Sunday, July 27, 2008
In my last post, I am going to talk about the hydrogen cycle and the sulphur cycle.
Hydrogen is one of the constituents of water. It recycles as in other biogeochemical cycles. It is actively involved with the other cycles like the carbon cycle, nitrogen cycle ,sulfur cycle and oxygen cycle as well.
Firstly, Water is split into hydrogen and oxygen by the process of elecrolysis, using electricity generated from renewable energy sources. Secondly, The oxygen is released into the atmosphere, whilst the hydrogen is stored and transported. Thirdly, Oxygen from the atmosphere is re-combined with the stored hydrogen in a fuel cell, producing electricity and water vapour and fourtly, The water vapour is released back into the environment, where it can become part of the cycle once again.
Sources:
Sulphur is one of the components that make up proteins and vitamins. Proteins consist of amino acids that contain sulphur atoms. Sulphur is important for the functioning of proteins and enzymes in plants, and in animals that depend upon plants for sulphur. Plants absorb sulphur when it is dissolved in water. Animals consume these plants, so that they take up enough sulphur to maintain their health.
We find many sulphur compounds on Earth. These include sulphur dioxide, elemental sulphur, sulphuric acid, salts of sulphate or organic sulphur compounds such as dimethylsulphide and even amino acids in our body. All these chemical compounds do not last forever. Most of the earth's sulphur is tied up in rocks and salts or buried deep in the ocean in oceanic sediments. Sulphur can also be found in the atmosphere. It enters the atmosphere through both natural and human sources. Natural recourses can be for instance volcanic eruptions, bacterial processes, evaporation from water, or decaying organisms. When sulphur enters the atmosphere through human activity, this is mainly a consequence of industrial processes where sulphur dioxide (SO2) and hydrogen sulphide (H2S) gases are emitted on a wide scale. All these particles will settle back onto earth, or react with rain and fall back onto earth as acid deposition. The particles will than be absorbed by plants again and are released back into the atmosphere, so that the sulphur cycle will start over again.
At the same time there are spatial / geographical cycles. One example is when sulphur compounds move from the ocean to the atmosphere, are transported to the land, come down with the rain and are transported by rivers to the ocean again.
Sources:
http://www.atmosphere.mpg.de/enid/Nr_6_Feb__2__6_acid_rain/C__The_sulphur_cycle_5i9.
http://www.lenntech.com/sulphur-cycle.htm
http://www.biosci.ohio-state.edu/~mgonzalez/Micro521/23.html
That's all I have for my biojournal entries! Thank You!
Environmentalist Blogged:3:12 PM
The nitrogen cycle is the biogeochemical cycle that describes the transformations of nitrogen and nitrogen-containing compounds in nature. It is a gaseous cycle.
Earth's atmosphere is about 78% nitrogen, making it the largest pool of nitrogen. Nitrogen is essential for many biological processes; and is crucial for any life here on Earth. It is in all amino acids, is incorporated into proteins, and is present in the bases that make up nucleic acids, such as DNA(Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses) and RNA(Ribonucleic acid (RNA) is a nucleic acid and consists of a long chain of nucleotide units). In plants, much of the nitrogen is used in chlorophyll molecules which are essential for photosynthesis and further growth.
Nitrogen Fixation
The conversion of nitrogen (N2) from the atmosphere into a form readily available to plants and hence to animals and humans is an important step in the nitrogen cycle, that determines the supply of this essential nutrient. There are four ways to convert N2 (atmospheric nitrogen gas) into more chemically reactive forms. They are biological fixation, industrail n-fixation, combustion of fossil fuels and other processes.
Nitrogen Mineralization
In most ecosystems nitrogen is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers, found in the upper soil layer, chemically modify the nitrogen found in organic matter from ammonia (NH3 ) to ammonium salts (NH4+ ). This process is known as mineralization and it is carried out by a variety of bacteria, actinomycetes, and fungi.
Nitrification
Some of the ammonium produced by decomposition is converted to nitrate via a process called nitrification. The bacteria that carry out this reaction gain energy from it. Nitrification requires the presence of oxygen, so nitrification can happen only in oxygen-rich environments like circulating or flowing waters and the very surface layers of soils and sediments.
Denitrification
Through denitrification, oxidized forms of nitrogen such as nitrate and nitrite (NO2-) are converted to dinitrogen (N2) and, to a lesser extent, nitrous oxide gas. Denitrification is an anaerobic process that is carried out by denitrifying bacteria, which convert nitrate to dinitrogen. They use the nitrate as an electron acceptor in the place of oxygen during respiration. These facultatively anaerobic bacteria can also live in aerobic conditions.
Ammonification
When a plant or animal dies, or an animal excretes, the initial form of nitrogen is organic. Bacteria, or in some cases, fungi, converts the organic nitrogen within the remains back into ammonia, a process called ammonification or mineralization.
Assimilation
Plants can absorb nitrate or ammonium ions from the soil via their root hairs. If nitrate is absorbed, it is first reduced to nitrite ions and then ammonium ions for incorporation into amino acids, nucleic acids, and chlorophyll. In plants which have a mutualistic relationship with rhizobia, some nitrogen is assimilated in the form of ammonium ions directly from the nodules. Animals, fungi, and other heterotrophic organisms absorb nitrogen as amino acids, nucleotides and other small organic molecules.
Currently, much research is devoted to understanding the effects of nitrogen enrichment in the air, groundwater and surface water. Scientists are also exploring alternative agricultural practices that will sustain high productivity while decreasing the negative impacts caused by fertilizer use. These studies not only help us quantify how humans have altered the natural world, but increase our understanding of the processes involved in the nitrogen cycle as a whole.
Sources:
Environmentalist Blogged:1:32 PM
Saturday, July 26, 2008
The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.The cycle is usually thought of as four major reservoirs of carbon interconnected by pathways of exchange.
These reservoirs are the atmosphere, the terrestrial biosphere, which is usually defined to include fresh water systems and non-living organic material, such as soil carbon, the oceans, including dissolved inorganic carbon and living and non-living marine biota and the sediments including fossil fuels.
Carbon is an element. It is part of oceans, air, rocks, soil and all living things. Carbon doesn’t stay in one place. It is always on the move! The Carbon Cycle is a complex series of processes through which all of the carbon atoms in existence rotate. The same carbon atoms in your body today have been used in countless other molecules since time began. The wood burned just a few decades ago could have produced carbon dioxide which through photosynthesis became part of a plant. When you eat that plant, the same carbon from the wood which was burnt can become part of you. The carbon cycle is the great natural recycler of carbon atoms. Unfortunately, the extent of its importance is rarely stressed enough. Without the proper functioning of the carbon cycle, every aspect of life could be changed dramatically.
Carbon moves from the atmosphere to plants
In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2). With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food from carbon.
Carbon moves from plants to animals
Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too.
Example:
Plants absorb carbon dioxide from the atmosphere and use it, combined with water they get from the soil, to make the substances they need for growth. The process of photosynthesis incorporates the carbon atoms from carbon dioxide into sugars.
Animals, such as the rabbit pictured here, eat the plants and use the carbon to build their own tissues. Other animals, such as the fox, eat the rabbit and then use the carbon for their own needs.
Carbon moves from plants and animals to the ground
When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. Some becomes buried miles underground and will become fossil fuels in millions and millions of years.
Carbon moves from living things to the atmosphere
Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration.
Carbon moves from fossil fuels to the atmosphere when fuels are burned
When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. That’s the weight of 100 million adult African elephants! Of the huge amount of carbon that is released from fuels, 3.3 billion tons enters the atmosphere and most of the rest becomes dissolved in seawater.
Carbon moves from the atmosphere to the oceans.
The oceans, and other bodies of water, soak up some carbon from the atmosphere.
Ultimately, the same carbon atom can move through many organisms and even end in the same place where it began. Herein lies the fascination of the carbon cycle; the same atoms can be recycled for millennia!
Sources:
Environmentalist Blogged:9:05 PM
In this post, I am going to continue on global warming. Not only is aquatic animals affected by global warming but also birds.
The climate is changing. The earth is warming up, and there is now overwhelming scientific consensus that it is happening, and human-induced. With global warming on the increase and species and their habitats on the decrease, chances for ecosystems to adapt naturally are diminishing. Many are agreed that climate change may be one of the greatest threats facing the planet. Recent years show increasing temperatures in various regions, and/or increasing extremities in weather patterns and because of this, migratory birds are greatly affected.
The results of several studies investigated show that as the temperatures becomes warmer, migrant species in temperate latitudes, such as the Pied Flycatcher (Ficedula hypoleuca) also arrive on their breeding grounds earlier than expected stated CMS in a release. Scientists have also been studying the dates on which red-winged blackbirds arrive in northern Michigan, found that warming temperatures have dramatically altered the birds' migration as they now arrive 21 days earlier than they did in 1960. The timing of migrations is critical to the survival of numerous bird species. Beginning their journey too early or late may mean that birds miss the food sources they need to survive. As a result of this, migratory birds are travelling thousands of miles only to find the insects they depend on had their breeding cycle a few weeks earlier based on the temperature rise.
Early spring might lead to a shift in the prey (insect hatching) or a shift in vegetation bloom. Unfortunately these shifts are not in line and may occur before the young birds hatch. As a result the birds may not provide enough food for their offspring.
Hence, please do your part to help the earth, these animals and most importantly YOURSELF by helping to slow down the process of global warming and cooling the Earth! =)
Sources:
http://www.sierraclub.org/globalwarming/habitat/wildlife.asp
http://www.nwf.org/birdsandglobalwarming/helpbirds.cfm
http://news.mongabay.com/2007/0507-birds.html
http://www.globalissues.org/EnvIssues/GlobalWarming.asp
Environmentalist Blogged:3:12 PM
Thursday, July 24, 2008
In this post, I will be touching on the oxygen cycle.
The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within and between its three main reservoirs: the atmosphere (air), the biosphere (living things), and the lithosphere (Earth's crust). The main driving factor of the oxygen cycle is photosynthesis, which is responsible for the modern Earth's atmosphere and life.
Just as water moves from the sky to the earth and back in the hydrologic cycle, oxygen is also cycled through the environment. Plants mark the beginning of the oxygen cycle. Plants are able to use the energy of sunlight to convert carbon dioxide and water into carbohydrates and oxygen in a process called photosynthesis. This means that plants "breathe" in carbon dioxide and "breathe" out oxygen. Animals form the other half of the oxygen cycle. We breathe in oxygen which we use to break carbohydrates down into energy in a process called respiration.
The photosynthesis takes place in the green plants, whereas the aerobic respiration takes place in all living organisms. The oxygen cycle is determined by the aerobic respiration of glucose, which consumes oxygen and produces carbon dioxide and water, and by the photosynthesis, which consumes carbon dioxide and water to produce organic matter (sugars) and molecular oxygen.
Carbon dioxide produced during respiration is breathed out by animals into the air, so oxygen is created in plants and used up by animals, but the oxygen cycle is not actually quite that simple. Plants must break carbohydrates down into energy just as animals do. During the day, plants hold onto a bit of the oxygen which they produced in photosynthesis and use that oxygen to break down carbohydrates. But in order to maintain their metabolism and continue respiration at night, the plants must absorb oxygen from the air and give off carbon dioxide just as animals do. Even though plants produce approximately ten times as much oxygen during the day as they consume at night, the night-time consumption of oxygen by plants can create low oxygen conditions in some water habitats.
In conclusion, in the day, photosynthesis produces oxygen which is taken in by humans and animals for respiration and carbon dioxide is given out during repiration and is taken in for photosynthesis. In this way, the oxygen and carbon dioxide can be "reused" and thus forming a cycle.
Sources:
http://wikipedia.org
http://water.me.vccs.edu/concepts/oxycycle.html
http://chimge.unil.ch/En/redox/1red33.htm
Environmentalist Blogged:9:56 PM
Tuesday, July 22, 2008
Qns: How many cycles are there in the world and what are they used for? Are they helpful to us?
In ecology and Earth science, a biogeochemical cycle is a circuit or pathway by which a chemical element or molecule moves through both biotic ("bio-") and abiotic ("geo-") compartments of an ecosystem. In effect, the element is recycled, although in some such cycles there may be places (called "sinks") where the element is accumulated or held for a long period of time. There are many different types of nutrient cycles. They are water, oxygen, carbon, nitrogen, phosphorus, sulfur and hydrogen. In this post, I am going to talk about the water cycle.
The Earth's water is always in movement, and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Since the water cycle is truly a "cycle," there is no beginning or end. Water can change states among liquid, vapor, and ice at various places in the water cycle, with these processes happening in the blink of an eye and over millions of years.
This cycle is made up of a few main parts. They are evaporation (transpiration), condensation, precipitation and collection. This is how the cycle goes. The Sun, which plays a major role in the water cycle, produces energy in the form of heat and causes the water in the water bodies such as oceans, rivers, canals and even the puddle in your backyard to evaporate. Transpiration is also involved as it is the process by which plants lose water out of their leaves. Transpiration gives evaporation a bit of a hand in getting the water vapour back up into the air. When the water gets heat, it forms water vapour which condenses in the cool air, changes into liquid and forms clouds.
As more and more water vapor cools into the clouds, the water droplets that form the clouds become larger and larger. These droplets get so big that the swirling winds in the atmosphere can no longer hold them up. The droplets fall from the sky. Precipitation is the term for the falling, condensed water molecules, which come down as rain, snow, sleet, or hail--depending on conditions in the atmosphere. When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the “ground water” that plants and animals use to drink or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts all over again.
Sources:
http://wikipedia.org/
http://www.kidzone.ws/WATER/
http://www.units.muohio.edu/dragonfly/water/watercycle.shtml
http://www.biologie.uni-hamburg.de/b-online/e54/54d.htm
Environmentalist Blogged:8:27 PM
Saturday, July 19, 2008
Qns: How has global warming destructed and detroyed some parts of the beautiful Earth?
Global warming has caused a destruction in polar bear's lives as it continues to melt the ice caps.
In southern portions of their range, such as Hudson bay and the Artic, the ice is melting vastly and quickly. When it is summer, the polar bears stay on land and do not hunt or even eat anything as they wait till there is ice before they hunt animals and continue their diet. In just 20 years the ice-free period in Hudson Bay has increased by an average 20 days, leaving nearly three weeks less time each year for the bears to hunt for seals on the ice.
In this case, they have lesser time to hunt for animals as the heat in the air increases. As a result, the bears are skinnier and have lower reproductive rates than when the ice persisted throughout the seals’ birthing period. As average bear weight has dropped by 15%, reproduction has declined and the population is down more than 20%.
Already, more than 25 percent of the world's polar bear populations are in decline and evidence of the dire impact of global warming on polar bears continues to mount. That evidence includes polar bear drownings, cannibalism, starvation, reduced cub survival and denning dislocation. So do your part to help and hold back global warming!
Rise in localised Arctic surface temperatures over last 50 years--->4°C
Extra ice melted between 1978 and 2005-1.3 million km² ---> an area five times the size of the UK
Polar bear's weight loss for every week earlier the ice melts--->10kg
Predicted collapse of the Arctic cod stocks--->15 years
Deadline for moratorium on oil drilling around Lofoten island in the Barents Sea to be renewed--->2010
Predicted loss of all summer Arctic ice--->2040
Predicted extinction of the polar bears--->By the end of the century
Sources:
http://www.nwf.org/polarbear/pdfs/NWFPolarBearBasics_1-28-08.pdfhttp://www.wwf.org.uk/investor/inv_0000004503.asphttp://www.savebiogems.org/polar/
Environmentalist Blogged:1:53 PM
