Thursday, March 11, 2010

IX. Biodiversity Loss (Endangered, Threatened and Extinct Species)

The Philippines is experiencing a very high rate of biodiversity loss, indicated by a phenomenal
decline in quality and number of habitats such as the forests, coral reefs, and mangroves. This loss has deleterious impacts on the long-term sustainability of community livelihood systems, political cohesion and governance, and overall national welfare. It is becoming evident that biodiversity loss has root causes in the social, institutional, economic, and political spheres. A host of socioeconomic factors, including economic and political history and rapid population growth, contribute to the erosion of environmental quality and biodiversity loss. Conservation efforts have failed to reverse the trend in large part because of inattention to these root causes. Despite investments by NGOs, government agencies, and international development banks, forest cover and other important habitats continue to decline.

The direct causes of forest cover loss in the Philippines are over-harvesting and habitat alteration. The major proximate causes of primary forest loss are commercial logging, community logging, kaingin (slash and burn agriculture), and conversion of forest lands to other uses. In mangrove ecosystems, extraction of fuel and construction materials, and development of fish ponds have been a major causes of rapid destruction. In the case of coral reefs, fishing techniques using dynamite and cyanide are probably the most important cause of biodiversity loss.

Biodiversity is built over millions of years and extremely diverse habitats such as tropical rainforests have taken long stretches of geologic time to develop. That's why the extinction of species is such an important issue: once they're gone, not only are they gone forever, but it takes millions of years for new species to evolve in their place.

Some extinctions are natural, but a variety of human activities have vastly increased the numbers of species disappearing every day. Habitat destruction is the main cause, especially since the richest habitats with the most species, such as tropical forests, are being destroyed at the fastest pace. Extinction rates are now hundreds or even thousands of times higher than before humans came to be so numerous. Some scientists have estimated that as many as one fifth of all species alive today could be extinct or nearly extinct by the year 2020.

What effects does the loss of biodiversity have on forests, and on humans?
The loss of even one species can ruin an entire forest ecosystem of plants and animals. The animals that depended on this vanished species as prey have now lost their food source. In turn, the animals that it fed on have lost a predator, and these species often undergo population explosions which are devastating for the plants or animals that they feed on.

The entire ecosystem can collapse in this manner, and is therefore prevented from performing its usual "ecosystem services", a utilitarian term for the natural processes which provide rich soil, clean water, and the air we breathe.

The loss of plant species also means the loss of unknown economic potential, as extinct plants can hardly be harvested for food crops, fibers, medicines, and other products that forests, especially rainforests, provide. Thousands of small plants, insects, and other less conspicuous creatures are vanishing before they are even discovered, but it is often these small, less spectacular species which have the greatest potential "usefulness" to humans.

Endangered and Threatened Species
What Are Endangered and Threatened Species?

A century ago, a bird called the passenger pigeon lived in North America. There were so many passenger pigeons that people often saw great flocks of them flying overhead containing thousands, even millions, of birds. Today, there is not a single one left. What happened?

The passenger pigeon became extinct. All living passenger pigeons disappeared from the earth entirely. The passenger pigeon became extinct for two reasons. First, the forests where it lived were cut down to make way for farms and cities. Second, many pigeons were shot for sport and because they were good to eat. At that time, there were no hunting laws to protect endangered species like there are now.

The passenger pigeon is one of the many plants and animals that once lived on our planet and have become extinct. For example, dinosaurs, mammoths, and saber-toothed tigers all became extinct long ago. More recently, the dodo bird and the sea mink also have disappeared. Extinction has been going on since life began on earth. But today, extinction is happening faster than ever before.

There are approximately 1300 endangered or threatened species in the United States today. Endangered species are those plants and animals that have become so rare they are in danger of becoming extinct. Threatened species are plants and animals that are likely to become endangered within the foreseeable future throughout all or a significant portion of its range.

How Does Extinction Happen?
Species disappear because of changes to the earth that are caused either by nature or by the actions of people. Sometimes a terrible natural event, like a volcano erupting, can kill an entire species. Other times, extinction will happen slowly as nature changes our world. For example, after the Ice Ages, when the great glaciers melted and the earth became warmer, many species died because they could not live in a warmer climate. Newer species that could survive a warmer environment took their places.

People can also cause the extinction of plants and animals. The main reason that many species are endangered or threatened today is because people have changed the homes or habitats upon which these species depend. A habitat includes not only the other plants and animals in an area, but all of the things needed for the species' survival -- from sunlight and wind to food and shelter. The United States has many habitats, from ocean beaches to mountain tops. Every species requires a certain habitat in order to live. A cactus, for example, needs the sunny, dry desert in order to grow. A polar bear, on the other hand, would not live in a desert, because it could not find enough food and water.

Pollution can also affect wildlife and contribute to extinction. The Nashville crayfish is endangered mainly because the creek where it lives has been polluted by people living nearby. Pesticides and other chemicals can poison plants and animals if they are not used correctly. The bald eagle is one bird that was harmed by pesticides. In the past, a pesticide called DDT was used by many farmers. Rains washed the pesticide into the lakes and streams where it poisoned fish. After eating the poisoned fish, the eagles would lay eggs with very thin shells. These eggs were usually crushed before they could hatch. Today, people are not allowed to use DDT, and this has contributed to the bald eagle being moved from endangered status up to threatened status.

People can also endanger plants and animals by moving, or introducing, new species into areas where they do not naturally live. Some of these species do so well in their new habitat that they endanger those species already living there, called the native species. These introduced species are called invasive species. For example, when some fish are introduced into a lake or stream, they may prey upon, or eat the food of the native fish. The native species may then have to find a new source of food or a new home, or face becoming endangered or extinct.

Another way that people harm animals and plants is by taking them from the wild. Some people might catch an insect like the Mission Blue Butterfly for a butterfly collection. Others might capture a wild animal for a pet, or pick a flower because it's pretty. In addition, some people illegally hunt animals for food, skins, or fur. In the past, lots of American crocodiles were killed so that their skins could be made into shoes and other clothing. This crocodile is now an endangered species.

Why Protect Endangered and Threatened Species?
Can you imagine walking in the woods without hearing birds singing in the trees, or picture what a field would be like without wildflowers blooming in the grasses? Our plants and wildlife make the world more interesting and beautiful place. More importantly, all living species, including people, depend on other species for survival. For example, if a fish such as the shortnose sturgeon becomes extinct, all of the species that rely on it for food will also suffer and may become threatened or endangered.

We all depend upon plants and wildlife. From studying them, we have learned new ways of growing foods, making clothing, and building houses. Scientists have discovered how to use certain plants and animals as sources of medicines. If we fail to protect threatened or endangered species, we will never know how they might have improved our lives.

Endangered and threatened species need our help. Government agencies, such as the U.S. Environmental Protection Agency, the U.S. Department of Agriculture, the U.S. Fish and Wildlife Service, and the National Park Service, along with state fish and wildlife agencies and private groups are making information available so people can better protect endangered and threatened species and their habitats. To do your part, contact these agencies for information and join the challenge in helping to protect endangered and threatened species, and all wildlife, from extinction.

VIII. El Nino and La Nina Weather Disturbances, Typhoons (Phil Setting)

El Niño/La Niña
In a previous Economic Issue of the Day (Vol. V, No. 1, July 2005), a basic understanding was presented on what the El Niño southern oscillation (ENSO) phenomenon is all about, its characteristics and two phases, and its implications.

ENSO is a phenomenon that takes place in the central and eastern equatorial Pacific largely characterized by an interaction between the ocean and the atmosphere and their combined effect on climate. The mutual interaction between the ocean and the atmosphere is a critical aspect of the ENSO phenomenon.

Major ENSO indicators are the sea surface temperature
anomaly (SSTA) and the southern oscillation index (SOI). SSTA refers to the departure or difference from the normal value in the sea or ocean surface temperature. El Niño events are characterized by positive values (greater than zero) within a defined warm temperature threshold while La Niña events are characterized by negative values (less than zero) within a defined cold temperature threshold.

The SOI, on the other hand, measures the differences or
fluctuations in air or atmospheric pressure that occur between the western and eastern tropical Pacific during El Niño and La Niña episodes. It is calculated on the basis of the differences in air pressure anomaly between Darwin in Australia (western Pacific) and Tahiti in French Polynesia (eastern Pacific). These two locations/stations are used in view of their having long data records.

Albeit the seeming straightforward description of these
ENSO-related events as noted in the above, it is to be emphasized that through the years, it has not been easy to come up with a commonly agreed definition and identification of these ENSOrelated events, i.e., El Niño or La Niña. The reason is due to the use of more than one standard index as basis in monitoring ENSO phenomena and the employ of different methods in determining the magnitude or value of such index and threshold as well as the length of time that such magnitude persists. In line with this, the Philippines adopted the World Meteorological Organization (WMO) Regional Association IV Consensus Index and Definitions of El Niño and La Niña. Region IV includes the North and Central America member nations of the WMO, whose operational definitions in use of the two ENSO phases are the following:

El Niño: A phenomenon in the equatorial Pacific Ocean characterized by a positive SST departure from normal (for the 1971-2000 base period) in the Niño 3.4 region, greater than or equal in magnitude to 0.5 degrees C, and averaged over three consecutive months. Defined when the threshold or value is met for a minimum of five consecutive overlapping seasons.

La Niña
: A phenomenon in the equatorial Pacific Ocean
characterized by a negative SST departure from normal (for the 1971-2000 base period) in the Niño 3.4 region greater than or equal in magnitude to 0.5 degrees C, and averaged over three consecutive months. Defined when the threshold or value is met for a minimum of five consecutive overlapping seasons.

When is El Niño/La Niña occurring?

Because ENSO-related phenomena have been a major source of interannual climate variability around the globe, especially in recent years, it is important to be able to determine or identify when an El Niño/La Niña is occurring or will take place.

As noted earlier, monitoring the occurrence of an El Niño/
La Niña involves the use of two most common indicators, the SSTA and the SOI, with the SSTA based on the magnitude of departures/anomalies in the sea surface temperature in the Niño regions (see box), and the SOI based on the difference in air pressure between Tahiti and Darwin.

PAGASA: monitoring El Niño/La Niña events
in the Philippines
In the Philippines, how is El Niño/La Niña identified/monitored? The country’s national meteorological agency, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), defines and identifies these phenomena on the basis of the abovementioned indicators which are also being used by the National Oceanic and Atmospheric Administration-National Centers for Environmental Prediction
(NOAA-NCEP) of the United States.

Typhoons in the Philippines
Describes the most notable tropical cyclones to enter the Philippine Area of Responsibility and affect the Philippines. Bagyo is a term referring to any tropical cyclone in the Philippine Islands. An average of 6 to 7 tropical cyclones hit the Philippines per year. A bagyo is categorized into four types according to its wind speed by the PAGASA. All tropical cyclones, regardless of strength, are named by PAGASA. Tropical depressions have maximum sustained winds of between 55 kilometres per hour (30 kn) and 64 kilometres per hour (35 kn) near its center. Tropical storms have maximum sustained winds of 65 kilometres per hour (35 kn) and 119 kilometres per hour (64 kn). Typhoons achieve maximum sustained winds of 120 kilometres per hour (65 kn) to 185 kilometres per hour (100 kn), with super typhoons having maximum winds exceeding 185 kilometres per hour (100 kn). The most destructive tropical cyclone to impact the Philippines was Tropical Storm Thelma in 1991, which killed thousands of people from its resultant flooding. The wettest known tropical cyclone to impact the archipelago was the July 1911 cyclone which dropped over 1,168 millimetres (46.0 in) of rainfall within a 24 hour period at Baguio City. At least 30 percent of the annual rainfall in the northern Philippines could be traced to tropical cyclones, while the southern islands receive less than 10 percent of their annual rainfall from tropical cyclones

Wednesday, March 10, 2010

VII. Mineral Depletion, Deforestation, Coral Bleaching, Mangrove Ecosystem

Mineral Depletion
Soil is the prime source of minerals on which every living cell depends for its structure and function. Vitamins, enzymes, amino acids (protein) and a host of other biologically active substances are essential for our bodies to function properly. They virtually all include minerals as an integral part of their chemical structure. Dr Linus Pauling, twice noble prize winner, said “you can trace every sickness, every disease and every ailment to a mineral deficiency”. Yet, all over the world, minerals are disappearing from agricultural soils at an alarming rate. In 1992, the official report of the Rio Earth Summit concluded “there is deep concern over continuing major declines in the mineral values in farm and range soils throughout the world”. This statement was based on data showing that over the last 100 years, average mineral levels in agricultural soils had fallen worldwide – by 72% in Europe, 76% in Asia and 85% in North America. What has caused this staggering decline?
Most of the blame lies with artificial chemical fertilisers. We now know that plants absorb 70 to 80 different minerals from the soil, while the number returned to it by plants grown with commercial fertilisers can be counted on the fingers of one hand. Every crop that is cut or animal that is sent to market marks a further depletion in the mineral status of the soil on which it was raised. Organic wastes that in former times would have been composted and returned to the land are nowadays mostly consigned to landfill sites or incineration.

There are many other ways in which the move to chemical farming prevents crops from taking up even the sparse amounts of trace minerals left in the soil. Soil contains bacteria, fungi, plant and animal life, in a state of constant interaction and balance. Every one of these organisms needs dozens of different minerals to survive and play its part in the ecosystem. Some bacteria have a vital role in converting soil minerals into chemical forms that plants can use. NPK fertilisers (fertilisers used in modern farming that only contain nitrogen, phosphorous and potassium) gradually change the soil pH towards acidic conditions in which these bacteria can not survive. To combat soil acidification farmers lay lime on the land adding back calcium and magnesium to raise the soil pH, but it also converts manganese and some other trace minerals into chemical forms that plants are unable to absorb.

Pesticides and herbicides also reduce the uptake of trace minerals by plants. Plants have an important relationship with certain fungi that can form networks covering several acres. The fungus obtains carbohydrates from the plant root, at the same time supplying the plant with nutrients it draws from the soil. This gives the plant access to a vastly greater mineral extraction system than is possible by their roots alone. Chemical fungicide sprays destroy these beneficial fungi and so again reduce the ability of plants to absorb soil minerals. Insecticides can also reduce trace mineral uptake by inactivating choline-containing enzymes in plants, essential for the absorption of manganese and other minerals.

The combined effect of soil mineral depletion and the reduced availability of those minerals that remain is that most of the food that we eat is mineral deficient. The table below summarizes the reductions in the average mineral content of 27 vegetables and 17 fruits, between 1940 and 1991. The results of the latest research are expected to show mineral values in continual decline.

A new study published earlier this year shows that, as might be expected, mineral levels in animal products reflect the picture in plant foods. Comparing levels measured in 2002 with those present in 1940, the iron content of milk was found to be 62% less, calcium and magnesium in parmesan cheese had each fallen by 70% and copper in dairy produce had plummeted by a remarkable 90%.
The UK government is putting resources into improving health by encouraging people to eat a healthy diet, including 5 portions of fruit and vegetables per day, but you scarcely hear a word about the problem of soil mineral depletion. Food seems to be considered as something quite separate from its source and means of production. But this is not rocket science – the foundation of human health is the quality of the food we eat, which relies ultimately on the vitality of the soil on which it is raised.

Minerals are needed for the proper formation of blood and bone, the maintenance of healthy nerve function, heartbeat regulation, reproduction and foetal development. They are essential to the process of growth, healing and energy release. And it is not just the presence of the mineral in the body that is important – they must be in the correct ratio to each other. The level of each mineral has an effect, directly or indirectly, on every other, so if one is out of kilter the whole system is affected.

Minerals are an essential part of our natural diet and a lack of them may in part account for our increasing susceptibility to the “diseases of civilisation” – such as heart disease (magnesium), cancer (selenium), diabetes (chromium) and mental illnesses (zinc). Every one of us should take care to get the minerals we need, for the good of our health.

Deforestation
Philippines Forest Figures
------------------------------------------------------------------
Forest CoverTotal forest area: 7,162,000 ha
% of land area: 24%
------------------------------------------------------------------
Primary forest cover: 829,000 ha
% of land area: 2.8%
% total forest area: 11.6%
------------------------------------------------------------------
Deforestation Rates, 2000-2005Annual change in forest cover: -157,400 ha
Annual deforestation rate: -2.1%
Change in defor. rate since '90s: -20.2%
Total forest loss since 1990: -3,412,000 ha
Total forest loss since 1990:-32.3%
------------------------------------------------------------------
Primary or "Old-growth" forests
Annual loss of primary forests: n/a
Annual deforestation rate: n/a
Change in deforestation rate since '90s: n/a
Primary forest loss since 1990: n/a
Primary forest loss since 1990:0.0%
------------------------------------------------------------------
Forest ClassificationPublic: 89.5%
Private: 10.5%
Other: n/a
Use
Production: 75%
Protection: 11%
Conservation: 12%
Social services: n/a
Multiple purpose: n/a
None or unknown: 2
------------------------------------------------------------------
Forest Area BreakdownTotal area: 7,162,000 ha
Primary: 829,000 ha
Modified natural: 5,713,000 ha
Semi-natural: n/a
Production plantation: 304,000 ha
Production plantation: 316,000 ha
------------------------------------------------------------------
PlantationsPlantations, 2005: 620,000 ha
% of total forest cover: 8.7%
Annual change rate (00-05): -46,400,000 ha
------------------------------------------------------------------
Carbon storageAbove-ground biomass: 1,566 M t
Below-ground biomass: 376 M t
------------------------------------------------------------------
Area annually affected byFire: 6,000 ha
Insects: n/a
Diseases: 1,000 ha
------------------------------------------------------------------
Number of tree species in IUCN red listNumber of native tree species: 3,000
Critically endangered: 46
Endangered: 35
Vulnerable: 134
------------------------------------------------------------------
Wood removal 2005Industrial roundwood: 403,000 m3 o.b.
Wood fuel: 138,000 m3 o.b.
------------------------------------------------------------------
Value of forest products, 2005Industrial roundwood: $60,272,000
Wood fuel: $722,000
Non-wood forest products (NWFPs): n/a
Total Value: $60,994,000
------------------------------------------------------------------

Almost two decades after the Catholic Church leaders warned against an ecological debacle in the country, the disappearance of forests remains. Between 1990 and 2005, the Philippines lost one-third of its forest cover. The current deforestation rate is around 2% per year, a 20 % drop from the rate of the 1990s.

“No one says there is an increase in real forest cover in the Philippines. Maybe there is an increase in the number of trees, but it is not the forest we idealize, romanticize, log or even live in,” says Peter Walpole, executive director of the Ateneo de Manila University's Environmental Science for Social Change. “We have lost most of our forest of hold over the past 50 years and, along with them, many of the ecological services they provide.”

According to the Department of Environment and Natural Resources (DENR), the principal cause of the decimation of the country’s forest cover are logging (both legal and illegal), shifting cultivation (locally known as kaingin), forest fires, natural calamities (like earthquake), as well as conversion to agricultural lands, human settlements and other land uses brought about by urbanization and increasing population pressure.

“Deforestation is a symptom of a bigger problem,” says Nicolo del Castillo, an architect by profession who teaches at the University of the Philippines. “ I probably sound tacky and outdated, but I see the problem in the prevailing system of values, that is, the greed, the need to be the biggest, the wealthiest, and sometimes you feel hopeless. I am an optimist, but possibly there will be more tragedies and maybe then more people will wake up.”

The removal of forest cover makes the Philippines susceptible to various environmental catastrophes. “Most of these were not seen in such intensity and magnitude before our time,” deplored Roy C. Alimoane, the current director of the Davao-based Mindanao Baptist Rural Life Center Foundation, Inc. “The signs cry out for immediate, nationwide attention.”

Deforestation has been increasingly blamed for soil erosion. Although not considered a serious threat, it is an unseen scourge. “Soil erosion is an enemy to any nation – far worse than any outside enemy into a country and conquering it because it is an enemy you cannot see vividly," warned Harold R. Watson, an American agriculturist who received a Ramon Magsaysay Award in 1985 for peace and international understanding. “It’s a slow creeping enemy that soon possesses the land.”
At least two provinces – Cebu and Batangas – have lost more than 80% of their topsoil to erosion. In Luzon, four major basins --- Bicol, Magat, Pampanga, and Agno – are in critical condition due to acute soil erosion and sedimentation.

The rampant cutting of trees has also significantly reduced the volume of groundwater available for domestic purposes. “If the forest perishes, so will the life of people,” said Diosmedes Demit, one of the farmers who joined the ‘Fast for the Forests’ in 1989. “The trees are our source of life. Without trees, there will be no water. If there is no water, there will be no life.”

Cebu, which has zero forest cover, is 99% dependent on groundwater. As a result, more than half of the towns and cities in Cebu, excluding Metro Cebu, have no access to potable water. In Metro Manila, where there are no forests to speak of, the water tables are being drawn at the rate of six to 12 meters a year causing saline water intrusion along the coastal areas.

Deforestation also brings too much water – in case of constant rain. “Rain which falls over a bare slope acts differently,” Gifford Pinchot wrote in A Primer for Forestry. “It is not caught by the crowns nor held by the floor, nor is its flow into the streams hindered by the timber. The result is that a great deal of water reaches the streams in a short time, which is the reason why floods occur.”
Remember the Ormoc tragedy in Leyte? More than five thousand people were reported to have perished from flash foods, injuring 292 others with 1,264 missing. The reported total cost of damage was P1.044 billion.

Deforestation also threatens the country’s wildlife resources. Two particular species of animals, the tamaraw and the Philippines eagle are almost extinct due to the massive deforestation. More than half the birds, amphibians and mammals endemic to the Philippines are threatened with extinction.
DENR’s Joselito Atienza said that 592 of the 1,137 species of amphibians, birds and mammals found only in the Philippines are considered “threatened or endangered.” Some 227 endemic species of plants are “critically endangered.”

Dr. Lee Talbot, former director of Southeast Asia Project on Wildlife Conservation of Nature and Natural Resources, issued this sober thought: “A few decades ago, the wildlife of the Philippines was notable for its abundance; now, it is notable for its variety. If present trend of destruction continues, Philippine wildlife will be notable for its absence.”
Deforestation has also altered the climatic condition in the country. Ask Father Jesus Ramon Villarin, a Jesuit scientist, who localized the global climate issue by exploring rainfall patterns in Mindanao in the last 50 years and the impact on crop production and the supply of freshwater resources.

This was what Father Villarin, who used to work with the Manila Observatory, has found: Rainfall over the northern coast of Mindanao has generally increased over the decades, with the northeast section receiving most of the increase. But the southern regions are experiencing decreasing rainfall, mostly in the south central parts.

Heherson Alvarez, who was formerly head of the environment department, once commented that if deforestation is not soon curbed, time would come that “we will be traveling to Manila and around Central Luzon by bancas (outriggers).”

Ben Malayang III, president of Silliman State University, commented: “That the forest, the foundations of our forests, or whatever forests remain in the country, is not a matter of technical forestry, but rather a symptom, or an indication, or a measure, of the failure of our political and social systems.”

Coral Bleaching
Ten percent of the world's reefs have been completely destroyed. In the Philippines, where coral reef destruction is the worst, over 70% have been destroyed and only 5% can be said to be in good condition. What has happened to destroy all of the reefs? Humans have happened.

There are two different ways in which humans have contributed to the degradation of the Earth's coral reefs, indirectly and directly. Indirectly, we have destroyed their environment. As you read earlier, coral reefs can live only within a certain temperature and salinity range. Global warming caused by the green house effect has raised the temperature of the oceans so high that the coral get sick and die. Even a rise of one degree in the average water temperature can hurt the coral. Due to global warming, 1998 was the hottest year in the last six centuries and 1998 was the worst year for coral.

The most obvious sign that coral is sick is coral bleaching. That is when either the algae inside die, or the algae leave the coral. The algae are what give coral its color, so without the algae the coral has no color and the white of the limestone shell shines through the transparent coral bodies. People have been noticing coral bleaching since the turn of the century, but only since the 1980s has it gotten really bad.

The warmer water also encourages the growth of harmful algae on top of the coral, which kills it, because it blocks out the sun. Without the sun, the zooxanthellae cannot perform photosynthesis and so they die. Without the zooxanthellae, the coral polyps die too. This algae is usually eaten by fish, but because of over fishing, there aren't enough fish left to eat all the algae. And the pollution we dump in the ocean is just what the algae needs to grow and be healthy, which means covering and eventually killing the coral reefs.

The direct way in which humans destroy coral reefs is by physically killing them. All over the world, but especially in the Philippines, divers catch the fish that live in and around coral reefs. They sell these fish to fancy restaurants in Asia and to fancy pet stores in the United States. This would be OK if the divers caught the fish carefully with nets and didn't hurt the reefs or take too many fish. But the divers want lots of fish and most of them are not very well trained at fish catching. Often they blow up a coral reef with explosives (picture below) and then catch all the stunned fish swimming around. This completely destroys the reefs, killing the coral polyps that make it as well as many of the plants and animals that call it home. And the creatures that do survive are left homeless.

Another way that divers catch coral reef fish is with cyanide. Cyanide is a poison. The divers pour this poison on the reef, which stuns the fish and kills the coral. Then they rip open the reef with crowbars and catch the fish while they are too sick from the poison to swim away. This poison kills 90% of the fish that live in the reef and the reef is completely destroyed both by the poison and then by being ripped apart.

All this may seem a bit depressing, but there are many groups in the world dedicated to saving the coral reefs. These groups work to educate people about the destruction of coral reefs. They lobby the United States Congress as well as the governments of other nations, trying to convince them not to buy fish that have been caught by destroying coral reefs. They encourage governments to crack down on pollution, both into the ocean and into the air, which causes global warming. They encourage visitors to coral reefs to be careful not to harm them. They even build artificial reefs to replace the reefs that have been destroyed. If you want to learn more about these groups, visit some of their websites, like the Coral Reef Alliance, Reef Relief, and the Planetary Coral Reef Foundation.

Some people help coral reefs by convincing governments to treat them with care. Other people help coral reefs by studying them. One way that people learn more about coral reefs is by slicing open dead ones and looking inside. The inside of a coral reef looks a lot like the inside of a tree (picture below) and the lines mean the same thing. A person who studies tree rings is called a dendrochronologist. " Dendro " means tree, " chron " means time and " ologist " means person who studies, so dendrochronologist means person who studies trees through time. Dendrochronologists count the number of rings in a slice of a tree to see how old the tree was when it died. There is one ring for each year the tree lived. The dendrochronologist also looks at the size of the rings. A thick ring means that that year there was lots of food and it was a good year for the tree. A thin ring can mean that there was a drought that year or maybe the tree was sick. In the same way, oceanographers can look at the rings in a slice of coral and see how old the coral is and which years were good years and which were not. The more we know about coral the better we will be able to protect them for years to come.

PHILIPPINES MANGROVE ECOSYSTEM & BIODIVERSITY
Mangroves - are salt-tolerant, woody, seed-bearing plants that are found in tropical and subtropical areas where they are subject to periodic tidal inundation. The Philippines has over 40 species of mangroves and is one of the most biodiverse regions in the world as there are only about 70 species of mangroves worldwide. The mangrove ecosystem is a very diverse one and is home to many birds, fish, mammals, crustaceans and other animals.

ROOT SYSTEM
Mangroves are very specialized plants and have adapted to survive i
n a very harsh environment where other plants cannot survive. An example of an interesting adaptation is the root system of mangroves. Since mangroves often live in muddy environments where gas exchange is difficult, the root systems of many mangrove species are highly specialized. One example of this is pneumatophores or breathing roots which look like fingers sticking out of the ground which are seen on Avicennia spp. (api-api) and Sonneratia spp. (pagatpat) trees. Other roots which grow out from branches and the trunk of mangrove trees such as those on Rhizophora spp. (bakaun) are called stilt or prop roots. These roots contain lenticels or breathing holes which allow gas exchange above the ground. These stilt roots also provide support and anchorage during high winds and wave action as well as serving as an attachment substrate for many marine organisms. Other species have knee or knob roots above the ground such as seen in Busain.

ADAPTATIONS: EXCRETERS/EXCLUDERS
Mangroves must also deal with the saltwater environment that they live in. While many mangrove trees grow best in a mixture of saltwater, an excessive amount of salt would certainly kill them. In order to deal with this mangrove species have developed a number of different adaptations. Certain trees such as api-api are excreters and they expel salt crystals from their leaves which is then washed away by the rain. Others are excluders and block salt from entering through their roots. They accomplish this by having a high innate concentration of salt in their roots which prevents water from entering against the osmotic gradient. Other plants are secluders which concentrate salt in certain leaves which turn yellow and die and expel the salt when these leaves die.

PROPAGULES

Mangroves also have adapted certain reproductive mechanisms to deal with the harsh salt water environment. One of these is the viviparous propagule or tungki found on bakuan. This propagule is already germinated on the tree and has a basic stem structure and can therefore easily be implanted in the substrate and quickly begin to grow. If the propagule does however fall in the water it has the ability to float for up to one year which aids greatly in dispersal of mangrove species.

FOOD FOR MARINE ORGANISMS

Mangroves provide an important nursery for fish, shellfish and other organisms. It is estimated that each hectare of mangrove produces 3,600 kg of litterfall which provides food for 1,000 kg of marine organisms. With the abundance of food for fish present in the mangroves, each year one hectare of forest yields 283.5 metric tons of fish per year. Mangroves also provide other important functions such as preventing soil erosion and protecting shoreline from typhoons and strong waves. Mangroves provide many other products and services such as medicines, alcohol, housing materials and are an area for research and tourism.

THREATS

Even with all of these known benefits the state of mangroves within the Philippines is very dim. In the early 1900’s there were approximately 500,000 hectares of mangroves but today there are only about 120,000 hectares. Many of the mangrove areas were destroyed to make way for fishponds and reclamation areas. They were used indiscriminately for housing materials and were disturbed by siltation and pollution. Now that the true benefit of these ecosystems is known there is protection and rehabilitation of these important ecosystems. It is now illegal to cut down mangroves for any purpose and local governments and community organizations have taken active roles in planting and managing mangrove plantations. There is hope that in the future mangroves will return to the healthy status that they once held in the past.

Friday, February 26, 2010

VI. Renewable-vs-Non Renewable Resources (types and uses)

Renewable energy resources
This are natural resources that replenish themselves within time limits that permit sustained use, in contrast to nonrenewable resources. That is, resources can be replenished by natural process at least as fast as they are used. Therefore it can be used over and over again. Five types of renewable resources are: Wind Power, Hydropower, Solar Energy, Geothermal Energy, Biomass Fuel and Wood.

Hydropower
Hydropower is the capture of the energy of moving water (falling of water from one level to another) for some useful purpose. This falling of water can be natural falling source or from a dam. The falling water is used to turn waterwheels or modern turbine blades which is used to powering a generator to produce electricity. Hydropower system is a clean source of energy systems that can neither be polluted or consumed during its operation. It eliminates the cost of fuel, making it immune to price increases for fossil fuels. As long there is a water source (lake, river etc.) it is renewable.

Solar Energy
Solar energy is the energy from the sun ( in the form of heat and light) that is directly capture and converted into thermal or electrical energy and harnessed as solar power. Solar power is the technology of obtaining (harnessing) usable energy from the light of the sun. Some applications of solar energy are hot water heating and space heating in the home. It is also used in the application of solar panels where individual homes (in region where it is warm and sunny) convert solar energy into thermal energy to generate electricity. The use of solar energy displaces conventional energy where it results in a proportional decrease in green house gas emissions. The energy from the sun is free with just the initial cost to set up the technology. The sun provides unlimited (renewable) supply of solar energy. The only draw back is that its requires a large area to collect the sun’s radiation and requires some means of storage.

Wind Power
Wind power is the conversion of wind energy into electricity using wind turbines (usually mounted on a tower). Wind power is used in large scale wind farms for national electrical grids. On a small scale it is also used to provide electricity to rural residences. Wind energy is ample, free, widely available, clean, renewable, produces no waste or greenhouse gases, need no fuel, good method of supplying energy to remote areas and can be a site for tourist attraction.

Biomass Fuel
Biomass Fuel (Biofuels) is any organic material produced by living organisms (plants, animals, or microorganisms) that can be burned directly as a heat source or converted into a liquid or gas. Some examples of biomass fuels are wood, crop residues, peat, manure, leaves, animal materials and other plant material.

There are two major sources of biomass;
i. trees, gains, sugar crops and oil-bearing plants.
ii. waste organic materials from industrial, commercial, domestic, or agricultural wastes. Examples, crop residues, animal wastes, garbage, and human sewage.

Biomass fuels (biofuels) are sustainable. It is cheap and is less demanding on the environment or Earth's resources. A major advantage of biomass fuel, is its low greenhouse gas emission characteristic where it adds less carbon to the environment when compared with burning fossil fuels. This is due to the fact that the carbon atoms released by burning biofuel already exists as part of the carbon cycle. Biomass absorbs an equal amount of carbon in growing as it releases when consumed as a fuel.

Fuel diversity is another advantage of biomass, it can be transformed into fuel in many ways such as in gasification, anaerobic digestion - fermentation of wet wastes (e.g. sugarcane or corn to produce alcohol (ethanol) and esters, and animal dung to produce biogas) and direct combustion - burning of dry organic wastes (e.g. wood and peat) just to name a few.

The use of biomass fuels can reduce dependence on foreign sources of oil whereby providing energy security for the country using it as a fuel. This will therefore promote an economic boost for both agriculture and the industry of that country. However, for it to be economical as a fuel for electricity, the source of biomass must be located near to where it is used for power generation.

Geothermal Energy
Geothermal Energy is power generated by the harnessing of heat from the interior of the earth when it comes to (or close to) the earth’s surface. The regions with highest underground temperatures are in areas with active or geologically young volcanoes. Chief energy resources are hot dry rock, magma (molten rock), hydrothermal (water/steam from geysers and fissures) and geo-pressure (methane-saturated water under tremendous pressure at great depths).

There are several methods of deriving energy from the earth’s heat where the heat energy that is generated by converting hot water or steam from deep beneath the Earth’s surface is converted into electricity. This hot water or steam come from a mile or more beneath the earth surface. geothermal applications includes:

i. Geothermal Electricity Production - generating electricity from the earth's heat. The steam rotates a turbine that activates a generator, which produces electricity.
ii. Geothermal Direct Use - Producing heat directly from hot water within the earth.
iii. Geothermal Heat Pumps - Using the shallow ground to heat and cool buildings.

Non-Renewable Resources
Energy sources are considered nonrenewable if they cannot be replenished (made again) in a short period of time.

Fossil fuels
Fossil fuels are found within the rocks of the Earth's surface. They are called fossil fuels because they are thought to have been formed many millions of years ago by geological processes acting on dead animals and plants, just like fossils.

Coal, oil and natural gas are fossil fuels. Because they took millions of years to form, once they are used up they cannot be replaced.

Oil and natural gas
What are they?
Oil and gas are chemicals made from molecules containing just carbon and hydrogen. All living things are made of complex molecules of long strings of carbon atoms. Connected to these carbon atoms are others such as hydrogen and oxygen. A simple molecule, called methane (CH4), is the main component of natural gas.
Crude oil (oil obtained from the ground) is a sticky, gooey black stuff. It contains many different molecules, but all are made of carbon and hydrogen atoms.

How were they formed?
Gas and oil were formed from the remains of small sea creatures and plants that died and fell to the bottom of seas. Over many millions of years, layers of mud or other sediments built up on top of these dead animals and plants. The pressure from these layers and heat from below the Earth's crust gradually changed the once-living material into oil and natural gas.

Over time, the layers of rocks in the Earth's crust move and may become squashed and folded. Gas and oil may move through porous rocks and may even come to the surface. In some places, pockets of oil and gas can be found, because non-porous rocks have trapped them. Pockets of oil and natural gas may become trapped between layers of non-porous rocks.

Where are they found?
Natural gas and crude oil can be found in many places around the world, such as the Middle East (about 70 per cent of the world's known resources of oil), the USA and under the North Sea off the coast of the UK.

What are they like as fuels?
When gas and oil burn they produce mainly carbon dioxide and water, releasing the energy they contain. Crude oil is a mixture of different chemicals and is usually separated out into fuels such as petrol, paraffin, kerosene and heavy fuel oils.

The oil-based fuels provide less energy per kilogram than natural gas. Both oil and natural gas produce carbon dioxide, which is a greenhouse gas.

How long will they last?
Oil and gas are non-renewable: they will not last forever. New sources of oil and gas are constantly being sought. It is thought that the current resources under the North Sea will last about another 20 years and the world resources will last for about 70 years.

Estimates vary, however, because we do not know where all the resources are and we do know how quickly we will use them. It is thought that with new discoveries these fossil fuels will last well into the next century.

Advantages
These sources of energy are relatively cheap and most are easy to get and can be used to generate electricity.

Disadvantages
When these fuels are burned they produce the gas carbon dioxide, which is a greenhouse gas and is a major contributor to global warming. Transporting oil around the world can produce oil slicks, pollute beaches and harm wildlife.

Coal
What is it?
Coal mainly consists of carbon atoms that come from plant material from ancient swamp forests. It is a black solid that is reasonably soft. You can scratch it with a fingernail. It is not as soft as charcoal, however, and is quite strong. It can be carved into shapes. There are different types of coal. Some contain impurities such as sulphur that pollute the atmosphere further when they burn, contributing to acid rain.

How was it formed?

Millions of years ago, trees and other plants grew rapidly in a tropical climate, and when they died they fell into swamps. The water in the swamps prevented the plant material from decaying completely and peat was formed.

As time passed, layer upon layer of peat built up. The pressure from these layers and heat from below the Earth's crust gradually changed the material into coal.

Where can it be found?
Coal can be found in parts of the world that were once covered with swampy forests, such as the UK about 250 million years ago. There are large deposits in China, USA, Europe and Russia. South Africa also has relatively large deposits.

What is it like as a fuel?

When coal burns it produces mainly carbon dioxide, some carbon monoxide and soot (which is unburned carbon). Many coals when burned produce smoky flames.
Their energy content weight for weight is not as great as oil. When coal burns it produces more carbon dioxide than oil.

How long will the supply of coal last?

The world has relatively large reserves of coal, more so than oil and gas. Estimates vary, but suggestions are that supplies will last well into the next century.

Advantages

Coal is relatively cheap, with large deposits left that are reasonably easy to obtain, some coal being close to the surface. It is relatively easy to transport because it is a solid.

Disadvantages

Some sources of coal are deep below the ground, as in the UK. They can be difficult, costly and dangerous to mine.

Burning coal without first purifying it contributes to global warming, as well as to the production of smog (smoke and fog), which is harmful to health. It is a finite resource and will eventually run out.

Nuclear fuel
What is it?
Nuclear fuel makes use of the radioactivity of some elements. The nucleus in the atom may spontaneously break down to release energy and produce fast-moving particles, atoms of other elements. The fast-moving particles that are ejected can also strike other atoms, causing them to break down.

Placing the atoms close together in a fuel rod means that atoms are more likely to be struck by these particles, and so produce more nuclear reactions. As the reactions proceed heat is produced. The task of a nuclear reactor is to control the reaction so that a steady flow of heat is produced.

How is nuclear fuel made?

Nuclear fuel is made from naturally occurring radioactive materials, such as uranium, found in rocks. These materials are extracted and concentrated. They are formed into 'fuel rods'.

When placed close together, the fuel rods set off nuclear reactions that generate heat. This heat is used to turn water into steam and generate electricity.

This fuel is classed as non-renewable, although concentrating the fuel further can recycle some of the 'spent fuel'.

Where can nuclear fuel be found?
There are deposits of the raw material uranium in Africa, Russia and North America.

How long will the supply of nuclear fuel last?

The world supply of radioactive material will provide a source of energy well into the next century and beyond.

Advantages

Nuclear fuel does not produce greenhouse gases, so will not contribute to global warming. There is a relatively long-lasting supply of raw material.

Disadvantages

The waste remains radioactive for a long time (100+ years). If the reaction is not contained and controlled well, then the nuclear reduction could go out of control, as at Chernobyl in 1986. Radioactive material could then escape into the environment.