Submerged

 

   Submerged plants are those underwater, and are generally anchored or rooted
in the benthic (pond bottom). They may draw fertility through a root system; however, foliar uptake from the water is a second and often primary mode.
Little of their mass is required for support structures in this weightless environment, and once growth conditions are met, these plants are typically fast growing. The low position of these plants puts them at a potential disadvantage for sunlight, a limitation consisting of a combination of water clarity and depth in the energized portion of a pond bottom is called a liminon. Submerged plants promote clarity, reducing the plankton algae through competition for fertility in solution, and reducing the turbidity caused by suspended clay colloids. This promotes an expansion of their realm as the season progresses.

Submerged plants exchange carbon dioxide for dissolved oxygen during the
periods of photosynthesis. This is something that plants with aerial leaves cannot do, and provides a relatively stable source of oxygen for the pond ecosystem. 

Coontail or Hornwort is a brittle plant often found in abundance. It lacks true roots so is unable to consolidate in flowing water. It can flower profusely although its main means of propagation is by vegetative fragmentation. This makes it a difficult plant to control if mechanical methods are used for it removal . It provides good cover for pond animals but its invasive nature can create problems, it has a tendency to prefer eutrophic waters.

 

Potamogeton Crispus, or Curlyleaf Pondweed, is a very versatile plant able to grow in many different forms of habitat, being found in both mesotrophic and eutrophic water either flowing or static. It can be found in very shallow water but prefers depths shallower than 1 m (39 inches) to water as deep as 6m (19.5 feet). The ability to grow on gravel, sand or even deep mud makes it very successful. The ability to spread by both seeding and vegetative means, can also make it a problem plant.

 

Potamogeton pusillus is a delicate leafed plant which is found in many types of habitat and can even tolerate slightly brackish water. It will grow over sand and gravel and also silty substrata so versatile as to growing conditions it needs. Stems can grow up to 1.5 m (5 ft) in length, they provide a good food source for a variety of wildfowl and also provide cover for aquatic creatures. They appear to be a low elevation species tending to only grow below 350m (1200 ft) altitude. The small leafed Potamagetons are numerous and it can be fairly difficult to identify individual members of the species.

 

Potamogeton natans if present can often be growing in abundance, with its floating leaves covering the surface of the entire water. It can tolerate a wide range of water quality and also bottom substrates. Its is most often found in water of moderate depth from 1-2 meters ( 3 - 6 feet) although it has been recorded from much greater depths in clear waters. The plant overwinters as rhizomes or dead looking stems, with new leaf growth appearing in the spring. It can be very invasive.

 

    The Common Water-starwort grows as either an aquatic plant in shallow water or a terrestrial species on open ground. In the aquatic environment the leaves can be either floating or submerged but submerged leaves tend to be well spaced and preference given by the plant to the floating. It is mostly found growing over fine organic or inorganic sediments but it never found in nutrient poor locality's. It is rarely found in deep water or at higher altitudes being a lowland plant

 

   Short-leaved Water-starwort, is a pioneer species often found in newly created lowland waters. Or those which have been greatly disturbed by management practices. It can grow over most types of bottom deposits from pebbles to silt, and although mostly found in shallow water can grow to depths as much as 1.5m (5 feet). It grows vigorously in clear water, but unlike C.stagnalis this is truly a submerged plant and the leaves are unlikely to reach the surface.

 

      Elodea densa is much larger than its relation canadensis, the stems which can be branched bear whorls of narrow linear leaves. It bears small white flowers which are insect pollinated. Again as with most of this group an invasive plant best avoided as it can quickly overtake all other submerged plants. Can spread by division as well as seed.

 

There are 10 aquatic species of Crassula to be found worldwide, most are evergreen perennials, The one shown helmsii will grow in water up to 3 meters (10 feet) but can be found in shallow water or bogs were it grows in dense masses which can overrun other species. Although flowering on only emergent stems, it also spreads by vegetative reproduction and is easily transported on footwear, boats or fishing tackle

 

Whorled Water-milfoil is a plant which grows well in still water, preferring lowland waters which are mildly eutrophic but if nutrient levels become excessive it will decline. The plant over winters as turions and vegetative spread is more likely than sexual reproduction. It can become survive short periods as a terrestrial if stranded above water.

 

 

Water-crowfoot is a fast growing robust plant which prefers eutrophic and often base-rich waters. Normally found growing in the shallows and is capable of surviving in quite turbid waters. It is an annual which flowers May to June but this can extend to late summer. It very quickly can produce surface cover in its attempt to flower. It can survive on damp mud thorough the summer but is only able to overwinter below water.

 

 

Ranunculus circinatus is a delicate plant found only in standing or very slow moving waters, and is unable to withstand desiccation. It only breaks surface to produce its flower, but the flowers can sometimes even emerge before the stem has reached the surface. It is intolerant of very eutrophic conditions, and grows in depths from 1-3 meters although it can be found in shallower waters only if levels remain stable.