Tutor profile: Jaidene W.
Briefly explain how Colored Dissolved Organic Material (CDOM) affect the environment.
Colored dissolved organic material, also known as chromophoric dissolved organic matter is the dissolved organic component of water that is optically measurable. It is found naturally in marine and freshwater systems mainly due to the breakdown of detritus resulting in tannins. Pure water or non-turbid water - water that contains little or no CDOM - appear blue as it can absorb red light. However, water that contains CDOM will appear green to brown depending on the amount of it present in the water body. CDOMs affect biological activity in aquatic systems as it diminishes the amount of light that can penetrate the water which will limit the rate of photosynthesis and phytoplankton growth. Photosynthetic plants and phytoplankton form the basis of any food chain and are also a source of oxygen. However, CDOMs can also absorb harmful rays of radiation which can protect organisms from DNA damage. Although this is positive, absorption of UV rays may cause CDOMs to photodegrade forming low molecular weight organic compounds. These compounds may be used by microbes and reactive oxygen species which may result in damaged tissues and alter the availability of trace metals.
Subject: Basic Chemistry
What are the forces of attraction?
The forces of attraction are those forces that exist within or between molecules. Forces that exist within molecules are known as intramolecular forces while forces that exist between molecules are known as intermolecular forces. Intramolecular forces are stronger than intermolecular forces and are as a result of chemical bonding. Intermolecular forces are as a result of the attraction between molecules. Intramolecular bonds include covalent, ionic and metallic bonding while intermolecular bonds include hydrogen bonding, Van der Waals forces and dipole bonds.
What is environmental tolerance?
All organisms on Earth have a range of environmental conditions (e.g. temperature) where they can successfully survive, grow and continue their species. This range is known as the environmental tolerance of a species and is specific to each species. Many factors affect the range of environmental conditions that an organism can thrive in such as their physiological, morphological and behavioral adaptations. For instance, cacti have a very thick waxy cuticle to help retain water in environments where water is limited and as such are able to tolerate drier conditions more than a normal flowering plant.