Mount Erebus – extreme habitats
This interactive provides a brief introduction to habitats that exist on Antarctica’s Mount Erebus along with some of the fascinating microorganisms that live there.
To use this interactive, move your mouse or finger over any of the labelled boxes and click to obtain more information.
Select here to view the full transcript and copyright information.
Mount Erebus is the southernmost active volcano in the world. It is located near Scott Base. Aotearoa New Zealand scientists have been braving the harsh conditions for decades to learn about the volcano and the life its geothermal systems support.
Background photo by Jana Newman, © Antarctica New Zealand Pictorial Collection. CC BY-NC-ND 3.0 NZ
Transcript
Tramway Ridge
Tramway Ridge is a rare ecosystem of exceptional scientific value. It is located around 3,450 m above sea level in the northwest part of the volcano’s crater. One hectare of the ridge is an Antarctic Specially Protected Area – one part is a reference site, in which almost all access is prohibited, and the other part is an active research site for sample collection.
To protect the area, snowmobiles have a designated off-site parking lot. To minimise the risk of contaminating the area with alien biota, scientists wear sterilised, protective suits as shown in this image.
The warm ground and the vegetation it supports is of interest to botanists, phycologists and microbiologists. Of particular interest are extensive moss beds and cyanobacterial mats, which increase the abundance and diversity of microbial communities living in the surrounding soils.
Photo by Craig Cary © Antarctica New Zealand Pictorial Collection, Number CD K023 09/10, 2009–2010.
Active lava lake
Mount Erebus is a stratovolcano. It has been built from many layers of lava and ash over 1.3 million years. Inside the main crater, the temperatures range from -20°C in summer to -50°C in winter. A lava lake inside the main crater has been actively producing gas, steam, magma and pyroclastic rocks for more than half a century. The walls of the main crater are not accessible for sampling but there are hot soils around the rim.
This sustained volcanic activity, along with Antarctica’s frigid climate, makes Mount Erebus one of the most extreme environments on Earth.
Photo by Colin Monteath © Antarctica New Zealand Pictorial Collection, Number ANZSC1062.6, 1978–1979.
Ice fumaroles
Fumaroles are vents or openings that release hot volcanic gases and steam but do not emit liquids or solids.
On Mount Erebus, fumaroles warm the ground, with temperatures reaching up to 65°C. The steam and heat melt snow and ice – creating sources of freely available water. The volcanic gases are often rich in carbon dioxide and mineral compounds.
The warm, moist conditions created by fumaroles are vastly different to the extremely cold and dry conditions found elsewhere. They create unique habitats – ranging from exposed soils to subglacial ice caves and ice towers.
This image shows a scientist searching for algae on warm ground inside an ice-covered fumarole on Mount Erebus.
Photo by Paul Broady © Antarctica New Zealand Pictorial Collection, 1982–1983.
Ice hummocks
Ice hummocks form over fumaroles. They are small snow enclosures – usually less than 0.5 m in diameter. Unlike ice caves, the hummocks found on the summit of Mount Erebus only last a short time as the ice often collapses between the seasons. Scientists sample the hot soils under the hummocks to measure the soil geochemistry and microbial communities.
This image shows the scale of an ice hummock compared to the person next to it.
Photo by Paul Broady © Antarctica New Zealand Pictorial Collection, 1982–1983.
Ice caves
Fumaroles are also responsible for creating ice caves and subglacial cave systems. The hot gases and heat melt the ice, forming open spaces and passageways.
The caves are dark – light cannot get through the thick ice. However, light does filter in through cave mouths or where the ice cover is thin. The caves are often warm – reaching temperatures up to 25°C.
The lack of UV light prevents photosynthesis, and organic matter is almost non-existent. Most microorganisms that live in the caves get their energy from chemical reactions with the rocks.
Photo by Commander John Bortniak, NOAA Corps.
Ice chimneys
Ice chimneys – also known as fumarolic ice towers – form over fumaroles. These large structures build up when volcanic gases and steam rise from the fumaroles, condense in the cold air and deposit layers of ice. The chimneys get taller with each layer of ice.
The chimneys vary in size but are usually 6–10 m high and 3–4 m in diameter. They often have ice caves at their base.
The chimneys get their name as steam can sometimes be seen rising from their hollow cores.
This image shows the scale of an ice chimney compared to the person next to it.
Geothermal soils
The geothermal areas on Mount Erebus create a variety of soil habitats. Abiotic factors – including water, sunlight, temperature, soil pH and topography – influence what lives in these habitats.
Tramway Ridge has hot soils, with temperatures reaching up to 65°C in places, and steaming fumaroles that produce gases such as CO₂ and water vapour. It is also protected from the wind, so the soils don’t dry out as quickly. These conditions support cyanobacterial mats and thick moss beds.
Western Crater is only 1 km away but its lack of fumaroles and more extreme exposure limits the microorganisms that live there.
Microbial communities often change as conditions change such as temperature gradients along and under the soil surface.
Photo by Paul Broady © Antarctica New Zealand Pictorial Collection, 1982–1983.
Bdelloid rotifers
Rotifers are microscopic animals common in freshwater environments all over the world. They are sometimes called wheel animals. The bdelloid species living in Antarctica have two rotating wheels of cilia on their heads. The cilia create currents in the water that direct food into their mouths.
Mount Erebus is a very dry environment. Bdelloid rotifers deal with this by rapidly dehydrating themselves and remaining dormant in this state until there’s enough water for them to rehydrate.
Rotifers are found in the moss beds at Tramway Ridge.
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Tardigrades and anhydrobiosis
Tardigrades, sometimes known as water bears or moss piglets, live in mosses, algae and freshwater on Mount Erebus. Acutuncus antarcticus is the most abundant tardigrade species in Antarctica.
Tardigrades are well known for surviving in extremely harsh environments. They can stop all measurable metabolic processes until environmental conditions become favourable again. This protects them from both desiccation and freezing. Watch a tardigrade move from an active state to a dormant state in this video.
Freshwater is scarce so tardigrades living on mosses or lichens on Mount Erebus are only active when they are covered by a thin film of water.
Image from Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012) Comparative proteome analysis of Milnesium tardigradum in early embryonic state versus adults in active and anhydrobiotic state. PLoS ONE 7(9): e45682. doi:10.1371/journal.pone.0045682
Extremophiles
Extremophilic microorganisms live at the extreme ends of survivability. Antarctica is such an extreme environment that some organisms living there are polyextremophiles – they can survive severe cold, heat, desiccation and/or intense UV radiation.
Scientists are interested in extremophiles for many reasons. Some are looking at the link to biotechnical opportunities. Others are figuring out how life can thrive in such harsh conditions and the insights this might provide about life on other planets.
Photo by Craig Cary © Antarctica New Zealand Pictorial Collection, image number K0230506, 2005–2006.
Acknowledgement
This resource was produced with the help of educators Carol Brieseman and Dianne Christenson. Carol and Dianne travelled to Antarctica as part of Antarctica New Zealand’s Community Engagement Programme.
