Download Eutrophication - IISME Community Site

Vocabulary:

Eutrophication: is a natural process;
where lakes, as they age, build up
nutrients which cause phytoplankton to
grow.

Phytoplankton: Microscopic free-floating
aquatic photosynthetic organisms such
as algae and cyanobacteria.
Vocabulary:

Nutrients: two of the most important
nutrients that algae use: Nitrogen in the
form of Ammonia (NH4+/NH3,) Nitrite
(NO2-), Nitrate (NO3-), and
Phosphorus. (PO4-3).
Vocabulary:

Cultural Eutrophication: refers to the
addition of nutrients from human activities.

The most common ways that humans
directly or indirectly affect eutrophication
are through: waste water/sewer effluent,
drinking water treatment, fertilizer run-off,
farm animal waste, industrial discharge,
and the paving of land with concrete.
Vocabulary:

Oligotrophic with low levels of nutrients
and phytoplankton (Lake Tahoe),
Mesotrophic with rising levels of
phytoplankton and nutrients (Lake
Berryessa),

Eutrophic or Hypertrophic with very high
levels of phytoplankton and nutrients,
murky appearance, where many species
can not survive (Tai Hu in China).
Vocabulary:
Ways to measure eutrophication:
 Dissolved Oxygen is the measure of
oxygen in the water, which is necessary
for most aquatic life. Algal blooms lead
to a decrease in total dissolved oxygen
by causing explosion in bacteria that
decompose the decaying organic
materials, which deplete oxygen levels
below the surface.

Vocabulary:

Ways to measure eutrophication:
Dissolved Oxygen is the measure of
oxygen in the water, which is necessary
for most aquatic life. Algal blooms lead
to a decrease in total dissolved oxygen
by causing explosion in bacteria that
decompose the decaying organic
materials, which deplete oxygen levels
below the surface.
Vocabulary:


Another way to measure eutrophication
is by measuring light attenuation, which
is basically how much light is blocked by
the algae. In extreme algal blooms, the
algae blocks light from penetrating the
first few feet of water, causing deaths
and oxygen dead zones.
Our Experiments:

In this two week-long lesson you will
study the effects of different variables,
representing effects of human activities,
on algal growth in water bottles
Our Experiments:

You will chose a variable that you would
like to test, and add it to a bottle filled
with distilled water and algae. We will
also compare your results to a negative
control (distilled water + algae), and
several positive controls (distilled water
+ nitrogen + phosphorus+
algae). These bottles will be placed
under grow lights for 14 (or more) days.
Our Experiments:
The possible variables that you can choose
from include:
 - Plant food (organic fertilizer, inorganic
plant food, worm tea)
 - Organic waste (grass clippings, fish food,
compost, sugar)
 - Things that alter water chemistry, pH or
salinity

Our Experiments:

We will be measuring algal growth using a
machine called a spectrophotometer, which
basically measure how much light (at a
specific wavelength) is able to pass
through a small glass vial. The less light
that can pass through (transparency) the
more algae growth.

Finally, you will present your data, and
discuss your results as part of a
presentation in front of the class.