Life in Estuaries
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Sea Grass Beds are one of the main producers in estuaries, are submerged in water, and are a keystone species (a species that the rest of the ecosystem depends on). They protect small fish and crabs from predators, and also provide protection for offspring before they are old enough to venture into the open sea. Their limiting factor is sunlight.
Phytoplankton are microscopic organisms that are the main autotrophs in estuaries. They float in the water and are eaten by fish and barnacles. These organisms, along with all of the other marine plants, account for 70% of the oxygen produced by photosynthesis.
Cordgrass is another producer in estuaries and is partially submerged in water. It can grow on land or in the water, making it ideal for surviving in the inconsistent water levels of estuaries due to the tides. In the winter, the stems of some plants break off of plants and the roots stay, allowing plants to grow back in the spring.
Barnacles are primary consumers in estuaries. They breath underwater, and have adapted to estuaries by trapping water inside themselves during low tide when they aren't submerged in water. Another adaptation in their ability to filter phytoplankton out of the water for food while the tides go in or out. They are r-strategists (many offspring, little parental care) and represent a type-3 survivorship curve.
Small fish are primary consumers and primarily feed on marine insects like worms but also eat vegetation like sea grass.
Fiddler crabs are primary consumers that usually eat algea. They breath out of the water and have adapted to the tides by burrowing in the sand when the tides come in.
Dragonflies live outside of the water and eat insects. They are r-strategists (many offspring, little parental care) and represent a type-3 survivorship curve.
Large fish are usually secondary consumers, usually eating small fish.
American Coot are secondary consumers and usually eat small fish. They are an example of a type-two survivorship curve.
Ospreys are tertiary consumers because they usually feed on larger fish that are secondary consumers. They are k-strategists (few offsrping, lots of parental care) and an example of a type 1 survivorship curve. One limiting factor for ospreys is the amount of large fish to consume.
Sea slugs and fish represent mutualism (where both species benefit from the interaction) in estuaries. The fish gets cleaned by the sea slug and the sea slug gets food from the fish, so both species benefit.
The boring sponge and oyster represent parasitism (where one species benefits and one is harmed) in estuaries. The boring sponge breaks through the oysters shell, benefiting the sponge but hurting the oyster in the process.
Western Snowy Plovers are an endangered species in estuaries. They rest in estuaries as they migrate to warmer climates. The destruction of estuary habitats has contributed to the decline of this species.
The Salt Marsh Harvest Mouse is another example of an endangered species in estuaries that has been impacted by the destruction and pollution of estuaries. These mice feed on pickleweed which is easily contaminated by pollution.
The Chinese Mitten Crab is an invasive species (a non-native species that outcompetes native species) that came to the US from Asia through bilge water in boats. It burrows into the sand near the banks, causing erosion, and outcompete native species of fish and crabs.
