Tag: Environment

Introduction

Algae are photosynthetic eukaryotes with one or more cells that live in watery environments. They serve as the foundation of aquatic food chains that supply nutrients to a variety of aquatic herbivores. An algal bloom occurs when the population of algae suddenly increases, usually as a result of changed environmental conditions. A bloom of algae resembles foam or scum floating over the water. Some algal blooms emit a foul stench as a result of the overgrowth of bacteria. A distinguishing characteristic of an algal bloom is the physical colouring of the water.

What is an Algal Bloom?

Algal blooms occur either in freshwater or marine water systems, resulting in the rapid growth of algae. As a result of the pigments, water appears red, brown, reddish-brown, or green. The size of algae may vary from unicellular organisms to macroscopic multicellular organisms. In contrast to multicellular entities, algal blooms are characterised by microscopic organisms. In stagnant water, an algal mat forms when the population size is elevated. As a result, aquatic organisms have less oxygen available to them.

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What are the causes of Algal Bloom?

Climate: 

• During the time of summer, ponds and lakes experience a marked increase in temperature and light intensity, both of which may lead to algal blooms.
• The stillness of stagnant water, such as ponds and lakes, causes the top layers of water to heat up while the deeper layers of water remain relatively cool. 
• As a result of low wind speeds, surface water tends to be still, allowing thermal stratification to occur. 
• Extended drought due to poor rainfall and reduced water flow into freshwater systems make them stagnant. This is an added advantage for algae to multiply their numbers.

Nutrient load:

• Dissolved minerals provide nutrients to aquatic species. When water is overloaded with nutrients (excess nitrogen and phosphorus), algae are fertilized and grow rapidly. The process of loading nutrients into the water body is known as eutrophication.
• Nitrogen and phosphorus-rich fertilizers are sprayed on farmlands and crops. Water streams drain fertilizer into lakes and reservoirs after heavy rains. Water bodies are polluted by urban wastes carried by stormwater runoff.
• Algal blooms on shorelines are caused by nutrients carried by rivers and deposited into oceans.

United effect:

• Algal bloom cannot be solely caused by nutrient enrichment. Several factors must come together to produce an unusual environmental condition for algae to bloom. 
• It is possible for algae not to bloom in muddy ponds, even though the water is nutrient-rich, warm, and stagnant.
• Due to the turbidity of muddy waters, and lack of sunlight needed for photosynthesis they cannot grow.

Importance of Algal Bloom   

• Algal blooms render water unsafe for consumption by both animals and humans. 
• Some algal blooms have a slimy appearance and a bad odour. 
• They cause serious economic losses by making the water unfit for leisure activities like swimming, boating, and fishing. 
• In the water, some algal blooms release poisons or compounds that can seriously ill human beings. They are referred to as harmful algal blooms (HAB).

Effects of Algal Bloom

Effect on the ecosystem:

• Algal bloom can be thought of as a disturbance to the natural environment because of its impact on it. Any species’ population fluctuations can have a direct or indirect impact on other creatures living in the particular ecosystem. A single algae species’ overpopulation stunts the development of other organisms, which has clear implications for the food chain. 
• Dead zone: The lifespan of algae is brief. After the life cycle is complete, a fast rise in population causes dead biomass to accumulate. It creates a need for extensive breakdown. Dissolved oxygen is depleted by decomposers, which reduces its availability to other life forms. Aquatic organisms have a difficult time surviving and exhibit significant mortality in a habitat with little dissolved oxygen. A dead zone results from this. Dead zones result in significant economic losses for the fishing and shellfish industries.
• The dead, rotting algae float as floating particles that block fish gills and kill them. 
• When algae create poisons that are detrimental to people and other living things, then they are known as harmful algal bloom (HAB). Direct contact with HAB can result in a deadly disease and severe sickness, fever, diarrhea, and skin rashes.
• Water that has algal blooms is unsafe for drinking and other recreational uses.

How does Algal Bloom affect the Quality of Water?

• Depending on the species, algal blooms can look like scum, froth, or paint. 
• They could tint the water and emit a foul, pungent stench. 
• Algal pigments give water its reddish, pinkish, yellowish, brownish, or golden appearance. 
• Water becomes unsafe for drinking when algae develop. Drinking water that contains dangerous algal blooms poses serious health hazards. 
• The neurological system, liver, and gastroenterological system are all negatively impacted by toxins. 
• Toxins in HAB water cannot be eliminated by boiling or cooking.

Summary

Algal blooms occur either in freshwater or marine water systems, resulting in the rapid growth of algae.  During the summer, ponds and lakes experience a marked increase in temperature and light intensity, both of which may lead to algal blooms. Algae are fertilized and grow rapidly when water is overloaded with nutrients (excess nitrogen and phosphorus). Algal blooms render water unsafe for consumption by both animals and humans.  The dead, rotting algae float as floating particles that block fish gills and kill them.

Frequently Asked Questions 

1.How Long does an Algal Bloom Last?
Ans. Algal blooms are a transient phenomenon that continues for a maximum of five months. While apparent algal blooms fade away as a result of cleaning and restoration efforts, toxins cannot disappear unless the water goes through an effective treatment procedure.

2. How can Algal blooms be Stopped in Lakes and Reservoirs?
Ans. Aerators are installed in lakes to prevent immobility. Aerators continuously circulate water to avoid stagnation since motionless water causes thermal stratification.

3. Describe Red Tide.
Ans. Algal bloom in oceans is frequently referred to as “red tide.” When ocean waters are physically discoloured, it is more acceptable. Red tides are not always dangerous algal blooms.

Introduction

The ecosystem is defined as a geographical area composed of living beings and non-living beings interacting with each other. Both of them are interdependent and hence together are responsible for maintaining the balance of the environment. Living beings in an ecosystem are termed biotic factors; they include microbes, plants, and animals. Non-living beings of an ecosystem are known as abiotic factors and they are physical or chemical non-living components of the ecosystem. These factors are essential for the survival of living organisms in the given ecosystem. They determine the structure, growth pattern, distribution, and behaviour of the living organism in an ecosystem. These factors include temperature, light, humidity, water, air, land, soil, pH, etc.

Types of Abiotic Factors

There are 3 types of abiotic factors-

• Inorganic compounds-Compounds and elements which are a part of various biogeochemical cycles are the inorganic compounds found in the ecosystem and they are very essential for the biotic components. Nitrogen, phosphorus, carbon, and other elements are examples of inorganic materials.
• Organic compounds- These are the substances that are present in dead and decaying organisms. These include biomolecules like lipids, proteins, and carbohydrates. These organic components are broken down into simpler compounds such as carbon, hydrogen, oxygen, and nitrogen which circulate in the ecosystem and nourish various abiotic factors such as soil, air, water, etc.
• Climatic and soil factors-These variables include the ecosystem’s physical elements, such as temperature, humidity, light, air, and soil. Climate variables are those that affect the weather or climatic condition of the ecosystem, whereas edaphic factors are those that affect the qualities of the soil, such as pH and topography.

For more help, you can Refer to Lesson 9 – Living Things and habitat in Science Class 6th. Checkout the video Lesson for a better understanding

Ecosystems Based on Abiotic Factors

Abiotic elements found in a given habitat can be used to categorize ecosystems.

• Aquatic ecosystem- An ecosystem is said to be aquatic if both its biotic and abiotic components are found in water. Depending upon the salinity of the water, aquatic ecosystems can be of two types- Freshwater ecosystems and Marine ecosystems.
• Terrestrial ecosystem- An ecosystem is referred to as a terrestrial ecosystem if the biotic and abiotic components reside on the land. Depending upon various factors such as availability of water, climatic conditions, and temperature. Terrestrial ecosystems can be of 4 types- Forest, Grassland, Mountain, and Desert ecosystem. 

Responses of Organisms Against Changes in Abiotic Factors

Biotic factors that inhabit a certain habitat react with the abiotic elements present there.  Hence, the abiotic factors become stimuli which results in the display of various effects on different organisms. Below are a few examples 

• Homeostasis-Homeostasis is the process by which the interior environment of organisms is maintained in a steady state, despite various external changes. Organisms can be divided into two categories: 
  • Regulators-These species can use energy to maintain homeostasis. They are active, widely dispersed, and maintain a steady internal body temperature and osmotic concentration. For e.g.- Birds and mammals.
  • Conformers- These species are unable to maintain homeostasis and hence can survive only in specific conditions. For eg- Fish, amphibians, reptiles, etc.
• Migration– Migration is the movement of living creators from one place to another. Such creatures temporarily migrate to a suitable location when there are unfavourable conditions in their native habitat. They return to their former habitat as soon as the environment is normalized. For example-  To avoid the severe winter climate, birds from Siberia travel to India.
• Suspension- When faced with unfavourable circumstances, certain species briefly halt their continuous metabolism i.e they suspend their growth and development for a while. For eg- Spores are formed by fungi and bacteria which can withstand severe conditions. Plants produce seeds that have a thick seed coat and a period of dormancy. While snails and frogs become dormant in the summer, bears hibernate during the colder months.

Summary

Abiotic elements are the nonliving parts of an ecosystem that surround living ones in any habitat. Both aquatic and terrestrial habitats include them. The biotic components are occasionally impacted by changing abiotic variables. To ensure their existence, these biotic components have a variety of strategies to deal with changes in these abiotic conditions.

Frequently Asked Questions

1. What is a Local and Global Ecosystem?
Ans: A local ecosystem consists of different types of habitats along with living organisms. A global ecosystem is a group of many local ecosystems.

2. What is Diapause?
Ans: Diapause is a response given by organisms under unsuitable environmental conditions. It is a spontaneous phenomenon wherein there is an interruption in the developmental stage of an organism due to changes in the abiotic factors. For instance, the monarch butterfly goes through reproductive diapause to get ready for its migration from North America to Mexico between late summer and fall.

3. What are the Abiotic Factors in a Forest Habitat?
Ans: The abiotic factors of forest habitat are-

•  Soil
•  Temperature
• Humidity
• Rocks
• Water

4. Give one Example of a Plant’s Response to Abiotic Factors of the Environment.
Ans: One example of a plant’s reaction to the abiotic component of light is phototropism. In contrast to the root, which grows away from the light source and exhibits negative phototropism, the plant’s shoot grows in the direction of the source of light and shows positive phototropism.