Factors Correlating to Water Quality Testing Data
ABIOTIC FACTORS (nonliving)
Dissolved Oxygen
Dissolved oxygen is the amount of oxygen dissolved in water and is required for gilled organisms to "breathe" under water; measured in PPM or parts per million; dissolved oxygen comes from either an oxygen transfer from the atmosphere into the water through a process called aeration, or oxygen is added to water by plants by photosynthesis. The higher the temperature, the less the DO. DO is at its peak right before the sun goes down, after the highest levels of light when photosynthesis in plants is producing the most oxygen. DO levels below those needed may harm the animal by reducing its ability to reproduce, feed or survive.
Metals (Mercury, Iron, Iodine, Copper, Magnesium, Lead)
Elemental metals in water affect productivity and produce carcinogens (cancer causing materials) and toxins and affect the growth of plants and animals.
Nutrients (Nitrate, Nitrite, Phosphate, Sulfate, Carbonate)
Nutrients are required by all plants and animals for healthy growth and affect the population growth of aquatic plants and phytoplankton. Excess nutrients coming from leaky sewers, developed areas, septic systems, and fertilizers may cause algal blooms (an exponential growth of algae or phytoplankton due to excess nutrients), reductions in estuarine oxygen levels and fish kills. In the ocean, red tide (dinoflagellates) may be caused by temperature, excess nutrients and food availability. Natural buildups of nutrients commonly lead to the periodic occurrence of these events. However, the presence of increased amounts of nutrients introduced by humans can cause these natural events to occur more frequently and with greater intensity.
pH
Negative log of the hydronium ion concentration; relates to acid or base; a pH below 7 is considered acidic with a H+ in abundance; a pH above 7 is considered basic or alkaline with the OH - ion in abundance; a 7 for pH is neutral; the lower the number for acids, the stronger the acid (possible acid problem); the higher the number for bases, the stronger the base (limestone or bleach could be factors); if the pH level changes in the environment beyond the critical limit, organisms may die or fail to reproduce; 8.5 is typical for saltwater, and, in freshwater, pH is lower.
Precipitation (Rain, Snow, Hail, Sleet)
Affects water levels in streams, ponds, lakes, tributaries and estuaries; higher levels may result in additional sediment added to water; more water entering into the ocean decreases salinity at the confluence of the tributary or estuary with the ocean; increases in the flow of water (rise of streams or rivers and bays in ocean environments) affects water temperature, salinity and dissolved which might alter reproduction (i.e., eggs hatching, offspring surviving).
Salinity
Salinity is the weight ratio between dissolved salts and water in seawater; measured in PPT or parts per thousand; the average salinity of seawater is 35 PPT, salinity determines which types of organisms live where; estuaries (places where saltwater and freshwater mix) have estuarine organisms, which are able to tolerate short-term changes in salinity; however, long-term changes can interfere with their biological systems and eventually cause death.
Sediments
Sediments containing rock and soil are mixed into water flowing over land and are carried to the sea by erosion. When the water reaches a river delta, the flow rate slows and the sediments drop out of the water column. In this way, nutrient rich sediments become the basic building materials for our rivers. The construction of dams along rivers keeps sediments from flowing downstream, thereby reducing the total amount that reaches our estuaries. Over time, new sediments no longer replace the sediment that is lost due to natural erosion. The long term result of this erosion can alter the topography of these shallow water areas enough that they are unable to support shallow water organisms.
Shade
Cools water, provides method of protection from predators, affects aquatic plant productivity.
Sunlight
Necessary for photosynthesis, aquatic plant productivity, phytoplankton in oceans, affects water temperature and air temperature.
Temperature (Air)
Cools surface of oceans, creates mixing of oxygen and nutrients in larger bodies of water such as lakes resulting in thermoclines or layering of water by temperature gradients.
Temperature (Water)
Water temperature is important because it regulates many biological, physical and chemical processes. One of the most important of these is the ability of water to hold certain chemicals. Cold water holds more oxygen, for example, than hot water. Promotes an upwelling in ocean water (bringing up nutrients and plankton for food from lower depths); cooler water temperatures increase the amount of dissolved oxygen present in water.
Total Dissolved Solids (TDS)
A measurement by weight of materials dissolved in a measured volume of water (mg/l); usually present as dissolved ions; if abundant in a solution of water, conduction of electrons is impaired; conductivity, which is a measure of current flow, is directly related to TDS.
Total Suspended Solids (TSS)
A measurement by weight of the amount of material suspended in a volume of water; includes zoo plankton, phytoplankton, silt, human sewage, wastes from animal and plants and industry; affects productivity, salinity, dissolved oxygen, pH, temperature, food availability; an overabundance can lead to pollution and toxicity.
Turbidity
High turbidity results from suspended materials such as sediments, chemicals or dense clouds of microscopic plants and animals called plankton. All of these increase turbidity and reduce the amount of light that penetrates the water. High levels can harm plants and animals by decreasing the amount of light available for the growth of algae and seagrasses. High levels can also clog the gills of fish, shellfish and others, killing them by suffocation.
Water Current (Fast Flowing)
Determines bottom substrate of rivers and streams, organisms found there and productivity; in oceans, larger currents dictate movement of water and nutrients resulting in productive areas for fishing and for navigation.
Water Current (Slow Flowing)
Distribution of nutrients, sedimentation, types and numbers of bottom dwelling organisms.
Wind
Produces air currents causing waves and specific wave patterns; large climactical changes can occur over oceans, which in turn affect weather patterns; high wind including hurricanes and tornadoes can affect climate and weather.
