Deep emergent marsh
Deep emergent marsh refers to the deepest parts of the marsh that transition to aquatic systems. Water depths can range from 6 in to 6.6 ft (15 cm to 2 m); water levels may fluctuate seasonally, but the substrate is rarely dry, and there is usually standing water in the fall (Edinger et al. 2002). Due to the range of water depths, deep emergent marshes can include emergent plants (such as cattail) in addition to floating leaf (plants with leaves that float on the surface of the water) and submersed plants (plants with most of their leaves growing below the water surface). Most emergent plants are discussed in the section on shallow emergent marsh, but I’ve listed them here again to emphasize the fact that these community labels are fluid and much overlap occurs between these categories. Here I focus mainly on the plants that grow in deeper water.
On the deep water end of the continuum, we shift into aquatic systems dominated by submersed plants. Again, the distinction between a deep marsh and an aquatic habitat is not sharp, with the main difference being that the wetland system tends to shallower and more variable water levels. Many of the same plants grow in both aquatic and deep emergent marshes.
Collectively, emergent, rooted, and submersed aquatic plants are called macrophytes. They provide important cover for fish, substrate for invertebrates to live on, and food for some fish and other wildlife. Many fish depend on macrophyte cover for spawning. These plants also add oxygen to the water through the photosynthetic process. They can also indicate water quality since they are sensitive to turbidity, which blocks light; salinity; and pollution or toxicants. Eutrophic (nutrient rich) systems can have excessive amounts of macrophytes that can actually lead to low oxygen conditions due to the overabundance of decomposing organic material.
For many years, the margins of Onondaga Lake had poor macrophyte cover due to the bottom substrate of calcareous wastes that lined the shore. More precisely, the sediments are composed of precipitated calcium carbonate, a poor plant rooting nutrient medium (Madsen et al. 1996). Water salinity was also high during the years of active soda ash production. Once the plant closed, water quality began to improve and macrophytes have responded well, with considerable increase in presence of native species (EcoLogic 2010).
On the deep water end of the continuum, we shift into aquatic systems dominated by submersed plants. Again, the distinction between a deep marsh and an aquatic habitat is not sharp, with the main difference being that the wetland system tends to shallower and more variable water levels. Many of the same plants grow in both aquatic and deep emergent marshes.
Collectively, emergent, rooted, and submersed aquatic plants are called macrophytes. They provide important cover for fish, substrate for invertebrates to live on, and food for some fish and other wildlife. Many fish depend on macrophyte cover for spawning. These plants also add oxygen to the water through the photosynthetic process. They can also indicate water quality since they are sensitive to turbidity, which blocks light; salinity; and pollution or toxicants. Eutrophic (nutrient rich) systems can have excessive amounts of macrophytes that can actually lead to low oxygen conditions due to the overabundance of decomposing organic material.
For many years, the margins of Onondaga Lake had poor macrophyte cover due to the bottom substrate of calcareous wastes that lined the shore. More precisely, the sediments are composed of precipitated calcium carbonate, a poor plant rooting nutrient medium (Madsen et al. 1996). Water salinity was also high during the years of active soda ash production. Once the plant closed, water quality began to improve and macrophytes have responded well, with considerable increase in presence of native species (EcoLogic 2010).