Abstract
Deep-sea currents and upwelling are thermohaline circulation and oceanographic processes acting on the ocean water resulting in ecosystem dynamics. Florida coast is part of the Gulf Stream system, a section of the world seawater receiving the significant impact of deep-sea currents and upwelling with swift and warm Atlantic Ocean currents, which stretches to the Gulf of Mexico. During high current flow, the Florida currents experience 25 percent increase in the mean seasonal speed by 10 centimeters in a second at a temperature of 26 degrees. These deep-sea currents facilitate the movement of cold and warm water within the South Pole, North Pole, and the equatorial regions of Florida. The overall impact of these processes includes a significant influence on both marine and terrestrial ecosystems.
Introduction
Deep-sea currents and upwelling are oceanographic phenomena that dominate seas and oceans. Deep-sea currents, also called submarine rivers, refer to the thermohaline circulation of seawater generated by forces acting on ocean water. Temperature difference, Coriolis forces of earth rotation, and water mass density caused by salinity variations are causes of these currents. The thermohaline circulation influences the movement and population of the marine ecosystem and heat redistribution both in the sea and on the earth’s surface. According to Mauritzen, Melsom, and Sutton (2012), oceans are essential components of the earth, for they regulate global warming through effective absorption of solar radiation. Thus, ocean currents act as conveyor belts to transport warm water from the equator towards the poles and relieve cold water from the poles to the tropics. This process of redistribution of uneven heat radiations on the earth’s surface regulates the overall global climate.
On the contrary, upwelling refers to oceanographic processes in which deep-sea water, rich in nutrients, rises to the surface of the sea to replace warm surface water displaced by strong wind waves. A net balance of Coriolis Effect and strong winds on the surface of ocean water produces a spiral movement of water layers, also called Ekman motion. The winds blowing across the ocean surface produces a net motion of wind-water interaction that displaces water on the upper layer of the ocean (Morrison, Frolicher, & Sarmiento, 2015). The mechanism allows the deep-sea water to rise from beneath and replace the displaced surface water. Upwelling replaces the nutrient-depleted surface water with deep ocean dense nutrient-rich water essential to the marine ecosystem. Therefore, this paper reviews deep-sea currents and upwelling in Florida ocean currents by examining causes, effects on the ecosystem, and their importance to humans along Florida coastal regions.
Ocean Currents along Florida Coast
Florida coast forms a section of Gulf Stream system (a deep-sea river) comprising swift and warm Atlantic Ocean currents stretching to the Gulf of Mexico. The Florida current receives water supply from two major sources, namely, Antilles currents and Loop currents, with the Loop current being the most significant source. Coriolis force of earth rotation produces a movement of warm water from the Atlantic into the Caribbean Sea, resulting in Florida currents (Morrison et al., 2015). The water flows to the Gulf of Mexico, where heating occurs and then forced out through Florida Straits. The estimated mean transport of Florida currents vary annually and on a seasonal scale. According to Dusek, Park, and Paternostro (2016), during high current flow, Florida currents experience 25 percent increase in the mean seasonal speed by 10 centimeters in a second at a temperature of 26 degrees. Thus a change in temperature linearly results in a compounded change in velocity. The outer edge of the Loop current produces large spiral currents that move into Florida Straits pushed along by gyres. These gyres help in nutrient and larvae transport between the Loop currents and the Florida Keys.
Overall, Florida currents have three forms of flow: the intermittent Miami terrace undercurrent, undercurrent jet on Florida shelf, and coastal countercurrents. Florida experiences the coastal countercurrent between the periods of October through January. However, from April to September, Florida experiences the southward flow in the form of undercurrent jet (Florida Current) along the continental slope. Florida Current moves towards the northern direction as the surface flow against the bottom flow, resulting in friction in the interface of the two currents. These deep-sea currents facilitate the movement of cold and warm water within the South Pole, the North Pole, and the equatorial regions of Florida.
Causes of Deep-Sea Currents in Florida
The leading causes of Florida currents include wind, salinity, and temperature variations. The wind flow determines the patterns of the current movement in the sea. In the winter, the winds blow out of the north while east and southeast winds prevail in the summer. Strong winds flowing over the surface enhance the speed of current flow and the overall pattern of current circulation (Dusek et al., 2016). Since the density of water masses in the ocean varies from one region to another, boundaries between water masses exist. Temperature and water density have an inverse relationship, in that, as temperature increases, water density reduces, making warm water to settle on the surface. In summer, Florida temperature rises as a result of the central location of the solar radiation leading to a low density of ocean surface water. On the contrary, as temperatures fall, sea water freezes, and the salt molecules freeze leading to high density. Therefore, as cold water is heavier than warm water, cold water tends to sink and settle in the deep-sea while warm water rises.
However, the salinity and density share a positive relationship. In Florida, the Gulf Stream system has high salt concentration due to the high rate of evaporation, sea ice, and river inflow. Water with high salt concentration is denser than water with low salt concentration. The water masses get positioned above or below each other according to their density. In this respect, less dense water masses flow in the upper position and float on denser water masses. Overall, the varying patterns of the density of water in the sea both horizontally and vertically lead to water movement. However, the velocity and the patterns of these currents depend on forces of earth rotation, wind direction, and gradient caused by landforms.
Causes of Upwelling in Florida
Wind is the main cause of upwelling in the sea; however, the earth’s rotation and water density are some of the causes that contribute to ocean upwelling significantly. Earth’s rotation plays a significant role in determining the direction of water flow and currents in the sea. When winds blow away water surface layers, the force of earth rotation provides Coriolis Effect resulting in the transportation of water away from the coast (Dusek et al., 2016). The winds blowing along coastal regions push away the surface water away and allow the deep-sea water to flow to the surface. In some other cases, water currents in the sea caused by wind collide and the frontal water from both sides upsurges and allows dense water rich in nutrient to rise.
Additionally, water density also plays a key role in upwelling process. As lighter water mass on the surface is pushed away by the wind, its density facilitates friction between the upper water layer and the layer beneath it causing the successive layers to move in the same direction. This process results in a spiral movement of water making more dense water beneath the sea to flow and occupy the area that was primarily covered by the lighter displaced water (Dusek et al., 2016). In the overall process, the wind flow causes a wind-water interaction, resulting in water movement sweeping away the surface layer and replacing it with a more dense water layer from beneath, rich in nutrients.
Effects on the Ocean
Water circulation is an important process in the marine ecosystem. Klemas (2012) states that the ocean water circulation significantly contributes to nutrient cycle, waste disposal, heat moderation, and climate conditions on the earth surface. Therefore, deep-sea currents and upwelling are critical for they aid in the redistribution of oxygen and nutrients, as well as regulation of heat in the sea.
Heat Regulation
The Florida current forms part of the Gulf Stream System acting as a conveyor belt that transports warm water from warm equatorial zones to the cold water in the southern and the northern poles. As the heat radiation from the sun falls on the earth surface, much of the heat energy is deposited in the water body. Upwelling pushes this warm surface water away and replaces with the deep cold dense water helping to enhance heat regulation (Mauritzen et al., 2012). However, distant southern and northern poles suffer from extensively cold periods due to low solar radiations. As a result, water acts as the appropriate mechanism for heat distribution within the earth surface. Morrison et al. (2015) explain that deep-sea currents flow from the poles towards the equatorial zones while the relatively less dense warm water layers get displaced and move to the cold regions. This process of water movement acts to counteract the uneven distribution of solar radiation reaching the earth surface and promotes the distribution of heat energy and the regulation of global temperature.
Nutrient Distribution
The nutrient content in the ocean water varies according to the water layers. The upper layer of the sea surfaces contains various species of organisms, with an entire food web but with a net loss of nutrients to the deep-dense water beneath due to the sinking of nutrients, fecal matter from the organisms, and the remains of the dead organisms sink into the sea. These biological processes in the upper layer of the sea water lead to net utilization of the nutrients elements reducing its nutrient level. Ekman transport in upwelling provides the mechanism for the transport of these nutrients from the deep water layers to the ocean surface.
Oxygen Level
Oxygen is continuously added to seawater through air-water interaction processes as well as through photosynthesis. As organisms require oxygen, its depletion has adverse effects on the marine ecosystem. Moreover, as temperature increases water loses the ability to hold oxygen. Thus, ocean currents help in lowering water temperatures necessary for enhancing the ability to hold more volume of dissolved oxygen. Moreover, the displacement of the upper layer of ocean water facilitates the transfer of oxygen to other sea areas. In general, upwelling and deep-sea currents promote distribution of oxygen within the water body.
Effect on Marine Ecosystem
Oceans form the main component that supports marine ecosystem. Current circulation is essential in marine life as it enhances primary production of the food chain for the ecosystem. According to Hays (2017), the continuous movement of seawater significantly affects the aquatic ecosystem through climate change moderation, movement of marine plants and animals, and the distribution of nutrients within the sea. The transport of nutrients by the currents from and to different locations and layers in the sea increases their bioavailability and accessibility. These ocean currents transport the leaked nutrients from the deep-sea back to the upper layer with a large population of living organisms. The marine creatures on the upper layer of the seawater include phytoplankton and seaweeds that have important roles in the food webs. These organisms are the primary producers in the food web that support other organisms such as fishes, worms, sea mammals, and humans.
Importance to Humans
In Florida, the ocean currents along the coastal regions have significantly influenced the way of life. Hay (2017) argues that ocean currents act as a mechanism that enhances marine life distribution and population shift. As such, marine ecosystem provides a favorable environment to marine organisms such fish, planktons, algae, mammals, and sea anemones. These animals have economic and social importance to humans for they promote fishing, recreation activities, and climate regulation.
Fishing plays an important role in economic development for it creates employment, generates revenues, and provides nutrition. In the ecosystem, fish provides proteins and minerals to humans. The deep-sea currents promote bioavailability of nutrients to fish from the deep-sea water through upwelling thus enhancing their reproduction. As nutrient content rises due to continuous ocean currents, the population of fish rises in these coastal regions and promotes the capacity of food security. Consequently, the supply of enough fish in ocean water opens an opportunity for employment and business activities leading to economic empowerment.
Besides, ocean currents provide humans with diverse conditions for recreational activities. Some of the favorite recreational activities along Florida coast include skiing, swimming, and fishing activities. As world technology advances, skiing activities continue to gain popularity among the young generation. Skiing, swimming, and fishing competitions enhance socialization across different age categories and strengthen relationships.
Conclusion
Deep-sea currents refer to the flow of water in the deep ocean due to forces generated by temperature difference, earthquakes, and salinity variations while upwelling refers to the process in which deep-sea water, rich in nutrients, rises to the surface and replaces warm surface water displaced by strong wind waves. These water circulation processes are essential to redistribution of water, oxygen, heat, and nutrients in the sea. Consequently, it helps promotes marine ecosystem by enhancing the primary production and food chain of the organisms. As such, oceans are essential for the overall health of both marine and terrestrial environment. The marine ecosystem provides a home to several lives that include different species of animals and plants such as fish, planktons, mammals, and corals. These animals have economic and social importance to humans. Overall, the socioeconomic benefits of deep-sea currents and upwelling are fishing, recreational activities, and climate regulation. Therefore, humans have the responsibility to control and manage these sea currents to promote sustenance of marine ecosystem for the benefit of humans as in the case of Florida.
References
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Hays, G. (2017). Ocean currents and marine life. Current Biology, 27(11), 470-473. Web.
Klemas, V. (2012). Remote sensing of coastal and ocean currents: An overview. Journal of Coastal Research, 28(3), 576-586. Web.
Mauritzen, C., Melsom, A., & Sutton, R. (2012). Importance of density-compensated temperature change for deep North Atlantic Ocean heat uptake. Nature Geoscience, 5(12) 905-910. Web.
Morrison, A., Frolicher, T., & Jorge, S. (2015). Upwelling in the southern ocean. Physics Today, 68(1), 27-41. Web.