Water Sampling Instructions

Joined: 23 Mar 2004 Posts: 84

Water Sampling

We have been taking water samples everyday from the shores of the Lena River to learn more about the water and how its chemistry changes during the ice breakup period when river discharge increases from low winter levels to the highest discharge of the year.

The chemistry of the water will give scientists information about where the water came from (precipitation or groundwater) and also about biogeochemical processes occurring in the Lena River watershed (a watershed is the area of land that catches rain and snow and drains into specific streams, rivers, or lakes). The physical characteristics of a watershed – including its slope, geology, and vegetation will affect the patterns, amount, and chemistry of the water that flows through the system. By carefully analyzing the samples that we take from the Lena River, scientists will find out all sorts of things about the Lena River watershed and they will be able to trace the Lena River water after it enters the Arctic Ocean. And by doing a few tests of your own, you too can learn more about the water in your watershed.

Nitrate and Phosphate - Plants need nitrogen and phosphorus to grow, and they often get if from nitrate (a molecule made up of nitrogen and oxygen) and phosphate (a molecule made up of phosphorus and oxygen). Humans also use nitrate and phosphate to fertilize their crops, gardens, and lawns, and produce them as waste products. If too much pf these nutrients gets into riverss or lake or the ocean, they can cause big problems. They can basically cause the ecosystem to get out of balance due to increased plant growth. Then when the plants die, it takes oxygen to break them down which can cause the oxygen levels in the water to get very low. When this happens, fish and other aquatic organisms can die.

Dissolved Oxygen-Organisms that live in the water need oxygen to live—but how do they get it underwater? They get it from oxygen that is dissolved in the water. Some freshwater organisms need high levels of dissolved oxygen, while others can handle a wide range of dissolved oxygen levels. The amount of dissolved oxygen in the water depends on things such as temperature, wind and current speed, as well as on the amount of photosynthesis (which produces oxygen) and respiration (which consumes oxygen) that has occurred in the water.

Air and Water Temperature - Water temperature affects many aspects of aquatic ecosystems, including the rates of photosynthesis and respiration, how fast many aquatic plants and animals grow, and the ability of oxygen to stay dissolved in water (cold water can hold more oxygen that warmer water). Air temperature is important because it directly impacts the temperature of the water.

pH - This will measure whether the water is acidic, basic, or neutral. Different organisms have adapted to life in water with specific pH, so if the pH changes, they might not survive. Changes in the pH of lakes and rivers are often a result of human activities.

Current Speed - You can measure the current speed by placing a meter stick or string next to the river and then use something that floats to see how far the thing floats in one second. Fast-flowing water tends to be cool and well oxygenated, and thus better able to support more kinds of life.

*** Some of these activities were modified from the Jason XIII Curriculum

Joined: 23 Mar 2004 Posts: 84

Here is a blank Data Sheet for Water Sampling:

Water Data Sheet

1. Date of Test:

2. Time of Test:

3. Name of aquatic site or description of where it is located:

4. Latitude_______ Longitude___________

5. Type of water: _____lake _____river _____other (explain)

6. Color of the water:

_____clear

_____tea-colored

_____oily

_____cloudy

_____muddy

_____black

_____foamy

_____rusty

_____green

_____gray

_____brown

7. Classify your site:

_____rural

_____suburban

_____urban

_____nature preserve

_____other (explain)

8. What is within 10 meters of the water’s edge?

_____concrete

_____soil

_____trees

_____rocks

_____other vegetation

_____other (explain)

9. What land uses do you see around the study area?

_____roads

_____mining

_____forests

_____discharge pipes

_____industry

_____houses

_____recreation area

_____businesses

_____schools

_____farms

_____landfills

How would any of the land uses that you checked above impact the watershed?

10. What kinds of plants/trees do you see around the site? Describe them.

11. Weather Observations:

Air Temperature:_____

Water Temperature:_____

Sky Conditions (circle): clear partly cloudy cloudy

Description, type, or drawing of any clouds present:

Current Precipitation: ____none type_________________________

Precipitation within the past 24 hours: _____none type____________________

Wind speed (circle): calm, gentle breeze, moderate breeze, strong breeze, gale, storm, hurricane.

12. pH circle one 1 2 3 4 5 6 7 8 9 10 11 12 13 14

13. Current Speed:_____cm/sec

14. Dissolved Oxygen-O_2 (use tablets)

15. Phosphate (use tablets)

16. Nitrate (use tablets)