©MathScience Innovation Center Our Backyard Waterways : Eutrophication Presented by: Rachel Martin...

Our Backyard Waterways:Eutrophication

Presented by: Rachel Martin

Day 2

Eutrophication

Nutrients

• Nutrients, like nitrogen and phosphorus, occur naturally in the water, soil & air.

• Just as the nitrogen & phosphorus in fertilizer aids the growth of grass, trees and agricultural crops, both nutrients are vital to the growth of plants in our local waters & beyond.

http://www.chesapeakebay.net/Info/nutr1.cfm

Nitrogen (N)• The most common gas found in the

earth's atmosphere.

• Nitrogen enters the ecosystem in several chemical forms & also occurs in other dissolved or particulate forms, such as animal waste and tissues of living & dead organisms.

http://www.chesapeakebay.net/Info/nutr1.cfm

Phosphorus (P)

• Phosphorus is found in dissolved organic & inorganic forms, often attached to particles of sediment.

• Once attached to sediment, phosphorous can be moved 100s to 1,000s of miles from were it was released by flowing through streams & rivers.

http://www.chesapeakebay.net/Info/nutr1.cfm

Phosphorus (P)

• It is a vital component in the process of converting sunlight into usable energy forms for the production of food and fiber.

• It is also essential to cellular growth and reproduction for organisms such as algae & bacteria.

http://www.chesapeakebay.net/Info/nutr1.cfm

Nutrients• Sources: sewage treatment

plants, industries, vehicle exhaust, acid rain, & runoff from agricultural, municipal, recreational (ex., golf courses), residential and urban areas

www.epa.gov/oppefed1/models/water/drt_april2005.htm

www.chesapeakebay.net/Info/nutr1.cfm

http://www.ens-newswire.com/ens/dec2002/2002-12-09-01.asp www.applegreens.com/photogallery6.htm

How does it work?

• Excess amounts of N & P cause rapid growth of algae (phytoplankton), creating dense populations, or blooms. These blooms become so dense that they reduce the amount of sunlight available to underwater grasses.

• Without light, plants cannot photosynthesize & produce the food they need to survive, eventually killing the grasses.

• Algae may also grow directly on the surface of these grasses.

Large photo: www.mdsg.umd.edu/SAV/

Skeletonema costatum

Inset photo: www.dnr.state.md.us/Bay/cblife/algae/diatom/skeletonema_costatum.html

• Unconsumed algae will ultimately sink & be decomposed by bacteria in a process that depletes the water of oxygen.

• All animals need oxygen to live, so when oxygen levels get low, fish swim away if they can - other aquatic animals that cannot move (ex. oysters) may die if oxygen levels get too low.

Photo: www.gotalgae.com/temperature_solutions.htm

Eutrophication Activity

Pea Soup Ponds

Summary Students will learn how water can be

polluted by algal blooms. They will grow algae with different concentrations of fertilizer or nutrients and analyze their results as environmental engineers working to protect a local water resource.

Engineering Connection

• Goal = to create useable water sources

• Test and monitor water sources• Implementation of pollution control

strategies or water treatment technology

Green Algae: What is it?

• It is a MICROSCOPIC PROTIST!• It is NOT a plant! But evolved from

plants.• Can photosynthesize, have

chloroplasts.• Mostly single celled, some form

colonies.• Many have flagella.

Algal Blooms

• Too many nutrients cause algae to reproduce quickly, causing the lake to turn a greenish color.

• When algae die in large numbers, the BACTERIA will start to DECOMPOSE the dead algae, using up vital oxygen in the water.

• Low oxygen concentrations can cause fish kills and strain on the water treatment facilities.

How will you set up an experiment to test the effect of fertilizer on algal

blooms?

Materials

• Algal culture

• 4 petri dishes

• Lawn fertilizer

• Water