Evolution on Earth

Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available in limited supplies. This is usually due to the long time it takes for them to be replenished. Renewable resources are replenished naturally and over relatively short periods of time.

enewable Resources

Renewable resources are resources that are replenished by the environment over relatively short periods of time. This type of resource is much more desirable to use because often a resource renews so fast that it will have regenerated by the time you've used it up.

Think of this like the ice cube maker in your refrigerator. As you take some ice out, more ice gets made. If you take a lot of ice out, it takes a little more time to refill the bin but not a very long time at all. Even if you completely emptied the entire ice cube bin, it would probably only take a few hours to 'renew' and refill that ice bin for you. Renewable resources in the natural environment work the same way.

Solar energy is one such resource because the sun shines all the time. Imagine trying to harness all of the sun's energy before it ran out! Wind energy is another renewable resource. You can't stop the wind from blowing any more than you can stop the sun from shining, which makes it easy to 'renew.'

Any plants that are grown for use in food and manufactured products are also renewable resources. Trees used for timber, cotton used for clothes, and food crops, such as corn and wheat, can all be replanted and regrown after the harvest is collected.

Animals are also considered a renewable resource because, like plants, you can breed them to make more. Livestock, like cows, pigs and chickens, all fall into this category. Fish are also considered renewable, but this one is a bit trickier because even though some fish are actually farmed for production, much of what we eat comes from wild stocks in lakes and oceans. These wild populations are in a delicate balance, and if that balance is upset by overfishing, that population may die out.

Water is also sometimes considered a renewable resource. You can't really 'use up' water, but you also can't make more of it. There is a limited supply of water on earth and it cycles through the planet in various forms - as a liquid (our oceans), a solid (our polar ice caps and glaciers) and a gas (as clouds and water vapor).

Liquid water can be used to generate hydroelectric power, which we get from water flowing through dams. This is considered a renewable resource because we don't actually take the water out of the system to get electricity. Like sunshine and wind, we simply sit back and let the resource do all the work!

Geothermal energy is a renewable resource that provides heat from the earth - 'geo' means 'earth' and 'thermal' means 'heat.' You know all of those volcanoes on Earth that spew hot lava when they erupt? That lava has got to come from somewhere, right? It's actually sitting underneath the earth's surface as incredibly hot rock and magma.

We find the most heat in places like plate boundaries because these are like large cracks under Earth's surface where the heat can escape as well as places on Earth where the crust is relatively thin. Old Faithful and other natural springs and geysers are the result of geothermal energy, and that water can be hotter than 430°F!

Biofuels are renewable resources that are fuels made from living organisms - literally biological fuels. Ethanol is a biofuel because it's derived from corn. Biodiesel is vehicle fuel made from vegetable oil, and I bet you didn't know that people can actually run their cars on used oil from restaurants! Firewood, animal dung and peat burned for heat and cooking purposes are also biofuels because they come from living (or once-living) organisms.

Non-Renewable Resources

In contrast to renewable resources, non-renewable resources are resources that are not easily replenished by the environment. Let's think about this in terms of that ice cube maker again. Imagine that this time you don't have an automatic ice maker at home, you have to wait for someone to bring it to you, and they only do this once a month.

If you used up all your ice quickly, it wouldn't regenerate in your refrigerator and you would be

The resources which are replenished very slowly are also considered non-renewable resources. This is because these resources will not be available again or available only after a long time.

The best examples of non-renewable resources are fossil fuels such as coal, oil, and natural gases. Fossil fuels are produced by the decay of animal and plant matter. Their rate of production is very slow as compared to the rate of their extraction and consumption.

Another example of a non-renewable resource is our lifetime. Once used up, any individual cannot get back lost time. Other good examples of non-renewable resources are; nuclear fuels, minerals, and shale.

Water is a controversial resource which can be categorized as both a renewable and non-renewable resource. The cyclic change of water makes it a renewable resource while its unmanaged usage is making it a non-renewable resource.

Advantages of Fossil Fuels

A major advantage of fossil fuels is their capacity to generate huge amounts of electricity in just a single location.

Fossil fuels are very easy to find.

When coal is used in power plants, they are very cost effective. Coal is also in abundant supply.

Transporting oil and gas to the power stations can be made through the use of pipes making it an easy task.

Power plants that utilize gas are very efficient.

Power stations that make use of fossil fuel can be constructed in almost any location. This is possible as long as large quantities of fuel can be easily brought to the power plants.

Disadvantages of Fossil Fuels

Pollution is a major disadvantage of fossil fuels. This is because they give off carbon dioxide when burned thereby causing a greenhouse effect. This is also the main contributory factor to the global warming experienced by the earth today.

Coal also produces carbon dioxide when burned compared to burning oil or gas. Additionally, it gives off sulphur dioxide, a kind of gas that creates acid rain.

Environmentally, the mining of coal results in the destruction of wide areas of land. Mining this fossil fuel is also difficult and may endanger the lives of miners. Coal mining is considered one of the most dangerous jobs in the world.

Power stations that utilize coal need large amounts of fuel. In other words, they not only need truckloads but trainloads of coal on a regular basis to continue operating and generating electricity. This only means that coal-fired power plants should have reserves of coal in a large area near the plant?s location.

Use of natural gas can cause unpleasant odors and some problems especially with transportation.

Use of crude oil causes pollution and poses environmental hazards such as oil spills when oil tankers, for instance, experience leaks or drown deep under the sea. Crude oil contains toxic chemicals which cause air pollutants when combusted.

Earth, also called the world and, less frequently, Gaia is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to accommodate life.

Compositional Layers

The Earth is a sphere of radius 6371km which is stratified or layered. Compositional layers differ in chemical composition. The Earth has three compositional layers:

1. The crust: low density silicate rock, 5-70 km thick. There are two distinct types of crust.2. Continental crust is variable in thickness and composition. Thickness ranges from 5-70 km. The

composition ranges from mafic to felsic.

3. Oceanic crust is uniform in thickness and composition. It is 5-6 km thick and is mafic in composition.

4. The differences in thickness and density between continental and oceanic are responsible for the existence of ocean basins due to isostatic balance as the crust floats on the more dense mantle.

5. The mantle: high density, ultramafic silicate rock which can flow when subjected to long duration stresses. The mantle is over 2900 km thick and makes up over 80% of the volume of the Earth. The mantle is not molten!

6. The core: iron and nickel, liquid outer region with a solid center. The core is just over half the diameter of the Earth.

These compositional layers have sharp or abrupt boundaries between them.

Whole earth composition is estimated from unbiased samples of meteorites. Earth structure is obtained by combining this with seismic data.

Motion of liquid iron and nickel in the outer core gives the Earth a dipole magnetic field, nearly aligned with the rotational axis. The magnetic field of the Earth reverses spontaneously at random times. Over the last several million years, the average time between reversals has been about 200,000 years. The last reversal was 730,000 years ago. Reversals probably take less that 5,000 years. Reversals of the field probably involve a period of time where the field weakens substantially and becomes disorganized (non-dipole), then reorganizes in the opposite polarity. People should wear lead underwear during a reversal, as the Earth's surface will be bombarded with a higher than normal amount of cosmic radiation!

Mechanical Layers

In addition to the compositional layers, the Earth has mechanical layers. Mechanical layers differ in their strength or rigidity. These layers do not correspond on a one-to-one basis with the compositional layers. The Earth has five mechanic layers:

1. The lithosphere is the outermost mechanical layer and is the most rigid layer of the Earth. The lithosphere consists of the crust, and some of the uppermost mantle. The lithosphere averages about 100 km thick. It is somewhat thicker beneath continents, and dramatically thinner under mid-ocean ridges.

2. The asthenosphere lies beneath the lithosphere. It is a part of the mantle, approximately 100 km thick, with very little strength. The asthenosphere flows relatively easily and accomodates the movement of the overlying lithosphere. The upper and lower boundaries of the asthenosphere are diffuse as they involve gradual changes in the rigidity of the mantle, not a change in composition.

3. The lower mantle or mesosphere consists of most of the mantle. This part of the mantle flows, but at much slower rates than the asthenosphere.

4. The outer core is liquid iron (with some nickel and other elements). This is the only internal layer of the Earth that is a true liquid. The core-mantle boundary is the one mechanical boundary that is also a compositional boundary. Movement of the electically conductive fluid in the outer core generates the Earth's magnetic field. The inner core is solid. It has the same composition as the outer core, and is about half the diameter of the core.

The changes in the atmosphere with height are results of specific physical conditions which exist on the earth and in its atmosphere. The vertical changes in temperature are important in constraining weather events to the lowest 10-12 km of the atmosphere. The ozone layer, located near 25 km above the earth's surface, causes the temperature to rapidly change in the middle atmosphere.

Troposphere

(~10 deg to -60 deg C)

From the earth's surface to 11-12 km above, temperature decreases with height.

This fact results from the sun's radiation striking the earth and the earth then warming the air above it. So the closer the air is to the ground, the warmer it becomes. The rate of change of air temperature with height is called the "lapse rate". In the troposphere, the lapse rate is generally about 6.5 deg C per kilometer increase in altitude.

The temperature can increase with height in the lower troposphere.

When this happens, it is called an "inversion". If the temperature remains the same with height, it is called "isothermal".

The actual lapse rate varies with location, time of day, weather conditions, season, etc.

Stratosphere

(~0 deg to -60 deg C)

The stratosphere is marked by a temperature inversion from about 11-12 km to 50 km above sea level.

Because warmer air lies above cooler air in this region, there are few overturning air currents and, thus, the stratosphere is a region of little mixing. Particles that travel from the troposphere into the stratosphere can stay aloft for many years without returning to the ground. For example, large volcanic eruptions force ash to be projected into the stratosphere, where it may remain for years and causing slight global cooling in the process.

Why does the temperature increase with height in the stratosphere?

Because the ozone (O3) layer mostly resides at this level in the atmosphere. Ozone absorbs UV radiation from the sun which, in turn, increases the motion of the ozone molecules. The ozone molecules then collide with other molecules in the air, increasing its temperature.

The importance of the ozone layer lies in the facts that (1) ozone helps the earth to maintain its heat balance, and (2) ozone reduces the amount of harmful UV radiation that reaches the earth's surface.

Ozone is both produced and destroyed in the stratosphere. Ozone destruction can be both natural (UV radiation or molecular collisions) or man-made (e.g., chlorofluorocarbons).

Mesosphere

(0 deg to -90 deg C)

The mesosphere resides from about 50 km to 80-90 km above the earth's surface.

Because 99.9% of the mass of the atmosphere lies below the stratopause, the air pressure and density in the mesosphere are extremely low (about 1/1000th of the surface).

There is not enough oxygen to breathe here, although the percentage of oxygen in the atmosphere is about the same.

There is not a layer of ozone to cause heating, so temperatures are colder as height increases.

The stratosphere warms the lowest levels of the mesosphere and the heat is slowly circulated throughout the mesosphere

Thermosphere

(500-1500 deg to -90 deg C)

The thermosphere lies above about 90 km. Oxygen absorbs UV radiation and gains significant kinetic energy (i.e., few molecules are around to bump into).

Unlike in the troposphere and stratosphere, temperatures in the thermosphere can change by hundreds of degrees depending on the amount of solar activity.

This region marks where the percentage of atmospheric constituents change.

There becomes far more atomic oxygen than molecular oxygen or even nitrogen.

Changes in Air Pressure with Height

Pressure always decreases with height and does so most rapidly near the ground. Why do sealed balloons increase in volume when they rise in the atmosphere? Why do your ears "pop" when you ride on an elevator in a tall building or when you take off in an airplane?

As we move upward in the atmosphere, the weight of the air upon us should decrease because there is less air above us. Thus, air pressure decreases with increasing height.

Pressure decreases with height more rapidly near the ground because the atmosphere is a gas which can compress in its response to the earth's gravitation effect.

If more air is packed into the same length vertical column, then the air column will weigh more and, hence, the air pressure will be greater.

So we may have horizontal variations of pressure if two air columns are next to one another, both of the same height but one with more molecules packed into it than the other. This is how we get high and low pressure systems.

The rate at which air pressure changes with height is determined primarily by the average temperature in the column under consideration.

In colder regions, atmospheric pressure decreases more rapidly with height than normal or than is observed in warmer areas.

Changes in Air Temperature with Height

Temperature has a more complicated structure, mostly because the temperature of the air relies on the energy its molecules receive from radiation.

The two main sources of radiation in the atmosphere are the sun and the earth. The sun's radiation is mostly near infrared (37%), visible (44%), and ultraviolet (7%) while the earth's radiation is mostly far

infrared. Infrared is generally what we feel as "heat", visible is what we see, and ultraviolet is what our skin absorbs to make us tan or burn. The temperature structure of the atmosphere is controlled significantly by whichever of these three types of radiation are affecting the region.

Temperature generally decreases with height in the lowest 10 km or so above the earth's surface.

This 'layer' is called the troposphere. How can we tell temperature decreases with height? Do mountains give us a clue?

Temperature increases with height from about 10 km to 50 km above the earth's surface.

This layer is called the stratosphere and results from absorption of solar radiation by ozone. How can we "see" the change from the troposphere to the stratosphere? The tops of large thunderstorm clouds can show us.

Temperature again decreases and increases with height above the stratosphere.

These layers are called the mesosphere and thermosphere, respectively.

Permafrost refers to a layer of soil or rock that is frozen all year round. Permafrost is found throughout much of Alaska, parts of Canada, and other countries in the far north. You might think a place with permafrost would be barren, but plants can still grow in the soil at the surface, which is not frozen during warmer parts of the year. However, there may be a thick layer of permafrost underneath. As air temperature rises, so does the temperature of the ground, which can cause permafrost to thaw (or melt).

As temperatures keep getting warmer, permafrost will continue to thaw. For example, the map on the right shows how permafrost in northwestern Alaska could change by the year 2100.

When permafrost melts, the land above it sinks or changes shape. Sinking land can damage buildings and infrastructure such as roads, airports, and water and sewer pipes. It also affects ecosystems. For example, the top photo shows a forest where the trees are leaning or falling over because the permafrost underneath them has melted.

Another reason to be concerned about permafrost is because it has a lot of carbon trapped inside. As permafrost thaws, this carbon is released to the atmosphere in the form of methane, a powerful greenhouse gas. This process leads to more climate change and is an example of a positive feedback loop, which happens when warming causes changes that lead to even more warming.

cli·max community (klī′măks′)

An ecological community in which populations of plants or animals remain stable and exist in balance with each other and their environment. A climax community is the final stage of succession, remaining relatively unchanged until destroyed by an event such as fire or human interference.

What are feedback mechanisms and how do they work?

Let’s revisit that very simple human-environment system diagram from the "What are coupled human-environment systems?" page:

The diagram shows that humanity impacts the environment, and that the environment impacts humanity. But if the environment impacts humanity, then that can in turn impact how humanity impacts the environment, which can in turn impact how the environment impacts humanity. So this diagram is perhaps not as “very simple” as it might initially appear!

This phenomenon of system components both impacting each other creates a feedback loop. Feedback is impact to a system component that is a consequence of an action performed by that component. For example, suppose you take the action of writing an email to the instructor, asking a question about the course. The email you get back is a feedback. A loop is a circumstance in which system components impact each other, such that an action by a component affects subsequent performances of that action. This circumstances has a circular, loop-like appearance in a system diagram, as seen in the diagram above.

There are two basic types of feedback: positive and negative. A positive feedback loop is a circumstance in which performing an action causes more performances of the action. For example, suppose that every time you e-mailed the instructor with a question about the course, the instructor wrote back with an e-mail so confusing that you had even more questions about the course, which cause you to write two e-mails back for more clarification. This would be a positive feedback loop.

A negative feedback loop is a circumstance in which performing an action causes fewer performances of the action. For example, suppose that every time you e-mailed the instructor with a question about the course, the instructor wrote back with an e-mail that clarified the course for you, so that you had fewer questions about the course and thus wrote fewer e-mails for clarification. This would be a negative feedback loop.

It is important to understand that for feedback loops, the terms positive and negative do not mean good and bad. A positive feedback loop can be a bad thing, and a negative feedback loop can be a good thing, or vice versa. Whether or not any given feedback loop is positive or negative is ultimately an ethical question. We’ll cover ethics in Module 3.

Carrying Capacity

As the Self Check indicates, population change can involve either positive or negative feedback loops. When population is growing exponentially, there is a positive feedback loop: more children brings more parents, which in turn brings even more children, and so on:

A box with the word 'parents' is above a box with the word 'children' The 'parents' box has an arrow pointing to the 'children' box. The words 'giving birth' are next to the arrow. The 'children' box has an arrow pointing to the 'parents' box. The words 'growing up' are next to the arrow. There are plus signs next to both arrows.

The +’s here signify that each set of parents brings more children, and each group of children brings more parents. If the birthrate is constant over time, and if each generation is larger than the previous, then there will be exponential population growth, as shown in Figure 2.10 in the Marten reading “What is human ecology?”. But population can’t maintain exponential growth forever. To do so would require an infinite amount of resources, but we live in a finite world. Here’s where the negative feedback loop comes in. The resources provide sustenance to the population: food, water, energy, or whatever other resources are being used. As the population runs out of resources, it can’t have as many children – or, the children can’t grow up to become parents.

The diagram has a box with the word 'individuals' above a box with the word 'resources.' The 'individuals' box has an arrow pointing to the 'resources' box. The word 'consumption' is next to the arrow and there is a minus sign next to the arrow. The 'resources' box has an arrow pointing to the 'individuals' box. The word 'sustenance' is next to the arrow and there is a plus sign next to the arrow.

The + here signifies that more resources bring more individuals, since individuals need resources to survive. The - here signifies that more individuals bring fewer resources, since a larger population will consume more, leaving fewer resources available for anyone else. If a population continues to grow exponentially for long enough, eventually it will hit a point where there aren’t enough resources for it to continue growing. At this point, the population has reached the largest size that the resources permit. This size is called the carrying capacity.

It is important to understand that the carrying capacity refers to the largest population that can be sustained over the long-term. Carry capacity is not constant and varies over time in response to changes in the environment. For example, disturbances from extreme natural events (e.g., volcanic eruptions) and human activities (e.g., pollution) can alter the environment to a great extent and consequently influence carrying capacity.

A population can temporarily exceed the carrying capacity. For example, imagine a population of rabbits that lives off of carrots. The rabbits have to leave enough carrots in the ground each year so that they will have enough carrots to eat the following year. The carrying capacity is thus the largest number of rabbits that can live one year while still leaving enough carrots left over for the same number of rabbits to live

the following year. The rabbits could exceed the carrying capacity one year, but then there wouldn’t be enough carrots the following year.

Eutrophication" is the enrichment of surface waters with plant nutrients. While eutrophication occurs naturally, it is normally associated with anthropogenic sources of nutrients. The "trophic status" of lakes is the central concept in lake management. It describes the relationship between nutrient status of a lake and the growth of organic matter in the lake. Eutrophication is the process of change from one trophic state to a higher trophic state by the addition of nutrient. Agriculture is a major factor in eutrophication of surface waters.

Although both nitrogen and phosphorus contribute to eutrophication, classification of trophic status usually focuses on that nutrient which is limiting. In the majority of cases, phosphorus is the limiting nutrient. While the effects of eutrophication such as algal blooms are readily visible, the process of eutrophication is complex and its measurement difficult.

The symptoms and impacts of eutrophication are:

· Increase in production and biomass of phytoplankton, attached algae, and macrophytes.

· Shift in habitat characteristics due to change in assemblage of aquatic plants.

· Replacement of desirable fish (e.g. salmonids in western countries) by less desirable species.

· Production of toxins by certain algae.

· Increasing operating expenses of public water supplies, including taste and odour problems, especially during periods of algal blooms.

· Deoxygenation of water, especially after collapse of algal blooms, usually resulting in fish kills.

· Infilling and clogging of irrigation canals with aquatic weeds (water hyacinth is a problem of introduction, not necessarily of eutrophication).

· Loss of recreational use of water due to slime, weed infestation, and noxious odour from decaying algae.

· Impediments to navigation due to dense weed growth.

· Economic loss due to change in fish species, fish kills, etc.

Eutrophication is when the environment becomes enriched with nutrients. This can be a problem in marine habitats such as lakes as it can cause algal blooms.

Fertilisers are often used in farming, sometimes these fertilisers run-off into nearby water causing an increase in nutrient levels.

This causes phytoplankton to grow and reproduce more rapidly, resulting in algal blooms.

This bloom of algae disrupts normal ecosystem functioning and causes many problems.

The algae may use up all the oxygen in the water, leaving none for other marine life. This results in the death of many aquatic organisms such as fish, which need the oxygen in the water to live.

The bloom of algae may also block sunlight from photosynthetic marine plants under the water surface.

Some algae even produce toxins that are harmful to higher forms of life. This can cause problems along the food chain and affect any animal that feeds on them.

WHAT IS EUTROPHICATION?

The runoff of nitrate and phosphate into lakes and streams fertilizes them, and causes accelerated eutrophication (eu = true or well; trophy = food) or enrichment of the waters.

Eutrophication is a natural process that typically occurs as lakes age. However, human-caused, accelerated eutrophication (called "cultural eutrophication") occurs more rapidly, and causes problems in the affected water bodies, as described below. It is estimated that 50-70% of all nutrients reaching surface water (principally N and P) originate on agricultural land as fertilizers or animal waste. (In the US, farm animals produce about 130 times as much waste as the country's people do! As of 2006, hogs in North Carolina alone produced as much feces and urine daily as do the combined human populations of New

York + Los Angeles + Chicago + Houston!) One clear example of agriculturally-related inputs is the Lake Erie basin, where farms (crop and livestock) are estimated to contribute as much nitrogen to the lake as would the sewage of 20 million people, twice the population of the Lake Erie basin!

Urban and industrial runoff also contribute to eutrophication. You have probably heard of the bans on (or reductions in allowed amounts of) phosphates from detergents? Those bans arose because of concerns about cultural eutrophication. Sewage discharges also contribute to eutrophication. These are largely point sources though, and have been easier to control than nonpoint, diffuse sources such as agricultural runoff.

In general, excess Nitrates is particularly a problem in coastal marine regions, where N is often more limiting than Phospate, whereas excess P is more threatening to freshwater systems.

Eutrophication

Eutrophication is the process by which a body of water becomes overly enriched by nutrients. You can recall this term by remembering that the word 'eutrophic' comes from the Greek language and means well-nourished. Therefore, a body of water that has undergone eutrophication is a 'well-nourished' lake.

While it might sound like a good thing to have extra nutrients added to water, eutrophication typically has a detrimental effect. An overabundance of nutrients stimulates the rapid growth of algae and aquatic plant life. This excessive growth depletes dissolved oxygen levels within the water to a point where other organisms, such as fish, cannot survive.

The problem is intensified when these large collections of algae die and begin to decay. The bacteria that decompose the dead algae require oxygen, which consumes even more dissolved oxygen in the water, essentially suffocating other organisms. Dissolved oxygen is the amount of oxygen contained in a body of water. It is an important indicator of the health of a water body and its ability to support a diverse balance of aquatic organisms.

When eutrophication occurs, a body of water can undergo explosive growth of algae at or near the surface of the water, referred to as algal blooms. When algal blooms are dense, they form visible green or yellowish-brown coverings that appear to float on the water surface. This blocks sunlight that is needed by organisms in the water and further depletes oxygen.

Human Causes of Eutrophication

Eutrophication can be a natural process that occurs over time due to natural runoff of soil nutrients and the decay of organic matter.

However, use of the term came into common usage when human causes of eutrophication were identified. Eutrophication is typically the result of human activities that contribute excess amounts of nitrogen and phosphorus into water.

Agricultural fertilizers are one of the main human causes of eutrophication. Fertilizers, used in farming to make soil more fertile, contain nitrogen and phosphorus. The use, or overuse, of fertilizers can cause these nutrients to runoff of the farmer's field and enter waterways. The same fertilizers that were intended to enhance crop growth now enhance the growth of algae and aquatic plants. Fertilizer runoff can occur from other sources, including lawns and golf courses, but agricultural practices are a main source of nutrient pollution.

Limit your fertilizer use and apply at appropriate times (UMD's Home and Garden Information Center)

"BayScape" your yard (Alliance for the Chesapeake Bay)

Control runoff and soil erosion (UMD's Home and Garden Information Center).

Start a compost pile and recycle yard waste (UMD's Home and Garden Information Center).

Conserve water and energy (Maryland Department of Natural Resources)

Plant trees (Maryland Department of Natural Resources).

Maintain your septic system (University of Maryland)

Drive less

Be a responsible boater and pump out wastes

eutrophication can be avoided by using mimimal required amounts of chemical fertilizers or better still do away with them and use natural ones instead.be sure not to have the fields close to the water bodies.take extra care while using fertilzers during monsoons as due to run-off,they get transmitted to the water bodies.then,they can cause blokage of waterways,death of marine life n breakage of food chain.

You can have an impact on the state of the Baltic Sea by modifying and being aware of your daily choices and consumption patterns. Here are some practical tips for environmentally friendly behaviour.

Consumption

Use biodegradable and non-phosphate detergents.

Never dump waste water directly into rivers, lakes or the sea.

Food

Where possible, eat food produced locally. Shorter transportation distances mean less air-borne nitrogen emissions which contribute to eutrophication.

Reduce your consumption of meat. Meat production produces large amounts of manure, a primary source of nutrients that cause eutrophication in the Baltic Sea. Large amounts of animal products can also raise nitrogen levels in human urine, which puts a strain on the Baltic Sea even after purification.

Waste

Minimise the amount of waste you create and compost all organic material.

Don’t dump waste water or rubbish into lakes, rivers or the sea.

Don’t release waste water from your boat into the sea, empty your boat’s septic tank into the waste water treatment systems in harbours.

Dishwashing

Don’t release dishwater directly to the water system. Instead, allow the soil to absorb it. If you have running water in your summer house, make sure the waste water treatment system is of the best available technology.

Use phosphate-free detergents.

Waste water discharge outside municipal wastewater treatment systems

Install effective waste water treatment systems in your summer house. As summer houses are increasingly evolving from ascetic cottages into round-year leisure residences, water treatment must be carefully considered.

Replace modern lavatories at your summer house with composting ones. This saves water and energy and more effectively reduces nutrients.

Outside recreation

Avoid excess cruising on motor boats and jet skis to reduce pollution, noise and emissions of nitrous oxides.

Don’t make bonfires close to the water where the nutritious ash can get to the water and eutrophicate it.

Eliminate the use of artificial fertilisers and pesticides in your garden as they can end up in water systems.

Managing the shore

Don’t alter the coast line at your summer cottage. Natural coast lines prevent nutrients from leaking into the water.

Avoid dredging as it may release nutrients and toxics stored in the sediment and foster eutrophication.

Sewage contains both organic and inorganic nutrients that can find their way into bodies of water. Biochemical oxygen demand or B.O.D. is a concept that is important to sewage treatment. It is defined as a measure of the amount of oxygen required by aerobic