BIO100g

what is the ozone hole

depletion of the ozone layer, focused around the Antarctic region.
ozone stops UV-B and UV-C from reaching the earth. hole causes much damage to DNA - causes cancer

where did the events that led to ozone depletion occur

in the Northern Hemisphere - much more industrial - pollution

physical properties of light

output from sun = divided into 5 wavelength bands (UV C, UV B, UV A, visible light & infrared).
as wavelength increases, amount of energy decreases.

what is UV-C

heavily absorbed by oxygen, ozone and water vapour in upper atmosphere. does not reach the surface of the earth. Highest energy (wavelength less than 280nm)

what is UV-B

capable of damaging DNA - potentially very harmful. how much reaches earth depends on amount of ozone. less energetic than UV-C, but is absorbed by ozone. wavelength = 280-320nm. thinner ozone = more UV-B - less absorbed

what is UV-A

not as dangerous as UV-B, but still considerable risks associated. lower energy - much reaches the surface of earth - doesn't interact with ozone. wavelength = 320-400nm

wavelength of visible light

400-760nm

wavelength of infra-red light

760-1000nm

what is ozone

form of oxygen - triatomic - O3. nearly colourless gas with odour of weak chlorine. formed when high energy UV (UV-C) radiation splits molecular oxygen (O2) into 3 free oxygen atoms. these collide with oxygen molecules (O2) - join to form O3. the sun's UV radiation is greatest in upper atmosphere (where O2 molecules are split). joining of free oxygen molecules occurs in dense lower atmosphere. ozone forms most at intermediate altitudes = stratosphere.

what are the different atmospheric layers characterised by

differences in density, temperature and chemical composition

what are the different atmospheric layers

troposphere = 0-11km
stratosphere = 11-50km (heated by UV-B absorption), movement of air towards poles.
mesosphere = 50-80km
thermosphere = 80-500km (where UV-C is absorbed , heated)
exosphere = more than 500km.
5 stratifies layers
maximum ozone concentration occurs at 32 km - in stratosphere.

natural ozone breakdown

UV-B & UV-C hit ozone & split into O2 & ozone.
continual balance of formation and destruction.

how is ozone measured

ozone forms protective layer that absorbs damaging UV-B &C. but in lower troposphere, ozone = pollutant. measured in atmosphere using Dobson Spectrophotometer. Dobson Unit (DU) = measure of ozone in air column above earth's surface. in mid latitudes, typical ozone concentration = 400DU

the ozone hole

significant reduction in ozone layer around Antarctic. early 1970's - aware of damage to ozone may be occuring due to human activities. 1980 - discovery of hole. scientists noticed trend of steady decline since 70's - confirmed by NASA scientists. Rowland, Molina & Crutzen determined causes of ozone depletion.
ozone hole forms in early spring

how much ozone is considered an ozone hole

ozone hole = below 220 DU
normal ozone = 400 DU

human destruction of ozone

involved man-made chemicals eg. chlorine-containing chemicals (Chlorofluorocarbons CFC) - common industrial products used in refrigeration systems, air conditioners etc. CFC's are v. stable & enter stratosphere where strong UV radiation breaks them down, releasing chlorine. other chlorine containing compound = nitrogen oxides from combustion processes eg. aircraft engines.
absorption of energy by ozone stratifies stratosphere - inhibits vertical mixing & promotes long distance movement of material (CFC's) from equators to poles - accumulate at poles, even though released in higher latitudes
ozone hole increases & decreases seasonally

the ozone hole in autumn

ozone formation & destruction occurs relatively constantly & inactive forms of chlorine accumulate (CFC'S chlorine nitrate & HCL).

the ozone hole in winter

polar vortex forms - supported by strong westerly winds - isolate Antarctic from other air currents - loss of thermal radiation to space, temperature drops. polar stratospheric clouds (PSC's) form in polar vortex - v. high altitude. because of high altitude, PSCs often appear bright & colourful. contain ice crystals - provides surface for reactions between forms of inactive chlorine - produces chlorine gas & leaves behind nitric acid on PSC. CFC'S accumulate

the ozone hole in spring

active chlorine formed by UV splitting free chloride atoms from CFC's and by splitting chlorine gas. free chlorine from CFC's interacts with ozone - forming chlorine monoxide & oxygen. 2 CLO molecules react - forms dichloride dioxide. UV causes CL2O2 to break down into O2 & free chloride atoms. chlorine atoms bow free to split oxygen. chlorine atom catalyses reaction of ozone destruction - balance between formation & destruction disturbed. single chlorine atom can destroy thousands of ozone molecules - ozone hole forms rapidly during spring

ozone hole in summer

polar vortex dissipates & polar stratospheric clouds disappear. reduces production of active chlorine. any active chlorine still produced is taken up by nitrous oxide & methane in atmosphere

the Montreal Protocol

signed in 1987 in response to scientific concerns. 180 signatory nations - agreed to cut CFC production in half by 1998. 5 follow up agreements strengthened by treaty - advanced timetable, included other ozone-depleting chemicals. 1990 = included complete phaseout of CFC's by year of 2000. today production & use of ozone-depleting compounds fallen by 95% since 1980's. CFCs are slow to break down - significant lag time between implementation of policy and environmental change. ozone hole is starting to shrink

plastic pollutions

75% all litter in oceans = plastic. 5-6 million tonnes of plastic waste enters ocean every year. pollution from both land & sea. sources can be direct (shipping or fishing) or indirect (plastics transported through marine currents into region). plastic doesn't naturally break down in the ocean, just gets smaller - especially in Antarctic due to extreme cold

what are the 3 types of plastic pollution

macroplastics - large eg. plastic bags/fishing nets - can cause entanglement/obstruction of organisms
microplastics - at least 5mm in diameter.
nanoplastics - invisible to the eye, accumulate up through food chain when consumed

microplastic & nanoplastic pollution

at least 51 trillion microplastic particles already in oceans. machine-washing a single garment released more than 1,900 microplastic fibres. a personal care or cosmetic product can contain as much plastic as the packaging it comes in - significant negative impact on Antarctic wildlife

hydrocarbon pollution

most human activities in Antarctica rely on fossil fuels - transportation via ships, planes. potentially major source of pollution. potential for oil spills.

oil spills from shipping accidents

no. shipping accidents have released large amounts of fuel into Antarctic environment - will have great impact in future.

what was the largest oil spill in Antarctic

from Argentine supply ship - paradise bay - ran aground on underwater ledge in 1989 close to Palmer station. was carrying 1.1 million litres of fuel - 600,000 litres fuel spilled. 1 km2 oil slick formed next to grounded vessel - spread over 4 hours to nearby harbours & beaches. ship was freed by winds, currents & tides & drifted to De Laca Island - rolled over & sank. oil spill now spread over large area. by time of sinking, spread over 100km2. American team, with Chile & Argentina, reached site week later & retrieved 65,000 litres fuel. remaining oil & other hazards removed by Argentine/Netherlands team in 1993, but hull remains. observed effects restricted to few Km from wreck. 50% intertidal limpets killed within 2km of De Laca island. 300 Adelie penguins & blue-eyed shags found dead & oiled. carrying degrees of contamination remained for at least a year - but nothing long term.

weather definition

specific conditions at localised site over hours/days

climate definition

long-term patterns in weather

evidence of climate change

mostly indirect - inferred from changes in indicators (proxies) that reflect climate eg. vegetation, glacial, sea level changes & ice core analysis
no direct evidence of climate change makes it controversial. over time, huge expanses of snow & ice have accumulated, preserving tiny bubbles of past atmosphere.

ice cores

scientists can analyse air bubbles trapped in annual layers that make up ice core & infer past climatic conditions. often done at near Vostok station (near middle of ice sheet). vostok = 420,000 yr record in ice.. Dome C = continuous record for 740,000 yrs.

3 biggest factors in Earth's climate

the sun
the oceans - store & transport heat & moisture
the atmosphere

what is global warming

refers specifically to increase in average near-surface temperature of the Earth. recent analyses suggest average near-surface atmospheric temp. rose 0.6 degrees in 20th Century. recent warming of troposphere is thought to be associated with increased greenhouse gases from human activities

solar & terrestrial radiation

virtually all solar radiation = shortwave radiation from sun & all terrestrial radiation = longwave radiation - with 4000nm the boundary. this is from absorbing infrared radiation from sun & re-transmittance into atmosphere - generates heat. greenhouse gases warm troposphere. long-wave infrared doesn't pass well through atmosphere, instead bounces back & causes heat release

what is terrestrial infrared radiation wavelength

500 to 50,000 nm wavelength

what is the greenhouse effect

the warming of the Earth's surface due to atmospheric absorbance and re-radiation of infrared energy

how does the greenhouse effect work

work

earth's atmosphere easily transmits shortwave radiation from sun, but is poor transmitter of longwave radiation from Earth's surface. selective transmission causes greenhouse effect in atmosphere - important heating process in troposphere. without effect, average temperature of earth would be -15, rather than present 15 degrees. natural greenhouse effect makes life on earth possible - increase in greenhouse gases has been accompanied by measurable increase in global temperature.

global warming

major GHG = water vapour and CO2. rising CO2 levels from fossil fuel combustion are most likely resposible for observed temperature rise. since industrial revolution, burning of fossil fuels has caused dramatic increase in CO2. but fossil fuel combustion also releases sulphate aerosols = thought to have slight cooling influence on global temperature.

other factors that influence climate change

in past, changes in CO2 and temperature have occurred as result of changes in Earth's orbit. Milankovic cycles 120,000 year cycle. but none as drastic as today - out of character - must be climate change

is Antarctica getting warmer

over last 30 yrs, little change in surface temp over much of Antarctic continent, but West Antarctica warmed slightly. Eastern coast of Antarctic penisular has seen rapid summer warming caused by strong westerly winds bringing warm, wet air into region from ocean. westerly winds over Southern Ocean = increased by 15%. stronger polar vortex has effectively isolated most of Antarctica from warming elsewhere on planet. ozone hole effectively protects the Antarctic.

Rising sea levels

mostly due to thermal expansion, not from melting ice caps, but once ice melts, huge sea level rise seen. many glaciers holding ice onto land - once glacier edges melt, ice sheets may slide off the land into the sea. catastrophic consequences. oceans may expand in volume as result of addition of water locked up in glaciers. increase of 1.5-4.5 degrees = leads to sea level rise of 15-95 cm. since peak of last glacial maximum (18,000 yrs ago), sea level has risen more than 120cm. sea level rose 17 cm during last century. expected to rise 50-200cm in next century.

changes in southern ocean & acidification

25% human generated CO2 absorbed into oceans. dissolves in seawater, forms carbonic acid - lowers pH. predicted that pH of oceans will drop 0.3-0.5 pH units by end of century. as seawater acidifies, extra hydrogen ions combine with carbonate ions (CO3^2-). carbonic acid dissociates, reducing carbonate ion concentration. carbonate ions are required for calcification - production of calcium carbonate by many marine organisms eg. corals & molluscs

effect of global warming in Antarctica

except for peninsular, effects have been minor on Antarctica. Ozone hole = increases polar vortex - isolated Antarctica from warming. changes in weather observed, but effects likely to be temporary. future changes due to global warming have potential to lead to large scale & possibly irreversible effects in Antarctic. extinction of some elements of Antarctic biota is possible as result of inability to cope with increased sea temperatures.

who were the earliest settlements established by

sealers and whalers. from early 19th C, they built primitive shelters on the sub-Antarctic & offshore islands.

who set up the first base on the Antarctic continent

Borchgrevink - Norwegian explorer. set up base at cape Adare in 1899. hut was prefabricated & made of Norwegian pine - withstood over century of gales & blizzards

who set up the 1st winter base in Antarctic

captain Scott in 1901 - at Hut Point on Ross Island. 'discovery hut' built by scott during discovery expedition 1901-1904.

what is the oldest continually occupied settlement in Antarctic

the Argentine scientific base of Orcadas - located in South Orkney islands. originally built as meteorological station in 1903

what was the 1st permanent base on Antarctic continent

1954 - Australia set up Mawson station. on east Antarctic coast & is the longest continuously operating station on continent. now has summer population of 24 people, with 16 remaining over winter. takes 10-12 days to reach Mawson from Hobart by ship. much more difficult to reach in winter (ice & cold).

the international geophysical year 1957/58

created a surge of interest in Antarctic research. IGY = series every 25/50 years of scientific Antarctic research. bases set up due to concerns that other countries would store nuclear weapons etc. bases staked claim in region. 50 government funded stations established representing 12 different nations. now more than 4- permanent scientific bases - greatest concentration around Peninsular (moderate climate and easier access from south America)

numbers of people in Antarctica

research stations support pop. in winter of 1000 people - 4000 in summer. since summer of 1990/91, more people visited Antarctica as tourists that as part of research program. 40,000 tourists each year.
but number of person days for research programs still far exceeds number for tourism. research programs have far greater infrastructure presence than tourism - permanent research stations with buildings.

NZ's permanent base in Antarctica

Scott Base - established 1959 , close to American McMurdo station (largest settlement in Antarctic). Scott base made up of collection of buildings linked by all-weather corridors. can accommodate 10 winter-over staff & up to 85 people in summer. McMurdo base = has 1000 people in summer

when was the 1st tourist visit to Antarctica

in 1957, when a Pan American Airline flight from Christchurch landed briefly at McMurdo.

when did tourism start to increase in popularity

in 1966 - when Lars-Eric Lindblad began offering boat trips, initially to South Shetland Islands

commercial overflights of Antarctica

began with Chileans in 1956, but were slow to gain popularity. number of overflights steadily increase, but suspended for many years after Air New Zealand flight TE901 crashed onto the slopes of Mt Erebus.

tourism as a growth industry in Antarctica

51,700 visitors to Antarctica in 2017/18 season & umbers projected to increase. however, more than 90% all tourism occurs around Antarctic Peninsula. majority of tourists come from USA, then Germany & Britain

what are the 3 types of tourism in the Antarctic

cruises on ships/yachts
overflights of the continent
extended land-bases expeditions - adventure tourism (climbing peaks etc).
Antarctica is unique in experience - has no hotels, no local markets, and shopping is restricted to a few shops at some research stations.

ship-based cruises

availability of low-cost, ice-strengthened ships from former Soviet Union made Antarctica more accessible & cheaper to go to. ship-based tourism is dominant tourism form. ships sail between 'gate-way' ports (christchurch, hobart & antarctica). most tourism occurs around peninsular & offshore islands to West of Peninsular. Limited sea cruises go to Ross Sea & East Antarctic region - often include visits to Antarctic peninsula, South Georgia & Falkland islands - take 2-3 weeks. the Orion conducts tours to sub-Antarctic island & Ross-Sea - crew of 75 & 1-6 guests. 24 day trip costs between 20,000-40,000 US dollars - luxury expedition cruise line.

overflights by passenger aircraft

majority originate from South America & fly over peninsular region. (S.A much closer then NZ). overflights from NZ or Australia are lengthy - large distances involved. round-trip from Australia takes 12 hours - only 4 hours spent over Antarctica. flights only take place in summer (dark in Winter).

when was the Mt. Erebus disaster

the 28th November 1979 - Air New Zealand Flight TE 901 was on a sightseeing flight over Antarctica when it crashed on Mt. Erebus, Ross Island. all 257 passengers and crew were killed. flight TE 901 took off from Auckland in the early morning, around lunchtime, McMurdo base lost contact with the plane and it was declared missing 15 hours after take-off

the Mount Erebus disaster

cause of crash initially thought to be aviators whiteout and computer error. the accident report released in 1980, cited pilot error as principal cause - captain descended below the minimum altitude of 1830m, and continued at this height when crew was unsure of their position. but combination of factors led captain to believe the plane was over flat ground, including fact that previous flights regularly flew low over the area. Royal commission enquiry into accident undertaken by Justice Mahon (NZ government)

what is aviators whiteout

form of spatial disorientation in which the horizon is not discernable, and sense of depth & orientation is lost.

The royal commission's enquiry into the Mount Erebus disaster

Justice Mahon's report released in April 1981 cleared crew of blame. dominant cause of crash was changing of aircraft's navigation computer to route that took flight over Mt Erebus without the crew being advised. due to whiteout conditions, crew was unable to see the mountain. Justice Mahon also found that radio communications centre at McMurdo station had authorized the Captain to descend to 450m. late court decisions questioned the way Mahon had conducted his investigation. public opinion remained divided on where blame for disaster should rest

the impact of tourists on the Antarctic

study in Antarctic penisular examined effects of tourists on pop. of Gentoo penguins. between 1966/67 over 4,300 tourists visited population - no effects found on hatching, laying, brood size, survival/chick growth. other studies showed Adelie penguins display increase in heart rate when humans are 30m away. a human standing 20m away from a penguin pathway can cause a 70m path deviation on penguins heading to & from the sea.
generally, research has revealed little evidence of lasting impact from tourism

which international polar year was renamed IGY (international Geophysical year)

the 3rd International polar year - 1957/58

where is the potential for conflict in Antarctica

Antarctica is the only place with no indigenous people and many countries claiming stakes to country. potential for conflict - Antarctic treaty made as agreement to govern and look after Antarctica - made by all 12 major nations involved in IGT

the First International Polar Year - 1882/83

1882/83. Karl Weyprecht (austrohungary) and Georg von Neumayer (German) proposed 1st IPY. realised studying the poles was fundamental to meteorology & geophysics. Groups called ' International Polar Commission" was established in 1879 - organised the 1st IPY. 12 nations participated & completed 15 polar expeditions (13 to Arctic & 2 to Antarctic - Cape Horn & South Georgia) - Arctic more accessible.
significant logistical problems, researchers spent more time trying to survive than researching. Despite objective of cooperation, many countries published result in own language - making access to results difficult.
Weyprecht died before 1st IPY, but set into motion the idea of collaborative , international scientific effort to study poles.
Richard Byrd (explorer) was 1st to fly over North pole & wanted to be 1st to fly over south pole. flew over south pole in 1929 - set up base "little America". one of Americas claims to Antarctica - 1st to fly over pole. Byrd returned to Antarctica in Dec 1933 with more private support - rebuilt little America & created new inland research station as part of second IPY in Antarctica

the Second International Polar Year 1932/33

second IPY much more successful than 1st. promoted by International Meteorological Organisation as wat to study the newly discovered Jet stream & its global effects, largely in fields of meteorology, magnetism, aural phenomena & radio science. 44 nations participated & vast amount of data collected. New inventions at time (airplanes, motorised sea & land vehicles) made life easier for scientists. financial limits associated with great depression of 1930's restricted establishment of Antarctic stations

the Third International Polar year / Geophysical Year - 1957/58

1957/58.
started in 1957, 25 years after last IPY & renamed the International Geophysical Year. broadened scope to embrace the entire globe, but with emphasis on polar regions - geophysical & biological. IGY lasted 18 months (1st July 1957 - 31 Dec 1958). global affair involving 67 nations. renewal of Russian interest in Antarctica at time of Cold War. 12 nations were involved in research based in Antarctica - argentina, australia, belgium, chile, france, japan, new zealand, norway, south africa, UK, USA, USSR

the Commonwealth Transantarctic Expedition

1955-58. 40 years after Shackleton's unsuccessful Transantarctic expedition. the commonwealth Antarctic Expedition (CTAE) completed the 1st overland crossing of the Antarctic continent. journey from Weddell sea, via South Pole, to Scott base, in the Ross sea.

what were the 2 teams of the Commonwealth Transantarctic Expedition

the Ross sea party = led by Sir Edmund Hillary (NZ) set up base in Ross sea, go from Ross sea to pole, set up a series of depots along the route and find a route for Fuchs to go back to the Ross sea (support for Fuchs)
the Crossing party = led by Sir Vivian Fuchs (British). start in the Weddell sea and set up a camp. go from Weddell sea to the pole, go from the Pole to the ross sea.

Hillary's Part (the Ross sea party) - The Commonwealth Transantarctic Expedition

very successful - originally tried to lay all depots by plane, took dogs, tractors, & plane - lots of equipment. arrived a year before & made way up Skelton Glacier. Tractors were more successful than planes for laying depots. when Hillary laid 1st depot, he was meant to return to Scott base & wait to Fuchs, but he decided to keep going to the Pole - arrived at the pole a few days before ****s - caused huge amount of tension between Hillary and Fuchs - international incident. Hillary = 1st person to get to pole by mechanical means.

Hillary & the Ross sea party (CTAE)

established Scott base on Ross island January 1957. spent summer of 1957 finding a route over the skelton glacier onto the plateau & establishing depots. after wintering over at scott base, Hillary and 3 others set out with 3 Massey Ferguson tractors filled with caravans for living in, establishing last 2 depots. after laying the last depot (depot 700), Hillary decided to continue to the pole, (800km away). Hilary reached Pole on 4th January 1958, 16 days before Fuchs.

the fourth international polar year 2007/9

involved over 160 projects, 1000's scientists from 60+ nations, examining range of physical, biological & social research topics. cost US $1.2 Billion. organised through International Council for science & the World Meteorological Organisation.
4 major goals:
make major advances in polar knowledge
leave a legacy of observational systems, facilities and infrastructure
inspire a new generation of polar scientists
elicit interest and participation from groups worldwide

the Antarctic treaty

after cold war - many interested in Antarctica, many thinking of using is a nuclear waste dump/weapons testing. after 3rd polar year, treaty needed to avoid conflict. Antarctica = surrounded by oceans, has no borders with any sovereign nation. Antarctic treaty system = collection of agreements made for purpose of regulating international relationships & human activity.
Treaty grew out of success of 3rd international polar year. signed in 1959

what is Antarctica defined as for the Antarctic treaty

all the land and ice shelves South of 60 degrees S latitude

When was the Antarctic treaty signed

in 1959, by representatives of all the 12 nations involved in the IGY

what were the dates of the 4 polar years

1882/3
1932/3
1957/8 (IGY)
2007/9

objectives of the Antarctic treaty

1st nuclear arms-control & 1st treaty to govern all human activities in region beyond countries' sovereign jurisdictions. to ensure Antarctica used exclusively for peaceful purposes & not become scene or object of international discord.
prohibit nuclear activity, except in support of science.
prohibit nuclear explosions & the disposal of nuclear waste.
promote scientific research & the exchange of data.
hold all territorial claims in abeyance. originally 12 signatories, now many more & measures adopted to further protect region's marine life.
at fist, treaty concerned with human activities and disputes, but conservation soon added,

what laws govern people in Antarctica

the laws of the country they come from

conservation of Antarctic Flora and Fauna (extension of the Antarctic treaty)

signed 1964, effective 1982, expired 2011, promoted protection, scientific study& rational use of Antarctic fauna & flora. allows importation under permit of sledge dogs, domestic/lab animals & plants, by prohibited living poultry. prohibited killing, wounding, capturing or molesting of any native mammal or bird, except by permit. permits provided for obtaining food for men & dogs & scientific specimens
agreement now replaced by Environmental protection protocol

convention for the conservation of Antarctic Seals (CCAS) - extension of Antarctic treaty

signed 1972, in force 1978. seal hunting was major economic activity in early C19. when seal populations depleted. purpose of CCAS= protection of some Antarctic species & to regulate the sealing industry for other species. applies to all seals living South of 60*S. 15-30 million crabeater seals in Antarctica & could have been hunted commercially. protects Ross, Elephant & fur seals, and put limit & seasons on crabeater, Leopard & Weddell seals.
Weddell seal pop. = 800,000/ sealing industry has not returned & CCAS focused on strengthening protection.

convention on conservation of Antarctic Marine Living Resources (CCAMLR) - extension of Antarctic treaty

signed 1980, enforced 1982. concern grew over potential large-scale exploitation of krill & effects of Antarctic organisms dependent on krill for food. CCAMLR controls commercial fishing in Southern Ocean - includes area between 60*S & Antarctic convergence. does not regulate whaling (controlled by international Whaling Commission). established to ensure stable recruitment into fish stocks, maintain ecological relationship between dependent species & minimise ecosystem change. krill harvesting strictly controlled.

convention on regulation of mineral resource activities (CRMAR) - Extension of Antarctic treaty

treaty didnt address regulation of mineral exploration & mining. voluntary moratorium on exploitation of Antarctic minerals put into place in 1976. in 1981, treaty nations started negotiations on comprehensive minerals regime. negotiations difficult & complec - resulted in CRAMRA, difficult due to increased interest in Antarctica by other countries. CRAMRA agreed to in 1988, but later abandoned when Austria & France refused to sign & later NZ, Italy & Belgium.

protocol on Environmental Protection - extension of Antarctic treaty

signed 1991, in force 1998. collapse of CRAMRA threatened stability of Antarctic treaty system, & foreshadowed need for comprehensive environmental protection protocol. bans mineral resource extractions (but reviewed in 2041). Environmental (Madrid protocol) built around 5 annexes focusing on environmental impact assessment, conservation, waste management, prevention of marine pollution & establishment & management of protected areas

what were the extensions of the Antarctic treaty

conservation of Antarctic flora & fauna - 1964
convention for conservation of Antarctic seals - 1972
convention on conservation of Antarctic Marine living resources - 1980
convention on regulation of Antarctic Mineral resources - 1988
protocol on environmental protection - 1991 - replaces the 1964 - more extensive

what is Antarctic ornitholgy

the study of Antarctic birds

what are the 3 features of Antarctic that are critical to understanding of its Ornithology

geographic position - most of its land mass is below 70*S.
continent is permanently covered with ice & snow with little exposed rock
Antarctica is isolated from all other substantial land masses by the Southern Ocean with its circumpolar air & water currents.

Low Avian diversity of Antarctica

v. few species of breeding birds compared with other continents. even when sub-Antarctic islands included, total number of species - just over 40 (compared to 1000's in Africa). although number of species is low, the number of individuals per species is very high. may of Antarctic avian species are endemic (found only in given region/location)

how many avian species are there in Antarctica

just over 40 - small number of species, but very high number of individuals per species

how many species of landbirds are there south of the Antarctic convergence

6 species. no land birds breed on the Continent & the 6 species that do breed south of the convergence are all on sub-Antarctic islands - due to little food availible on continent

types of landbirds

charadriiiformes (sheathbills) -2 species
Anseriformes (ducks & teals) - 3 species
Passeriformes (south Georgia pipit) - 1 species - perching birds

charadriiformes (sheathbills)

only family of birds entirely restricted to Sub-Antarctic region. bear superficial resemblance to pigeons both when walking & in flight. mostly scavengers along shoreline, feeding on marine animals & carrion (carcasses). remain on land during winter & in summer nests in crevices & under protected overhangs near penguin colonies (can scavenge on dead chicks). 2 species - snowy & lesser sheathbill. both found on number of sub-Antarctic islands. breeding activity limited to South Georgia, Falkland islands & south Orkney
derive name from horny sheath that partially covers upper mandible of their beaks. skin around the eye & above the bill is bare & includes carbuncular swellings

almost all birds nesting in Antarctica are seabirds

due to vast stretches of ocean & small area of ice-free land. of 10,000 species on earth, only 2.5% are seabirds. of 250 seabird species in world, 62 breed south of 50*S, and 29 breed south of Antarctic convergence. seabirds are usually much larger than landbirds & have larger eggs, typically in small clutches. seabirds obtain almost all food from sea, but must come ashore to find mate, build nest & lay eggs,

nasal glands in seabirds

all seabirds have nasal gland in head that can excrete concentrated salt (NaCl). gland secretes highly concentration salt solution (5% NaCl) that allows sea birds to drink seawater (3% NaCl). salt solution excreted out of nostrils seen as drip off tip of break. gland acts as adjunct to kidneys that cannot handle all salt load. nasal glands are large & usually sit in indentations in the skull just above the orbits (eyes). secretary tubules take NaCl out of blood & into the lumen, which combines into central duct and is excreted.

29 species of nesting birds in Antarctica

procellariiformes - albatrosses (4), Fulmars (11), storm Petrels (2)
Pelecamiiformes - cormorant/shags (1)
charadriiformes - gulls & turns (2), Skua (2)
schenisciformes - penguins (7)

charadriiformes - Skua

have heavier bodies than gulls. have hooked bills & claws (predators). plumage is predominantly dark, with conspicuous white patches on top & bottom of wings. female = larger than males by 11-17% (reverse sexual dimorphism). long lived (up to 40 years), very faithful to territory & their mates. migrate northward during winter. hold record for longest migration. 2 species of skua

what are the 2 species of skua

brown skua - wingspan 1.5m, weigh 1.6-2kg. breed in sub-Antarctic and on tip of Antarctic peninsula.
south pole skua (wingspan 1.3m) breeds further south - south of polar front, mainly on the Antarctic continent, mainly on exposed beaches. predatory seabird, produces 2 eggs that are laid a number of days apart. 1 chick will hatch a few days earlier - one chick is slightly bigger. of the 2 chicks, usually only 1 survives - siblicide.

siblicide in south polar Skua

fatal sibling aggression. aggressive attacks by older chick happen soon after younger chick hatches. the old chick can kill the younger, but more commonly it prevents it from getting food from the adults. younger chick will either die from starvation or willl stray into other territories, usually to be killed & eaten by other adult skua.

theories to explain siblicide

occur in situations where 'costs' to offspring are greater than benefits they receive from helping close relative. eg. when parents are unable to meet demands of offspring. correlate with resource competition, provision of food to nestling in small units, weaponry, spatial confinement, competitive disparities between siblings

why do parents continue to produce offspring which are often/always killed by their sibling

resource tracking - to be able to capitalise on unpredictably favourable ecological conditions - on a good year, both chicks may survive
replacement offspring/insurance - equipped with backup offspring to stand in for one that is flawed/dead.
offspring facilitation hypothesis - fielding team of offspring capable of assisting one another in various ways eg. source of food