The Effects Of Overpopulation On Human Population

Erin Williams April 30, 2015 Anthropology Edwin Accomando Paging Captain Planet We need a major reduction in human population, stat! Ok, maybe that’s not a viable solution, but it does beg the question; â€Å"How many people does it take to break the world?† Currently, there are a little over 7 billion people on the planet and there is already some cause for concern. Overpopulation, extreme weather, and a drought that’s causing a water shortage. Is the abundance of humans the cause or is it simply happening because it can? Overpopulation can cause many issues for the inhabitants of the affected area as well as the planet. With more people comes more use of the planet’s resources. More wood for houses means less trees for the absorption of carbon dioxide and other harmful gasses. More cars to meet the demand of the people means more output of carbon monoxide and the depletion of the ozone layer that protects the planet from solar radiation. More solar radiation means climate shifts that affect weather patterns, agriculture, and the geographical composition of the planet. Take California for instance, the state is currently in an unprecedented drought that is threatening the state’s water supply. Is global warming the culprit? Yes and no. The drought itself may be the effect of something else because droughts have happened outside of human interference but the increasing temperatures certainly isn’t helping the situation. As stated in â€Å"Anthropogenic warming has increasedShow Mo reRelatedThe Effects Of Overpopulation On The Human Population1532 Words   |  7 PagesWith rapid population growth and urbanization escalating, overcrowding has concerned many scientists, researchers, and the human populace as a whole. Overpopulation, the condition where an area holds more people than in which the area can properly function, is a serious issue which has many adverse effects on the well-being of a healthy human population. A growing seven billion people live on Earth and factors such as pollution, and human well being may all be affected by overpopulation, and continuedRead MoreThe Environmental Impact of Overpopulation Essay862 Words   |  4 PagesThe human population has continued to grow through the decades. The increasingly large number of people that have become apart of the world population has become a major problem. The consequences of the world being over populated has numerous effects which include: Environmental effects, depletion of natural resourc es, effects on the economy, food and water instability, and mass species extinction. Without a solution to the rise in human population, by the year 2020, 8 billion people will liveRead MoreCauses And Effects Of Overpopulation1073 Words   |  5 PagesWhat are the effects of overpopulation? Overpopulation is an undesirable condition where the number of existing people on earth exceeds the carrying capacity of the earth. However, overpopulation has not always been a problem. At the dawn of agriculture, 8000 B.C., the population was approximately 5 million. 8000 years later, 1 A.D., the number of people existing on earth was between 200-300 million. That’s a growth rate under 0,05% per year. A tremendous change occurred with the industrial revolutionRead MoreThe Effects Of Human Overpopulation On The Environment1242 Words   |  5 PagesThe Effects of Human Overpopulation on the Environment â€Å"Can one apple slice feed the world?† If the world were an apple, farmland would only be one very thin slice. The growing population on this Earth has some serious questions that it needs to consider as a whole. How are we all going to eat with eight billion mouths to eat? Farmers have an interesting proposition, they need to feed a growing population with very little land. Overpopulation also has negative effects on the earth through pollutionRead MoreOverpopulation Is More Than Just A Crowded Planet1343 Words   |  6 PagesIn the year 1 A.D., the Earth’s population was 300 million. In 1850, after many decades of consistent population growth, it eventually surpassed one billion. From that point on in history, the world population began to climb rapidly (Haub). Each year, the world population surpasses what any scientist has ever thought possible. Some would consider this expansion as a sign of success considering the causes of a rapidly growing population inclu de improved health care, new technology, progressive erasRead MoreOverpopulation : We Must Figure It Out For Save The World Essay1645 Words   |  7 Pages Overpopulation: We Must Figure It Out to Save the World It may not be something you think about often, but human population growth is a big issue in our world today and this problem needs to be solved in the future to save our planet. Overpopulation is a condition that will be in effect if the population exceeds the carrying capacity on Earth. The carrying capacity is the peak population that can sustain human life on Earth. It is uncertain what Earth’s carrying capacity is for the human raceRead MoreHuman Overpopulation1505 Words   |  7 PagesThe topic of overpopulation has different perspectives regarding whether or not it is happening as well as its apparent effects of both the environment and its inhabitants. The idea of human overpopulation being a problem most clearly begins around the time of Thomas Robert Malthus’ publishing of An Essay on the Principle of Population as It Affects the Future Improvement of Society, with Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers. In his writing, Ma lthus describesRead MoreOverpopulation Is A Serious Problem1442 Words   |  6 Pagesbe the greatest threat to the entire world is overpopulation. Overpopulation is a serious problem that is having an extreme effect on the health of every citizen of every country. The problems caused by overpopulation could even prove to be a fatal epidemic to the human population. Oftentimes overpopulation is overlooked due to a lack of knowledge or simply because many government officials have dismissed overpopulation and call it a myth. Overpopulation is an enormous and serious global problem thatRead MoreThe Problem Of Overpopulation And Overpopulation872 Words   |  4 PagesHuman overpopulation. Human population can be defined as the condition whereby, the total count of the human inhabiting a certain area exceeds the carrying capacity of the area Bongaarts, (2011). This brings out an issue of the carrying capacity of the region which alludes to the number of individuals who can inhabit a certain area for a given period. It may also be looked at as the situation whereby the available renewable resources in a certain area can satisfactorily support the current populationRead MoreOverpopulation Is Not An Issue1357 Words   |  6 PagesOverpopulation is not an issue many people in developing countries face at this point in time. Put simply, overpopulation is â€Å"the condition of having a population so dense that it causes environmental deterioration, an impaired quality of life, or a population crash† (Merriam-Webster). It should not be taken lightly because it cannot be reversed in a short time period. Changes must be made gradually so that future generations do n ot suffer consequences that current generations have place upon

Anxiety Disorders Essay Example For Students

Anxiety Disorders Essay Anxiety is a normal reaction to a threatening situation and results from an increase in the amount of adrenaline from the sympathetic nervous system. This increased adrenaline speeds the heart and respiration rate, raises blood pressure, and diverts blood flow to the muscles. These physical reactions are appropriate for escaping from danger but when they cause anxiety in many situations throughout the day, they may be detrimental to a normal lifestyle. An anxiety disorder is a disorder where feelings of fear, apprehension, or anxiety are disruptive or cause distortions in behavior, (Coon, 526); they are psychiatric illnesses that are not useful for normal functioning. At times, an underlying illness or disease can cause persistent anxiety. Treatment of the illness or disease will stop the anxiety. Anxiety illnesses affect more than 23 million Americans with about 10 million Americans suffering from the most common, general anxiety disorder . (Harvard, 1). Common anxiety disorders are panic attacks (panic disorder), phobias, and general anxiety disorder (GAD). Panic attacksPanic attacks can begin with a feeling of intense terror followed by physical symptoms of anxiety. A panic attack is characterized by unpredictable attacks of severe anxiety with symptoms not related to any particular situation. (Hale, 1886). The person experiencing the attack may not be aware of the cause. Symptoms include four or more of the following: pounding heart, difficulty breathing, dizziness, chest pain, shaking, sweating, choking, nausea, depersonalization, numbness, fear of dying, flushes, fear of going crazy. Heredity, metabolic factors, hyperventilation, and psychological factors may contribute to anxiety causing panic attacks. (Hale, 1886)Panic disorder tends to run in families with first degree relatives of patients having four to seven times greater risk than the general population. Metabolically, the levels of three neurotransmitters, nor-epinephrine, gamma-aminobutyric acid (GABA), and serotonin, may play a role in anxiety. These neurotransmitters act as signals between brain cells. Drugs that change the levels of these neurotransmitters are useful in the treatment of anxiety. Hyperventilation (rapid shallow breathing) can cause a decrease in carbon dioxide in the blood. This decrease in carbon dioxide has been associated with anxiety. Anxiety can be caused by psychological factors as well. One theory is that there is an unconscious conflict between certain wishes and desires, and guilt associated with these desires. Another theory is that certain fearful childhood situations provoke anxiety later. This later theory has been associated with agoraphobia in that the fear of being abandoned in the past may lead to fear of public places. Panic disorder is treated with drugs, cognitive- behavior therapy and other forms of psychotherapy, and/or a combination of the two. Relaxation therapy is also used in combination with other treatments. Phobias Phobias are extreme and disabling fear of something that poses little or no danger and leads to avoidance of objects or situations. There are three types of phobias: agoraphobia, social phobia, and specific phobias. (Public Health, 293). People with agoraphobia fear that something extremely embarrassing will happen to them. (Coon, 533). This phobia tends to start between the ages of 15 and 35 and is twice as common in women as in men. Anxiety occurs when the person is in or thinks about being in a place where escape may be difficult or help may not be available. The condition is managed with behavioral techniques such as exposure therapy and it is believed that these techniques may be more effective than drug therapy. Social phobia is a fear of being the focus of attention or scrutiny or of doing something extremely humiliating. Patients are afraid that others will think they are stupid, weak or crazy. Anxiety can occur from exposure to a particular situation or the mere thought of being in the situation. People with social phobias realize that their fears are irrational but they still experience the dread and anxiety. Treatment consists of cognitive-behavior therapy or medication or a combination of the two. (Pamphlet, 5-6). .u1012a4bb5ce54297f3886614ee3860e5 , .u1012a4bb5ce54297f3886614ee3860e5 .postImageUrl , .u1012a4bb5ce54297f3886614ee3860e5 .centered-text-area { min-height: 80px; position: relative; } .u1012a4bb5ce54297f3886614ee3860e5 , .u1012a4bb5ce54297f3886614ee3860e5:hover , .u1012a4bb5ce54297f3886614ee3860e5:visited , .u1012a4bb5ce54297f3886614ee3860e5:active { border:0!important; } .u1012a4bb5ce54297f3886614ee3860e5 .clearfix:after { content: ""; display: table; clear: both; } .u1012a4bb5ce54297f3886614ee3860e5 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u1012a4bb5ce54297f3886614ee3860e5:active , .u1012a4bb5ce54297f3886614ee3860e5:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u1012a4bb5ce54297f3886614ee3860e5 .centered-text-area { width: 100%; position: relative ; } .u1012a4bb5ce54297f3886614ee3860e5 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u1012a4bb5ce54297f3886614ee3860e5 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u1012a4bb5ce54297f3886614ee3860e5 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u1012a4bb5ce54297f3886614ee3860e5:hover .ctaButton { background-color: #34495E!important; } .u1012a4bb5ce54297f3886614ee3860e5 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u1012a4bb5ce54297f3886614ee3860e5 .u1012a4bb5ce54297f3886614ee3860e5-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u1012a4bb5ce54297f3886614ee3860e5:after { content: ""; display: block; clear: both; } READ: The nursing field EssayMany people experience specific phobias intense, irrational fears of certain things. Some of the more common specific phobias are dogs, closed-in places, heights, tunnels, bridges, and flying. Specific phobias tend to run in families and are more common in women. They strike more than one in ten peole and no one knows just what causes them. Important career or personal decisions may be affected by a persons specific phobia but many of the feared things are easily avoidable and help is not sought. Treatment employs desensitization or exposure therapy and is beneficial in three-fourths of patients. There are currently no drugs recommended for specific phobias however, certain medications may be prescribed to help relieve anxiety symptoms. Relaxation and breathing exercises are also helpful. General anxiety disorder (GAD) GAD affects two to five percent of the general population, but it accounts for almost 30% of psychiatric consultations in general practice. GAD is chronic or exaggerated worry and tension. Worrying is often accompanied by physical symptoms like trembling, muscle tension, headache and nausea. People with GAD cant seem to shake their concerns, seem unable to relax, have trouble falling or staying asleep, or feel lightheaded or out of breath. Some individuals startle more easily than other people, tend to feel tired, have trouble concentrating, and sometimes suffer depression. (Pamphlet, 2). Although GAD is the most common anxiety disorder, it is the least understood. It affects people of both sexes and all ages but is diagnosed more frequently in women than in men. The diagnosis of GAD is chronic, exaggerated worry and tension that has lasted for more than six months, although most people with the disorder can trace it back to childhood or adolescence. (Harvard, 2). Only 25% of people with the disorder seek professional care leaving millions of sufferers to go without simple treatments which can make a great difference. (Wickelgren, 56). Treatment consists of a mixture of medication and counseling, finding the most useful combination for each patient. Anxiety disorders can be confused with stress reactions. Stress reactions may have anxiety as a primary feature and include rapid response to sudden stressful life events, leading to disorientation, and adjustment reactions slower responses to life events that occur days or weeks later as symptoms of anxiety, irritability, and depression. These are usually limited and helped by reassurance, ventilation, and problem solving. Anxiety disorders oftentimes cannot be linked to specific life events and persist for months if not years at a time. Many people with anxiety disorders can be helped with treatment. Most of the medications which are prescribed are started at low doses and tapered off when treatment is near an end. Side effects generally become tolerated or diminished with time. Behavioral therapy and cognitive-behavioral therapy can be effective for treating several of the anxiety disorders. Behavioral therapy focuses on changing specific actions and uses different techniques to alter unwanted behavior. Techniques include special breathing exercises and exposure therapy gradually exposing patients to what frightens them and helps them cope with their fears. Cognitive-behavioral therapy teaches patients to react differently to the situations and bodily sensations that trigger panic attacks and other anxiety symptoms. Patients also learn to understand how to change their thoughts so that symptoms are less likely to occur. These techniques are designed to help people confront their fears. Without treatment, anxiety d isorders can be extremely disabling and disrupt family, work and social relationships. Psychology Essays

London has always been a multi... free essay sample

London has always been a multi-ethnic society. Due to the fact that London is a global city, there are thousands of people moving to London each year. There might be so many reasons for migration, such as fall in the birth rates of developing countries which, in time, causes a shortage on labour. In some developing countries human rights are not as respected as it is in London and in other European cities, and citizens do not have as much freedom. Nevertheless, we are used to seeing poverty and low incomes as well as high unemployment rates in developing countries. In this paper, I will be focusing on Muslim students who mostly second generation immigrants in London and discuss how integrated they are in the Western society of London. Where do you think Muslim migrants in London would on a scale from 1 to 10?Nowadays, we can quite often hear that someone is a British-Muslim, which is a very big step showing that the migrants have the feeling of belonging to the country they live in. We will write a custom essay sample on London has always been a multi or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The Muslims who classify themselves as British-Muslims are often born in the UK so they are usually either the second or the third generation who are the immigrant we will be discussing in this paper. Most of the time you can hear them saying that their first language is English and they are often not fluent in their mother tongues. The research that I will be talking about were attempted to young mostly second generation immigrant. A number of students who are Muslim and Christians about specific topics and compared them by using questionnaires as well as detailed interviews. It was found that the younger generation of Muslims who are in higher education are willing to integrate into the Western society as most of them grew up in this culture. It is found that young people clearly believe that the key to there future their education. This ideology is actually quite similar to the Western ideology and no major differences can easily be seen. Muslim parents often choose to send their children to single sexed Muslim schools, perhaps as they want them to get an education which reflects their culture. However, it is found that about 16 percent of Muslims either have never worked or are unemployed for a long time, where this number drops to only 3 percent on national scale. This clearly reflects that in terms of work force Muslims are more isolated and perhaps the employers have a prejudice against the Muslims; due to the fact that there is no physical difference that shows a Muslim cannot work as good as a citizen who has a different religious belief. Almost 6 percent of Muslim women are not allowed to work outside the home environment (this number is 4 percent for Christian women- which is not very far from each other). This shows that most Muslim women are allowed to work and have socio-economic rights and as well as a chance for integration. On the contrary, it is not really accepted for Muslim women to have any kind of desire to imitate women of the Western world. Islamic marriages are largely different to Christian marriages as polygamy is common and accepted in Islamic marriages yet it is generally not accepted in Christianity. According to the researches most Muslims are also against the idea of polygamy as much as Christians and there is no major clash of views in this sense. This clearly shows that there is a cohesion of ideas about marriage.

Biology essays

Biology essays Ontological Hierarchy and Moral Decisions Plato first posited the theory of an ontological hierarchy in his account of human beings a priori knowledge. He believed that humans gained universal knowledge through the direct contact between perfect, other-worldly Forms and our pre-natal souls. Augustine borrowed from this theory of an ontological hierarchy in his essay on moral decision making. In his, On the Free Choice of the Will, Augustine attempts to resolve the problem of how there could be evil in a world created by an all-powerful, all-knowing, and benevolent God, and how we might arrive at good, moral decisions with a corruptible free will. He starts at the very beginning by describing the nature of existence and being. He says that there is a hierarchical system at work in nature, as things that understand (humans) are better than things that merely live (beasts), which are better than things that simply exist (stones). Humans, because of their ability to reason and understand, are at the top of the natural hierarchical structure, but if there were something superior (higher in the hierarchy) to human reason, then that being would be God, unless there is something superior to it, which then would be God. With this theory in place, Augustine goes on to show that there is something superior to human reason, namely a common truth that exists. This truth accounts for the human understanding of numbers and wisdom, which could not be grasped simply by reason. Therefore, since there is something superior to human reason, there must be a God. The problem of how to make the right moral decisions still remains, though, for our free will has the ability to make bad or evil choices. Since we are imperfect beings, merely a deformed copy of the superior God, we are not fully able to make the right moral decisions simply based upon what we believe to be right, for evil is a deformity of the good, Go...

Financial analysis of Morrisons and comparison with Tesco Coursework

Financial analysis of Morrisons and comparison with Tesco - Coursework Example Ratio analysis of an organization presents facts on a comparative basis and enables the drawing of inference regarding the performance of a firm (Khan & Jain, 2006). This analysis gives a useful indication of the performance of the organization. Financial ratios are often used by shareholders, bankers, trade creditors, analysts, management and the general public at large to measure the performance of the company in various aspects such as liquidity, profitability, debt and market position (Stoltz et al., 2007). However, these ratios often should be analyzed keeping in mind the accounting policies and the principles used by companies and is dependent on the industries under consideration (Siegel and Shim, 2006). The objective of this report is to analyze the performance of Morrison’s. In order to do this, ratios will be calculated for the company over a period of two years: 2009 and 2010. The ratios will be compared to Tesco which is a leading competitor in the same industry. F our categories of ratio will be calculated for both the companies: 1. Profitability 2. Liquidity 3. Efficiency 4. Gearing ratios Analysis Profitability Ratios Profitability ratios can be used to measure how good the company is using its assets and how well the company is controlling its costs to generate an acceptable rate of return (Gitman and McDaniel, 2008). The various profitability ratios are given below Gross Margin Gross margin can be defined as the ratio of gross profit to total sales. The graph below shows the trend of the same: As can be seen from the graph, the gross margin of Tesco is more than that of Morrison’s in the year of 2009. However, while the gross margin has increased for Morrison’s from 2009 to 2010 while the same has decreased for Tesco. One point to note here is the sales done by both the companies. While Tesco had sales of the order of ? 56,910m in 2010, Morrison’s had just ? 15,410m. This difference is an indication of the size of the two companies. It is evident that in terms of sales, Tesco is well ahead of Morrison’s. Profit Margin Profit margin of a company can be defined as: The graph below shows the trend for profit margin for both the companies: Here again, the margin is more for Tesco as compared to that of Morrison’s in 2009. While the profit margin has increased considerably from 2009 to 2010, the same has remained almost equal for Tesco. The higher profit margin of Tesco indicates that the company is having a better control over its costs as compared to Morrison’s (Investopedia). Just like the gross sales, the value of net profit of Tesco (? 2,336m) is almost four times that of Morrison’s (? 598m). Return on assets and investments While return on assets measure the amount of net income generated for each unit of assets, return on investment measures the amount of income generated from each unit of owners’ equity. Return on assets is an ideal tool for comparing compan ies within the same industry. RoA is an indication of both the profit margin as well as asset turnover (Needles et al., 2010). The graph on the side here shows the Return on Assets for both the organization. The RoA is almost equal for both the companies. This indicates that both the organizations have almost equal efficiency in utilizing their assets. The graph on the side here shows the Return on Investment for both the organizations. RoI is more for Tesco in 2009 which indicates better return on investor wealth. One issue being faced by Tesco is a reduction in the RoI from 2009 to 2010. This imply that the average profit generated from the amount of income generated from owner’

FINANCIAL ACCOUNTING Essay Example | Topics and Well Written Essays - 1750 words

FINANCIAL ACCOUNTING - Essay Example â€Å"The terms depreciation and amortization have various meanings in finance and investing. For example, depreciation can refer to the devaluation of a currency, and amortization can be used to describe the payment structure in a common type of loan† (What is the difference between Depreciation and Amortization? 2003). Depreciation is charged to tangible assets, whereas amortization is charged to intangible assets. Fixed or tangible assets are those assets of the organization, which last more than one year, for example: furniture, buildings and machinery. Intangible assets are invisible assets that incur cost to the company, in terms of brand recognition, intellectual property and goodwill. Both amortization and depreciation are non cash cost of the industry and they cause reduction in the earning, whereas, on the other hand, they lead to an increase in the cash flow. The reason for recording depreciation as a cost is to increase the early purchase cost of the fixed asset mo re than its useful life. Whenever an industry makes its financial statements, it records a cost of depreciation to assign the loss in price of equipment, machines and other fixed assets it has purchased. On the other hand, unlike other costs, depreciation is a non-cash charge. This means that no money is actually paid at the period in which the expenditure is incurred. The function of depreciation is to match the price of a creative asset to the incomes earned from using the asset. Since it is difficult to observe a direct relation to revenues, the asset’s price is usually assigned to the years in which the property is used. â€Å"Depreciation systematically allocates or moves the asset’s cost from the balance sheet to expense on the income statement over the asset’s useful life. In other words, depreciation is an allocation process in order to achieve the matching principle; it is not a technique for determining the fair market value of the asset† (What is the Purpose of Depreciation, 2004). The International Accounting Standard Board (IASB) states that it is appropriate for plant and machinery to be depreciated and intangible assets to be amortized by employing a revenue-based amortization or depreciation method. A revenue based amortization or depreciation process is one that is derived from the transaction between price and units, and this considers the possible future fluctuations in price as the basis of depreciation distribute the quantity of an asset that is to be amortized or depreciated. Tax benefits are also likely to arise along with depreciation. While depreciation stands for non-cash payments in the income statement, it does decrease the industry’s net income. Lesser net income will result in a lesser tax liability. To expand this benefit, industries frequently utilize an accelerated depreciation process. According to the International Accounting Standards Committee, depreciation is the part of the depreciable p rice of an asset more than its expected useful life. â€Å"Depreciation for the accounting period is charged to income either directly or indirectly. Thus, it is clear from the above definition that depreciation is a loss arising on account of circumstances, some of which are known whereas others are not† (Need Help with Accounting Assignment? 2002). The Internal Revenue Service provides organizations with an

Marine Phytoplankton Essay Example for Free

Marine Phytoplankton Essay Phytoplankton From Wikipedia, the free encyclopedia Jump to: navigation, search Diatoms are one of the most common types of phytoplankton. Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words cpur?v (phyton), meaning plant, and TIXay? «?q (planktos), meaning wanderer or drifter. [l] Most phytoplankton are too small to be individually seen with the unaided eye. However, when present in high enough numbers, they may appear as a green discoloration of the water due to the presence f chlorophyll within their cells (although the actual color may vary with the species of phytoplankton present due to varying levels of chlorophyll or the presence of accessory pigments such as phycobiliproteins, xanthophylls, etc. ). Contents [hide] * 1 Ecology * 2 Aquaculture * 3 Blooms * 4 See also * 5 References * 6 External links [edit] Ecology Phytoplankton are the foundation of the oceanic food chain. Of these, the best known are dinoflagellate genera such as Noctiluca and Dinophysis, that obtain organic carbon by ingesting other organisms or detrital material. The term phytoplankton encompasses all photoautotrophic microorganisms in quatic food webs. Phytoplankton serve as the base of the aquatic food web, providing an essential ecological function for all aquatic life. However, unlike terrestrial communities, where most autotrophs are plants, phytoplankton are a diverse group, incorporating protistan eukaryotes and both eubacterial and archaebacterial prokaryotes. There are about 5,000 species of marine phytoplankton. [8] There is uncertainty in how such diversity has evolved in an environment where competition for only a few resources would suggest limited potential for niche differentiation. [9] In terms of numbers, the most important groups of phytoplankton include the diatoms, cyanobacteria and dinoflagellates, although many other groups of algae are represented. One group, the coccolithophorids, is responsible (in part) for the release of significant amounts of dimethyl sulfide (DMS) into the atmosphere. DMS is converted to sulfate and these sulfate molecules act as cloud condensation nuclei, increasing general cloud cover. In oligotrophic oceanic regions such as the Sargasso Sea or the South Pacific Gyre, phytoplankton is dominated by the small sized cells, alled picoplankton, mostly composed of cyanobacteria (Prochlorococcus, Synechococcus) and picoeucaryotes such as Micromonas. [edit] Aquaculture Diagrams of some typical phytoplankton. Main article: Algaculture Phytoplankton are a key food item in both aquaculture and mariculture. Both utilize phytoplankton for the feeding of the animals being farmed. In mariculture, the phytoplankton is naturally occurring and is introduced into enclosures with the normal circulation of seawater. In aquaculture, phytoplankton must be obtained and introduced directly. The plankton can either be collected from a body of water or foodstock for the production of rotifers[10], which are in turn used to feed other organisms. Phytoplankton is also used to feed many varieties of aquacultured molluscs, including pearl oysters and giant clams. The production of phytoplankton under artificial conditions is itself a form of aquaculture. Phytoplankton is cultured for a variety of purposes, including foodstock for other aquacultured organisms[10], a nutritional supplement for captive invertebrates in aquaria. Culture sizes range from small-scale laboratory cultures of ess than 1 L to several tens of thousands of liters for commercial aquaculture[10]. Regardless of the size of the culture, certain conditions must be provided for efficient growth of plankton. The majority of cultured plankton is marine, and seawater of a specific gravity of 1. 010 to 1. 026 may be used as a culture medium. This water must be sterilized, usually by either high temperatures in an autoclave or by exposure to ultraviolet radiation, to prevent biological contamination of the culture. Various fertilizers are added to the culture medium to facilitate the growth of plankton. A culture must be aerated or agitated in some way to keep plankton suspended, as well as to provide dissolved carbon dioxide for photosynthesis. In addition to constant aeration, most cultures are manually mixed or stirred on a regular basis. Light must be provided for the growth of phytoplankton. The colour temperature of illumination should be approximately 6,500 K, but values from 4,000 K to upwards of 20,000 K have been used successfully. The duration of light exposure should be approximately 16 hours daily; this is the most efficient artificial day length[10]