science pbl (what we've learned ppt)

HELLO :DWe’ve learned aboutAshes & Ecosystem : 

HELLO :DWe’ve learned aboutAshes & Ecosystem Slides by : ♥ May ♥ Yanni ♥ Mingsiew ♥ Yushan

How the ashes in the waters affect the marine ecosystem: : 

The ashes in the water will block out sunlight which make the marine plants unable to photosynthesize. Plants are producers and the energy is passed on to other animals either directly or indirectly. If plants are unable to photosynthesize, animals that depend on them would be affected, as well as other animals that depend on other animals for food. In other words, the food chain will be disturbed. This may pose a threat to the marine ecosystem as the many of the consumers suffers, without enough food, many of the marine animals would die. There will also be competition between the organisms for resources such as food, oxygen and light. Etc. How the ashes in the waters affect the marine ecosystem:

Ecosystem : 

It is made up of abiotic and biotic components and these basic components are important to nearly all types of ecosystems. It consists of the biological community that occurs in some locale, and the physical and chemical factors that make up is non-living or abiotic environment. Some examples of Ecosystems are: pond, forest, grassland. Ecosystem

Factors : 

Abiotic factors (non living, environmental): Examples: Sunlight Temperature Precipitation Water or moisture Air currents, Soil Factors

Biotic components: : 

The living things that shape an ecosystem. They are any living component that affects another organism. Such things include animals which consume the organism and the living food that the organism consumes. As opposed to abiotic components (non-living components of an organism's environment), biotic components are the living components of an organism's environment, such as predators and prey. Biotic components:

Factors : 

Biotic Factors: (living) Primary producer Herbivores Carnivores Omnivores Detritivores - scavengers which feed on dead plants and animals or their waste. Decomposers Etc. Factors

Temperature How temperature changes in water? : 

Surface water, be it a lake or a stream, tends to stay relatively stable in terms of temperatures. Seasonal changes bring about slow changes in temperatures that the waterway's plant and animal life can tolerate. Industries often use nearby water resources as cool water then discharge the warmed water back into the ecosystem. This action creates an unnatural and a too rapid increase in the water's temperature. Temperature How temperature changes in water?

Effects of temperature change : 

A sudden change in water temperature affects the organisms living in the water. Changes in water temperature can change fishes’ metabolism. Fish's metabolism slows in colder times where food resources are limited. If the water is warmed, the fish's metabolism increases however the fish is likely to die with the limited food resources. Effects of temperature change

Causes of the problem : 

Thermal pollution is caused by several types of industry. Cooling waters are often needed for electricity generation and nuclear power. Other industries such as paper mills also rely on cooling waters to conduct their manufacturing processes. Causes of the problem

Other Effects : 

Discharge waters from factories can have other effects on the ecosystem: If water flow is strong, it can introduce sediment into the water and cause soil erosion along the shorelines. The resulting cloudy water can block light, preventing plants to photosynthesize. Photosynthesis is the process by which plants make food. If a plant cannot make food or produce energy, it will die, further impacting the water quality. Other Effects

Turbidity : 

Turbidity describes how murky or cloudy water is. Water containing high levels of suspended particles is very turbid. Turbidity impacts dissolved oxygen levels in many ways: Turbidity-causing particles absorb a lot of Sun rays. When dark colored particles absorb rays, energy is released hence turbid water gets heated by the sun very rapidly. Water loses its ability to hold dissolved oxygen therefore turbidity can lead to a decrease in oxygen levels Turbidity is often caused by tiny soil particles washed off from the land. These particles contain nutrients that enhance growth of algae when combined with water and sunlight. When algae dies and decomposes a lot of oxygen will be depleted. Hence turbidity can cause lower levels of dissolved oxygen in water by causing algal blooms. Turbidity

Water Chemistry impacts on water chemistry : 

As water temperature rises, the amount of dissolved oxygen available for living organisms decreases. For cold water fishes such as trout, this change can kill the fishes. When water temperature changes too suddenly, fishes become stressed and vulnerable to disease. Then when great number of fishes die, the water chemistry is altered when the ammonia and nitrite levels increase. If left unchecked, the water becomes an ecological dead zone, unable to support any life. Water Chemistry impacts on water chemistry

We’ve also learned aboutAlgae Blooms : 

Presentation by: May (24) Mingsiew (32) Yushan (33) Yanni (34) We’ve also learned aboutAlgae Blooms

Contents : 

Contents Nutrients cycle and Eutropicaation Algal Bloom and Toxic Algae Toxic Algae Phytoplankton & Decomposers

Nutrients Cycle & Eutropicaation:D : 

Presenter: Myat  Nutrients Cycle & Eutropicaation:D

Nutrient cycle : 

Nutrient cycle Nutrient cycling plays is important in the maintenance of an ecosystem Nutrients are central to the function and growth of organisms. In an ecosystem, decomposers are essential in breaking down biomass matter and cycling nutrients. Eg. Animal waste and dead organic matter are broken down by bacteria and fungi into their constituent elements.

Nutrient Cycle : 

Nutrient Cycle Some nutrients are released into the soil for roots of the plants to take in Elements such as oxygen, hydrogen and carbon are transmitted by air and water to the living components of an ecosystems. Decomposition of dead and waste organic material returns hydrogen and carbon to the atmosphere. Carbon is released as carbon dioxide from the decay of carbohydrates. Hydrogen and nitrogen are released from the decaying protein as ammonia.

Weathering : 

Weathering Weathering also assists in releasing nutrients into the soil. However nutrients are also lost in the soil.  litter stays in an ecosystem through run-off. Acid rain is an example of nutrient pollution in ecosystems.

Case Study : 

Case Study We will now observe a particular ecosystem to further illustrate the importance of nutrient cycling in ecosystems. In the Amazon basin nutrient inputs occur through precipitation, wind borne dust, ash, nitrogen fixation by organisms, weathering of sediments and aerosols. Essentially producer organisms are responsible for the intake of mineral nutrients into the ecosystem. Thus they construct the very substance of life. Consumer organisms break down organic tissue and return the material in an form to be used again by plants.

General effects of eutrophication : 

General effects of eutrophication Algae are different from microscopic animal life in our water bodies in terms of their mode of respiration they release more oxygen during the day than they use, and absorb more carbon dioxide than they release, Other non-photosynthetic organisms release carbon dioxide and absorb oxygen from their environment. Algae usually react in an opposite manner during the night, when they act as dead organic matter adding BOD load. It is important to carefully consider any action of removal of algae from a body of water oxygen supplied by algae during photosynthesis in beneficial to most forms of life in streams, thus the removal would often be a detriment rather than a benefit.

main effects of eutrophication : 

main effects of eutrophication Species diversity decreases Dominant biota changes Plant and animal biomass increase Turbidity increases Rate of sedimentation increases, shortens the lifespan of the lake Anoxic conditions may develop Because of the high concentration of organisms in a eutrophic system, there is often a lot of competition for resources and predator pressure. This high degree of competition and the sometimes-high chemical or physical stress make high the struggle for survival in eutrophic systems. As a result the diversity of organisms is lower in eutrophic than in oligotrophic systems.

changes in nutrient levels and biology : 

changes in nutrient levels and biology The changes in nutrient levels and biology can directly affect human activities. The water can be injurious to health The amenity value of the water may decline Increased vegetation may impede water flow and navigation Commercially important species of fish may disappear Treatment of drinking water may be difficult and supply can have an unacceptable taste or odour

Algal and cyanobacterial blooms : 

Algal and cyanobacterial blooms Cultural eutrophication causes excessive algal bloom in water bodies, with consequent algal overload. Under certain conditions of darkness and warm temperatures these blooms may die, decompose and produce offensive sewage-like odor. If the receiving water is used as a raw water supply for some public or private agency, algae may be difficult to remove and hence add certain objectionable tastes to the delivered water. Algae also have the tendency to absorb and concentrate mineral nutrients in their cells. When they die, at the end of the growing season, they settle to the stream or lake bottom, from which they release these mineral and organic nutrients at the beginning of the next growing season.

Algal and cyanobacterial blooms : 

Algal and cyanobacterial blooms In this way they serve as a form of secondary pollution. One of the most common symptoms of lake eutrophycation is the development of blue-green algal (Cyanobacteria) blooms. They can be generated by human activity. Eg sediment runoff from construction sites may greatly diminish water clarity therefore decrease the amount of light available for phytoplankton. Cyanobacteria are able to maintain themselves near the surface of the water by means of special gas-filled vacuoles that give the plants slight positive buoyancy.

Cyanobacteria : 

Cyanobacteria Once cyanobacteria or more generally algal blooms reach high concentrations, problems can occur: They have a negative impact on water quality, They creat odorous problems They interfer with certain water treatment processes. When certain bacteria populations reach very high proportions, they can also produce toxins that can render water unsafe for consumption.

Algal Bloom & Toxic Algae : 

Presenter: YuShan  Algal Bloom & Toxic Algae

Algal bloom : 

Algal bloom Algal bloom is a rapid increase or accumulation in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Only one or a small number of phytoplankton species are involved. Although there is no officially recognized threshold level, algae can be considered to be blooming at concentrations of hundreds to thousands of cells per milliliter, depending on the severity.

Freshwater algal blooms : 

Freshwater algal blooms Freshwater algal blooms are the result of an excess of nutrients. The excess of nutrients may originate from fertilizers that are applied to land for agricultural or recreational purposes (ash?) Algae tend to grow very quickly under high nutrient availability, but each alga is short- lived, and the result is a high concentration of dead organic matter which starts to decay. The decay process consumes dissolved oxygen in the water. Without sufficient dissolved oxygen in the water, death rate of the marine creatures increases rapidly. http://en.wikipedia.org/wiki/Algal_bloom

Toxic algae : 

Toxic algae Large numbers of "blooming" algae can at times produce toxins or result in lower oxygen levels in seawater, causing marine creatures to die at an increasing rate. It may also produce marine toxins that enter the marine food web when consumed by mussels. Typically, these mussels have a capacity to concentrate and accumulate very large amounts of these toxins without apparent harm to themselves. Toxin levels can be so high that consuming only a few mussels could be lethal. When blooms produce such deleterious effects, they are called harmful algal blooms. http://www.answers.com/topic/toxic-algae

Toxic Algae : 

Presenter: Yanni  Toxic Algae

Toxic algae : 

Toxic algae are generally thought of as organisms similar to red tide dinoflagellates, which can kill numerous fish, crabs, and other species. Toxic algae blooms also can occur near floating fish aquaculture cages where there is a build up of fish excrement and uneaten food under/near the cages downstream from waste discharges from pig farms, etc. There are many types of causative organisms of toxic algae blooms.

Causative organisms of toxic algae : 

Causative organisms of toxic algae The causative organisms of toxic algae are toxic blue green algae, various species of phytoplankton including toxic dinoflagellates, toxic diatoms, other types of algae. There are various toxins (brevetoxins, domoic acid, saxitoxins, etc.) involved, including those that produce Amnesic Shellfish Poisoning (ASP), Ciguatera Fish Poisoning (CFP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP), and Paralytic Shellfish Poisoning (PSP) in humans.

How living organisms are affected : 

How living organisms are affected Human, and other animal, deaths from toxic algae occur each year from contaminated dialysis water, contaminated drinking water, consumption of affected organisms, and from consumption of organisms (filter-feeders) that concentrate the offending algae, etc.

Toxic algae : 

Toxic algae Some aquarists may be unaware, but toxic algae organisms can "bloom" in fish tanks (and ponds) and cause distress and death to tank occupants. Algae blooms, toxic or not, can occur in closed systems when high organics or nutrients are present, can occur in both freshwater or salt water tanks with sufficient lighting and nutrients, and can occur in tanks as small as 10 gallons. Since most fish tanks are aerated well, here we are talking about the algae that release toxins and cause problems, NOT the non-toxic algae blooms that die, decompose, and cause oxygen depletion and subsequent death of fishes due to low oxygen levels in nature. Various species of algae that are toxic release their toxins upon death; these toxins in the water can irritate and cause severe distress or death to tank (pond) occupants that have no way to escape.

What are Harmful Algal Blooms(HABs)? : 

What are Harmful Algal Blooms(HABs)? Marine and fresh waters teem with life, much of it microscopic, and most of it harmless; in fact, it is this microscopic life on which all aquatic life ultimately depends for food. While most of these species of phytoplankton and cyanobacteria are harmless, there are a few dozen that create potent toxins given the right conditions. Harmful algal blooms may cause harm through the production of toxins or by their accumulated biomass, which can affect co-occurring organisms and alter food-web dynamics. Impacts include human illness and mortality following consumption of or indirect exposure to HAB toxins, substantial economic losses to coastal communities and commercial fisheries, and HAB-associated fish, bird and mammal mortalities.  To the human eye, blooms can appear greenish, brown, and even reddish- orange depending upon the algal species, the aquatic ecosystem, and the concentration of the organisms.

Phytoplankton & Decomposers : 

Presenter: Mingsiew  Phytoplankton & Decomposers

What are phytoplankton ? : 

What are phytoplankton ? Phytoplankton are microscopic plants that live in the ocean. These small plants are very important to the ocean and to the world They are at the base of the food chain. Many small fish and whales eat them. Then bigger fishes eat the little fishes, etc. The food chain continues at some point in time we (people) come into it when we eat the fish. So the energy of plankton  becomes our energy too

How do phytoplankton live? : 

How do phytoplankton live? Phytoplankton live near the surface of the ocean because they need sunlight like all green plants. They also need water and nutrients to live. Phytoplankton use water and CO2 to grow, but phytoplankton still need other vitamins and minerals, like iron to survive. When the surface of the ocean is cold, the deeper parts of the ocean bring these nutrients to the surface and the plankton live. But, when the surface of the ocean is warm, as in El Niño, the ocean does not bring as many of these essential nutrients and the phytoplankton die. Hence the entire food chain is affected.

Decomposers : 

Decomposers Decomposers and scavengers break down dead plants and animals. They also break down the waste of other organisms. Decomposers are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up. There are two kinds of decomposers, scavengers and decomposers.

Scavengers : 

Scavengers They are animals that find dead animals or plants and eat them. While they eat them, they break them into small bits. Eg of scavengers are flies, wasps Cockroaches and Earthworms but they only break down plants.

Decomposers : 

Decomposers Once a scavenger is done, the decomposers take over and finish the job. Many kinds of decomposers are microscopic, meaning that they can't be seen without a microscope. Others, like fungi, can be seen. Different kinds of decomposers do different jobs in the ecosystem. Others, like some kinds of bacteria, prefer breaking down meat or waste from carnivores

Relationship of Phytoplankton & Decomposers : 

Relationship of Phytoplankton & Decomposers Is plankton a producer consumer or decomposer? Plankton may be both producer (phytoplankton) and consumer (zoo plankton) but not a decomposer (this is the job of bacteria). Phytoplankton is the producer, which is eaten by zooplankton, which is then eaten by other organisms in the ocean. So, Phytoplankton is NOT a decomposer.

Thank Youuuuuu~ for your kind attention : 

Presenters: HELLO  May (24) Mingsiew (32) YuShan (33) Yanni (34) Thank Youuuuuu~ for your kind attention