Salt Water Marshes Journal- A firstime field work experience

The below is a description of a student's experience taking data at a salt marsh located on cape cod. Working with WHOI, their data was utilized to survey and document changes in the environment of the salt marsh. Salt marshes act as carbon sinks and have great capabilities to store carbon dioxide and other greenhouse gasses, however a surplus of such gasses may lead to ecosystem instability. Through testing such as the below detailed scientists gain a better understanding of the state of salt marshes and thus the overall wellbeing of our marine ecosystems.

We arrived at the marshes at around 9:15 AM on the 26th of June. The air was sticky and humid although it wasn’t sunny out. In silence we trekked through the long grass towards the shallow creek snaking through the terrain. 

My group of four was assigned to a mud bank bordering the right fork of the creek. We took data on two locations near this location; a spot in the creek near a raised sandbank(41.575621, -70.640083) and the edge of a mud pond(41.575489, -70.639954). We started with testing the temperature and pH of both locations(documented below) utilizing a thermometer and a digital pH meter. 

Next we tested for nitrates and ammonia using the below procedure and testing kits.

Nitrate:

1. Fill a clean test tube with 5ml of sample water

2. Add 10 drops of nitrate solution #1

3. Shake thoroughly

4. Add 10 drops of nitrate solution #2 

5. Shake thoroughly

6. Wait for 5 minutes before matching sample water color with nitrate indicator strip

Ammonia:

1. Fill a clean test tube with 5ml of sample water

2. Add 8 drops of ammonia solution #1 and 8 drops of ammonia solution #2 

3. Shake thoroughly

4. Wait for 5 minutes before matching sample water color with ammonia indicator strip

We also tested for dissolved oxygen content in the water(an indicator of acidity) using the below methodology.

1. Rinse dissolved oxygen bottle three times before fully submerging under water and capping under water. Ensure that there are no air bubbles

2. Uncap bottle and add 8 drops each of manganous sulfate solution and alkaline potassium iodide azide

3. Cap and mix by inverting the bottle several times. Allow debris to settle at the bottom

4. Add 8 drops of sulfuric acid

5. Cap and gently shake dissolved oxygen bottle

6. Fill the test tube with 20 ml of solution from dissolved oxygen bottle

7. Insert titrator into Sodium Thiosulfate

8. Extract 10 ml with no air bubbles

9. Insert full titrator into hole in the cap of test tube 

10. Titrate until liquid is clear

11. Add 8 drops of Starch Indicator solution

12. Repeat step 10

13. Record the number shown by the titrator(represents oxygen ppt)