PASCO ME-6937 User Manual

®

Instruction Manual

Rack

Bottles

Lid

25%

50%

75%

100%

0%

Latch

012-10941A

Aquatic Productivity Bottles

ME-6937

Introduction

The ME-6937 Aquatic Productivity Bottles rest in a rack
that provides consistent and reliable light control for
quantitative aquatic productivity studies. Students fill
the bottles with algae solution or pond water and then
measure the dissolved oxygen concentration in the solu­tions before and after incubation in fluorescent light. By
comparing the dissolved oxygen concentrations in each
solution, students learn about the relationship between
light intensity, dissolved oxygen concentration, photo­synthetic activity, and the primary productivity of
aquatic ecosystems.

• The identical transparent bottles nest in each of
five rack positions.

• The custom design of the rack shields the bottles
from light by blocking a fixed percentage of light
in 25% increments from zero to 100%.

Sensor Model

PASPORT Dissolved Oxygen Sensor PS-2108

Dissolved Oxygen Sensor CI-6542

Option Model

PASPORT Water Quality Sensor PS-2169

The PASPORT Water Quality Sensor measures tempera­ture, pH, dissolved oxygen, and conductivity. It also
supports Ion Selective Electrodes (ISE) and the Oxygen
Reduction Potential Electrode (ORP). It is designed for
a wide range of water studies.

The PASPORT Dissolved Oxygen Sensor and Water
Quality Sensor work with a PASPORT interface such as
the ones listed below.

PASPORT Interface Model

Xplorer GLX PS-2002

Xplorer PS-2000

PowerLink PS-2001

USB Link PS-2100

SPARK Science Learning System PS-2008

SPARKlink PS-2009

800-772-8700 www.pasco.com

Model No. ME-6937 Sample Activity

An option is to use the PS-2169
Water Quality Sensor with its
Dissolved Oxygen Probe.

The CI-6542 Dissolved Oxygen Sensor works with a ScienceWorkshop interface.

ScienceWorkshop Interface Model

ScienceWorkshop 750 CI-7650

ScienceWorkshop 500 CI-6400

See the PASCO catalog or the PASCO web site at www.pasco.com

for more information about PASCO sensors and interfaces.

Sample Activity

Measuring the Effects of Light Intensity on the Dissolved Oxygen Concentration
and Primary Productivity of an Algae Solution

Teacher Preparation

Materials: algae solution or pond water, test tube rack, sterile disposable pipet, large sterile container (9 L), Alga-Gro® concen-
trate, Aquatic Productivity Bottles, wax pencil, sticker or marker, fluorescent light source

• Prepare algae culture (for 8 groups): Each group will need at least 1500 mL of algae culture. If you buy your

algae from a biological supply company, immediately remove it from the container when it arrives. Remove
the test tube from the container, place it in a test tube rack, and remove the cap. Use a disposable pipet to squirt
air bubbles into the test tube and then place the algae in a cool place with indirect light until ready to culture.

• When you are ready to make the culture, obtain a large, sterile container (at least 9 L). Mix all of the algae with

8 L of distilled water and 160 mL of Alga-Gro

®

concentrate. Stir to mix. Place the algae in a cool place in
direct light until ready to use. If you are making culture for a different number of groups, use 20 mL of
Alga-Gro

®

per liter of water and test tube of algae.

• To prevent students from mixing up their bottles of algae after incubation, they should label the bottom of the
bottles. To save time, you can label the bottles prior to the lab. With a wax pencil, sticker or marker, write the
percentages of light on the bottom of each bottle (e.g., 0%, 25%, 50%, 75%, 100%).

• Set up a light source for incubation of the Aquatic Productivity Bottles: Place the bottles far enough from the
light source that they will not be heated. To ensure this, place your hand where you want the bottles to sit. You
should not feel any warmth from the light. Another option is to create a heat sink by placing a large, clear ves­sel of water between the light source and the bottles.

• If you do not have access to an algae culture, you can use local pond water. In this case, no culturing is neces­sary. Dissolved oxygen data will vary greatly depending upon the algae source. Pond water may have a higher
level of heterotrophic and decomposing organisms than pure algae culture. These organisms consume oxygen
through respiration and can affect your results

Day One

Materials: algae culture, Dissolved Oxygen Sensor and PASCO Interface, wash bottle, Aquatic Productivity Bottles and rack, fluo­rescent light, wax pencil, sticker or marker, paper towels

1. Start a new experiment on the data collection system.

2. Connect a dissolved oxygen (DO) sensor to the data collection system.

3. Display Dissolved Oxygen (mg/L) in a digits display.

4. Obtain approximately 1500 mL of algae culture.

2