Maryland Department of Natural Resources Bay Grasses in Classes
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Expected Results for the Wild Celery Experiment
This experiment is designed to demonstrate the influence of light time on the growth rate of Wild Celery (Vallisneria americana). Chamber A will be on a 24 hour light time, and chamber B will have either a 12 or 16 hour light time. Both growth chambers (black tubs) are identically setup except for the light time

a line graph showing the increasing growth rate and the increasing light time

Expected Results
Plant Height:
Photoperiod is the number of hours per day that the sun is up. The amount of light that is available to bay grasses will determine how quickly they will grow. As the light time (photo period) decreases, growth rates will decrease.

Maximum Wild Celery growth rates typically occur in when there is a long photoperiod and the temperatures are high. While there are no areas of the Bay where the photo period is 24 hours, this experiment will demonstrate how longer photo period will result in faster growth rates.

a line graph showing the effects of light time on wild celery (plant height)Photo-period is a cue for Wild Celery to begin preparing for the winter. In early September, Wild Celery will begin producing over-wintering structures (tubers) and seed pods. As available light continues to decrease, the long leaf blades and roots will decompose. By late November, only the seeds and tubers will remain. When light time increases and water temperatures increase in spring, the remaining seeds and tubers will produce another bed of Wild Celery.

pH: The pH scale is a measure of the acid-base balance of water, with a pH of <7 representing Ďacidicí solutions, and pH of >7 representing Ďbasicí solutions. Pure water would be perfectly neutral (pH of 7), but water naturally contains a certain amount of dissolved substances that act either as acids or as bases. If the water contains more acids (H+) than bases, it is said to be acidic; if it contains more bases (OH-) than acids, it is basic or alkaline. If acids and bases are present in equal amounts, the water is said to be chemically neutral.

a line graph showing the effects of light time on wild celery (pH)When CO2 is in short supply, many aquatic plants (including Vallisneria species and some algae) take CO2 from the hardening constituents of the water (CO3 and HCO3). When this happens, more OH-1 molecules are generated, increasing the pH of the water. So as more and more OH-1 molecules are generated by the shortage of CO2 and the production of more oxygen, the pH in the growth chambers will increase over time. Because the Wild Celery in the 24 hour tank chamber will have a longer photoperiod than the Wild Celery at 12 or 16 hours, pHís may be slightly higher in the 24 hour tank.

This increase in pH also occurs in the Chesapeake Bay as the water temperature warms and the amount of lights increases. During the summer months, large amounts of algae can grow in the water column changing the water color to a green or dark brown color driving up the pH to 10! In some areas of the Bay that have dense bay grass beds, pH levels can also get above 10. Thatís a lot of OH-1's!

pH values above 10 have been shown in lab tests to decrease photosynthesis of wild celery, which in turn decreases itís growth rate. When the pH values are acidic (below 7) a lot of OH-1 is in water, and the CO2 (carbon dioxide) that plants need for photosynthesis turns into CO3, which plants canít use. The plants have a harder time "breathing," and as a result they grow more slowly. Causes of low pH can be the result of acid rain (local rain pH is about 5) and the poor buffering capacity of the land due to variations in geology. Wild Celery can be found in pHís ranging from 6 to 10 with a preferred pH around 8.

Nitrates: Nitrogen is one of the most important plant nutrients (along with phosphorus). With the help of bacteria, nitrogen goes through a cycle of chemical changes as it is absorbed, used and then restored to a form which it can again be used. Most plants absorb nitrogen from the sediment or water column in the form of nitrate (NO3-) or ammonium (NH4+). Other common forms of nitrogen (nitrite (NO2), ammonia (NH3), etc) arenít available to plants, and can even be toxic at high levels.

a line graph showing the effects of light time on wild celery (nitrate)Wild celery and algae primarily use nitrogen as nitrate (NO3) and ammonium (NH4+), and can obtain these molecules from both the sediment mixture in your growth chamber and the water itself. Any excess nitrate (and phosphate) in the water will contribute to increased algal growth. Since the sediment mixture contains a large amount of nitrogen from the topsoil, it is common to see an initial increase in the nitrate levels prior to the growth of the Wild Celery and algae. As the Wild Celery and algae increase over time and consume the available nitrate and ammonium, concentrations in the water will decline. Slight variations in nitrate concentrations may occur between growth chambers as a result of the varying growth rates of the Wild Celery and algae. The24 hour tank with the fastest growing plants may remove nitrate at a faster rate than the 12 or 16 hour tank.

In the Chesapeake Bay, areas with excess nutrients typically have large concentrations of short lived microscopic plants called phytoplankton (algae). Large concentrations of phytoplankton (algal blooms) can color the water green or brown and greatly reduce or eliminate the amount of light available for bay grasses. In addition, since algae are also plants, they produce oxygen during the day and consume it at night. A large algal bloom can remove so much oxygen in an area at night that it may kill any fish and crabs present! When phytoplankton die, they decompose (consuming oxygen) and release a large amount of nutrients back into the water which can fuel more algal blooms.

Wild Celery (and other bay grasses) are important because they consume nutrients as they grow and only slowly release them back into the water column late in the year when the water temperature has cooled below the preferred temperature of the phytoplankton

Expected Results of Wild Celery Temperature Experiments
This experiment is designed to test the influence of water temperature on the growth rate of Wild Celery (Vallisneria americana). The water temperature in growth chamber A will be set at 24C (75F) while growth chamber B will be set at 29C(84F) or 33C(92F). Both growth chambers (black tubs) are identically setup except for the water temperature

a bell curve graph showing increasing temperature and increasing growth rate

Expected Results
Plant Height:
All bay grasses have an optimal temperature range which maximizes growth. As temperatures deviate from this optimal range, growth rates decrease.

Maximum Wild Celery growth rates typically occur between 27C(80F) and 35C(95F). As temperatures are increased above ~35C(~95F) or below 27C(80F), growth rates will decline until the plants eventually die. In the Chesapeake Bay, these conditions maybe found in the summer in very shallow, poorly flushed areas.

a line graph showing the effects of water temperature on wild celery (plant height)As temperatures decrease below 27C(80F), growth rates will decline. A decline in water temperature is a cue for Wild Celery to begin preparing for the winter. In early September, Wild Celery will begin producing over-wintering structures (tubers) and seed pods. As temperatures continue to decrease, the leaves and roots will decompose. By late November, only the seeds and tubers will remain. When water temperatures increase the next Spring, the remaining seeds and tubers will produce another bed of Wild Celery.

pH: The pH scale is a measure of the acid-base balance of water, with a pH of <7 representing Ďacidicí solutions, and pH of >7 representing Ďbasicí solutions. Pure water would be perfectly neutral (pH of 7), but water naturally contains a certain amount of dissolved substances that act either as acids or as bases. If the water contains more acids (H+) than bases, it is said to be acidic; if it contains more bases (OH-) than acids, it is basic or alkaline. If acids and bases are present in equal amounts, the water is said to be chemically neutral.

When CO2 is in short supply, many aquatic plants (including Vallisneria species and some algae) take CO2 from the hardening constituents of the water (CO3 and HCO3). When this happens, more OH-1 molecules are generated, increasing the pH of the water. So as more and more OH-1 molecules are generated by the shortage of CO2 and the production of more oxygen, the pH in the growth chambers will increase over time. Because the Wild Celery in the 92F growth chamber will be growing slightly faster than the Wild Celery at 75F, pHís may be slightly higher in the warmer tank.

This increase in pH also occurs in the Chesapeake Bay as the water temperature warms and the amount of bay grasses and algae increase. During the summer months, large amounts of algae can grow in the water column changing the water color to a green or dark brown color driving up the pH to 10! In some areas of the Bay that have dense bay grass beds, pH levels can also get above 10. Thatís a lot of OH-1's!

pH values above 10 have been shown in lab tests to decrease photosynthesis of wild celery, which in turn decreases itís growth rate. When the pH values are acidic (below 7) a lot of OH-1 is in water, and the CO2 (carbon dioxide) that plants need for photosynthesis turns into CO3, which plants canít use. The plants have a harder time "breathing," and as a result they grow more slowly. Causes of low pH can be the result of acid rain (local rain pH is about 5) and the poor buffering capacity of the land due to variations in geology. Wild Celery can be found in pHís ranging from 6 to 10 with a preferred pH around 8.

Nitrates: Nitrogen is one of the most important plant nutrients (along with phosphorus). With the help of bacteria, nitrogen goes through a cycle of chemical changes as it is absorbed, used and then restored to a form which it can again be used. Most plants absorb nitrogen from the sediment or water column in the form of nitrate (NO3-) or ammonium (NH4+). Other common forms of nitrogen (nitrite (NO2), ammonia (NH3), etc) arenít available to plants, and can even be toxic at high levels.

Wild celery and algae primarily use nitrogen as nitrate (NO3) and ammonium (NH4+), and can obtain these molecules from both the sediment mixture in your growth chamber and the water itself. Any excess nitrate (and phosphate) in the water will contribute to increased algal growth. Since the sediment mixture contains a large amount of nitrogen from the topsoil, it is common to see an initial increase in the nitrate levels prior to the growth of the Wild Celery and algae. As the Wild Celery and algae increase over time and consume the available nitrate and ammonium, concentrations in the water will decline. Slight variations in nitrate concentrations may occur between growth chambers as a result of the varying growth rates of the Wild Celery and algae. The warmer tank with the fastest growing plants may remove nitrate at a faster rate than the cooler tank.

In the Chesapeake Bay, areas with excess nutrients typically have large concentrations of short lived microscopic plants called phytoplankton (algae). Large concentrations of phytoplankton (algal blooms) can color the water green or brown and greatly reduce or eliminate the amount of light available for bay grasses. In addition, since algae are also plants, they produce oxygen during the day and consume it at night. A large algal bloom can remove so much oxygen in an area at night that it may kill any fish and crabs present! When phytoplankton die, they decompose (consuming oxygen) and release a large amount of nutrients back into the water which can fuel more algal blooms.

Wild Celery (and other bay grasses) are important because they consume nutrients as they grow and only slowly release them back into the water column late in the year when the water temperature has cooled below the preferred temperature of the phytoplankton.

Expected Results of Wild Celery Sediment Experiments
This experiment is designed to demonstrate the influence of sediment type on the growth rate of Wild Celery (Vallisneria americana). The sediment in chamber A will have a mixture of 75% soil and 25% sand and Chamber B will have a mixture of 25% soil and 75% sand. Both growth chambers (black tubs) are identically setup except for the sediment type.

a line graph showing the increasing soil percentage and the increasing growth rate

Expected Results
Plant Height:
Wild celery can grow in many different sediment types, but there is an optimum ratio for soil to sand that will allow maximum growth while still allowing us to successfully transplant the grasses. Wild celery needs a good substrate to keep the root system in place does not grow well in soft, shifting sediments, although it can grow in soil. Mixing sand and soil will create a firm substrate that can be transplanted easily.

The sediment not only acts as a medium for the root systems to attach, but as a source of nutrients. In addition to light, plants require nutrients from the water and the substrate. The amount of organic materials such as nitrogen and phosphorous in the sand/soil mixture is important for plant growth. The plants will grow slowly if there is not enough organic material.

a line graph showing the effects of sediment on wild celery (plant height)In the Chesapeake Bay, you will typically find Wild Celery in sediments high in organic carbon and nitrogen, and it grows best in silty sand. It can be found in gravel and hard clay substrates as well. This experiment mimics the various concentrations of sand and soil that Wild celery can grow.

pH: The pH scale is a measure of the acid-base balance of water, with a pH of<7 representing Ďacidicí solutions, and pH of >7 representing Ďbasicí solutions. Pure water would be perfectly neutral (pH of 7), but water naturally contains a certain amount of dissolved substances that act either as acids or as bases. If the water contains more acids (H+) than bases, it is said to be acidic; if it contains more bases (OH-) than acids, it is basic or alkaline. If acids and bases are present in equal amounts, the water is said to be chemically neutral.

a line graph showing the effects of sediment on wild celery (pH)When CO2 is in short supply, many aquatic plants (including Vallisneria species and some algae) take CO2 from the hardening constituents of the water (CO3 and HCO3). When this happens, more OH-1 molecules are generated, increasing the pH of the water. So as more and more OH-1 molecules are generated by the shortage of CO2 and the production of more oxygen, the pH in the growth chambers will rise. The sediment mixtures that have more topsoil than sand will allow the plants to grow faster, which will in turn increase the number of OH-1 molecules. In contrast, sediment mixtures with small amounts of topsoil will not grow as quickly, producing fewer OH-1 ions and lowering the pH.

Nitrates: Nitrogen is one of the most important plant nutrients (along with phosphorus). With the help of bacteria, nitrogen goes through a cycle of chemical changes as it is absorbed, used and then restored to a form which it can again be used. Most plants absorb nitrogen from the sediment or water column in the form of nitrate (NO3-) or ammonium (NH4+). Other common forms of nitrogen (nitrite (NO2), ammonia (NH3), etc) arenít available to plants, and can even be toxic at high levels.

a line graph showing the effects of sediment on wild celery (nitrate)Wild celery and algae primarily use nitrogen as nitrate (NO3) and ammonium (NH4+), and can obtain these molecules from both the sediment mixture in your growth chamber and the water itself. Any excess nitrate (and phosphate) in the water will contribute to increased algal growth. Since the sediment mixture contains a large amount of nitrogen from the topsoil, it is common to see an initial increase in the nitrate levels prior to the growth of the Wild Celery and algae. As the Wild Celery and algae increase over time and consume the available nitrate and ammonium, concentrations in the water will decline.

In the Chesapeake Bay, areas with excess nutrients typically have large concentrations of short lived microscopic plants called phytoplankton (algae). Large concentrations of phytoplankton (algal blooms) can color the water green or brown and greatly reduce or eliminate the amount of light available for bay grasses. In addition, since algae are also plants, they produce oxygen during the day and consume it at night. A large algal bloom can remove so much oxygen in an area at night that it may kill any fish and crabs present! When phytoplankton die, they decompose (consuming oxygen) and release a large amount of nutrients back into the water which can fuel more algal blooms.

Wild Celery (and other bay grasses) are important because they consume nutrients as they grow and only slowly release them back into the water column late in the year when the water temperature has cooled below the preferred temperature of the phytoplankton.

Expected Results of Wild Celery Flow Rate Experiments
This experiment is designed to demonstrate the influence of water flow on the growth rate of Wild Celery (Vallisneria americana). Chamber A will have a powerhead in the tank to create a circular flow throughout the tank. Chamber B will have no powerhead and the water will remain still. Both growth chambers (black tubs) are set up identically except for the powerhead.

a bell curve graph showing increasing flow rate and increasing growth rate

Expected Results
Plant Height:
All bay grasses have an optimum amount of flow to maximize growth. Plants in area with little or no flow will grow slowly, and plants in areas of fast moving current will become uprooted or damaged.

The rate at which plants can absorb carbon dioxide is one of the factors that affect how quickly the plant will grow. Mixing of the water surrounding the bay grass created by wave action and tides greatly increases this rate.

a line graph showing the effects of flow rate on wild celery (plant height) In the Bay, tidal areas have two high and two low tides each day. As the tide changes, so does the water that immediately surrounds the plant. This constant movement of water allows the plant to absorb more carbon dioxide, nitrogen and other vital nutrients. Non-tidal bodies of water will not have as much water movement, but can experience mixing due to wind action on the water.

pH: The pH scale is a measure of the acid-base balance of water, with a pH of<7 representing Ďacidicí solutions, and pH of >7 representing Ďbasicí solutions. Pure water would be perfectly neutral (pH of 7), but water naturally contains a certain amount of dissolved substances that act either as acids or as bases. If the water contains more acids (H+) than bases, it is said to be acidic; if it contains more bases (OH-) than acids, it is basic or alkaline. If acids and bases are present in equal amounts, the water is said to be chemically neutral.

a line graph showing the effects of flow rate on wild celery (pH) This increase in pH also occurs in the Chesapeake Bay as the water temperature warms and the amount of bay grasses and algae increase. During the summer months, large amounts of algae can grow in the water column changing the water color to a green or dark brown color driving up the pH to 10! In some areas of the Bay that have dense bay grass beds, pH levels can also get above 10. Thatís a lot of OH-1's!

pH values above 10 have been shown in lab tests to decrease photosynthesis of wild celery, which in turn decreases itís growth rate. When the pH values are acidic (below 7) a lot of OH-1 is in water, and the CO2 (carbon dioxide) that plants need for photosynthesis turns into CO3, which plants canít use. The plants have a harder time "breathing," and as a result they grow more slowly. You will see low pH can be the result of acid rain (local rain pH is about 5) and the poor buffering capacity of the land due to variations in geology. Wild Celery can be found in pHís ranging from 6 to 10 with a preferred pH around 8. The plants that have more flow rate will be able to exchange nutrients faster, which will lead to a lower pH. Conversely, plants with little or no flow will have a slower growth rate, resulting in a higher pH.

Nitrates: Nitrogen is one of the most important plant nutrients (along with phosphorus). With the help of bacteria, nitrogen goes through a cycle of chemical changes as it is absorbed, used and then restored to a form which it can again be used. Most plants absorb nitrogen from the sediment or water column in the form of nitrate (NO3-) or ammonium (NH4+). Other common forms of nitrogen (nitrite (NO2), ammonia (NH3), etc) arenít available to plants, and can even be toxic at high levels.

a line graph showing the effects of flow rate on wild celery (nitrate) Wild celery and algae primarily use nitrogen as nitrate (NO3) and ammonium (NH4+), and can obtain these molecules from both the sediment mixture in your growth chamber and the water itself. Any excess nitrate (and phosphate) in the water will contribute to increased algal growth. Since the sediment mixture contains a large amount of nitrogen from the topsoil, it is common to see an initial increase in the nitrate levels prior to the growth of the Wild Celery and algae. As the Wild Celery and algae increase over time and consume the available nitrate and ammonium, concentrations in the water will decline. Slight variations in nitrate concentrations may occur between growth chambers as a result of the varying growth rates of the Wild Celery and algae. The tank with a higher flow rate and the fastest growing plants may remove nitrate at a faster rate than the tank with no flow.

In the Chesapeake Bay, areas with excess nutrients typically have large concentrations of short lived microscopic plants called phytoplankton (algae). Large concentrations of phytoplankton (algal blooms) can color the water green or brown and greatly reduce or eliminate the amount of light available for bay grasses. In addition, since algae are also plants, they produce oxygen during the day and consume it at night. A large algal bloom can remove so much oxygen in an area at night that it may kill any fish and crabs present! When phytoplankton die, they decompose (consuming oxygen) and release a large amount of nutrients back into the water which can fuel more algal blooms.

Wild Celery (and other bay grasses) are important because they consume nutrients as they grow and only slowly release them back into the water column late in the year when the water temperature has cooled below the preferred temperature of the phytoplankton.


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