LAB REPORT 4

Lab Report 4

Lab Report 4

Answer 1

Organisms that are used in this way are called 'biological indicators.' An organism that is commonly used to monitor aquatic ecosystems is an algal species called Pseudokirchneriella subcapitata.

Answer 2

There is great concern about the damaging effects of acid precipitation on aquatic and terrestrial ecosystems. Lakes, rivers and forests in the U.S., Canada, and Europe have suffered damage from rain, snow and fog. The acids arise from sulphur and nitrogen oxides in air emissions. Runoff from strip mines also can lead to acidification of waterways. Fish, invertebrates and micro organisms (such as Pseudokirchneriella) are all sensitive to the pH of the water in which they live.

Answer 3

By using Pseudokirchneriella as a bio indicator species in a properly designed experiment, we can assess whether the properties of the water, in general, are deleterious to the growth of this and possibly other aquatic organisms. By determining the effects on the growth of Pseudokirchneriella in different water samples we can monitor changes in the water quality over time, and this is the objective of this exercise. Data that you collect this year will be combined with that collected in past and future years as an assessment of the quality of water.

Answer 4

Phosphorus has a complicated story. Pure, "elemental" phosphorus (P) is rare. In nature, phosphorus usually exists as part of a phosphate molecule (PO4). Phosphorus in aquatic systems occurs as organic phosphate and inorganic phosphate. Organic phosphate consists of a phosphate molecule associated with a carbon-based molecule, as in plant or animal tissue. Phosphate that is not associated with organic material is inorganic. Inorganic phosphorus is the form required by plants. Animals can use either organic or inorganic phosphate.

Both organic and inorganic phosphorus can either be dissolved in the water or suspended

Phosphorus cycles through the environment, changing form ...