Restoring the Earth: The Age of Nature episode 1 – Documentary series about nature’s resilience. How ecosystems devastated by human impact can be revived and become sustainable for future generations.
Visiting Bikini Atoll, Panama, Norway, Mozambique and China, we discover the extent of nature’s resilience and how ecosystems devastated by human impact can be revived, how human prosperity is dependent on the natural world and how when working within nature’s limits, resources can be maintained for future generations.
Restoring the Earth: The Age of Nature episode 1
Bikini Atoll sometimes known as Eschscholtz Atoll between the 1800s and 1946 (see Etymology section below for history and orthography of the endonym), is a coral reef in the Marshall Islands consisting of 23 islands surrounding a 229.4-square-mile (594.1 km2) central lagoon. Post Second World War, the atoll’s inhabitants were forcibly relocated in 1946, after which the islands and lagoon were the site of 23 nuclear tests by the United States until 1958.
The atoll is at the northern end of the Ralik Chain, approximately 530 miles (850 km) northwest of the capital Majuro. Three families were resettled on Bikini island in 1970, totaling about 100 residents. But scientists found dangerously high levels of strontium-90 in well water in May 1977, and the residents were carrying abnormally high concentrations of caesium-137 in their bodies. They were evacuated in 1980. The atoll is occasionally visited today by divers and a few scientists, and is occupied by a handful of caretakers.
The islanders cultivated native foods including coconut, pandanus, papaya, banana, arrowroot, taro, limes, breadfruit, and pumpkin. A wide variety of other trees and plants are also present on the islands.
The islanders were skilled fishermen. They used fishing line made from coconut husk and hooks from sharpened sea shells. They used more than 25 methods of fishing. The islanders raised ducks, pigs, and chickens for food and kept dogs and cats as pets. Animal life in the atoll was severely affected by the atomic bomb testing. Existing land species include small lizards, hermit crabs, and coconut crabs. The islands are frequented by a wide variety of birds.
To allow vessels with a larger draft to enter the lagoon and to prepare for the atomic bomb testing, the United States used explosives to cut a channel through the reef and to blow up large coral heads in the lagoon. The underwater nuclear explosions carved large holes in the bottom of the lagoon that were partially refilled by blast debris. The explosions distributed vast amounts of irradiated, pulverized coral and mud across wide expanses of the lagoon and surrounding islands. As of 2008, the atoll had recovered nearly 65% of the biodiversity that existed prior to radioactive contamination, but 28 species of coral appear to be locally extinct.
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
Coral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian.
Sometimes called rainforests of the sea, shallow coral reefs form some of Earth’s most diverse ecosystems. They occupy less than 0.1% of the world’s ocean area, about half the area of France, yet they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians. Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas.
Coral reefs have declined by 50% since 1950, partly because they are sensitive to water conditions. They are under threat from excess nutrients (nitrogen and phosphorus), rising temperatures, oceanic acidification, overfishing (e.g., from blast fishing, cyanide fishing, spearfishing on scuba), sunscreen use, and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools).
Ecosystem – Restoring the Earth
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes.
Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. Internal factors are controlled, for example, by decomposition, root competition, shading, disturbance, succession, and the types of species present. While the resource inputs are generally controlled by external processes, the availability of these resources within the ecosystem is controlled by internal factors. Therefore, internal factors not only control ecosystem processes but are also controlled by them.
Ecosystems are dynamic entities—they are subject to periodic disturbances and are always in the process of recovering from some past disturbance. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance, is termed its resistance. The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its ecological resilience.
Ecosystems can be studied through a variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. Biomes are general classes or categories of ecosystems. However, there is no clear distinction between biomes and ecosystems. Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of the definition of ecosystems: a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy.