The Effect of Nutrients on the Propagation and Growth of Potamogeton Perfoliatus (Redhead Grass) (page 2)
- What is the effect of infusing nutrients into the sediment on Potamogeton perfoliatus (Redhead Grass) propagation and growth?
- How does the addition of nutrients to the sediment affect the water quality?
- What is the rate of growth for Potamogeton perfoliatus?
General Submerged Aquatic Vegetation Information
- Abbreviated to SAV
- Improve health of the Chesapeake Bay
- Can survive in all salinity levels
- Live in Chesapeake Bay and its tributaries
- Declining in Chesapeake Bay and its tributaries
- Need light, phosphorus, and nitrogen
- Many types live in the Chesapeake Bay- both native and invasive species
- Food for wildfowl
- Habitat for marine mammals
Types of SAV Commonly Found in the Chesapeake Bay
|Sago Pondweed||Potamogeton pectinatus|
|Redhead Grass||Potamogeton perfoliatus|
|Curly Pondweed||Potamogeton pusillus|
|Slender Pondweed||Potamogeton crispus|
|Horned Pondweed||Zanniehellia palustris|
|Eurasian Watermilfoil||Myriophyllum spicatum|
|Wild Celery||Vallisneria americana|
|Water Stargrass||Heteranthea dubia|
|Common Elodea||Elodea canadenis|
|no common name||Najas minor|
|Northern Naiad||Najas flexilis|
|Slender Naiad||Najas gracillima|
|Southern Naiad||Najas guadalupensis|
|Widgeon Grass||Ruppia maritima|
Water Quality and SAV Decline
These two factors create a dust bowl effect and without one the other is not balanced. SAV reduce turbidity levels by anchoring the topsoil with their roots and keeping it from washing away. When the SAV dies back the rich topsoil floats in to the water and therefore increases the turbidity. When turbidity increases continually in a body of water, the SAV cannot carryout photosynthesis to live, and the cycle starts over. As plants, SAV use nitrogen and phosphorus to grow, and there is less in the water. When the SAV die back there is more nitrogen and phosphorus in the water for algae to bloom in excessive amounts. When algae blooms occur the turbidity also decreases, which kill the SAV, thereby allowing nutrients to build up and the cycle starts again.
History of SAV in the Chesapeake Bay
Timeline of Specific Events:
- 1930- ‘Wasting Disease’ kills SAV
- 1933- Storm killing SAV beds
- 1940- Eelgrass beds return to Chesapeake Bay and tributaries
- 1950-60- Eurasian Watermilfoil declines
- 1962- Introduction of the Mute Swan to Bay area
- 1972- Hurricane Agnes
- 1972- Die back of beds, linked to Hurricane Agnes
- 1978- 18% decline since 1971
- 1999- Hurricane Floyd
- 1999- Further die back of beds, not yet linked to Hurricane Floyd.
Historic Uses for SAV:
- Mattress filling
- Animal bedding
- Cattle forage
- Food- from seeds
Role of SAV in the Chesapeake Bay Ecosystem
SAV provide food and shelter to many of the bay organisms. Wildfowl, snails, zooplankton, fish, small mammals, and amphipods eat many SAV species. SAV are a nursery for herring, croaker, menhaden, shod, spot and silversides. They also provide shelter for minnows, bluegill, small striped bass, shellfish, invertebrates, barnacles, larvae, algae, protozoan, isopods, sea squirts, sponges and seahorses.
SAV not only benefit animal they also improve water quality. They decompose slowly so very little dissolved oxygen is lost during the decomposition process, whereas algae decompose quickly and easily deplete the oxygen supply of a stream overnight. SAV use nutrients, which means that there are not enough extra nutrients for an algae bloom. SAV also slow down erosion of the rich topsoil, by anchoring it with the roots; they slow water, trap and stabilize sediment; this increases turbidity levels.
Redhead Grass (Potamogeton perfoliatus) Specifics
Due to its flat leaves epiphytes grow easily on this species’ leaves and spread to the stems. The seeds, stems, and rootstock are eaten by the redhead duck, canvasback duck, mallard, ring-necked duck, black duck, Canadian goose, mute swan and tundra swan.
Preferred Habitat of Potamogeton perfoliatus:
- Fresh to brackish water
- High pH
- Muddy, fine sediment
- Slow moving water
- Shallow water
Physiology of SAV- How they Survive Underwater
SAV have adapted in many ways to living under water:
- They lack plant tissues for structural support
- The leaves, stems, and petioles contain aereachyma - thin celled walls with air spaces
- Aereachyma provide buoyancy to the plant
- Lack cuticle - waxy covering- on surfaces
- Lack of cuticle increases exchange of nutrients, water, and gasses
- When SAV are out of water they rapidly lose moisture
- SAV have reduced root systems
- Reduced amounts of xylem - which transports water and dissolved minerals
- Thin leaves
SAV Propagation- How a Cutting Grows Roots
There are three methods of growing plants, seed germination, a root or stem cutting, and tissue culture. The second of these three is also known as propagation, which is a form of cloning. Propagation requires cutting from the desired plant, and placing the cutting in the sediment. In 7-14 days adventitious roots will begin to form from the stem and leaves. These propagated plants mature earlier than germinated plants and are genetic duplicates of the ‘mother’ plant.
When propagating Potamogeton perfoliatus, the bottom leaves must be removed because the roots will grow form both the stem and petioles.