Give diffferences/contrast between a Marine environment and an estuarine environment.
http://omp.gso.uri.edu/ompweb/doee/science/descript/whats.htm
http://jncc.defra.gov.uk/page-3079
To understand the differences between a marine environment and an estuarine environment, we need to first define them.
A marine environment refers to the ecosystem that exists in the open ocean and coastal areas. It consists of saltwater bodies and supports a wide range of marine life. On the other hand, an estuarine environment is a partially enclosed coastal body of water, with a mix of fresh and saltwater. Estuaries are usually found where rivers meet the sea and are characterized by fluctuating salinity levels.
Now, let's look at the contrasting features of marine and estuarine environments:
1. Salinity: One of the key differences is the salinity or salt concentration of the water. Marine environments have a consistently high salinity since they are directly influenced by the ocean. In contrast, estuarine environments experience significant variations in salinity due to the mixture of freshwater from rivers and the incoming seawater.
2. Biodiversity: Both marine and estuarine environments support diverse ecosystems, but they differ in the composition of species. Marine environments are home to a wide range of marine organisms such as fishes, whales, corals, and various invertebrates. Estuarine environments, with their unique mix of freshwater and seawater, provide habitat for different species including estuarine crocodiles, mangroves, and various fish species adapted to the changing salinity.
3. Nutrient availability: Estuarine environments receive a substantial amount of nutrients carried by rivers, making them highly productive areas. These nutrients support the growth of phytoplankton and other primary producers, which, in turn, serve as a food source for various organisms. In marine environments, nutrients may be more evenly distributed or supplied by oceanic upwelling.
4. Physical characteristics: Estuarine environments tend to have more sheltered conditions, with less wave action compared to open marine environments that are directly exposed to winds and ocean currents. Estuaries often have soft sediments, muddy substrates, and extensive intertidal areas which are important for feeding, breeding, and nesting activities.
5. Human impact: Due to their proximity to populated areas, estuarine environments are frequently influenced by human activities, such as commercial fishing, agriculture, and urban development. Marine environments can also be impacted by human activities, but they tend to be subject to different stressors such as overfishing, pollution from shipping activities, and offshore oil and gas exploration.
Understanding these differences is crucial when studying or conserving these ecosystems as they each have unique ecological dynamics and require specific management strategies.