Karlie Jaeger General Ecology 19 September 2014 Salt Marshes Karlie Jaeger General Ecology 19 September 2014

What is a salt marsh? Concentrated along low-lying coasts with sandy shores “Transitional Ecosystem” Driven by lunar tides In its most simple definition, a salt marsh is a biome where the land meets the sea, mainly concentrated along low-lying coasts with sandy shores and dominated with herbaceous material. Its often referred to as a transitional ecosystem because, like I said, it’s a region formed from two very different environments mixing together—both land and sea—to create a distinctive habitat. Salt marshes are created due to the lunar tides and I’ll explain in further detail at a later slide, but just note that the ecosystem of salt marshes are highly dependent on the highs and lows of the tides during each day.

Here I have a map of where in the world salt marshes can be found Here I have a map of where in the world salt marshes can be found. As you can see, there is a bit of a trend; they are found primarily along temperate to high latitudes--so anywhere above the Tropic of Cancer and below the Tropic of Capricorn.

Tidal Creeks Channels that fill and empty with the tides Network of channels Salt pans Salt marshes generally include channels, called tidal creeks, that fill and empty with the tides. The repetitive rising and receding of the tides eventually form a network of channels, as you can see in this background picture; its really rather complex. Anyway, tidal creeks are bordered by natural levees. Periodically, during high tide, water will flow over these levees and collect in small basins named salt pans, termed because as the water evaporates, a salt layer is left behind. This comparative picture is just here to show you the difference that the tide can have on the salt marsh; this is low tide versus high tide.

Salinity High Tides create saltwater currents that move up within the channels Low tides move saltwater seaward Species are Halophytes Tides are extremely important to salt marshes, as I’ve said before. Not only do they help to transport organisms from this biome to the sea, but tides also help to renew nutrients such as oxygen, and remove waste. The flow of high and low tides is what is responsible for the fluctuations in salinity, which is highly variable depending on the time of day. In salt marshes, the salinity of seawater can drop to nearly that of freshwater an hour after the tide turns. And depending on where the salt marsh is located, in hot, dry climates, the salinity may exceed that of open ocean water due to evaporation. So you have pretty high extremes of salinity within hours of a day. If you look at that from a biological standpoint, you need to have really strong species to live there. So, most plants and organisms need to be salt-tolerant while still able to adapt to low salt concentrations. Typically, salt marshes are dominated by these halophytic grasses.

Overall, salt marshes are a pretty unique biome Overall, salt marshes are a pretty unique biome. Not only do they provide a habitat for organisms, but they also help take nutrients out of the water coming from upland areas to protect coastal bays from over-pollution and they protect coastal cities from storms.

Work Cited Molles, Manuel C. "Life in Water." Ecology: Concepts and Applications. 6th ed. New York: McGraw-Hill, 2013. 58-61. Print. Woodward, Susan L. "Salt Marsh." Biomes of the World. Radford University, 1 Jan. 2012. Web. 19 Sept. 2014. All pictures taken from Google under the search ‘salt marsh’