Surf zone

As ocean surface waves come closer to shore they break, forming the foamy, bubbly surface called surf. The region of breaking waves defines the surf zone. After breaking in the surf zone, the waves (now reduced in height) continue to move in, and they run up onto the sloping front of the beach, forming an uprush of water called swash. The water then runs back again as backswash. The nearshore zone where wave water comes onto the beach is the surf zone. The water in the surf zone, or breaker zone, is shallow, usually between 5 and 10 m (16 and 33 ft) deep; this causes the waves to be unstable.

Animal life

The animals that often are found living in the surf zone are crabs, clams, and snails. Surf clams and mole crabs are two species that stand out as inhabitants of the surf zone. Both of these animals are very fast burrowers. The surf clam, also known as the variable coquina, is a filter feeder that uses its gills to filter microalgae, tiny zooplankton, and small particulates out of seawater. The mole crab is a suspension feeder that eats by capturing zooplankton with its antennae. All of these creatures burrow down into the sand to escape from being pulled into the ocean from the tides and waves. They also burrow themselves in the sand to protect themselves from predators. The surf zone is full of nutrients, oxygen, and sunlight which leaves the zone very productive with animal life.

Rip currents

Rip Current
Rip current in the ocean. Rip currents are often very difficult to spot with one's bare eyes, take caution in any body of water

The surf zone can contain dangerous rip currents: strong local currents which flow offshore and pose a threat to swimmers. Rip-current outlooks use the following set of qualifications:

  1. Low-risk rip currents: Wind and/or wave conditions are not expected to support the development of rip currents; however, rip currents can sometimes occur, especially in the vicinity of jetties and piers. Know how to swim and heed the advice of lifeguards.
  2. Moderate-risk rip currents: Wind and/or wave conditions support stronger or more frequent rip currents. Only experienced surf swimmers should enter the water.
  3. High-risk rip currents: Wind and/or wave conditions support dangerous rip currents. Rip currents are life-threatening to anyone entering the surf.

See also

References

  • Pinet, Paul R (2008) Invitation to Oceanography, Chapter 11: The Dynamic Shoreline. Edition 5 revised. Jones & Bartlett Learning, ISBN 0-7637-5993-7
  • "Breaker Zone." The Free Dictionary. Farlex Inc, 2012. Web. 18 Apr. 2012. <http://www.thefreedictionary.com/breaker+zone>.

External links

Albuquerque Biological Park

The Albuquerque Biological Park (or Albuquerque BioPark) is an environmental museum located in Albuquerque, New Mexico. It contains four separate facilities:

Albuquerque Aquarium - An aquarium with a 285,000-US-gallon (1,080,000 l) ocean tank containing Gulf of Mexico saltwater species from estuaries, surf zone, shallow waters, coral reefs, and ocean, as well as many other exhibits.

ABQ BioPark Botanic Garden - A 36-acre (15 ha) botanic garden that includes a 10,000-square-foot (930 m2) glass conservatory housing plants from desert and Mediterranean climate zones.

Rio Grande Zoo - A 64-acre (26 ha) zoo, with 2.5 miles (4.0 km) of paths and more than 250 species of exotic and native animals. Elephants, giraffes, camels, lions, tigers, snow leopards, polar bears, hippos, gorillas, chimpanzees, zebras, and seals can be found here, along with more unusual animals such as koalas, hyenas, white rhinos, Tasmanian devils, wombats and African wild dogs. There is a variety of birds, from storks and eagles to roadrunners.

Tingley Beach - fishing lake, model boating lake, picnic areas, narrow gauge railroad, and paths.The Albuquerque Biological Park is an accredited member of the Association of Zoos and Aquariums (AZA).City records indicate more than 1,100 animals are in the BioPark’s care during the fiscal year (as of December 2016).The BioPark also operates a 36" narrow gauge railroad that connects these facilities.

California corbina

The California corbina (Menticirrhus undulatus) is marine demersal fish in the croaker family. It can often be found along sandy beaches and in shallow bays. This species travels in small groups along the surf zone in a few inches of water to depths of 20 meters (66 ft). Other names include "California kingcroaker," "California whiting," and "kingfish".

Chthamalidae

The Chthamalidae are a family of chthamaloid barnacles, living entirely in intertidal/subtidal habitats, characterized by a primary shell wall of eight, six, or four plates, lacking imbricating plate whorls, and either membraneous or more rarely calcareous basis. They are not found below immediate subtidal habitats, and more likely are found in the highest tier of shallow-water barnacle fauna. They can be found in the most rigorous wave-washed locations, and some species are found in the surf zone above high tide mark, only receiving water from wave action at high tide.

Coastal morphodynamics

Coastal morphodynamics (i.e. the dynamics of beach morphology) refers to the study of the interaction and adjustment of the seafloor topography and fluid hydrodynamic processes, seafloor morphologies and sequences of change dynamics involving the motion of sediment. Hydrodynamic processes include those of waves, tides and wind-induced currents.

While hydrodynamic processes respond instantaneously to morphological change, morphological change requires the redistribution of sediment. As sediment takes a finite time to move, there is a lag in the morphological response to hydrodynamic forcing. Sediment can therefore be considered to be a time-dependent coupling mechanism. Since the boundary conditions of hydrodynamic forcing change regularly, this may mean that the beach never attains equilibrium. Morphodynamic processes exhibit positive and negative feedbacks (such that beaches can, over different timescales, be considered to be both self-forcing and self-organised systems), nonlinearities and threshold behaviour.

This systems approach to the coast was first developed by Wright and Thom in 1977 and finalized by Wright and Short in 1984. According to their dynamic and morphological characteristics, exposed sandy beaches can be classified into several morphodynamic types (Wright and Short, 1984; Short, 1996). There is a large scale of morphodynamic states, this scale ranges from the "dissipative state" to the "reflective extremes".

Dissipative beaches are flat, have fine sand, incorporating waves that tend to break far from the intertidal zone and dissipate force progressively along wide surf zones. Dissipative beaches are wide and flat in profile, with a wide shoaling and surf zone, composed of finer sediment, and characterised by spilling breakers.

Reflective beaches are steep, and are known for their coarse sand; they have no surf zone, and the waves break brusquely on the intertidal zone. Reflective beaches are typically steep in profile with a narrow shoaling and surf zone, composed of coarse sediment, and characterised by surging breakers. Coarser sediment allows percolation during the swash part of the wave cycle, thus reducing the strength of backwash and allowing material to be deposited in the swash zone

Depending on beach state, near bottom currents show variations in the relative dominance of motions due to: incident waves, subharmonic oscillations, infragravity oscillations, and mean longshore and rip currents. On reflective beaches, incident waves and subharmonic edge waves are dominant. In highly dissipative surf zones, shoreward decay of incident waves is accompanied by shoreward growth of infragravity energy; in the inner surf zone, currents associated with infragravity standing waves dominate. On intermediate states with pronounced bar-trough (straight or crescentic) topographies, incident wave orbital velocities are generally dominant but significant roles are also played by subharmonic and infragravity standing waves, longshore currents, and rips. The strongest rips and associated feeder currents occur in association with intermediate transverse bar and rip topographies.

Transitions between beach states are often caused by changes in wave energy, with storms causing reflective beach profiles to flatten (offshore movement of sediment under steeper waves), thus adopting a more dissipative profile. Morphodynamic processes are also associated with other coastal landforms, for example spur and groove formation topography on coral reefs and tidal flats in infilling estuaries.

Eretmodini

Eretmodini is a tribe of African cichlids.

It contains five species of freshwater fish endemic to Lake Tanganyika. They are small fish with reduced swim bladders that are found near the bottom in the turbulent, coastal surf zone. They are mouthbrooders.

Hypomesus pretiosus

Hypomesus pretiosus, or surf smelt, is a marine smelt with a range from Prince William Sound, Alaska to Long Beach, California, although its population declines south of San Francisco. The surf smelt grows to be about 10 inches in southern waters, and 8​3⁄4 inches in northern waters near Canada. On average, surf smelt weigh about 10 to the pound.Spawning occurs in the nighttime, which is why it is sometimes called the night smelt, peaking in the months from May to October. With a maximum age of three to four years, some females will spawn at the age of one, and all will spawn at the age of two. Females lay from 1,500-30,000 sticky eggs in the surf zone per spawn, which they may do three to five or more times in a season.H. pretiosus feed on polychaete worms, larval fish and jellyfish, but they primarily feed on small crustaceans. They can be important parts of salmon and halibut diets, and are the most economically important fish among California smelts. Around 225,000 kilograms are harvested there every year.

Longshore drift

Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand and shingle) along a coast parallel to the shoreline, which is dependent on oblique incoming wind direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone.

Beach sand is also moved on such oblique wind days, due to the swash and backwash of water on the beach. Breaking surf sends water up the beach (swash) at an oblique angle and gravity then drains the water straight downslope (backwash) perpendicular to the shoreline. Thus beach sand can move downbeach in a zig zag fashion many tens of meters (yards) per day. This process is called "beach drift" but some workers regard it as simply part of "longshore drift" because of the overall movement of sand parallel to the coast.

Longshore drift affects numerous sediment sizes as it works in slightly different ways depending on the sediment (e.g. the difference in long-shore drift of sediments from a sandy beach to that of sediments from a shingle beach). Sand is largely affected by the oscillatory force of breaking waves, the motion of sediment due to the impact of breaking waves and bed shear from long-shore current. Because shingle beaches are much steeper than sandy ones, plunging breakers are more likely to form, causing the majority of long shore transport to occur in the swash zone, due to a lack of an extended surf zone.

Natal shyshark

The Natal shyshark, eastern shyshark or happy chappie (Haploblepharus kistnasamyi) is a species of catshark, belonging to the family Scyliorhinidae. It was once regarded as the "Natal" form of the puffadder shyshark (H. edwardsii). This shark is endemic to a small area off South Africa from the Western Cape to KwaZulu-Natal. It is found close to the coast, from the surf zone to a depth of 30 m (98 ft), and has benthic habits. Reaching 50 cm (20 in) in length, the Natal shyshark is similar to the puffadder shyshark in appearance but has a stockier body, less flattened head, a compressed caudal peduncle, and a different color pattern. Rare and under threat from habitat degradation and commercial fishing, it has been assessed as Critically Endangered by the International Union for Conservation of Nature (IUCN).

Radiation stress

In fluid dynamics, the radiation stress is the depth-integrated – and thereafter phase-averaged – excess momentum flux caused by the presence of the surface gravity waves, which is exerted on the mean flow. The radiation stresses behave as a second-order tensor.

The radiation stress tensor describes the additional forcing due to the presence of the waves, which changes the mean depth-integrated horizontal momentum in the fluid layer. As a result, varying radiation stresses induce changes in the mean surface elevation (wave setup) and the mean flow (wave-induced currents).

For the mean energy density in the oscillatory part of the fluid motion, the radiation stress tensor is important for its dynamics, in case of an inhomogeneous mean-flow field.

The radiation stress tensor, as well as several of its implications on the physics of surface gravity waves and mean flows, were formulated in a series of papers by Longuet-Higgins and Stewart in 1960–1964.

Radiation stress derives its name from the analogous effect of radiation pressure for electromagnetic radiation.

Sargo

The sargo or white seabream (Diplodus sargus) is a species of seabream native to the eastern Atlantic and western Indian Oceans. It is found from the Bay of Biscay southwards to South Africa, including Madeira and the Canary Islands, the Mediterranean and (rarely) the Black Sea. Occasionally individuals are found off the Indian Ocean coasts of South Africa, Mozambique and Madagascar, and they are very rarely found elsewhere in the Indian Ocean, such as off Oman. An active fish, they inhabit the surf zone, but they may be found down to 50 m.

They consume small crustaceans, mollusks and some seaweed and coral, using their strong jaws to crush shells. Individuals can reach 45 cm, but average 22 cm.

Diplodus sargus are protandrous hermaphrodites, with individuals starting out life as males, and some becoming female later on.

It is commercially fished, with 3,713 t taken in 2008. Some are reared using aquacultural techniques. The catch is eaten immediately or marketed locally, as the flesh tastes good only when fresh.

Two US Navy submarines were named for this nimble fish, USS Sargo (SS-188) and USS Sargo (SSN-583).

Sea foam

Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids) derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. As the seawater is churned by breaking waves in the surf zone adjacent to the shore, the surfactants under these turbulent conditions trap air, forming persistent bubbles that stick to each other through surface tension. Sea foam is a global phenomenon and it varies depending on location and the potential influence of the surrounding marine, freshwater, and/or terrestrial environments. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beach face inland.

Spotfin goby cichlid

The spotfin goby cichlid (Tanganicodus irsacae) is a species of cichlid endemic to Lake Tanganyika where it is only known from the northern end of the lake. They live amongst pebbles in the surf-zone. This species can reach a length of 7 centimetres (2.8 in) TL. This species can also be found in the aquarium trade.

Surf kayaking

Surf kayaking is the sport, technique, and equipment, used in surfing ocean waves with kayaks. Surf kayaking has many similarities to surf board surfing, but with boats designed for use in surf zones, and with a paddle. A number of kayak designs are used, but all are aimed at better using the waves to propel the craft.

Surf kayaking is popular in many areas frequented by surf board surfers. The sport has grown in popularity over the last decades, in pace with the rise of sea kayaking, and modern materials and techniques.

Surfing

Surfing is a surface water sport in which the wave rider, referred to as a surfer, rides on the forward or face of a moving wave, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found in the ocean, but can also be found in lakes or rivers in the form of a standing wave or tidal bore. However, surfers can also utilize artificial waves such as those from boat wakes and the waves created in artificial wave pools.

The term surfing refers to the act of riding a wave, regardless of whether the wave is ridden with a board or without a board, and regardless of the stance used. The native peoples of the Pacific, for instance, surfed waves on alaia, paipo, and other such craft, and did so on their belly and knees. The modern-day definition of surfing, however, most often refers to a surfer riding a wave standing up on a surfboard; this is also referred to as stand-up surfing.

Another prominent form of surfing is body boarding, when a surfer rides a wave on a bodyboard, either lying on their belly, drop knee, or sometimes even standing up on a body board. Other types of surfing include knee boarding, surf matting (riding inflatable mats), and using foils. Body surfing, where the wave is surfed without a board, using the surfer's own body to catch and ride the wave, is very common and is considered by some to be the purest form of surfing.

Three major subdivisions within stand-up surfing are stand-up paddling, long boarding and short boarding with several major differences including the board design and length, the riding style, and the kind of wave that is ridden.

In tow-in surfing (most often, but not exclusively, associated with big wave surfing), a motorized water vehicle, such as a personal watercraft, tows the surfer into the wave front, helping the surfer match a large wave's speed, which is generally a higher speed than a self-propelled surfer can produce. Surfing-related sports such as paddle boarding and sea kayaking do not require waves, and other derivative sports such as kite surfing and windsurfing rely primarily on wind for power, yet all of these platforms may also be used to ride waves. Recently with the use of V-drive boats, Wakesurfing, in which one surfs on the wake of a boat, has emerged. The Guinness Book of World Records recognized a 23.8 m (78 ft) wave ride by Garrett McNamara at Nazaré, Portugal as the largest wave ever surfed.

Swash

Swash, or forewash in geography, is a turbulent layer of water that washes up on the beach after an incoming wave has broken. The swash action can move beach materials up and down the beach, which results in the cross-shore sediment exchange. The time-scale of swash motion varies from seconds to minutes depending on the type of beach (see Figure 1 for beach types). Greater swash generally occurs on flatter beaches. The swash motion plays the primary role in the formation of morphological features and their changes in the swash zone. The swash action also plays an important role as one of the instantaneous processes in wider coastal morphodynamics.

There are two approaches that describe swash motions: (1) swash resulting from the collapse of high-frequency bores (f>0.05 Hz) on the beachface; and (2) swash characterised by standing, low-frequency (f<0.05 Hz) motions. Which type of swash motion prevails is dependent on the wave conditions and the beach morphology and this can be predicted by calculating the surf similarity parameter εb (Guza & Inman 1975):

Where Hb is the breaker height, g is gravity, T is the incident-wave period and tan β is the beach gradient. Values εb>20 indicate dissipative conditions where swash is characterised by standing long-wave motion. Values εb<2.5 indicate reflective conditions where swash is dominated by wave bores.

Undertow (water waves)

In physical oceanography, undertow is the under-current that is moving offshore when waves are approaching the shore. Undertow is a natural and universal feature for almost any large body of water: it is a return flow compensating for the onshore-directed average transport of water by the waves in the zone above the wave troughs. The undertow's flow velocities are generally strongest in the surf zone, where the water is shallow and the waves are high due to shoaling.In popular usage, the word "undertow" is often misapplied to rip currents. An undertow occurs everywhere underneath shore-approaching waves, whereas rip currents are localized narrow offshore currents occurring at certain locations along the coast. Unlike undertow, rip currents are strong at the surface.

United States Marine Corps Combatant Diver Course

The USMC Combatant Diver Course is taught at the Navy Diving and Salvage Training Center, Naval Support Activity Panama City, Panama City, Florida. Both of the Marine Air-Ground Task Force reconnaissance assets, FMF Recon and MarDiv Recon, widely use combatant diving. During this eight-week course, trainees are introduced to open and closed-circuit diving (using the Dräger LAR-V rebreather), diving physics and medical aid. Most of the training in combatant diving is done at night.

The course provides underwater tactical training and the skills needed to successfully conduct underwater navigation for infiltration and exfiltration. The candidates negotiate long distances in open water, infiltrating by surface and sub-surface, learning to deal with the hazards of a surf zone tangle and simulated equipment malfunctions.

The combatant divers course combines lecture, demonstration, and practical application in oxygen charging procedures using the USMC Oxygen Transfer Pump System, or USMC OTPS. Upon the completion of this course, the Marines (of any MOS that attends) are given the Special "B" MOS 0324 Reconnaissance Man, Combatant Diver Qualified (NMOS) [formerly 8653].

Wave setup

In fluid dynamics, wave setup is the increase in mean water level due to the presence of breaking waves. Similarly, wave setdown is a wave-induced decrease of the mean water level before the waves break (during the shoaling process). For short, the whole phenomenon is often denoted as wave setup, including both increase and decrease of mean elevation. This setup is primarily present in and near the coastal surf zone. Besides a spatial variation in the (mean) wave setup, also a variation in time may be present – known as surf beat – causing infragravity wave radiation.

Wave setup can be mathematically modeled by considering the variation in radiation stress (Longuet-Higgins & Stewart 1962). Radiation stress is the tensor of excess horizontal-momentum fluxes due to the presence of the waves.

White croaker

White croaker (Genyonemus lineatus) is a species of croaker occurring in the Eastern Pacific. White croakers have been taken from Magdalena Bay, Baja California, to Vancouver Island, British Columbia, but are not abundant north of San Francisco. White croakers swim in loose schools at or near the bottom of sandy areas. Sometimes they aggregate in the surf zone or in shallow bays and lagoons. Most of the time they are found in offshore areas at depths of 3 to 30 meters (9.8 to 98.4 ft). On rare occasions they are fairly abundant at depths as great as 200 meters (660 feet).

The white croaker is the only species of in the genus Genyonemus. Other common names for the fish include Pasadena trout, tommy croaker, and little bass.

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