Abiotic Factors: The marine ecosystems of the national park are located in the tropical ocean with tropical maritime climates. May through October is considered the wet season with about 14 centimeters of rain each month. (1) During this wet season water temperatures are about 80 degrees Fahrenheit. (1) November through April is known as the dry season with an average of 5 centimeters of rain each month. (1) The water during the dry season are about 75 degrees Fahrenheit. (1) The temperature and rainfall most directly affects the coral in this ecosystem because coral need to stay in the photic layer of the ocean receiving a lot of sunlight but are still protected by the layers of water. Ocean temperatures need to stay within 70-85 degrees Fahrenheit in order for the coral to have a chance at survival. Hurricanes have a 13-16% chance of occurring between June 1st and November 30th. (1)Hurricanes can harm coral reefs by breaking coral and disorienting many organisms. These hurricanes also stir up fine sediments into the water reducing sunlight and covering coral polyps causing the coral to die. The Gulf Stream is a northward current that moves warm water up toward Biscayne National Park ensuring that the water temperature remains warm enough. Lastly, salinity must range between 3.3 and 3.6%. (1) If salinity is too high then the concentration in the ocean is too high and there is a higher chance of silt landing on the polyps of coral.
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Biotic Factors: Turtle grass, manatee grass, shoal grass, star grass, and paddle grass are all types of seagrass that can be found in Biscayne National Park. (8) These different types of seagrasses are categorized as an ecosystem for the amount of life that they protect and support. Manatees, one of the many endangered species in Biscayne National Park, feed off of manatee grasses. Because the grasses are relatively close to the surface of the water, manatees are often struck and injured by boat propellers. In Biscayne National Park 28 different crabs have been identified including the likes of speckled crabs, blue crabs, and decorator crabs. Crabs provide a multitude of services in the environment such as algae eaters, prey to larger animals, and predators of smaller fish and snails. (8) Fish such as blue angelfish, reef butterfly fish, and ladyfish are non-invasive species that flourish in Biscayne National Park and contribute to its diversity increasing their energy level. (8) While most of the biotic factors are non-invasive, the lion fish is an invasive fish species that causes major environmental and safety threats due to its venomous spines and lack of numerous predators. Lionfish reproduce in increasingly large numbers due to the fact that they don't have any natural predators and that they have protective venom. Anemones, comb jellies, corallimorph, hydrocorals, hydroids, jellyfish, siphonophores, octocorals, stony corals, zoanthids, brittle stars, sea cucumbers, sea urchins, sand dollars, sponges, and worms are just some of the many invertebrates that have been located in Biscayne National Park. (8) Some common names of these categories include turtle grass anemone, branching fire coral, staghorn coral, Florida sea cucumber, and barrell sponge. (8) The many corals found in Biscayne National Park make up coral reefs which is an ecosystem that houses multiple other species such as fish and snakes.
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LIMITING FACTORS: sdf
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DENSITY-INDEPENDENT:
Hurricanes(6): Hurricanes are considered density-independent factors because they are a natural disaster. Hurricanes affect the ecosystem but do not require a population density change in order to occur. Hurricanes cause massive destruction of coral reefs, affecting the species that feed off of coral and use coral reefs as their homes. The growth of the ecosystem is dependent on how many coral reefs are still alive after a hurrican comes through as well as dependent on how many new species are introduced into their environment due to displacement during the storm.
Fishermen(6): Fishermen are considered density-independent factors because they disrupt the ecosystem. Fishermen can damage coral reefs, overfish, or catch sea turtles, which are endangered. The growth of the ecosystem is affected by how many fishermen are abusing their licenses and how many species they harm.
Nitrogen/Phorphorous Levels: Nitrogen and phosphorous are considered limiting nutrients which are elements that must be added for production to increase. (4) Three processes that are considered to be nutrient limiting are: growth of populations currently present,net primary production (defined as gross production or photo-synthesis minus respiration of the producers), and net ecosystem production (defined as NPP minus heterotrophic respiration). (10) Nitrogen and Phosphorous cause an increase in primary production, increasing photosynthesis, which increases primary consumers and so on up to tertiary consumers. The entire ecosystem relies on these nutrients because they are what is needed to set the base of the energy pyramid.
DENSITY-DEPENDENT:
Competition(6): As populations in an ecosystem increase in size, competition increases for food and shelter. This is considered a density-dependent factor because competition is caused by an increase in population size and is therefor dependent on the number of species. An example of this could be lionfish out-competing native species for their food and habitat.
Predation(6): Predator/prey relationships regulate population control. If the amount of prey increase so will the amount of predators. When the amount of predators increases the amount of prey decreases. When the amount of prey decreases the amount of predators decrease and the cycle starts again. This cycle is density-dependent because the predator and the prey are each dependent on the density of the population of the other. An example of this preddator/prey relationship could be between queen parrotfish and coral.
Parasitism(6): Parasites are dependent on the population density of their host. The larger the host density the larger the parasitic density. The larger the parasitic density the smaller the host density. The smaller the host density the smaller the parasitic density and the cycle repeats. Parasitism is density dependent because the parasite relies on the host population and the host population size is dependent on the number of parasites.