streams that appear during austral summer when the temperatures are warm enough for glacial melt to form rivers across the valleys. My research here (season 3) will take me into the Valleys near the Asgard range of the Transantarctic mountains.

antarctica_dry_valleys_insetEven though the Dry Valleys look close to McMurdo Station, they are actually a 45 minute helicopter ride apart. McMurdo sits on Ross Island, while the Valleys are part of the Antarctic continent.

fast ice shelf-  a sheet of sea ice attached to firmly to the coastline that spreads out towards the deeper ocean. These shelves don’t move due to wind, waves, or tides, and usually the edge of this shelf occurs in a spot where waves/winds/tides become too strong to allow further freezing of water. Because of this edge, sea ice that floats in the open ocean often gets crushed against this boundary and creates pressure ridges or other ice formations near the shore, similar to the way that tectonic plates scrape against each other to create mountains.

grasshopper effect- a process that causes semi-volatile compounds to deposit in cold climates, leading to higher concentrations of certain persistent organic pollutants created in temperate regions to spread out and deposit at the poles

halocarbons- chemicals that include carbon and at least one halogen; a class of elements including Fluorine, Chlorine, Bromine, and Iodine that are on the second-to-last column of the periodic table. Many halocarbons are volatile and prefer to exist as gases rather than liquids, they are often very good at degrading the ozone layer, and have other adverse environmental effects.

hydrology- study of the movement, distribution, and quality of water on Earth

LTER- the Long Term Ecological Research program, created by the National Science Foundation to study particular ecological zones on long (multi-decadal) time spans. Having longer research spans is important in order to get an accurate ‘baseline’ of how particular ecological zones behave in order to identify whether particular patterns indicate change to the environment or simply fluctuations in a variable climate. The NSF LTER website link is available here. The McMurdo Dry Valleys is an LTER area of study in Antarctica.

MacTown- nickname for McMurdo station, see below.

McMurdo- the largest Antarctic base, run by the United States Antarctic Program and situated on Ross Island. This is generally the ‘base of operations’ for fieldwork and projects farther inland in Antarctica. More than 900 people can work at McMurdo during the summer season, and McMurdo runs the largest airport off-continent to Christchurch, New Zealand. Many field scientists, including myself, fly to McMurdo base first and then after re-organizing our supplies we fly to our final destinations farther away from this area of “civilization”. Many of the field scientists who work at small camps away from McMurdo refer to it either as “MacTown” or simply “town”. So if you’re spending your time working in the Dry Valleys and need to fly back to fix some equipment, you might say you’re flying back to “town”, because it’s the closest thing to civilization that Antarctica can boast.

McMurdo Dry Valleys– see ‘Dry Valleys’. I’ll generally call this area simply the dry valleys in the context of this blog in order to differentiate its location from McMurdo station.

overwinter- to stay in Antarctica beyond the ‘regular’ November-February season, into the austral winter in June-August. Very few people overwinter in Antarctica, and those who do are fairly isolated; if you overwinter, you may not be able to leave the continent until September-November, when the sun returns to Antarctica and planes are able to land on the Ice once again.

ozone hole- an area above Antarctica where the ozone layer is thinner or missing during the Austral summer season. This was caused by the presence of halocarbons and other compounds that break the bonds between the three oxygen atoms that make up each molecule of ozone. The ozone layer protects earth from receiving too much radiation from the sun, so the ozone hole in Antarctica allows more radiation to reach the sky and surface layers of the continent.

season- in the context of this blog, a ‘season’ in Antarctica refers to the austral summer, or summer in the Southern Hemisphere, which is November- February. The vast majority of people who go to Antarctica only work there during the summer season, while a few people ‘overwinter’ and stay a full year.

Southern hemisphere- the bottom half of the planet below the equator. Since the Southern hemisphere’s seasons are opposite to those in the Northern hemisphere, summer in Antarctica is November- February.

Southern ocean- the area where the Atlantic, Pacific, and Indian oceans combine south of the 60 degree southern latitude and surrounding Antarctica.

STEM- acronym for Science, Technology, Engineering, and Math

sublimate- to change directly from a solid to gaseous form. In this blog, it generally refers to snow that vaporizes due to cold temperatures, low humidity, and high sunlight; conditions that are extremely common in Antarctica.

“the Ice”- common nickname for Antarctica

toxicology- the study of harmful chemicals

volatile- an adjective that describes chemicals that like to ‘volatilize’, or transform into a gas rather than stay in liquid form

Want something explained in this glossary? Send a message and I’ll try to update with more detail as I go along!

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