Sand Dune Evernote Notes Quiz

When an obstacle such as a rock outcrop or a stand of vegetation is present, it creates a barrier that slows down the wind speed. As a result, the sand particles carried by the wind lose their momentum and start to accumulate on the leeward side of the obstacle, forming a mound. This happens because the windward side of the obstacle has higher wind speeds, which causes the sand to be carried away, while the leeward side experiences lower wind speeds, allowing the sand to settle and create a "sand shadow".

The correct answer is "Behind the frontal dune, the salt spray causes tree and shrub branches to grow stunted and appear sculpted." This is because salt spray can have a detrimental effect on the growth of plants, causing them to become stunted and distorted in shape. The salt in the spray can inhibit the plant's ability to take up water and nutrients, leading to stunted growth. Additionally, the constant exposure to salt spray can cause the branches to become sculpted and twisted in appearance.

Surface creep refers to the phenomenon where larger grains of sand are moved forward along the surface when they are struck by smaller saltating grains of sand. This movement occurs when the larger grains are larger than one millimeter in diameter. The impact of the smaller grains causes the larger grains to shift slightly forward, resulting in surface creep.

Sand dune habitats form through the process of wind transport of sand and the growth of stabilizing vegetation. This means that the sand is moved by the wind and then deposited in certain areas, creating dunes. As the dunes form, vegetation such as grasses and shrubs start to grow, which helps stabilize the sand and prevent further movement. This combination of wind transport and vegetation growth is what leads to the formation of sand dune habitats.

Salt spray provides the main source of nutrients on frontal dunes. Salt spray contains dissolved minerals and nutrients that are deposited on the dunes through the process of evaporation. These nutrients support the growth of plants and other organisms on the dunes, making salt spray the main source of nutrients in this ecosystem.

Dunes are made of finer sands because only the smallest grains of beach sand usually move. This is because the smaller grains are lighter and more easily carried by wind or water. The larger grains are heavier and tend to stay in place. As a result, over time, the larger grains settle at the bottom while the smaller grains are transported and accumulated to form dunes.

Saltating sand grains strike heavy grains of sand on the surface. These saltating grains do not have enough energy to lift the heavier grains into the air. However, they do have enough force to push the heavy grains slightly forward or cause them to "creep" along the surface. This explains the relationship between heavier grains of sand and the "creep" movement of sand.

The correct answer is 10 mph. This means that once the wind reaches a velocity of at least 10 mph, it is strong enough to start moving sand particles.

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Sand tends to accumulate into piles rather than spread out evenly over an area because when there is a sufficient reduction of wind energy in the direction that sand drifts in, and any obstacle such as a rock outcrop or a stand of vegetation, it forces sand accumulation by lowering the wind speed. This reduction in wind energy and the presence of obstacles create conditions that allow the sand particles to settle and accumulate in certain areas, forming piles.

Sand dune tidal litter refers to the debris and organic matter that accumulates on sand dunes due to tidal action. This can include decomposing grasses and remains of various organisms. The correct answer states that sand dune tidal litter includes decomposing grasses and organism remains, which accurately describes the typical components of this type of litter.

Vegetation at the high tide line or in a dune increases sand accumulation by reducing the wind velocity. When vegetation is present, it acts as a barrier and slows down the wind, preventing it from carrying away the sand particles. This allows the sand to settle and accumulate, leading to increased sand accumulation.

The deep root system of American beach grass and sea oats helps these plants avoid surface heat and evaporation. The deep roots allow the plants to access water from deeper soil layers, reducing the risk of dehydration caused by surface heat and evaporation.

The fluid threshold of saltation refers to the wind speed required for sand particles to start saltating, which means to be lifted and moved by the wind. It is specifically the wind speed at which sand particles begin to move under the direct pressure of the wind.

Dune plants hydrate by capturing moisture from rainfall and using their deep root system to reach the water table below the dunes. This is because water supply is scarce on the frontal dune, so the plants have adapted to obtain water from these sources.

Saltation of sand along the surface refers to the process where sand grains are lifted and bounced along the ground by the force of the wind. This is the most common mode of sand movement by wind. It is estimated that about 75% of all sand movement is accounted for by saltation. This means that the majority of sand is transported by wind through this process, making it the most significant mechanism for sand movement.

Sand moves by saltation. This happens when sand, lifted by wind energy, bounces along a loose sand surface and sets other grains in motion by its impact.

The correct answer is #1 sand, #2 silt, #3 clay. This answer correctly identifies each sediment particle size. Sand particles are larger than silt particles, and silt particles are larger than clay particles.

The correct answer is #1 suspension, #2 saltation, #3 creep. In the diagram, the sand particles are initially lifted and carried in the air by the wind, which is known as suspension. As the wind speed decreases, the sand particles start to fall back to the ground in a hopping motion, which is called saltation. Finally, the sand particles move along the ground surface slowly due to the force of gravity, which is known as creep.

Sand grains average about two thousand times the weight of the atmosphere, meaning that they are much heavier than the air. This indicates that sand grains are not easily moved by all winds, as the force required to lift and transport them is significantly higher.