Oil Composition and Chemistry and the Effects on Wildlife
To evaluate the consequences of oil spills on wildlife it is important to understand the properties and chemistry of crude oils and petroleum products. Oil, depending upon its form and chemistry, causes a range of physiological and toxic effects.
For example, the low molecular weight aliphatics of oil can have anaesthetic properties and aromatic components such as benzine are known carcinogens and very toxic to humans and wildlife. Some polynuclear aromatics are also carcinogenic and toxic and, are concentrated in the food chain eg. in tissues of water filter feeding shell fish like mussels and oysters.
Volatile components of oil can burn eyes, burn skin, irritate or damage sensitive membranes in the nose, eyes and mouth. Hydrocarbons can trigger pneumonia if it enters lungs. Benzine, toluene and other light hydrocarbons of oil and fuels if inhaled, are transferred rapidly to the bloodstream from the lungs and can damage red blood cells, suppress immune systems, strain the liver, spleen and kidneys and even interfere with the reproductive system of animals and humans.
In general, refined petroleum products tend to be more toxic to organisms but less persistent in the environment. Crude oils and heavy fuel oils like bunker fuels tend to be less toxic but are more persistent and more likely to have physical impacts on wildlife eg coating feather, fur and skin.
This compositional variation of oil also governs its behaviour, weathering and fate after being spilt in the marine environment. For example; volatility of hydrocarbons into the air from the oil, solubility of toxic components into seawater from the slick and dispersed oil, formation and stability of emulsions, rate of natural oil dispersion, persistence, adherence to surfaces ("stickiness") and physical state, and rate of natural biodegradation.
The chemistry of crude oils and refined petroleum products varies significantly. Each spilt oil or fuel will behave differently and it is difficult to predict accurately the impacts on wildlife. For example, some oils will become more "sticky" as they weather and have a greater tendency to adhere to surfaces such as animal skins, fur, hair or feathers. Some liquid oils will form solid waxes very quickly after only a few hours of weathering at sea, others will leave little residue and other oils may contain high levels of persistent hydrocarbons.
Ambient wind and water conditions can modify the impact of oil on wildlife. For example, on a warmer sea and in high winds, evaporation may remove the lighter aromatic compounds. As a result they do not dissolve into the water column and affect marine life and are incorporated into the food chain.
Effects of Oil on Sea Birds
Many oil spills have resulted in the death of a large number of sea birds, which very sensitive to both internal and external affects of crude oil and its refined products.
Sea birds have a high risk of contact to spilled oil due to the amount of time they spend on or near the surface of the sea and on oil affected foreshores. Sea birds may also come in contact with spilled oil while searching for food, since several species of fish are able to survive beneath floating oil.
Oil-coated birds can suffer hypothermia, dehydration, drowning and starvation, and become easy prey.
Sea birds are affected by oil in several ways..
Contact with crude oil or refined fuel oils. This causes feathers to collapse and matt and change the insulation properties of feathers and down.
Matting of feathers. This can severely hamper the ability of birds to fly.
A breakdown in the water proofing and thermal insulation provided by the feathers. This often causes hypothermia.
Oiled feathers. This can cause the seabirds to lose buoyancy, sink and drown because of increased weight or lack of air trapped in the feathers.
Body weight decreases quickly as the metabolism attempts to counteract low body temperature.
Severe irritation of the skin.
They ingest the oil in an attempt to preen themselves.
Irritation or ulceration of the eyes, skin, mouth, or nasal cavities
The food searching instincts such as diving and swimming are inhibited.
Ingestion of oil via their prey if their food chain becomes contaminated.
Poisoning or intoxication.
Ingestion of oil can be sub-lethal or acute and will depend to a large extent on the type of oil, its weathering stage and inherent toxicity.
These internal effects can include:
the destruction of red blood cells, important for the immune response,
alterations of liver metabolism,
adrenal tissue damage,
pneumonia,
intestinal damage,
reduced reproduction ability,
reduction in the number of eggs laid,
decreased fertility of eggs,
decreased shell thickness and
disruption of the normal breeding and incubating behaviours.
It has been estimated that as little as four microlitres of petroleum contaminating a fertile egg can cause the embryo to die
Most scientists recognize 17 species of penguins:
1.emperor Aptenodytes forsteri
2.king Aptenodytes patagonicus
3.Adélie Pygoscelis adeliae
4.gentoo Pygoscelis papua
5.chinstrap / Pygoscelis antarctica
6.rockhopper / Eudyptes chrysocome
7.macaroni / Eudyptes chrysolophus
8.royal / Eudyptes schlegeli
9.Fiordland crested / Eudyptes pachyrhynchus
10.erect-crested / Eudyptes sclateri
11.Snares Island / Eudyptes robustus
12.yellow-eyed / Megadyptes antipodes
13.fairy(also known as little blue)/Eudyptula minor
14.Magellanic / Spheniscus magellanicus
15.Humboldt / Spheniscus humboldti
16.African(formerly known as black-footed) / Spheniscus demersus
17.Galapagos / Spheniscus mendiculus
A Penguins Habitat
Penguins generally live on islands and remote continental regions that are free of land predators, where their inability to fly is not detrimental to their survival.
These highly specialized marine birds are adapted to living at sea. Some species spend as much as 75% of their lives at sea. They usually are found near nutrient-rich, cold-water currents that provide an abundant supply of food.
Penguin species are found on every continent in the Southern Hemisphere. They are abundant on many temperate and subantarctic islands. Different species thrive in varying climates, ranging from Galapagos penguins on tropical islands at the equator to emperor penguins restricted to the pack ice of Antarctica.
The seasonal changes of the Southern Hemisphere are opposite those of the Northern Hemisphere. While continents above the equator experience spring and summer, the areas below the equator experience fall and winter.
Migration
Penguins generally do not migrate great distances. They tend to disperse from breeding rookeries to feed in nearby coastal waters.
Young birds usually disperse when they leave their colonies, and may wander thousands of kilometers. They generally return to the colonies where they were hatched to molt and breed.
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Social behaviorPenguins are among the most social of all birds. All species are colonial to some degree.
Penguins communicate by vocalizing and performing physical behaviors called "displays."
Penguins may swim and feed in groups, but some may be solitary when diving for food. Emperor penguins have been observed feeding in groups with coordinated diving.
During the breeding season some species come ashore and nest in huge colonies called rookeries. Some rookeries include hundreds of thousands of penguins and cover hundreds of square kilometers.
Penguins exhibit intricate courting and mate-recognition behavior. Elaborate visual and vocal displays help establish and maintain nesting territories.
Although king penguins are highly gregarious at rookery sites throughout the year, they usually travel in small groups of 5 to 20 individuals.
Penguins communicate by vocalizing and performing physical behaviors called "displays." They use many vocal and visual displays to communicate nesting territories and mating information. They also use displays in partner and chick recognition, and defense against intruders.
Individual behavior
Navigation
Studies with Adélies indicate that they use the sun to navigate from land to sea. They adjust for the sun's changing position in the sky throughout the day.
Preening
Penguins preen their feathers frequently. Feathers must be maintained in prime condition to ensure waterproofing and insulation.
Penguins preen with their bills. A gland near the base of the tail secretes oil that the penguin distributes throughout its feathers.
Penguins preen for several minutes in the water by rubbing their bodies with their flippers while twisting and turning over.
Fossil records
Scientists recognize 32 species of extinct penguins.
Penguins probably evolved from flying birds more than 40 million years ago. As the ancestors of penguins became adapted to an oceanic environment, structural changes for diving and swimming required the loss of flying adaptations.
To date, the discovery of all penguin fossil fragments has been limited to the Southern Hemisphere. Records show that prehistoric penguins were found within the range of present-day penguins.
The first penguin fossil fragments were found in New Zealand in the mid-1800s. One fossil penguin, Palaeeudyptes antarcticus, lived in the Eocene Period (38 to 42 million years ago). It was estimated to stand 4-5 ft. This specimen is maintained in London's British Natural History Museum.
Fossil records show that the largest extinct species lived in the Miocene Period (11 to 25 million years ago). Pachydyptes ponderosus probably stood 4.5-5 ft. and may have weighed 198-298 lb., and Anthropomis nordenskjoldi probably stood 5-5.9 ft. and weighed 198-298 lb. Measurements are estimates, since only a few bone fragments have been found.
Scientists believe that ancient penguins began disappearing about the same time that the number of prehistoric seals and small whales started increasing in the oceans. Some scientists hypothesize that seals, whales, and penguins may have competed for the same food source, and that the penguins may have become prey themselves. Both factors may have contributed to their extinction.
The closest living relatives to penguins are in the order Procellariiformes (the albatrosses, shearwaters, and petrels), and the order Gaviiformes (loons and grebes). DNA studies also suggest a relationship with the frigatebirds (order Pelecaniformes).
Discovery of modern penguins
The first European explorers to see penguins probably were part of the Portuguese expedition of Bartholomeu Dias de Novaes in 1487-88. They were the first to travel around what is now known as the Cape of Good Hope in southern Africa.
The first documentation of penguin sightings is credited to members of the Portuguese voyage of Vasco da Gama in 1497. They described penguins they saw along the southern coasts of Africa.
The discovery of South America's Magellanic penguin was chronicled during the journey of Spanish explorer Ferdinand Magellan in 1520.
The origin of the word "penguin" has been a subject of debate. Researchers' and historians' theories range from references to the amount of fat penguins possess to the claim that the word was derived from two Welsh words meaning "white head". The most agreed-upon explanation is that "penguin" was used as a name for the now-extinct great auk, which the modern-day penguin resembles and for which it was mistaken.
Sexual maturity
Like most seabirds, penguins tend to be long-lived. They may take three to eight years to reach sexual maturity.
With some of the smaller species, breeding may begin at three or four years, but most larger species are not accomplished breeders until much later. On average, breeding does not begin until the fifth year, and a few males do not breed until the eighth year.
Mating activity
Breeding seasons differ from species to species.
Most species have an annual breeding season - spring through summer.
The king penguin has the longest breeding cycle of all the penguin species, lasting 14 to 16 months. A female king penguin may produce a chick twice in every three breeding seasons.
Emperor penguins breed annually during the antarctic winter, June through August.
During the emperor breeding season, winds may reach speeds up to 124 mph.
For most of the winter, antarctic penguins live in an environment of darkness or half-light. Why emperors breed during the harshest season of the year is unknown, but some scientists speculate that when the chicks become independent five months later (in January or February, the antarctic summer), environmental conditions are more favorable for the young birds.
The fairy penguin breeds throughout the year and has the shortest breeding cycle, about 50 days.
Some of the temperate penguins, like the Humboldt and the African, tend to nest throughout the year.
Courtship
Courtship varies among the species. It generally begins with both visual and auditory displays. In many species, males display first to establish a nest site and then to attract a mate.
Most penguin species are monogamous (one male breeds with one female during a mating season);however, research has shown that some females may have one to three partners in one season and some males may have one or two partners.
Mate selection is up to the female, and it is the females that compete for the males.
A female usually selects the same male from the preceding season. Adélie penguins have been documented re-pairing with the previous year's mate 62% of the time. Chinstraps re-paired in 82% of possible cases, and gentoos re-paired 90% of the time. In one study of Adélies, females paired with males within minutes of arriving at the colony.
When a female selects a different mate it is usually because her mate from the previous season fails to return to the nesting area. Another reason may be mistiming in returning to the nesting area. If they arrive at different times and miss each other, one or the other penguin may obtain a new mate.
Nesting
Nest site fidelity.
Studies have shown that most penguin species tend to be faithful to the same rookeries and return each year. Most penguins return to the same territory within the rookery. Male Adélie penguins were 99% faithful to the previous year's territory, chinstraps were 94% faithful, and gentoos were 63% faithful.
Males arrive first to the rookeries to establish and defend their nesting sites. In a study on Adélie and chinstrap penguins, females arrived one day and five days after the males, respectively.
Some scientists believe that penguins build up numbers in a single rookery rather than colonize new areas because mature birds return to the rookery where they hatched when it is time to breed. Some penguin rookeries number millions of birds.
Nesting habitats vary among species.
Emperor penguins form colonies around the shoreline of the antarctic continent and adjacent islands. They prefer sites on a fairly level surface of ice in areas sheltered from wind, with easy access to feeding areas.
King penguins nest and breed on subantarctic and antarctic islands. They prefer beaches and valleys of level ground or gentle slopes, free of snow and ice, and accessible to the sea.
Adélies often nest 31.1-37.3 mi. from the edge of the sea ice on the antarctic continent and nearby on rocky islands, peninsulas, beaches, hillsides, valleys, and other areas free of ice.
Gentoo penguin colonies can be inland or coastal on antarctic and subantarctic islands and peninsulas. They tend to breed on ice-free ground on beaches, in valleys, on inland hills, and on cliff tops.
Chinstrap penguins nest on fairly steep slopes.
Fiordland crested penguins nest in a wet, coastal rain forest habitat, under bushes, between tree roots, in holes, or in caves.
Galapagos penguins nest in volcanic caves or cracks in rock.
Some penguins, like these gentoos, construct nests of small stones.
The temperate penguins and the fairy penguin nest underground in burrows. These species breed in areas where the climate can range from tropical to subantarctic. Underground burrows provide an environment with a relatively constant temperature (about 25° to 29°C, or 70° to 84°F) for the eggs and chicks.
Humboldt penguins burrow and create nesting sites in guano (fecal) deposits (Scolaro).
Nesting materials vary from species to species and from location to location.
Adélies build nests of small stones. They are known to take stones from other Adélie nests. This stone-stealing behavior may be credited to the Adélies' nest-relieving display in which the returning penguin sometimes brings its mate a stone as a soothing gesture or greeting.
Chinstrap penguins usually construct nests with perimeters of eight to ten stones, just enough to prevent eggs from rolling away.
Gentoo penguins use nesting materials ranging from pebbles and molted feathers in Antarctica to vegetation on subantarctic islands. One medium-sized gentoo nest was composed of 1,700 pebbles and 70 molled tail feathers.
Emperor and king penguins build no nests. They stand upright while incubating a single egg on the tops of their feet under a loose fold of abdominal skin. Under this loose fold is a featherless patch of skin called a broodpatch, which occurs in all incubating birds. The brood patch contains numerous blood vessels, that, when engorged with blood, transfer body heat to the eggs.
Eggs
Eggs may be white to bluish or greenish. The shape varies among species. In Humboldts and Adélies the egg is more or less round. In emperors and kings the egg is rather pear-shaped, with one end tapering almost to a point.
Egg size and weight varies with species. From the records of SeaWorld's successful penguin breeding programs, emperor penguin eggs measure 4.4-5 in. long and weigh 12.1-18 oz., and Adélie penguin eggs measure 2.2-3.4 in. and weigh 2.1-5.4 oz.
A nest of eggs is called a clutch, and with the exception of emperor and king penguins, clutches usually contain two eggs. (Emperor and king penguins lay a single egg. ) A clutch with more than one egg presents a better chance of at least one chick surviving.
In the Eudyptuia, Spheniscus, and Pygoscelis genera, the first-laid egg is generally larger than the second, and usually hatches first (except in the chinstrap species). Usually the first chick to hatch has the survival advantage since it will already have fed and will be larger by the time the second egg hatches. The second, usually smaller, chick cannot compete with the larger chick for food and usually perishes.
In the Eudyptes genus, the second-laid egg and subsequent chick is usually the larger of the two. The second chick usually is the survivor. Researchers have yet to find an adequate theoretical explanation for this reversed pattern.
The chinstrap and yellow-eyed species usually lay two eggs. Parents typically raise both chicks, which are nearly equal in size