BIOELEMENTS IN FOOD CHAINS By Pamela Yugsi THE
BIO-ELEMENTS IN FOOD CHAINS By Pamela Yugsi
THE CYCLE OF OXYGEN THROUGH AN ECOSYSTEM Atmospheric oxygen is required by all terrestrial and aquatic plants and animals for respiration: the breakdown of organic compounds for carbon and energy necessary to cellular maintenance and growth. Plants and animals then return oxygen back to the atmosphere, soil or water, though there are multiple pathways for oxygen to take, primarily by interacting with other molecules in soil and water. Air, Soil and Water • Earth's atmosphere has an oxygen concentration of 21 percent and the element is rapidly cycled between plants, animals and the atmosphere through photosynthesis and respiration. In water, oxygen moves much slower, so oxygen consumption through respiration often exceeds production through photosynthesis, resulting in daily shifts in dissolved oxygen concentrations. Similarly, oxygen penetration into saturated soil is much slower than in dry soil which leads to different oxygen concentrations in different parts of the soil. This, in turn, influences further oxygen transport. Photosynthesis • In photosynthesis, atmospheric carbon dioxide is converted into glucose inside the leaves of plants. Oxygen is a byproduct of photosynthesis and is released by the plants back into the atmosphere. It can also be released through the root system, providing oxygen to the soil. Submerged aquatic vegetation and phytoplankton release oxygen produced during photosynthesis into the water. Both terrestrial and aquatic plants make oxygen available for respiration by other plants and animals.
After this the oxygen molecule is back released in the atmosphere and again it is inhaled by us. This cycle repeats and carbon and oxygen cycle through the atmosphere.
The above figure is an oxygen cycle which shows the both the processes Respirati on • Respiration is a process in which the O 2 molecule gets inhaled by the animal body. Then it is taken to the Alveolar space inside the lungs. • From there it is taken by the blood capillaries and then the oxygenated blood is circulated throughout the animal body. • After this the Deoxygenated blood / CO 2 rich blood is collected from all the parts of the body and is back transported to the alveolar space via blood capillaries. • After this the CO 2 is exhaled.
NITROGEN IN FOOD CHAINS By Pamela Yugsi
KEY POINTS Nitrogen exists in the atmosphere as N_2 N 2 N, start subscript, 2, end Nitrogen is a key subscript gas. In nitrogen component of the bodies of fixation, bacteria convert living organisms. Nitrogen N_2 N 2 N, start subscript, 2, atoms are found in all end subscript into proteins and {DNA} DNAD, ammonia, a form of N, A. nitrogen usable by plants. When animals eat the plants, they acquire usable nitrogen compounds. Nitrogen is a common limiting nutrient in nature, and agriculture. A limiting nutrient is the nutrient that's in shortest supply and limits growth. When fertilizers containing nitrogen and phosphorous are carried in runoff to lakes and rivers, they can result in blooms of algae this is called eutrophication
INTRODUCTION Nitrogen is everywhere! In fact, text N_2 N 2 N, start subscript, 2, end subscript gas makes up about 78% of Earth's atmosphere by volume, far surpassing the O 2 O 2 O, start subscript, 2, end subscript we often think of as "air". ^11 start superscript, 1, end superscript But having nitrogen around and being able to make use of it are two different things. Your body, and the bodies of other plants and animals, have no good way to convert N_2 N 2 N, start subscript, 2, end subscript into a usable form. We animals and our plant compatriots just don't have the right enzymes to capture, or fix, atmospheric nitrogen. Still, your {DNA} DNAD, N, A and proteins contain quite a bit of nitrogen. Where does that nitrogen come from? In the natural world, it comes from bacteria!
Bacteria play a key role in the nitrogen cycle. Nitrogen enters the living world by way of bacteria and other single-celled prokaryotes Some species of nitrogen-fixing bacteria are free-living in soil or water, while others are beneficial symbionts that live inside of plants. Nitrogen-fixing microorganisms capture atmospheric nitrogen The nitrogen-containing molecules are passed to animals when the plants are eaten. They may be incorporated into the animal's body or broken down and excreted as waste, such as the urea found in urine.
NITROGEN CYCLING IN MARINE ECOSYSTEMS So far, we’ve focused on the natural nitrogen cycle as it occurs in terrestrial ecosystems. However, generally similar steps occur in the marine nitrogen cycle. There, the ammonification, nitrification, and denitrification processes are performed by marine bacteria and archaea.
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