Tag: ecosystem

Deep lakes at mid-latitudes have well-pronounced stratification which leads to the lakes experiencing wealthy internal waves dynamics. These lakes also possess seasonal water mixing during the spring and autumn transitional periods. This is due to the non-linear thermal expansion of water when its temperature reaches 4$^0$C and the density of water is maximum.  Further, with the increasing latitudes support the general cyclonic water circulation. Hence the large lakes along mid-latitudes show a large variety of these physical processes.

A Freshwater ecosystem is one of  the aquatic ecosystems of the earth and includes lakes, ponds, rivers, streams and wetlands. This ecosystem is essential as it not only provides human beings their drinking water, but these are also home to more than 40 percent of the world's fish species. The seasonal changes occur in the freshwater ecosystem with regards to temperature-density relationship and since it contains continuous running water so materials are recycled more quickly than in ocean ecosystems.

Robert Constanga et al have tried to put price tags on natures life support services. He gave price tags to the ecosystem services. Out of these services, 50% accounts for the soil formation. The ecosystem services he put price on includes purify water and air, mitigate droughts and floods, nutrient cycling, habitat for wild life.

Chlorophyll is the pigment responsible for photosynthesis. The light active in photosynthesis is a small part in the visible spectrum (400- 700 nm). The chlorophyll pigments mainly absorb blue and red light. Maximum absorption is in blue light but maximum photosynthesis occurs in red light.

Photosynthetically active radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. Sunlight comprises all effective lights PAR (photosynthetically active radiations) as required for photosynthesis. Thus, option A is correct.

• Around 50% of the total radiation from sunlight falls under photosynthetically active radiation and supports the process of photosynthesis. It constitutes the light of 400-700 nm wavelength which is absorbed by chlorophyll pigment. Out of which only 2 - 10% are captured by plants. Thus, the correct answer is option B.

Source of energy in an ecosystem is solar energy. 50 per cent of the solar energy incident over Earth is present in PAR (photosynthetically active radiation). Almost 1 to 5 percent of incident solar energy or 2 to 10 percent of PAR is captured by photosynthetic organisms in synthesis of organic matter. 

Sunlight is like a rain of photons of different frequencies. Visible light consists of radiations having a wavelength of 390-760 nm. Part of spectrum used in photosynthesis has a wavelength of 400-700 nm. It is called photosynthetically active radiation (PAR). The proportion of PAR of the total solar radiation is less than 50%. Only 2-10% of PAR is captured by the plants.

• Ultraviolet rays: UV rays have a wavelength of 0.01 - 10 nm. These rays can have adverse effects like sunburn, skin cancer if exposure occurs for a long period of time.
• Visible light: Visible spectrum lies in the range of wavelength 400 - 700 nm. These rays are perceived by human eyes. A part of the visible spectrum is used by plants for photosynthesis.
• Infrared rays: These rays have a wavelength beyond the visible spectrum. Most of the radiation emitted from the sun is in the form of infrared radiation.

Photosynthesis is the process by which light energy is converted to chemical energy. In plants, light is absorbed by pigments such as chlorophyll. Light hits these molecules and raises them to a higher energy. Light, however, occurs in a spectrum of wavelengths ranging from ultraviolet to visible light to infrared. The energy accompanying the absorption of light is dependent on the wavelength of the light. The amount of energy absorbed during the processes of photosynthesis depends on the wavelength of light absorbed. For processes requiring more energy, pigment molecules must be able to absorb the necessary wavelengths. 680 nm wavelength is absorbed maximum for photosynthesis because, 680 nm will be utilized by both the pigment systems.