Großlebensräume der Erde Christian Griebler Department of Limnology & Bio-Oceanography Ökologie der Großlebensräume der Erde Programme WS2019 (UZA I, HS2) Part 3 – Limnic ecosystems (Inland Waters) Monday 09.12.2019 – Class I - Glaciers Tuesday 10.12.2019 – Class II – Groundwater & Aquifers Monday 16.12.2020 – Class III - Springs Tuesday 17.12.2020 – Class IV – Streams & Rivers Tuesday 07.01.2020 – Class V – Lakes Monday 13.01.2020 – Class VI - Wetlands Exam (1st date) – Mid of January 2020 Before we start Lecture in German but most slides in English No slides beforehand Later slides will be sent to you as pdf file Textbook knowledge with inclusion of key publications & results from own research References & glossary where appropriate Interactive teaching “I like to ask questions – feel free to do the same” Handouts only when needed Ökologie der Großlebensräume der Erde Class I (09.12.2019) Glaciers − − − − − Formation Behavior Types Biota Retreat of glaciers Water renewal time Wetzel, 2001 Glacier Quiz! Source: Wikipedia Perito-Moreno-Gletscher? Aletschgletscher? Vatnajökull? Pasterze? Source: Wikipedia Vatnajökull Perito-Moreno-Gletscher Aletschgletscher Pasterze Glacier Quiz! Pasterze • Longest glacier in Austria • It lies within the Glockner Group in Carinthia • 8.4 kilometres in length • The length is currently decreasing by about 10 m each year • Its volume has diminished by half since the first measurements in 1851 Source: Wikipedia Petrito-Moreno-Gletscher • Located in the Los Glaciares National Park in southwest Santa Cruz Province, Argentina • 250 km2 ice formation • 30 km in length • One of 48 glaciers fed by the Southern Patagonian Ice Field (Andes) • The Southern Patagonian ice field is one of the world's largest reserve of fresh water Source: Wikipedia Aletschgletscher • Switzerland • largest glacier in the Alps • 81.7 km2 • Length: 23 km • Since 1980 it lost 1.3 kilometres of its length • Since 1870 it lost 3.2 kilometres and more than 300 metres of its thickness Source: Wikipedia Vatnajökull • Iceland (the glacier is covering approximately 8% of the country) • 7900 km² • Largest ice cap in Europe • Average thickness of the ice is 380 m (max. 950 m) • Under the ice cap are several volcanoes Source: Wikipedia What is a glacier? Some characteristics • The term “glacier” comes from the French word glace, which means ice Glaciers occupy about 10% of global land area, mostly in polar regions (Antarctica, Greenland, and the Canadian Arctic) Glaciers are remnants from the last Ice Age, when ice covered nearly 32% of the land, and 30% of the oceans https://www.nationalgeographic.org/encyclopedia/glacier/ • Ice masses formed from snow & pressure • Moves over land • Two main-groups of glaciers - alpine glaciers - ice sheets • Alpine glaciers form on mountain slides and move downward through valleys • Ice sheets (or continental glaciers) are not limited to mountainous areas. They form broad domes and spread out from their centers in all directions. Formation of glacial ice from snow https://slideplayer.com/slide/7049512/24/images/4/Formation+of+Glacial+Ice+from+Snow.jpg Formation of glacial ice from snow Steps in the process of formation of glacial ice from snow, granules, and firn. Earle, 2015 Glacier formation https://ccin.ca/ccw/glaciers/formation Behaviour of glaciers Simplified cross-sectional profiles the continental ice sheets in Greenland and Antarctica – both drawn to the same scale. Earle, 2015 Behaviour of glaciers Schematic ice-flow diagram for the Antarctic Ice Sheet. Earle, 2015 Behaviour of glaciers Schematic ice-flow diagram for an alpine glacier. Earle, 2015 Behaviour of glaciers Location of the equilibrium line Earle, 2015 Behaviour of glaciers Stress within a valley glacier (red numbers) as determined from the slope of the ice surface and the depth within the ice. The ice will deform and flow where the stress is greater than 100 kilopascals. Any deformation motion in the lower ice will be transmitted to the ice above it, so although the red arrows get shorter toward the top, the ice velocity increases upward (blue arrows). The upper ice (above the red dashed line) does not flow, but it is pushed along with the lower ice. Earle, 2015 Behaviour of glaciers Figure 16.17 Just as the base of a glacier moves more slowly than the surface, the edges, which are more affected by friction along the sides, move more slowly than the middle. If we were to place a series of markers across an alpine glacier and come back a year later, we would see that the ones in the middle had moved farther forward than the ones near the edges. Markers on an alpine glacier move forward over a period of time. Earle, 2015 Glacial Erosion Earle, 2015 U-shaped valleys: Glaciers produce wide valleys with relatively flat bottoms and steep sides Nunatak: A peak that extends above the surrounding glacier Arêtes: Sharp ridges between U-shaped glacial valleys Cols: Low points along arêtes that constitute passes between glacial valleys Horns: Steep peaks that have been glacially and freeze-thaw eroded on three or more sides Cirques: bowl-shaped basins that form at the head of a glacial valley Hanging valleys: U-shaped valleys of tributary glaciers that hang above the main valley Truncated spurs: The ends of arêtes that have been eroded into steep triangle-shaped cliffs Glacial Erosion Earle, 2015 A view from the International Space Station onto the Swiss Alps in the area of the Aletsch Glacier. A variety of alpine glacial erosion features are labelled. Glacial Deposition Earle, 2015 Moraines Linear rock deposits Lateral moraines: Form at the edges of the glacier as material drops onto the glacier from erosion of the valley walls Medial moraines: Form where the lateral moraines of two tributary glaciers join together Ground moraine: Sediment from underneath the glacier becomes a ground moraine after the glacier melts Terminal moraines: Long ridges of till left at the furthest point the glacier reached End moraines: Deposited where the glacier stopped for a long enough period to create a rocky ridge as it retreated ILLUSTRATION BY TIM GUNTHER Glacier types Ice sheet Surge-type glacier Ice shelve Outlet glacier Piedmont glacier https://ccin.ca/ccw/glaciers/formation Temperate glacier Kryal Ice and snow fed Low temperatures (0-4°C) High turbidity Strong variation in discharge Unstable substratum Short growth periods Bare rock banks Transition to running waters! - see upcoming class Glacier Creek http://www.geo.uzh.ch/microsite/alpecole/static/course/lessons/20/20s/kryal.htm Cryoseston Cryosestic communities are composed of Hetertrophic and autotrophic microorganisms (bacteria, cyanobacteria, fungi, algae) Insects (spring tails, midges) Worms (e.g. nematodes) Birds, seals, pinguins, ... Kryal – Lebensraum im Bereich von Schnee und Eis (Gletscher) Not too cold ! Spheric cell found in Lowest recorded temperature for ancient Antarctic ice active microbial communities is – from as deep as 18°C (Rothschild & Mancinelli 2001) 1,249m beneath Vostok Station. How? Spheric cell found in ancient Antarctic ice from as deep as 1,249m beneath Vostok Station. Many microbes can stand freezing at -196°C Microbes produce alcohols to prevent intracellular freezing when living in snow, ice and permafrost soils. Microbes may survive hundreds of years in frozen soils. Microbes in snow and ice gigantic reservoir of microbial life, trapped longer than modern humans have walked the planet ice melting at an alarming rate living bacteria in cores of 420,000-year-old ice that are still able to grow and divide Source: https://www.scientificamerican.com/article/bugs-in-the-ice-sheet/?redirect=1 Life below ice Blood Falls glacier, Antarctica, -20°C average temp. Outcrop of reduced subglacial brines with dissolved Fe(II), abundant psychrophilic bacterial chemolithoautotrophs. Oxidised Fe(III) gives red colour http://microbewiki.kenyon.edu Cryoflora The cryoflora is mainly composed of small and unicellular ‚snow‘ algae. Green snow Brown snow 2 - Chloromonas nivalis (vegetative cell) 3 - Chloromonas nivalis (zygospore) 5 - Chloromonas rosae (resting spore) 6 - Chloromonas brevispina (zygospore) 8 - Chlamydomonas nivalis (resting spore Red snow Seckbach 2007 Snow and Ice algae • Growing on the surface during the snow melt in summer • Blooms coloration of the snow (green/yellow/red) Green: Chlorophyll Yellow: Fucoxanthin Red: Astaxanthin Source: Wikipedia Glacier Biota: Chlamydomonas nivalis unicellular red-coloured photosynthetic green algae dominant in microbial snow algae communities Can form blooms (106 cells mL-1 melted snow) Causing the phenomenon of “Blutschnee” or “Watermelon snow” Secondary carotenoids (Astaxanthin), thick cell wall, particles on the cell wall Spring/Summer: Green motile offspring are produced Winter: Development in red dormant cysts (in this stage they spend most of their life cycle) Source: Wikipedia (a) Vegetative stages of Chlamydomonas nivalis. (b) Chlamydomonas nivalis aplanospores filled with the red pigment astaxanthin and with attached particles. https://en.wiktionary.org/wiki/watermelon_snow Glacier Biota: Microbes Zygnematales Chlamydomonas sp. Phormidesmis priestleyi Chlamydomonas sp. Anesio et al., 2017 Cryofauna Animals that live in or close to ice and snow Communities are mainly composed of spring tails, midges, and nematodes Diamesa kohshimai Panagrolaimus davidi … midge from the Yala glacier in Nepal Himalayas – still active at -18°C … a nematode which can stand freezing of all body water Glacier flea (Gletscherfloh) Springtail (Collembola) discovered 16th century and described in the 19th century dark body colouring hopping motion live all year round in 20-40cm depth in the glaciers and snowfields can stand temperatures of -20°C Body liquid contains alcohol and sugars Sensitive to elevated temperatures (>10°C) feed on substances such as cryoconite (mud, pollen, plant remains, snow algae) https://www.eispavillon-saasfee.ch/wpcontent/uploads/2016/07/Gletscherfloh.jpg https://gletscherg2g.wordpress.com/gruppe4-gletscherg2b_g4/ Dramatic retreat of glaciers https://www.meinbezirk.at/spittal/c-lokales/dem-rueckgang-der-pasterze-auf-der-spur_a2248170 Dramatic retreat of glaciers On the sheltered slopes of the highest peaks of Glacier National Park in the U.S. Rocky Mountains of Montana, the area of each glacier has been mapped for decades by the NPS and the USGS. Glaciers started to retreat since 1850. Repeat photography show the Grinnell Glacier retreating. 1938 T.J. Hileman GNP 1981 Carl Key (USGS) 1998 Dan Fagre (USGS) 2009 Lindsey Bengtson (USGS) Dramatic retreat of glaciers CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=694314 Dramatic retreat of glaciers CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1168903 Dramatic retreat of glaciers Glacier mass balance annual variability and cumulative values (a) in meters of water equivalent, and (b) in km3, computed for the entire system of glaciers and ice caps with an aggregate area of 785 x 103 km2. The results of direct mass balance observations on 300 glaciers worldwide are averaged by size of individual glaciers, 49 primary systems, 12 larger regions, 6 continentalsize regions, and globally to get the one “global curve” (all in water equivalent). Vertical bars are estimated standard errors and represent the uncertainty range due to spatial mass balance distribution patterns. Dyurgerov, 2004 Retreat of glaciers Glacier contribution to rise in sea level from glaciers and ice caps with an aggregate area of 785 x 103 km2. Glacier volume change in terms of contribution to sea level. Dyurgerov, 2004 Retreat of glaciers Other consequences? Loss of stored freshwater Release of sequestered carbon and nutrients Loss of microclimate and effects to regional climate … Ökologie der Großlebensräume der Erde Next time Class II (10.12.2019) Groundwater & Aquifers References Anesio, A. M., Lutz, S., Chrismas, N., & Benning, L. G. (2017). The microbiome of glaciers and ice sheets. NPJ biofilms and microbiomes, 3, 10. doi:10.1038/s41522-017-0019-0 Benn, Douglas I., and David J. A. Evans. Glaciers & Glaciation. 2nd ed., Hodder Education, 2010. Dyurgerov, Mark & F Meier, Mark. (2004). Glaciers and the Changing Earth System: A 2004 Snapshot. 58. Earle, S. (2015). Physical Geology. Victoria, B.C.: BCcampus. Retrieved from https://opentextbc.ca/geology/. Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp. 817-823. Seckbach, J. (2007) Algae and cyanobacteria in extreme environments. Springer Wetzel R.G. (2001) Limnology. Lake and River Ecosystems. Academic Press
