523019.edited.docx - Surname 1 Student’s Name Professor’s...

Surname 1
Student’s Name
Professor’s Name
Course
Date
Eutrophication to Hypoxia
Overview
Eutrophication describes the gradual increase in chemical concentration into an aquatic
ecosystem, leading to the uncontrolled growth of algae and the subsequent loss of habitat for fish
and other large creatures inside the water. The primary cause of eutrophication is the large
volumes of organic matter that are supplied into the ecosystem due to human activities. There is
a host of physical, chemical, and biological changes that occur as a result of the increased supply
of organic matter into the aquatic ecosystems.
The initial change is the concentration of nitrogen in the soil. Most of the chemicals
introduced to the ecosystem contain nitrogen, and their introduction is called nitrogen loading.
Under normal circumstances, the growth of plants is regulated by the balanced concentrations of
nitrogen in the soil. However, nitrogen loading disrupts the limited availability of nitrogen in the
soil, and the resulting increase in the soil's nitrogen levels results in an increase in plant growth.
When the nitrogen concentration of the water body rises, there may result in an expansion
in the growth of aggressive aquatic plant species that are already present in the aquatic
ecosystem. Eventually, the aquatic ecosystem becomes saturated with the blooming plant species
and over a wide area. In most cases, the enriching of the aquatic ecosystems with nitrogen
favors the growth of algae around estuaries and coastal waters.

Surname 2
The accumulation of algae does not readily affect the aquatic environment until they die
and decompose. The excess algae and plant matter, upon dying, settles at the bottom of the water
body floor. Their decomposition sets room for a biological harmful process called hypoxia.
Hypoxia is the absence of oxygen used up by aerobic bacteria that act on the decomposing algae
matter.
Eutrophication occurs as a chain process, involving nitrogen loading, algal bloom,
microbial activity, cellular respiration, and hypoxia. Understanding the entire process requires a
basic understanding of the hydrology of the watershed.
Watershed hydrology
A watershed generally describes a catchment area or a tract of land from which various
small sources of the water drain off into a single basin or water body. Water from watershed will
flow and accumulate in a single area- the end of this flow could be a basin, larger stream, lake, or
ocean. Watersheds have their water sources from the headwaters. The headwaters reference the
starting point of a watershed or uplands from where the waters of the watershed seem to be
originating from. They could be the highest points marking the start of the watershed. Then there
is the mouth of a watershed that references the area towards the end of this watershed through
which it feeds another larger stream or river.