Shoreline

A shoreline, which is commonly referred to as a coastline, is visually “the boundary of a coast, where land meets water." Shorelines are vastly created by the waves and tide from the ocean. This happens “when waves crash onto shore and they wear away at, or erode, the land. But they also leave behind little parts of the sea, such as shells, sand dollars, seaweeds, and hermit crabs." Shorelines can be commonly made up of sand, but the makeup of shorelines can vary greatly. Some shorelines across the world are made of granite, quartz, or calcium carbonate, and as a result they will appear differently as a result of their composition [1].

Shorelines are a dynamic environment, being changed by the same process that can create them. Erosion has been recognized as the main reason for the physical change of shorelines. Coastal erosion takes place when “local sea level rise, strong wave action, and coastal flooding wear down or carry away rocks, soils, and/or sands along the coast” [2]. The level of erosion depends on the makeup of the shoreline, if it consists of a harder material, such as granite, erosion will be slower, but if it is a softer material, such as calcium carbonate or sand, erosion can occur much more quickly. Sandy shorelines see changes almost daily due to erosion, because of the consistency of the sand. The size of a shoreline can also affect the rate of erosion. When a shoreline is larger, there is “more room for waves to spread their energy and deposits” and comparatively “coastlines with small, narrow beaches have less room for waves to spread out” [1].

As shorelines are directly adjacent to the ocean, “tides, the rise and fall of the ocean, affect where sediment and other objects are deposited on the coast (the shoreline). The water slowly rises up over the shore and then slowly falls back again, leaving material behind." When it is high tide more sediment will be left on the shoreline inland, but when it is low tide, the sediment will be left closer to the ocean [1].

Since shorelines are dynamic, “they are important ecosystems that provide unique homes for marine plants, animals, and insects." Shorelines often face some of the worst treatment when it comes to human interaction. They are constantly “affected by pollution, oil spills, and garbage from both land and sea. Pollution negatively affects the way a coast looks and is damaging to the marine life that lives there." In an effort to combat the poor treatment, many non-profit organizations have been started to promote clean shorelines [1].

References

[1] National Geographic Society, Morgan Stanley. (2012, October 9). Coast. Retrieved (2021, July 20), from www.nationalgeographic.org/encyclopedia/coast/

[2] U.S. Climate Resilience Toolkit. (2021, April 1). Coastal Erosion. Retrieved (2021, July 20), from https://toolkit.climate.gov/topics/coastal-flood-risk/coastal-erosion