Pollution's Impact On Antarctica's Wildlife

Antarctica is one of the cleanest places on Earth, but it is not exempt from the effects of pollution. The continent is largely affected by anthropogenic pollution, despite having no permanent human settlement. Pollution in Antarctica is primarily caused by external sources, such as industrial activities and emissions from other parts of the world. The unique environment of Antarctica, with its cold temperatures and low precipitation, means that pollutants accumulate in the ice and snow. These pollutants, including chlorofluorocarbons (CFCs), lead, and other heavy metals, are transported to the continent through atmospheric circulation and ocean currents. While the levels of pollutants in Antarctica are generally lower than in other regions, they still have significant impacts on the local wildlife.

How does plastic pollution affect Antarctic animals?

Antarctica is known for its clean and natural environment, but plastic pollution has reached even this remote region. The effects of plastic pollution on the local wildlife are devastating.

Plastic pollution in Antarctica comes from two sources. Firstly, debris left behind by humans is blown away by extreme weather conditions and scattered into the snowy terrain and icy waters. Secondly, debris from other parts of the world is carried to Antarctica by ocean currents.

The Antarctic Circumpolar Current was historically thought to act as a buffer zone, protecting the region from plastic pollution. However, recent studies have shown that plastics are getting across the current. Microplastics, in particular, have been detected in water and snow samples from Antarctica.

The impact of plastic pollution on Antarctic wildlife is twofold. Larger plastics can entangle birds and seals, leading to injury or death. Microplastics, on the other hand, are ingested by small animals such as Antarctic zooplankton and krill, which are a crucial food source for larger animals. Studies have shown that krill embryos exposed to both nanoplastics and ocean acidification had a harder time developing, with fewer embryos developing limbs and hatching.

The well-being of Antarctica and its surrounding marine life depends on addressing plastic pollution. Urgent action is needed to tackle the problem at its source and protect the fragile ecosystem of this remote region.

How does ozone depletion affect Antarctic animals?

Antarctica is one of the cleanest places on Earth, but it is not immune to the effects of pollution. The ozone layer, a protective layer in the Earth's stratosphere, has been thinning over Antarctica since the early 1980s. This depletion is caused by chlorofluorocarbons (CFCs), long-lasting chemicals used in refrigeration and aerosol sprays. The ozone hole over Antarctica allows increased UVB radiation from the sun to reach the Earth's surface, causing harm to the DNA of Antarctic animals.

The ozone layer plays a critical role in safeguarding life on Earth by absorbing ultraviolet (UV) light, which can damage DNA and lead to sunburns and skin cancer in plants and animals, including humans. In the 1980s, scientists discovered that the ozone layer over the South Pole was thinning significantly each spring, coining the term "ozone hole." This depletion is primarily attributed to CFCs, which, when broken down by UV light in the upper stratosphere, release chlorine atoms that catalyze ozone destruction.

The effects of ozone depletion are far-reaching, and Antarctic animals are particularly vulnerable. Researchers have found direct evidence that increased UVB radiation damages the DNA of animals in Antarctica, specifically the eggs and larvae of icefish, a native Antarctic species. The excess UVB light can hinder fish growth, disrupt cellular processes, and divert energy away from other vital functions to DNA repair. This damage to fish eggs and larvae could have significant implications for the Southern Ocean food web, as larval and adult fish, krill, copepods, and zooplankton form the basis of the food chain for seabirds, whales, and seals.

Additionally, the ozone hole's impact is not limited to aquatic life. Minute traces of manufactured chemicals are being detected in the snow that falls over Antarctica, and these chemicals can accumulate in the bodies of animals such as seals, penguins, and whales, potentially causing long-term harm.

The recognition of the destructive potential of CFCs led to the Montreal Protocol in 1987, a treaty that phased out the production of ozone-depleting chemicals. While the concentration of ozone-depleting substances is expected to return to pre-1980 levels by the middle of this century, the Antarctic ozone layer is predicted to recover mostly by 2040.

How does sewage affect Antarctic animals?

Antarctica is one of the cleanest places on Earth, but it is not untouched by human activity. The continent is affected by anthropogenic pollution, including sewage.

Sewage in Antarctica

Sewage disposal and its impact on wildlife health in Antarctica is an important topic because the disposal of untreated sewage effluent into the Antarctic marine environment is both allowed and commonplace. Human sewage contains enteric bacteria and has the potential to contain parasites, bacteria, and viruses that may be pathogenic to Antarctic wildlife. While treatment can reduce levels of microorganisms in sewage effluent, it is not a requirement of the Environmental Protocol to the Antarctic Treaty (the Madrid Protocol). The deliberate release of non-native organisms for any other reason is prohibited. Therefore, the disposal of sewage effluent into the marine environment is the only activity routinely undertaken in Antarctica knowing that it will likely result in the release of large numbers of potentially non-native species.

History of Sewage Disposal in Antarctica

Historically, early Antarctic explorers disposed of shipboard human wastes overboard, while terrestrial huts were equipped with latrines that were emptied at sea or with pit latrines where wastes were buried. These practices continued until the 1960s. More recently, increasing station populations and commensurate increases in sewage and wastewater production have led to the installation of piped continuous discharges at some bases.

Current Sewage Management Practices in Antarctica

The most common forms of primary treatment at Antarctic stations are maceration, comminution, screening, and settling. Aerobic biological secondary treatment is the most common technology and is used at a number of stations. At some coastal stations, untreated or macerated sewage is still discharged directly into the sea. Discharge points may be submerged or above sea level. Inland bases and field camps typically discharge wastewater and sewage into ice pits, sub-surface ice wells, or nearby lakes.

Environmental Impacts of Sewage Effluent

Sewage can impact the environment in several ways, including the aesthetic nuisance created by the sight and smell of effluent, the physical effects of releasing large quantities of particulate material, and the introduction of living and potentially infectious or invasive microorganisms.

The high levels of nutrients in sewage can upset the balance of ecosystems, particularly those that are naturally nutrient-limited, a common characteristic of both Antarctic terrestrial and lake systems. The accumulation of organic material from sewage in marine environments can create anaerobic conditions, which can lead to the generation of reduced sulfur compounds that are toxic to marine invertebrates.

Links Between Sewage Exposure and Ill Health in Wildlife

While there is limited research on the links between sewage exposure and ill health in wildlife, it is known that sewage effluent introduces a great variety of microorganisms, likely including human-disease-causing pathogens, into the Antarctic environment. Whether or not exposure of Antarctic wildlife to sewage effluent can result in disease remains unproven.

Sewage treatment and disposal technologies currently in use at many Antarctic stations introduce a range of microorganisms into the environment. While there is limited evidence of direct causal links between sewage-derived microorganisms and disease in wildlife, the practice of discharging sewage effluent stands out as the only activity permitted in Antarctica that will inevitably lead to the introduction of non-native species and genetic material on a large scale.

How does lead pollution affect Antarctic animals?

Antarctica is a unique continent with demanding environmental conditions, an unyielding cold climate, and geographical isolation. The continent is covered in ice and snow, with a temperature that can go as low as −60 °C in the interior plateau during winter.

The levels of pollutants in Antarctica are generally lower than elsewhere in the world. This is due to the lack of industry and farming in the Southern Hemisphere. However, human activities have been reported to be the major cause of the accumulation of heavy metal contaminants.

Sources of Lead Pollution in Antarctica

Natural Sources

Lead is a naturally occurring metal that can be distributed through long-range transport, both natural and anthropogenic. It is a natural component of soils and can be found in rocks and metalliferous minerals. Mobilisation of lead happens through pedogenetic processes such as mineral weathering and soil erosion. Volatile metalloids such as arsenic and mercury are distributed and transported as gases or enriched in particles.

Anthropogenic Sources

Human activities have been reported to be the main cause of lead pollution in Antarctica. The use of lead ammunition for hunting is correlated with increased blood lead levels in humans. For example, Indigenous people living in western James Bay in northern Ontario had increased levels of lead after the spring hunting season. In addition, lead levels in vegetation are usually elevated near mining sites.

The establishment of research stations, flourishing tourism, and the consumption of coal and fossil fuels by these stations and the tourism industry have also contributed to lead pollution. The burning of fossil fuels releases metallic elements, and exhaust emissions from transportation to and within the continent can spread these pollutants.

Effects of Lead Pollution on Antarctic Animals

Lead is considered one of the most hazardous and cumulative environmental pollutants, affecting all biological systems through exposure to air, water, and food sources. Exposure to lead can induce clinicopathological changes through toxicity occurring in the kidney and endocrine system. A high level of lead in animals has resulted in reproductive failure, poor performance, poisoning, and death.

Lead is a heavy metal that is both poisonous and a ubiquitous environmental toxicant. It can interfere with the endogenous development of the opiate system and has binary impacts on neurotransmitter release, enhancing spontaneous neurotransmitter release while inhibiting stimulated release.

Lead also affects the cardiovascular system by influencing important neural and hormonal systems that contribute to the rule of peripheral vascular resistance, cardiac output, and heart rate. Exposure to low levels of lead may cause hypertension in both humans and animals, and can also lead to cerebrovascular accidents, peripheral vascular disease, and ischemic coronary heart disease.

Lead exposure can also cause renal dysfunction, even at low levels. Acute nephropathy can be categorised morphologically by degenerative changes in the tubular epithelium, while chronic nephropathy may cause irreversible morphological and functional changes, including hyperuricemia, hypertension, and renal breakdown.

Lead has toxic effects on a wide variety of organs, causing impairments in the nervous, hematopoietic, renal, cardiovascular, and reproductive systems following ingestion, inhalation, or skin absorption. There are two types of anaemia that result from lead poisoning: frank anaemia, which occurs when the level of lead in the blood is significantly raised for an extended period, and hemolytic anaemia, which is related to a seriously high level of exposure to lead.

Remediation of Lead Pollution in Antarctica

Physicochemical and biological approaches have been employed to address lead pollution in Antarctica. Physicochemical approaches include wastewater treatment plants, which aim to separate water-soluble heavy metals through physical methods. Biological treatments, on the other hand, utilise resistant organisms such as plants and microorganisms to remove or break down contaminants into less toxic forms.

While the levels of pollutants in Antarctica are generally lower than in other parts of the world, human activities have led to an accumulation of heavy metal contaminants, particularly lead. These contaminants can have detrimental effects on the health and well-being of Antarctic animals, affecting various organs and systems. Efforts to remediate lead pollution in Antarctica include the use of wastewater treatment plants and biological treatments, such as bioremediation using resistant organisms.

How does ocean acidification affect Antarctic animals?

Ocean acidification is a global threat to the world's oceans, estuaries, and waterways. It is caused by the ocean absorbing carbon dioxide from the atmosphere, which leads to lower pH levels and greater acidity. This process is often referred to as "climate change's evil twin" and is projected to grow as carbon dioxide continues to be emitted at record-high levels.

The Southern Ocean, which surrounds Antarctica, is particularly vulnerable to ocean acidification due to its cold temperatures, naturally low levels of calcium carbonate, and upwelling that brings deep carbon dioxide-rich waters to the surface. As a result, Antarctic marine animals are being negatively impacted by ocean acidification.

One of the most affected groups is invertebrates, which include amphipods, krill, brachiopods, sea stars, sea urchins, bivalves, pteropods, limpets, sea snails, and nemertean worms. Invertebrates show reduced fertilization rates, increased occurrence of larval abnormalities, decreased calcification rates, and increased shell dissolution when exposed to elevated levels of carbon dioxide. This is particularly true for any increase in carbon dioxide levels above 1,500 µatm.

Another group affected by ocean acidification is autotrophic organisms, mainly phytoplankton. They experience a decline in chlorophyll a concentration, productivity, and photosynthetic health, as well as a shift in community composition when carbon dioxide levels exceed 1,000 µatm.

Ocean acidification also has negative consequences for fish, although there are relatively fewer studies on this group. Some studies suggest that fish may expend more energy to maintain osmoregulation when exposed to elevated carbon dioxide levels over more extended periods.

Overall, ocean acidification is expected to have negative effects on many marine species in Antarctica, altering marine food chains and food supply to humans. It is crucial to conduct further studies to fully understand the impact of ocean acidification on Antarctic animals and to develop strategies to mitigate these effects.

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