The Mona Passage ( es, Canal de la Mona) is a

strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean channe ...

that separates the islands of

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

and

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

. The Mona Passage connects the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

to the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

and is an important shipping route between the Atlantic and the

Panama Canal The Panama Canal ( es, Canal de Panamá, link=no) is an artificial waterway in Panama that connects the Atlantic Ocean with the Pacific Ocean and divides North and South America. The canal cuts across the Isthmus of Panama and is a conduit ...

. The Mona Passage is 80 miles (130 kilometer). It is fraught with variable tidal currents created by large islands on either side of it, and by sand banks that extend out from both coasts.

Islands

There are three small islands in the Mona Passage: *

Mona Island Mona ( es, Isla de Mona) is the third-largest island of the Puerto Rican archipelago, after the main island of Puerto Rico and Vieques. It is the largest of three islands in the Mona Passage, a strait between the Dominican Republic and Puerto R ...

lies close to the middle of the Mona Passage. *Five kilometers northwest of Mona Island is the much smaller

Monito Island Monito Island (English: ''Little Mona'', es, Islote Monito) is an uninhabited island about northwest of the much larger Mona Island. ''Monito'' is the masculine diminutive form of ''Mona'' in Spanish, which also translates to ''little monkey ...

. *Fifty kilometers northeast of Mona Island and much closer (21km) to the Puerto Rican mainland is

Desecheo Island Desecheo ( es, Isla Desecheo) () is a small uninhabited island of the archipelago of Puerto Rico located in the northeast of the Mona Passage; from Rincón on the west coast ( Punta Higüero) of the main island of Puerto Rico and northeast ...

Structure and seismicity

The Passage was the site of a devastating earthquake and resulting tsunami that hit western Puerto Rico in 1918.http://soundwaves.usgs.gov/2007/05/ Uri ten Brink, ''New Bathymetric Map of Mona Passage, Northeastern Caribbean, Aids in Earthquake- and Tsunami-Hazard Mitigation,'' USGS Sound Waves Newsletter, May 2007 It is the site of frequent small earthquakes. The passage is underlain by a seismically active

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

zone that overprints an older partly eroded tilted-block structure.

sits on the Desecheo ridge, a narrow east–west ridge that extends west from the northwest corner of Puerto Rico. The ridge forms the southern boundary of the 4000 m deep

Mona Canyon Mona Canyon (Spanish language, Spanish: ''Cañón de la Mona'') is an 87-mile long (140 km) submarine canyon located in the Mona Passage, between the islands of Hispaniola (particularly the Dominican Republic) and Puerto Rico, with steep wall ...

which extends toward the north to the

strike slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

zones which bound Puerto Rico and Hispaniola. The east face of the rift has a sharp relief of 3km and is controlled by the N - S trending Mona Rift Fault. The

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

of the 1918 earthquake was located along the east or southeast edge of the Mona Rift.

Physical oceanography

The Mona Passage connects the

waters and

waters, above a sill depth of 400 to 500 meters. The sill runs along a northwest to the southeast direction between Cabo Engaño (DR) in the west and the Cabo Rojo Shelf (PR) in the east margin of the Mona Passage. The vertical profile of the low-frequency (periods longer than 2 days) mean meridional water transport is characterized by a two-layer structure. The upper layer lies above a depth of 300 meters, with the upper water masses, the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...

Surface Water, Subtropical Underwater and Sargasso Sea Water entering the Caribbean Sea from the Atlantic Ocean. Below this layer, the Tropical Central Water exits toward the Atlantic Ocean. The mean value for the meridional (North-South) transport for a sampled year was -1.85 ± 0.25

sverdrup In oceanography, the sverdrup (symbol: Sv) is a non- SI metric unit of volumetric flow rate, with equal to . It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm3/s or hm3⋅s−1): 1 Sv is equal to 1 hm3/s. It is used ...

(Sv) into the Caribbean Sea. The barotropic tide (surface tide) propagates from northeast to southwest along Mona Passage. The "principal lunar semi-diurnal" constituent, also known as the ''M2'' (or ''M''₂) accounts for 52.35% of the total variance observed in the ocean currents and the semidiurnal current ellipses, with a clockwise rotation, are roughly aligned in a north–south direction. Semidiurnal tidal currents impinging on a submarine ridge known as ''El Pichincho'' can force the generation of an

internal tide Internal tides are generated as the surface tides move stratified water up and down sloping topography, which produces a wave in the ocean interior. So internal tides are internal waves at a tidal frequency. The other major source of internal wav ...

with a wave height of 40 meters.

Underwater glider An underwater glider is a type of autonomous underwater vehicle (AUV) that employs variable-buoyancy propulsion instead of traditional propellers or thrusters. It employs variable buoyancy in a similar way to a profiling float, but unlike a flo ...

observations reveal wave damping as the internal tide propagates south along the Mona Passage towards the open Caribbean Sea. Internal tides at ''El Pichincho'' can elevate the turbulent vertical diffusivity values (or

Eddy diffusion Eddy diffusion, eddy dispersion, or turbulent diffusion is a process by which substances are mixed in the atmosphere, the ocean or in any fluid system due to eddy motion. In other words, it is mixing that is caused by eddies that can vary in size f ...

), and with a reduction of the

Richardson number The Richardson number (Ri) is named after Lewis Fry Richardson (1881–1953). It is the dimensionless number that expresses the ratio of the buoyancy term to the flow shear term: : \mathrm = \frac = \frac \frac where g is gravity, \rho is de ...

at the base of the pycnocline. The development of Kelvin-Helmholtz instability during the breaking of the internal tide can explain the formation of high diffusivity patches that generate a vertical flux of

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

(NO₃⁻) into the

photic zone The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological proc ...

and can sustain

new production In biological oceanography, new production is supported by nutrient inputs from outside the euphotic zone, especially upwelling of nutrients from deep water, but also from terrestrial and atmosphere sources (as opposite to regenerated production, ...

locally. Higher values of

primary productivity In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through c ...

were observed near the wave trough, than those observed during periods of maximum solar irradiance at noon. Images from the

Moderate-Resolution Imaging Spectroradiometer The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra (EOS AM) satellite, launched by NASA in 19 ...

(MODIS) and

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

(ISS) photography show the sea-surface manifestation of packets of internal

solitons In mathematics and physics, a soliton or solitary wave is a self-reinforcing wave packet that maintains its shape while it propagates at a constant velocity. Solitons are caused by a cancellation of nonlinear and dispersive effects in the medium ...

(or nonlinear internal waves) generated at ''Banco Engaño'', located at the northwest margin of the Mona Passage. The packets propagate either into the Caribbean Sea or the Atlantic Ocean depending on the direction of the currents that forced their generation. Surface tides, internal tides, internal solitons, inertial currents and the low frequency water mass transport between the Atlantic Ocean and the Caribbean Sea make the Mona Passage a very dynamic environment.

Boating

Cruising boaters entering the Caribbean from the north often do so via a stop at Samaná in the northeastern part of the

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...

, then continuing across the Mona Passage to Puerto Rico without stopping. Under sail it means an even longer distance because of having to "tack" a zig-zag course into the easterly

trade winds The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisph ...

. At the stop of

Saona Island Saona Island ( es, Isla Saona) is a 110 square kilometer tropical island located off the south-east coast in Dominican Republic's La Altagracia province. It is a government-protected nature reserve and is part of '' Parque Nacional Cotubanamá''. ...

on the southeast coast of the Dominican Republic, boaters can sit and wait for a lull in the trade winds when seas are down to start their eastward crossing. This is an advantage that is not possible when departing from Samaná. It is only about from Saona to the protected anchorage inside the barrier coral reef on the west coast of Mona Island. And from there it is another to the popular and spacious cruising anchorage at Boquerón in Puerto Rico.

References

External links