WHAT IS MARINE ECOLOGY?

Marine Ecology is the scientific study of marine-life habitat, populations, and interactions among organisms and the surrounding environment including their abiotic (non-living physical and chemical factors that affect the ability of organisms to survive and reproduce) and biotic factors (living things or the materials that directly or indirectly affect an organism in its environment).

Marine ecology is a subset of the study of marine biology and includes observations at the biochemical, cellular, individual, and community levels as well as the study of marine ecosystems and the biosphere.

The study of marine ecology also includes the influence of geology, geography, meteorology, pedology, chemistry, and physics on marine environments. The impact of human activity such as medical research, development, agriculture, fisheries, and forestry is also studied under marine ecology. In some ways, marine ecology is more complex than the relatively straightforward study of a particular organism or environment because of the numerous interconnections, symbiotic relationships, and influence of many factors on a particular environment.

WHAT IS NEEDED TO SUSTAIN LIFE ON EARTH?

Earth has been divided by ecologists into four areas: the hydrosphere, the lithosphere, the atmosphere, and the biosphere. The hydrosphere refers to water on the planet, the lithosphere consists of soil and rocks, the atmosphere is the air, and the biosphere refers to all of the life on Earth. The biosphere can be visualized as a thin surface layer on the Earth from 11,000 m below sea level to 15,000 m above sea level, even though there are no permanent residents living in the atmosphere.

The first life on Earth was formed in the photic zone of the hydrosphere when organisms with more than one cell evolved in the deep ocean benthic zones. After the ozone layer formed, which protects land organisms from harmful UV rays, life began to evolve on land. After the continents separated and reformed, biodiversity began to increase as life began to adapt to new environments. Biodiversity can be observed at the genetic level, the species level, the population level, and the ecological level.

Abiotic elements like carbon, nitrogen and oxygen are present in great quantities in the biosphere. Phosphorus, calcium, and potassium are also present in smaller amounts. All are elements critical to the existence of life. Every element in the ecosystem transforms from mineral to organic forms and back to minerals and is never destroyed. Life depends on energy from the sun and the organisms that are capable of transforming light into chemical energy form the basis for the food chain. The process of photosynthesis converts light into chemical energy, resulting in the production of glucose and oxygen. Other organisms depend on glucose produced by photosynthesis for energy to fuel biological processes such as cellular respiration. During cellular respiration, organisms split glucose back into water and carbon dioxide. The breaking down of glucose releases and utilizes energy from the sun stored by photosynthesizing plants. The oxygen level of the Earth’s atmosphere is largely reliant on the amount of photosynthetic activity and respiration going on in the biosphere. A build up of elements in areas with a lot of organisms is prevented by circulation of the atmosphere with global air currents.

The Earth is full of cycles simultaneously occurring and interlaced. Water is cycled through the hydrosphere, lithosphere, atmosphere, and biosphere in relatively predictable movements.

The flow of basic elements and the stability of the Earth’s climate and temperature depend on oceanic currents and the vast amount of water stored in the ocean. Ecologists often depend on computer modeling to determine how human activity can influence the intricate cycling of the biosphere.

Biogeochemical cycles are present when minerals and organic materials are used by organisms and sent out as waste. Ecosystems can remain relatively stable when untouched by catastrophic events, detrimental human activities, or other unusual occurrences. Homeostasis, or self-regulation of ecosystems, occurs when supported by natural control mechanisms.

An ecological crisis can take place when species or populations evolve in an unsustainable way. Sometimes the quality of the environment is lost after trauma, like a lack of rain or an increase in the temperature of a region. Other times, too much predation can ruin the balance of an ecosystem, as can be seen with overfishing by humans. Sometimes, too many organisms in one place will cause a poor living environment for others. There are different time scales for ecological crises ranging anywhere from a few months to millions of years. Extinction events

can affect many species or just a few individual species. Human activities, like oil spills, can cause local crises as well as global crises like global warming. Even with a local crisis, the loss of a few species can have a disastrous effect on the survival of others in the food chain. A global crisis can result in a loss of nearly all species on Earth. The most common example of such a crisis is the extinction of the dinosaurs. Other examples of well-known ecological crises are the Permian-Triassic extinction event, the Cretaceous-Tertiary Event, Global Warming from the Greenhouse effect, the hole in the ozone layer, desertification and deforestation, and nuclear meltdowns like Chernobyl. Fortunately, nature always prevails and when species disappear, new species evolve.

WHAT IS MARINE BIOLOGY?

Simply put, marine biology is the study of life in the oceans and other saltwater environments such as estuaries and wetlands. All plant and animal life forms are included from the microscopic picoplankton all the way to the majestic blue whale, the largest creature in the sea—and for that matter in the world.

The study of marine biology includes a wide variety of disciplines such as astronomy, biological oceanography, cellular biology, chemistry, ecology, geology, meteorology, molecular biology, physical oceanography and zoology and the new science of marine conservation biology draws on many longstanding scientific disciplines such as marine ecology, biogeography, zoology, botany, genetics, fisheries biology, anthropology, economics and law.

Like all scientific disciplines, the study of marine biology also follows the scientific method. The overriding goal in all of science is to find the truth. Although following the scientific method is not by any means a rigid process, research is usually conducted systematically and logically to narrow the inevitable margin of error that exists in any scientific study, and to avoid as much bias on behalf of the researcher as possible. The primary component of scientific research is characterization by observations. Hypotheses are then formulated and then tested based on a number of observations in order to determine the degree to which the hypothesis is a true statement and whether or not it can be accepted or rejected. Testing is then often done by experiments if hypotheses can produce predictions based on the initial observations.

WHY STUDY MARINE BIOLOGY?

Life in the sea has been a subject of fascination for thousands of years. One of the most important reasons for the study of sea life is simply to understand the world in which we live. The oceans cover 71% (and rising) of this world, and yet we have only scratched the surface when it comes to understanding them. Scientists estimate that no more than 5% of the oceans have been explored. Yet, we need to understand the marine environment that helps support life on this planet, for example:

Health of the oceans/planetClimate changePollution (toxicology, dumping, runoff, impact of recreation, blooms) Coral reefsInvasive species....

Human healthAir quality Dissolution of carbon dioxide....

Sustainability and biodiversityOverfishingEndangered speciesImpacts on the food chain....

Research and product developmentPharmaceuticalsBiomedical applicationsAlternate energy sources....

MARINE POLLUTION AND HABITAT DEGRADATION

Pollution poses a threat to marine mammals in many forms. Plastic debris, including the ubiquitous beverage six-pack rings, can become entangled around the snouts and necks of seals and sea lions, preventing proper breathing and feeding. Razor-thin nylon fishing lines slice off flukes and fins of whales and dolphins that have become entangled in them.

Oil spills, such as the horrific 1989 Exxon Valdez spill in Prince William Sound, Alaska, and the even more massive 2002 Prestige spill off the coast of Spain, may kill and injure hundreds or even thousands of marine mammals and birds. Direct

damage includes the oiling of fur and feathers, which destroys their insulating properties; injury to internal organs through ingesting oil, especially as a result of cleaning it off fur or feathers; and pneumonia from inhaling it, especially in the case of whales and dolphins, who may inhale air through the oil slick at the surface of the water. Finally, a frequently overlooked threat to marine mammal populations is habitat destruction from oil spills that occur as side effects of other events.

Bottlenose dolphins, beluga whales, manatees, polar bears, and other marine mammals are threatened by industrial pollution (from sources such as heavy metals, PCBs and other organic pollutants) and the destruction of coastal habitats by agricultural runoff and other forms of environmental degradation. The large-scale die-off of bottlenose dolphins along the mid-Atlantic coast of the United States in the mid-1980s may have been the direct or indirect result of increasing levels of toxic waste from industrial sources in these waters. Such pollutants can depress the immune system of marine mammals, making the animals susceptible to diseases they could normally fight off. Polar bears in Svalbard, Norway, are exhibiting serious congenital abnormalities, the result of exposure to toxic pollutants in their otherwise pristine environment. These pollutants have apparently circulated to the Arctic from distant sources in Europe.

Marine mammals are also threatened by increasing vessel traffic. A prime example is the threat facing manatees in Florida as growing numbers of high-speed boats take to coastal waterways. These vessels often strike these slow-moving, surface-dwelling herbivores, scarring them for life or killing them. Right whales, the most endangered great whale species in the ocean, are also threatened by ship strikes. Their slow, surface-foraging behavior makes them highly susceptible to collisions in the busy shipping lanes of the North American Atlantic coast, their preferred habitat.

WHY SPECIES BECOME ENDANGERED?

Species become endangered for a wide variety of reasons. However, when individual cases are grouped and studied, the same broad causes appear again and again: Rapid habitat destruction is the main reason that species become endangered. Natural changes usually occur at a slow rate, so the effects on individual species are usually slight, at least over the short term. When the rate of change is greatly speeded up, there may be no time for individual species to

adapt to new conditions. The results can be disastrous. This increase in the rate of habitat destruction is directly linked to the rise in human population. As more people use more space--for homes, farms, shopping centers, and so on--there is less living space for species that cannot adapt to changing conditions. People also affect plant and animal habitats when they take wood, oil, and other products from the land. Another people-related problem that harms wildlife is the introduction of exotic species - foreign species that are deliberately or accidentally introduced into new habitats by human activities. Sometimes an introduced species causes no obvious harm, but in other cases the introduced species causes serious problems. The worst of these problems is when introduced species begin to prey on native species and cause them harm.

Another cause of the decline of species is commercial hunting. Plume hunters in the late 1800s and early 1900s nearly wiped out many species of herons, egrets and other birds. Hunting for food caused the extinction of the Passenger Pigeon and the Great Auk. Commercial hunting for their tongues and to destroy the basis of survival for the plains Indians brought the American Bison or buffalo to the brink of extinction. The great whale species such as the Blue, Gray, and Humpback Whale are all endangered because of commercial whaling which is now banned. Many other species, however, are still at risk. Some other animal species experience high rates of exploitation because of the trade in animal parts. Currently, this trade is centered in several parts of Asia where there is a strong market for traditional medicines made from items like tiger bone and rhino horn. Other people-related problems that put plant and animal species at risk include poaching, pollution, and over collecting Pesticides and toxic chemicals also harm wildlife and can cause their decline. The pesticide DDT, which was banned in 1973 interfered with egg production in birds of prey such as the Bald Eagle and Peregrine Falcon and nearly wiped them out. Both are now recovering and are being considered for removal from the endangered species list. Pollution, such as acid rain, can harm fish and other aquatic species as well as plants. Forest downwind from industrial plants in was destroyed by pollution. Toxic chemicals such as PCBs are harming fish and birds that feed on them in places like the Great Lakes. Pollution, pesticides, and excess UV light from a thinning ozone layer (caused by CFCs and other pollutants) may be causing the decline of many frogs and other amphibian species. Global warming, caused by carbon dioxide and other gasses humans add to the atmosphere is a potentially devastating threat to species.

African Penguin(Jackass)

More commonly known as jackass or Blackfoot penguin, this species lives off the coast of southern Africa. The nickname "jackass" was given them because of the donkey-like sounds they make.They live in colonies on 24 different islands between Namibia and Port Elizabeth, S. Africa. Diet consists of fish (including sardines, sancord, and anchovies) and squid.Standing about 2 feet tall (60cm) and weighing between 6.8 to 8 pounds (3.1-3.6 kg), the male is larger and has a longer bill than the female. They swim at a speed of 4.3 - 15 mph (7-24 kph).African penguins have shiny, waterproof feathers that help keep their skin dry. They have more feathers than most other birds - about 70 feathers per square inch. Once a year, penguins molt, losing their old feathers and growing new ones. While molting (which takes about 3 weeks), they cannot swim nor eat.Jackass penguins nest by burrowing into guano (bird droppings) and sand where the females lay two eggs. The incubation period is from 38 to 42 days. Both parents guard the nest and feed the hatchlings regurgitated food. These penguins reach maturity at 3 to 4 years of age.Populations are declining rapidly due to many factors, including reduction of their food supply (by overfishing), pollution (from oil tankers), egg harvesting by people, disease, and guano (bird droppings) removal from their nesting grounds for use as a fertilizer.

Boulder Darter

The boulder darter is an olive to gray colored fish; it lacks the red spots which are common to most darters. Females are lighter colored than males. Both sexes have a gray to black colored bar below their eyes; a similar colored spot is located behind their eyes. The species grows to a maximum length of 3 inches.

Range and Population Level: Historically, boulder darters are only known from the Elk River (including Richland and Indian Creeks) and Shoal Creek (from which it appears to have been extirpated), a Tennessee River tributary. Boulder darters are presently known from a few localities within a 60-mile stretch of the Elk River including the lower reaches of Richland and Indian Creeks. Although little data exists to document the historic range or past population of this species, suitable habitat existed in the

Tennessee River and in the lower portions of its southern bend tributaries. These tributaries may have supported boulder darters from the Paint Rock River downstream to at least Shoal Creek (O'Bara and Etnier, 1987).

Habitat: The boulder darter inhabits warm-water Rivers and large creeks. Adult specimens have been found in association with limestone rubble or natural accumulations of limestone slabs. Juveniles have been collected from gravel riffles (Etnier and Starnes, 1993).

Threats: Most of the habitat in the Elk River consists of a gravel and cobble substrate, and most of the river reaches have long, slow pools. To survive, the boulder darter requires moderate to fast runs over boulder and slab substrates. Not only is its available habitat limited, the fish is also threatened by the construction of reservoirs, phosphate mining in the watershed, land use changes, pesticides, and toxic chemical spills. It is possible that the boulder darter's elimination from the upper Elk River was caused by cold water releases from Tims Ford Reservoir. If the species historically existed in the Tennessee River as theorized, it may have been extirpated when its habitat was flooded by Wheeler and Wilson Dams. The pollution of Shoal Creek, a Tennessee River tributary, may also be partially responsible for that population loss.Populations are declining rapidly due to many factors, including reduction of their food supply (by overfishing), pollution (from oil tankers), egg harvesting by people, disease, and guano (bird droppings) removal from their nesting grounds for use as a fertilizer.

Dugongs

Dugongs are of the order Sirenia (Sea cows) and are believed to have descended from an ancestor shared with elephants. Only four species of sea cow survive today: 1 dugong (family Dugongidae) and 3 manatees (family Trichechidae).

The dugong dugong dugon has a head to tail length up to three meters (10 feet) and weight of 400 to 500 kilograms (880 to 1100 pounds).

The dugong's range spans the coastal and island waters of 43 countries in the Indo Pacific region between East Africa and Vanuatu. They are restricted to the sea while manatees occur in rivers and estuaries.

The dugong's body is shaped like a dolphin's with similar tail flukes. The external ears are small holes, one on each side of the head. They have very acute hearing. The dugong can surface without its body breaking water because the nostrils are on top of the head and close with valve-like flaps.

The lifespan of sirenians is long and reproductive rate low. The age of dugongs can be counted by layers laid down each year in their tusks, like growth rings in a tree. Individuals may live for 70 years or more, but a female does not have her first half until she is at least 10 years old, and then only bears a single calf every three to five years, after a gestation period of about a year. Although it starts eating plants soon after birth, a calf continues to nurse from mammary glands at the base of each of its mother's flippers until it is up to 18 months old.

Dugongs and manatees have delicious meat, docile natures, few defenses, low reproductive rates, and geographic ranges that span the waters of many protein-starved developing countries. It is no wonder that all are classified as vulnerable to extinction.

Giant Otter

Habitat: Lakes, slow-moving forested rivers, creeks, reservoirs, and swamps

Range: South America

Threats: Fur trading by humans, fishermen, mercury poisoning through gold mining operations, habitat loss, and disturbance of waterways by boaters. Giant otters, which inhabit the rivers of northern South America, may measure more than six feet long, their flat and almost beaver like tail accounting for about a third of the length. A giant otter is chocolate brown on the back, lighter on the belly, and streaked with light and dark hairs on the throat and chest. Its head is flat and its neck thick, sometimes broader than the head in older animals. Both

front and hind feet are webbed. Underwater, the giant otter uses its tail and hind legs to propel itself. Often it floats on its back, like the sea otter.

Hunters have cut so deeply into the giant otter's population that it is now an endangered species. The trade in otter pelts has been banned, but unfortunately, illegal hunting continues.

Whales

The blue whale is thought to be the largest animal ever to inhabit the earth. At one time it may have reached lengths of up to 31 meters (100 feet)--roughly the length of a basketball court (commercial hunting for the largest individuals has, over time, resulted in a decrease in their overall size). Blue whales have weighed up to 146 metric tonnes (160 tons). They feed on small shrimp-like crustaceans and can consume up to eight tons of krill a day. The loudest sound ever recorded from an animal was produced by a blue whale, and some scientists have speculated that they may be able to remain in touch with each other over hundreds of miles. The number of blue whales in the Southern Hemisphere was severely depleted by whaling to less than ten percent of its original number.

Humpback Whale:

The humpback whale (shown at right) reaches a maximum length of about 15.6 meters (51 feet) and a maximum weight of about 34 metric tonnes (37.5 tons). In the Southern Hemisphere its primary food is krill, but in the Northern Hemisphere it eats schooling fish such as anchovies, cod, sand lance, and capelin. The humpback is one of the most popular whales for whale-watching on both the East and West Coasts. It is often photographed leaping out of the water--an activity called breaching. The humpback is also called the "singing whale" for their ability to produce complex, repeating "songs." A male's song may be as long as half an hour and changes slightly from year to year. Scientists estimate that there are 10,000 humpbacks worldwide--only about eight percent of its estimated initial population.

Gray Whale:

The gray whale is the only living member of the baleen whale family Eschrichtiidae. The gray whale differs from the other two baleen whale families primarily in its feeding behavior – it is a bottom feeder. Female gray whales average 14.1 m (46 ft.) and may weigh almost 32,000 kg (70,000 lb.). Male gray whales are generally smaller than females, averaging 13 m (43 ft.).

The use of the harpoon gun and factory ships brought most of the large whales to the verge of extinction. Since the ban on commercial whaling, numbers of some species such as the humpback whale, appear to be increasing slowly.

People have hunted whales for centuries. Norse fishermen made whale carvings 4000 years ago and Eskimos have eaten them for at least 3500 years. But commercial whaling, the real culprit, started as early as the tenth to twelfth centuries A.D. whales were hunted for their meat, oil, and bones. Humpbacks were one of the easiest whales to catch, so they were harpoon by the hundreds. When huge factory ships with sonar, helicopters, explosive harpoon guns, and onboard processing appeared, whales were doomed. In 1946, the International Whaling Commission was established to regulate whaling. In 1973 the United States Marine Mammal Act prohibited taking these animals and their products, except by native peoples. At the same time, the United Nations Conference on the Human Environment city worldwide ten-year moratorium on whaling. The Commission did not abide by this ruling and finally, thanks to the concern of many scientists and the growing concern of the public, a ban on all commercial whaling took effect in 1986. This is the first time in human history that whales have been protected. Even so, Japan, Iceland, and Norway still harvest whales under the guise of research, and 95 percent of the humpbacks are now gone.Other endangered whales: Bowhead whale Balaena mysticetus, Finback whale Balaenoptera physalus, Right whale Balaena glacialis, Sei whale Balaenoptera borealis, and Sperm whale Physeter catodon.

CONSERVATION OF MARINE LIFE & HABITAT

Conservation and protection of marine life is becoming more important as we better understand the importance of the oceans and our impacts on them. Learn about conservation issues, current events and threats to marine life, ways to help the ocean and how to become an ocean activist.

What Is the International Coastal Cleanup?Each year, hundreds of thousands of volunteers gather to clean the coastline during the International Coastal Cleanup, which was started over 20 years ago by the Ocean Conservancy. Learn about the International Coastal Cleanup, why to do beach cleanups and how you can sign up for the International Coastal Cleanup.

Shark Conservation Act of 2009To aid in shark conservation and demonstrate the importance of sharks to the U.S., the Shark Conservation Act of 2009 was introduced. Over 70 million sharks are killed annually, and many shark species are considered overfished. Sharks are fished for sport, caught as and hunted for their fins in a practice called shark finning. Overfishing of sharks could be drastic to the ocean food web.

What Is Shark FinningShark finning is the process of cutting a fin off a shark. The rest of the shark's body is cast into the sea, sometimes still alive. Even though the fins do not have any taste, they are a sought-after commodity for shark fin soup, which is a delicacy in Asian cultures and a dish served at special occasions.

Turtle Excluder Device (TED) Turtle excluder devices (TEDs) were created to protect sea turtles from getting caught in shrimp nets. The TED is attached to a shrimp trawling net and is a grid of metal bars that has an opening at the top or bottom, creating a hatch that allows sea turtles and larger fish to escape. Small animals such as shrimp go between the bars and are caught in the end of the trawl.

World Oceans Day - What Is World Oceans DayThis year, the United Nations officially declared June 8 of each year World Oceans Day, a day to celebrate the oceans. Learn about the history of World Oceans Day, why the oceans are important and what you can do to protect the oceans.Easy Ways to Protect Marine LifeThe ocean is downstream of everything, so all of our actions, no matter where we live, affect the ocean and the marine life it holds. Those who live right on the coastline will have the most direct impact on the ocean, but even if you live far inland, there are many things you can do that will help marine life.

What Is Ocean Acidification?Ocean acidification is the process by which the pH of the oceans is lowered due to absorption of carbon dioxide. The oceans have helped the global warming problem for thousands of years by absorbing carbon dioxide. Now the basic chemistry of the oceans is changing because of our activities, with devastating consequences for marine life.

What Is Coral Bleaching?Coral bleaching happens when coral polyps, the animals that build corals, shed the algae - zooxanthellae - that give them their color, and which are necessary for their survival. The coral is then bleached, or white in appearance.

Whaling and the International Whaling CommissionWhaling ended its popularity in the U.S. in the 18th century, so some are surprised to find out it still occurs in the world. The International Whaling Commission (IWC) put a pause in whaling, or a moratorium, in place in 1982, and it became effective in 1985-86. If a country wants to hunt whales these days, there are three ways it can do so.

Supreme Court Allows U.S. Navy to Use Sonar That May Harm WhalesThe U.S. Supreme Court ruled on November 12, 2008 that the U.S. Navy could continue using high-powered sonar as part of its training exercises, possibly at the expense of whales and other marine mammals. Sonar has been demonstrated to cause hearing and organ damage, and symptoms similar to the "bends" in whales, and also disrupts their ability to find prey, breed and navigate.

NOAA Fisheries - National Marine Fisheries ServiceNOAA is charged with managing fisheries, protecting marine species and conserving marine habitat in the U.S. Visit the NOAA site to learn about marine regulations, careers and the work of NOAA.IUCN Red List of Endangered SpeciesThe IUCN evaluates animal and plant species and reports on their taxonomy, distribution and status. The Red List classifies the species of most concern to help further their conservation.

Trash Islands - The Ocean Garbage Patch Trash IslandsAs our global population expands so too does the amount of trash we produce. A

large portion of this trash then ends up in the world's oceans. Due to oceanic currents much of the trash in the sea is carried to a number of areas where the currents meet.

MarineBioMarineBio is a non-profit organization that describes itself as "an evolving online tribute to ocean life, an introduction to marine biology and what you need to know about marine conservation." Visit this site for information on marine species, careers, conservation information and more.

American Cetacean SocietyThe American Cetacean Society, founded in 1967, protects whales, dolphins, porpoises, and their habitats through public education, research grants, and conservation actions.

International Whaling CommissionThe International Whaling Commission provides for the conservation of whale stocks and management of whaling. It provides information on whales, what is going on with whaling and hunting regulations around the world.

Marine Fish Conservation NetworkThe Marine Fish Conservation Network is a national coalition that promotes the long-term sustainability of marine fish. Its members include environmental organizations, fishing associations, aquariums and marine science groups. Learn about current legislation regarding marine fish, conservation issues and different marine fish species.