Estuaries

5 Common Plants of the Estuaries

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Sea Grass (Posidonia australis)

Saltwort (batis maritima)

Mangrove (Schizophrenia mangle)

Smooth Cordgrass (Spartina alterniflora)

Bristle Grass (Setaria megaphylla)

5 Common Animals of the Estuaries

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Dugong (Dugong dugon)

Irrawaddy Dolphins (Orcaella brevirostris)

Giant Brazilian Otter (Pteronura brasiliensis)

Mud Crab (Scylla serrata)

New Holland seahorse ( (Hippocampus whitei)

Limiting Factors

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Density-Dependent:
1. One example would be the food and water supply of most of the birds in estuaries. Only so much food and water can be produced, and based on the density of animals, so may die off because there is not enough food to allow them to survive.
2. Another example would be disease. If a fish gets a disease, if the water flow is very populated, then it's more likely that the disease will spread, because there is more interactions happening.

Density-Independent:
1. The temperature of an estuary is a density independent factor. No matter how many fish there are, some fish can not survive because the water is too cold, or too hot.
2.Another would be natural disasters. If a hurricane came into an estuary, It would be a threat to wildlife, not matter how much there was.

Interesting Fact

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There are 102 estuaries in the U.S according to the EPA. Of these, 28 have been designated by their states and the federal government to be of national importance.

Environmental Damage

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Increasing pressures from human-induced activities are causing habitat loss and degradation, fisheries declines, and overall reductions in estuarine health and productivity. Associated physical alterations, such as dredging, damming, and bulkheading, change the natural flow of fresh water to estuaries, dramatically affecting water quality. Toxic substances and excess nutrients contribute to fish diseases, algal blooms, and low dissolved oxygen and can pose a threat to the health of humans and estuarine wildlife. Because of this drop of wildlife, humans could lose needed areas for fishing, healthy drinking water, or good soil to grow crops. With such pollutants, humans could lose what they desperately need to survive.

Eco - tourism

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1.They are the nurseries of the oceans. Many species may spawn there and many other species may live portions of their lives in estuaries.

2.The higher salinity of an estuary helps protect some young creatures from predators.

3.Estuaries, especially mangrove areas really do a lot of cleansing. Mangrove leaves start to decay on the tree before they fall off. Once they hit the water they
break down and are the basis of many marine food chains. Thus they are one of the most beneficial systems.

4.Grass flats also produce food. At any one time, there could be millions of tons of sea-grasses floating on the gulf stream or settling on reefs all along the east coast. Fuelling many food webs.

5. They are the cradle of the sea, and the most fragile areas too. Just one storm-water project 50 years ago, has been determined to have killed 4 bays at the mouth of this watershed. Too much freshwater upset the delicate balance of the salinity in the estuaries and they "died".

Ecological succession in Estuaries

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First, I think it's important to define primary and secondary ecological succession:

Primary succession is the series of community changes which occur on an entirely new habitat which has never been colonized before. For example, a newly quarried rock face or sand dunes.
Secondary succession is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat. For example, after felling trees in a woodland, land clearance or a fire.

For example, in estuaries, primary succession is shown when a small plant begins to sprout on a moist rock, and the roots slowly break this rock and turn it into a more fertile area. Or, a small seed floating in the brackish area, and then landing on a small island area not to far out from the coast, and growing there on this previously uninhabited land.

For secondary succession, this could be shown by a hurricane coming i to an already fertile estuary, destroying most of the plants and animals, and then other organisms come to re-populate the already fertile area.

Coevolution Mechanisms in the Estuaries

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Camouflage- Small fish are common pray in the estuaries. In order to not be eaten, some fish have avoided being meals by the use of camouflage. This rock goby, (Gobius paganellus) has the advantage of its skin being similar color to the rocks in shallow water, making it less detectable by the eye of predators.

Mimicry- Some animals may use mimicry to avoid being eaten, or to drag in pray. mimic octopus are a type of octopus that use there tentacles to mimic the actions of another animal, tricking their opponent. It is common for a mimic octopus to mimic a banded sea snake to scare off a damselfish, which is a predator of the octopus.

The phosphorus cycle in estuaries

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The carbon cycle in estuaries

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Water Cycle in Estuaries

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Nitrogen cycle in Estuaries

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Oyster Drills as introduced species

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While aquaculture species such as the Japanese oyster, Crassostrea gigas, were introduced intentionally, they also brought with them many undesirable hitchhikers, including oyster drills. Oyster drills are small predatory snails that use there drill to bore in small shellfish. These shelfsih are then destroyed, and Oyster drills are most prevelently taking out the american oyster. Not only does this hurt the food web, but also the local economy.

Predators of Estuaries

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Bull Sharks are a common predator of hardhead (Arius felis) and gafftopsail (Barge marinus) catfish.

The Bonnethead Shark is a common predator of Swimming crabs, octopuses, squid, fishes, and shrimp

The Great Blue Heron is a common predator of estuaries, eating mostly small fish and amphibians like frogs.

Competitive

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Many types of snails and oysters are only able to survive on hard surfaces like rocks. This is a stable area where they can be safe and have available food. The snails and oysters compete food available space, and when one dies many others compete for the new area.

Parasitism

2011-12-06T09:36:00.000-08:00

oysters are very common in Estuaries. Boring spongers, a type of sponges found in estuaries, are a parasite. They will drill trough the shell of the oyster, but will not actually eat the oyster. However, this process is known to kill the oyster.

Commensalism

2011-12-06T09:30:00.000-08:00

Sharks are very fast swimming creatures. Sometimes, small fish are able to attach to the otter for a short period of time. This doesn't affect the shark, however the fish is able to get a quick ride to somewhere whereas normally it would take longer and it would have no protection.

Mutualism

2011-12-06T09:24:00.000-08:00

In estuaries, sea anemones and clown fish are able to help each other. The sea anemones providers shelter for the clown fish, as most fish are prone the the sting of sea anemones. When the sea anemone stings a fish, the clown fish is able to eat the remains, providing food for the clown fish and cleaning the area of the sea anemone. Clown fish can even attract food to the sea anemone by having other fish notices its bright coloration.

Biotic and Abiotic Features

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Some biotic features would be Bristle Grass (Setaria megaphylla) or Irrawaddy Dolphins (Orcaella brevirostris). Abiotic Features would be the Precipitation, that can vary between 100mm and 1000m. Another abiotic feature is temperature. Like precipitation, estuaries are incredibly varied in temperatures. The Amazon estuary in the summer can reach 100 degrees Fahrenheit while an Alaskan estuary in the winter may be -30 degrees Fahrenheit.

Estuary Soil Types

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The top soil layer found in an estuary or salt marsh is composed mostly of peat or salt crust. In dense areas with higher concentrations of organic material, this layer will contain undecomposed plants and sea animals. Invertebrates are an integral part of this type of soil creation, helping to break down the peat ingredients into plant nutrients.

Clay is an interesting and ever-changing soil. On an atomic level, the negatively charged particles that make up clay tend to repel each other. Yet, it is these negative charges that allow the soil to attract positive particles such as the nutrients of potassium and magnesium. Upon drying, the soil cracks and breaks apart, providing habitat for flora and fauna.

Yellow soils, ranging from sand to clay loams, are produced by high concentrations of sulfur. The existing sulfur oxidizes, producing a butter-yellow appearance. These soil types are extremely acidic in pH. Sometimes the soil can become too acidic, due to water table depth and water salinity, providing additional challenges to plant life proliferation.

Alluvial soils are found in floodplain areas. These soils are quite rich in nutrients. They exist due to the erosion of small particles washed down from higher areas and deposited into an estuary or delta. These fine particles, a compilation of sand, clay and silt, are called alluvium. Alluvium contains potash, lime and phosphoric acid, all which are beneficial to plant life.

Endangered Species of Estuaries: Light-Footed Clapper Rail

2011-10-26T09:31:00.000-07:00

The light-footed clapper rail was placed on the Endangered Species List in 1973. This brown bird about the size of a chicken lives along the coasts of southern California and northern Baja, Mexico. Human development is this bird's main threat. Housing developments and marina dredging have reduced its habitat, and the runoff from development continues to impact what habitat is left.

Average Monthly Precipitation and Temperature for Estuaries around Tokyo and Nagasaki

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Estuary Food Web

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Bristle Grass

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Setaria megaphylla

Cordgrass

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Spartina