Algeciras Bay

The Bay of Algeciras (in English: Bay of Gibraltar) is located in the south of the Iberian Peninsula, on the northern shore of the Strait of Gibraltar. It includes the stretch of coast delimited by Punta Carnero and Punta Europa with a depth of about 10 km, a minimum width of 8 km, a surface area of 7,500 hectares and with depths of up to 400 m. Its shoreline runs from west to east and in clockwise to the Spanish municipalities of Algeciras, Los Barrios, San Roque and La Línea de la Concepción and to the British Overseas Territory of Gibraltar with a total population of more than 250,000 inhabitants.

It has a complex geological history conditioned by its position between three tectonic plates and the superposition of at least three stratigraphic series of sedimentary rocks dating from the Mesozoic to the Oligocene. Geomorphologically, it originates after fluvial and marine sedimentation in an old river valley and next to the rocky promontory of the Rock of Gibraltar.

Its natural values are the result of its geographical location between the Atlantic Ocean and the Mediterranean Sea and between the European and African continents. It is a transit point for migratory species of both birds and cetaceans. Its resident flora and fauna participate in several biogeographic provinces, with the endemic component of the region being very important. Several of the present ecosystems are protected by various environmental figures, although the intense urbanization process and the present port facilities have caused during the second half of the 20th century a strong degradation of the environment.

The human presence in the bay of Algeciras has been confirmed for at least 600,000 years by the discovery of lithic tools belonging to the Acheulean technocomplex linked to Homo heidelbergensis. It was a place of refuge for the last populations of Homo neanderthalensis according to research carried out with the skeletal remains located in Gibraltar. The first stable settlement that is known in the area is that of the Phoenician city of Carteya, an important commercial colony of the century VII a. C. During the 1st century the economy of the region was based on fishing and the processing of products derived from it with two active ports, the aforementioned Carteya and Iulia Traducta. From the year 711 after the conquest Muslim of the Iberian Peninsula human settlements in the region will play an important role in trade between Europe and Africa with the city of Al-Yazirat Al-Hadra as the administrative center. It will be after the Taking of Gibraltar in 1704 and as a consequence of this when the current population centers appear.

Today the bay of Algeciras is a place of strong economic activity with an important industrial hub dedicated mainly to the transformation of petroleum products and the important ports of Gibraltar and Algeciras, specialized in the transfer of fuel and passenger traffic the first and in the transport of goods the second.

Geography

The bay of Algeciras is located at the southern end of the Iberian Peninsula, delimited by the stretch of coast located between Punta Europa and Punta Carnero. Its waters occupy approximately an area of 70 km² and a volume of 6.2 km³ that communicate with those of the Mediterranean Sea through the 8,000 meters that separate their boundary points. It is almost circular in shape and reaches its maximum width at 9,200 m. The maximum depth is reached at 460 m located at the mouth of the bay and which corresponds to the so-called Algeciras canyon that originates around the mouth of the Palmones and Guadarranque rivers.

The waters of the Bay of Algeciras are slightly colder than those of the surrounding areas of the Alboran Sea and the Strait of Gibraltar, possibly due to the penetration and sudden rise of deep currents from the Mediterranean. The tides are of little importance, with the maximum tidal level being 0.8 m almost constantly along the entire bank.

Geological history

The Bay of Algeciras as a geomorphological unit had its genesis in the accumulation of sediments throughout the Quaternary in the river valleys and the isthmus of Gibraltar. The geological history of this geographical area is still the subject of study due to its peculiar situation as the limit of three tectonic plates, the African, the Iberian and the Alboran. The continuous movements of these since the Cretaceous have led to the superposition of at least four different geological units.

From the end of the Cretaceous to the beginning of the Eocene, a first orogenic phase took place in which a mountain range or elevated land mass was formed in the Alboran Sea that would be eroded shortly afterwards to form strong sedimentary deposits. During the upper Eocene, the Pyrenean orogeny caused the elevation of the sedimentary rocks formed in the basin and the formation of the Penibetic mountain range. At the same time, a communication was opened in the current depression of the Guadalquivir between the seas located on both shores of the Strait. At this time, a mountain range without a solution of continuity was formed between the northern and southern shores of the Strait, the so-called Gibraltar arc, while the Alboran Sea acquired greater depth. During the Miocene, tectonic movements in the area ceased or slowed down, filling the passage of the Betic depression with sediments from the new mountain ranges until the communication between the Atlantic Ocean and the Mediterranean was closed.

Throughout the Miocene the Mediterranean Sea dried up after being isolated from the ocean. In this way, the arch of the Strait remained as a barrier and weakest point against the pressure exerted by the Atlantic Ocean. At this time, the Algeciras canyon, the maximum depth of the bay, was formed by the erosion of the Palmones and Guadarranque rivers on the old oceanic platform. Although it is not well known how this could have happened, during the late Pliocene the passage through the Strait of Gibraltar was opened. Certain theories point to a sudden change in the rainfall regime caused by a change in the climate that could dismantle the Gibraltar arc mountain range, other theories attribute this rupture to the establishment of a new tectonic regime that would cause a change of direction in the African plates. and Iberian from the Tortonian. After the opening of the Strait, subsequent erosive and sedimentary processes would give rise to an abrupt coastline with deep river valleys resulting from the periods in which the Mediterranean remained dry (Guadaranque-Palmones valleys). These valleys would be filled by sediments during later times until forming the current coastline.

Geology and geomorphology

From all these processes comes the current geology of the region, similar to that of the rest of the Betic and Rife mountain ranges, although more complex due to its position as the extreme point of the arc formed by both. The main geological element and ultimately responsible for the formation of the bay is the Rock of Gibraltar, a rocky promontory 426 m high with a steep dip on its west face and steep cliffs on its east face and in the south. This is part of the so-called Tariquides unit composed of Mesozoic limestones that have very discontinuous outcrops along the entire Betic-Rife mountain range and that in the bay of Algeciras has an equivalent in the quarry of Los Pastores, Algeciras. Three stratigraphic series appear on the Rock of Gibraltar, formed by different types of limestone, dolomite, marl and pelite. These series are dated to the Upper Triassic (Carnian), Upper Sinemurian and Middle Lías (Domerian) and their relationship with other adjacent series is unknown. In the Los Pastores quarry, on the other side of the bay, three stratigraphic series of similar composition also appear but dated to the Trías, the Lías-Dogger, and the Malm-Upper Cretaceous. The origin of the Taríchides unit is unknown, with various theories pointing to its allochthonous origin with respect to the rest of the Baetic units.

Except for these two outcrops mentioned, the rest of the area corresponds to the Algeciras unit, belonging to the Campo de Gibraltar complex. The Algeciras unit occupies a lower position in the Complex and the Aljibe unit rides on it in most of the region. However, in the vicinity of the bay of Algeciras the unit of Algeciras appears individualized, forming the mountain ranges closest to the coast, mainly the Cerro de la Horca, part of the landscape unit called cerros del Strait. Geologically, the large cliffs formed around Punta Carnero stand out. In these cliffs the sequence reaches a depth of a thousand meters with several strata of very variable thickness formed by marl and sandstone originating from submarine fans. Its dating is uncertain due to the lack of indicator fossils, although it has been determined that its base had its origin in the Upper Oligocene and would possibly extend until the beginning of the Burdigalian.

Although it is in Punta Carnero where these sequences are best appreciated, the Algeciras unit extends throughout the bay. It also appears in the cliffs at Punta de San García or Torrealmirante, with heights of up to 20 meters and wide abrasion platforms, in the sinuous hills on which the cities of Algeciras, Los Barrios and San Roque are located, to the foothills of Sierra Carbonera.. To the north of La Línea de la Concepción, forming part of the Carbonera mountain range, sandstone flyschs called La Línea flyschs emerge, which have been interpreted as part of the Aljibe unit. , occupying its base or as a transition element between this unit and Algeciras.

In the basins of the Palmones-Guadarranque and Pícaro-Marchenilla rivers and occupying the old river valleys, post-orogenic sedimentary basins appear that currently form a large plain topped by fine sand beaches on its coastal front. The materials that emerge in this area are clays, sands, gravels and silts from the weathering of surrounding materials and transported by surface waters during the Pliocene and Quaternary. The isthmus of Gibraltar and much of the land on which it is located in the city of La Línea de la Concepción, they are formed by sediments of marine origin and form a very extensive area of low elevation.

Although sedimentation in the areas closest to the continent must have begun simultaneously with that of the mouth of the Palmones-Guadarranque, the accumulation of the sands that form the isthmus is very recent in time. Various researchers point to the insular nature of the Rock even during the Middle Ages based on writings from the time. The sedimentation must have been so recent that in engravings from the 18th century the isthmus of Gibraltar still appears marked by small lagoons and canals in progress. of clogging. Something similar would occur in the areas closest to the sea of the meadows of the main rivers of the bay that were filled in in historical times.

Under the waters of the bay there appears a wider continental shelf than in the adjacent areas of the Strait of Gibraltar and the coast of the province of Málaga, but less than on the western coast of the province of Cádiz. This continental shelf is interrupted by the Algeciras Canyon which, born two kilometers from the mouth of the Guadarranque River, continues beyond the limits of the bay. Its bottoms are mainly sandy.

Hydrology

Navy

Currently the marine current regime of the bay of Algeciras is profoundly transformed by the construction of port facilities. Before this transformation there was a network of secondary currents originated after the main current coming from the west of the Strait of Gibraltar was diverted in different coastal features. This primary current was responsible for the erosion of the coast of the Rock of Gibraltar and the distribution of its own sediments and those deposited by the river courses.

The main sediment receiving areas are found on the western shore of the bay while in the northern area the currents act mainly by transporting them. Thus, strong sedimentation occurs on the beaches of Palmones and Rinconcillo. After passing the points of Paredones and San García, the currents continued parallel to the coast, transporting sediments through the Getares inlet and the coast of the Strait to Los Lances beach, in Tarifa.

Port infrastructures, however, have modified this flow regime. The profound modification of the coastline during the second half of the XX century has meant an increase in the coastline corresponding to the ports from 9983 m in 1956 to 33,332 m in 1997. Thus the coastline of the bay of Algeciras in 1956 was 31,490 m and 50,996 m in 1997. The obstacles offered by the port facilities cause the refraction of marine currents. that stop circulating parallel to the coast to enter deeper areas of the bay. Transport and sedimentation processes are therefore reduced, increasing erosion, mainly on beaches.

Various reports highlight the need to carry out more in-depth studies on the current regime inside the bay of Algeciras because although in recent years companies based in the area have carried out specific measurements and simulations related to the environmental impact of a new construction lacks a global vision of the process.

Riparia and lacustrine

The channel of the rivers that flow into the bay of Algeciras is conditioned by the rainfall regime of the area and the topology of the place. In those areas where elevations of the land are located very close to the coast, mainly in cliff areas, these rivers have a short course and a marked low level that keeps them active only during rainy seasons. An example of them would be the Aguada stream. Those rivers that run largely through flat terrain are, however, long with a very extensive river basin made up of a multitude of tributaries that maintain flow all year round. The Palmones, Guadacorte and Guadarranque rivers belong to this type. In intermediate situations, running in their last section through flat land but rising in mountains relatively close to the coast, the Pícaro, Miel, Lobo stream, Saladillo stream, Las Cañas stream and Gallegos stream appear, all of them. channeled as they pass through urban centers.

Due to the dimensions of its basins, its great flow and its influence on the topology of the bay, two rivers stand out, both with an extensive network of tributaries. The Palmones or de las Cañas river, with a total length of 37 km and a hydrographic basin of 312 km², rises in the Aljibe mountain range and its mouth serves as a dividing line between the municipalities of Algeciras and Los Barrios. forming a tidal marsh of approximately 58 ha, and the Guadarranque River with 43 km in length, a hydrographic basin of 264.3 km² and which originates in Mogea del Rayo in the municipality of Jimena de la Frontera and flows into the bay. acting as a dividing line between the municipalities of Los Barrios and San Roque.

Both rivers, and the current tributary of the Palmones, called the Guadacorte River, shared the same mouth of about 4 km wide during the Pleistocene. This great river course, because the sea level was lower than today, penetrated into the current bay of Algeciras forming a deep and wide valley that remains submerged today, the Algeciras canyon, and a large river fan in the Strait of Gibraltar.

The groundwater of the Bay of Algeciras forms two aquifers in the areas occupied by Quaternary deposits. The La Línea Quaternary Aquifer extends from the foothills of the Carbonera mountain range under the towns of La Línea de la Concepción and Campamento to the rock of Gibraltar itself. It is about 10 km² and has a thickness of 20 m corresponding to the sands accumulated in the isthmus and surrounding areas. The Guadaranque-Palmones Plioquaternary Aquifer is more extensive, about 105 km², with the waters at a depth of between 20 and 70 m. It corresponds to the alluvial plains of the two rivers that give it its name and extends along its channels, leaving a large part of the municipal areas of Algeciras, Los Barrios, San Roque and Castellar de la Frontera, including its main centers, above it.

Climatology

The Algeciras Bay region has a temperate Mediterranean type climate with predominantly mild temperatures during the winter (around 16°C) and moderately high temperatures during the summer (with an average of 27°C). The average annual temperature is 19°C and sunshine is around 2600 hours per year. The precipitation regime follows the usual pattern of the Mediterranean region with rainy winters and dry summers, although the average precipitation is higher than that of other areas with a similar climate. The average precipitation is between 700 and 1000 mm annually, although this precipitation is concentrated during the months of November to March and is highly conditioned by the orography.

Wind is an important factor both in the water regime of the area and in the circulation of surface waters, and the formation of condensation clouds is also common when the wind currents come into contact with the elevations near the coast, increasing locally. precipitation and ambient humidity. The predominant winds in the bay are from the East and West, called Levante and Poniente respectively. The frequency of easterly component winds is higher with 15.5% of the percentage compared to 11% of western component winds. However, the highest percentages are presented by the winds from the Northwest and Northeast with 30% and 17.8% respectively, while the winds from the North have an incidence of 11.2%.

Natural environment

The bay of Algeciras, like the entire northern area of the Strait of Gibraltar, has characteristics of a transition place between the Atlantic Ocean and the Mediterranean Sea and between Europe and Africa in terms of its flora and fauna. The geological history of the area has meant that there have been very strong episodes of biological isolation and speciation since the Miocene that have given rise to a biota with a high degree of endemism along with Iberomauritan and Mediterranean elements.

Navy

As a transition place between the Mediterranean Sea and the Atlantic Ocean, the waters of the Bay of Algeciras have biological communities typical of both biogeographic regions, although the Mediterranean component prevails. The present biological richness is very high, although due to the coastal transformation processes that have developed during the second half of the XX century, there are specific areas, mainly inside the ports, where biodiversity is very low.

The benthic communities developed on intertidal platforms are very important in the region. These communities have a very high biodiversity, more in areas near the coast with currents that distribute nutrients and prevent sedimentation than in the interior of the bay where the high depths and currents prevent their further development. From the coastline to 30 m depth, a total of 1,465 benthic species, both animals and plants, have been censused, a number slightly lower than that of less transformed areas of the Strait of Gibraltar (1,731). In this aspect, the stretches of coast from Punta Carnero to Punta de San García and the areas surrounding the ports of Gibraltar and Crinavis stand out. Particularly important is the presence of Patella ferruginosa, the only mollusk marine cataloged as in danger of extinction from the Iberian Peninsula, and the species classified as Vulnerable Dendropoma petraeum, Charonia lampas lampas , and Cymbula nigra.

One of the largest underwater ecosystems in the bay is the sublittoral terraces, permanently submerged sandbanks with less than 20 cm of water, a habitat of environmental interest with the presence of numerous species of bivalves, gastropods and echinoderms. among which stand out Donax trunculus, Ensis minor, Chamelea gallina, Acanthocardia tuberculata or Callista chione. The underwater meadows of Zostera marina, Posidonia oceanica, Cymodocea nodosa and Zostera noltii, Very abundant in the recent past, they have suffered a strong decline, disappearing in most of the bay and being found only in very specific points such as in the vicinity of Punta Carnero.

The environmental impact studies carried out in the area have revealed a loss of biodiversity associated with the port facilities and the continuous movements of sediments carried out. The main biological indicators analyzed in these studies are benthic organisms, seagrass meadows and invertebrates whose presence has already been named. The regression of many of these communities and the proliferation of others indicates a significant deterioration of the marine biota. Several algae of the genus Ulva, whose presence indicates a high degree of degradation of the environment and which contribute to eutrophication processes, have been located specifically in areas previously occupied by phanerogams. Regarding phytoplankton, associated with nitrogenous discharges, the reports carried out have not detected growth patterns that could suggest pollution problems.

With respect to the ichthyofauna, the bay of Algeciras does not differ in its fauna from other sectors of the Mediterranean coast, although the fish associated with the intertidal pools are notable for their abundance. These groups develop on rocky coasts associated with cliffs, with Gobius cobitis, Liza sp. and Lepadogaster purpurea appearing as the predominant species. Special relevance It has the presence of Chromogobius quadrivittatus, with very high biodiversity indices found, mainly in Punta Carnero. The presence of stable populations of cetaceans linked to fish schools, mainly the striped dolphin, the common dolphin and the dolphin bottlenose whale, although there are also permanent populations or those from other areas of the Strait of Gibraltar of the pilot whale, the sperm whale, the gray pilot whale and the orca or the seasonal passage of the fin whale.

Terrestrial

One of the best preserved natural areas of the bay of Algeciras corresponds to the Getares cove and Punta Carnero within the geomorphological unit called cerros del Estrecho, where it is possible to observe the best developed vegetation of the area. The developed forests are of the type Myrto communis-Querceto suberis or xerophytic cork oaks and on the limestone outcrops the series Tamo communis-Oleeto sylvestris or wild olive trees. On the cliffs there are communities. Very specialized vegetables with the characteristic presence of Crithmum maritimum, Calendula suffruticosa and Asteriscus maritimus on vertical rock strata.

The Rock of Gibraltar, characterized by its topography, maintains numerous plant species belonging to the same vegetation series as the rest of the area, although it has a strong endemic component linked mainly to the coastal cliffs. Its floristic richness is estimated at around 500 or 600 species, highlighting the endemisms Cerastium gibraltaricum, Silene tormentosa, Iberis gibraltaica or Limonium emarginatum, many of them not limited to the rock but also shared by other areas of the bay of Algeciras.

On the beaches appears the plant community called Ononido variegatae-Linarietum pedunculatae, the series of vegetation typical of the region's coastline with species such as Ononis variegata, Linaria pedunculata and Pseudorlaya pumila. Regarding the riparian ecosystems associated with the coast, the tidal marshes present at the mouth of the Palmones River stand out. These ecosystems once had a greater extension, expanding to the mouths of the Pícaro and Guadarranque rivers, today highly degraded by anthropogenic actions. In the marshes of the Palmones River, the geoseries called geomacroserie of salt marshes and salt flats and geomacroserie of dunes and coastal sands are present. In them, halophytic species appear, adapted to high salinity because they are partially submerged in brackish waters in the first geoseries, and therophytic species, adapted to living in areas with little available water. The plant communities are made up of Spartina maritima, Zostera noltii, Sarcocornia perennis and Juncus maritimus and provide shelter to communities of birds, with censuses of more than 200 species, both resident and migrating.

Environmental protection

Given the biodiversity and variety of habitats present in the geographical environment of the Bay of Algeciras, there are several protection figures present in the area. The stretch of coast and inland lands from Punta Carnero to Punta de Getares and the stretch corresponding to Punta de San García is included within the Strait Natural Park. This same natural park protects a mile of coastal waters from Punta de San García to Punta Carnero. These sectors correspond to the least transformed area of the bay and with the highest biodiversity indices.

Towards the north, at the mouth of the Palmones River are the tidal marshes protected under the figure of natural site protection and integrating within their limits 9 habitats of community interest. The natural area of the Palmones River marshes has an area of 113 hectares corresponding to the marshes, the primary dune range and the flood plains. This peculiar ecosystem is a resting and nesting place for a large number of birds, which is why the area was also declared a Special Protection Area for Birds (Z.E.P.A.) and a Special Conservation Area (Z.E.C.), becoming part of the Natura Network. 2000. Part of the lower course of the Palmones River is also protected by the general urban planning plans (P.G.O.U.) of the towns of Algeciras and Los Barrios. Thus, the sectors called "unprotected marshes of Palmones" and "acebuchales and river plain" of the respective P.G.O.U. They become part of the protected areas within the Special supramunicipal plan for the middle and lower course of the Palmones River. In front of the mouth of the Palmones River is the Place of Community Importance called Seabeds Palmones River marshes, 88 hectares long that complements the natural area, protecting the breeding ground for several species of fish and the only colony of Posidonia oceanica in the bay.

The Upper rock nature reserve (Rock of Gibraltar Nature Reserve) is a nature reserve declared in 1993 in the upper half of the Rock of Gibraltar by the Government of Gibraltar. It was expanded in 2011 with the cliffs of Punta de Europa and adjacent areas representing more than 40% of its surface. Several ecosystems of great environmental interest are protected by this reserve, where the Mediterranean olive forest predominates but where approximately 350 species of wild olive trees also appear. plants, many of which are endemic to the region. The role of this reserve in the passage of migratory birds through the Strait of Gibraltar is also important.

The surrounding waters of the Rock of Gibraltar are protected by both the Government of Spain and the Government of Gibraltar under the names of Eastern Strait and Southern Waters of Gibraltar. Due to the existing conflict between both governments over the territoriality of these waters, there is a dispute over the legality of these protection figures. Both areas were accepted in compliance with the Habitat Directive of the European Union Places of Community Importance (L.I.C.) to be integrated in the Natura 2000 Network even coinciding in part of its extension.

The site called Southern Waters of Gibraltar was proposed as a Site of Community Importance by the Government of Gibraltar and accepted by the European Commission on July 19, 2006. For its part, the site Eastern Strait was proposed by the Government of Spain and approved by the same commission on December 12, 2008. After the approval by the European Commission of the Community Sites of Interest, it is the responsibility of the proposing countries to declare them. and conversion into Special Conservation Areas (Z.E.C.), a fact that in the case of the L.I.C. Southern Waters of Gibraltar took place on March 10, 2011, while the L.I.C. Eastern Strait took place by Royal Decree on November 30, 2012. Regardless of the disputes over the ownership of the waters surrounding the Rock of Gibraltar, the truth is that the protected waters are considered to be an area of of great biological and environmental importance, subject to a strong transformation process and very aggressive maritime traffic. The Z.E.C. Southern Waters of Gibraltar occupies 5486.5 hectares while the Z.E.C. Eastern Strait occupies 23,640 hectares, protecting ecosystems such as reefs, underwater caves with animal species as important due to their delicate state of conservation as the loggerhead turtle or the bottlenose dolphin. Also noteworthy is the large number of seabirds present in the area, both nesting and passing through, which has led to both Z.E.C. have also been declared Special Protection Areas for birds (Z.E.P.A.).

Environmental controversy

The bay of Algeciras, due mainly to the intense maritime traffic and the high concentration of industries, is subject to constant episodes of environmental pollution. Particularly noteworthy are those related to hydrocarbon spills into its waters by damaged ships and air pollution by industry.

Maritime accidents in the area are frequent. Due to its importance, the accident of the Panamanian ship Petrogen One on May 26, 1985 is noteworthy. This oil tanker with 2,000 tons of fuel in its holds exploded while carrying out a transfer at the Gibraltar refinery facilities. San Roque in San Roque also exploding another ship that was next to it, the Camponavia, and causing the death of 33 people and injuries to more than 70. Most of the accidents in the area results in the dumping of more or less significant quantities of fuel into the sea. The accidents of the Spabunker IV vessels in the monobuoy of the Gibraltar-San Roque refinery on January 21, 2003, the Sierra Nava on January 28, 2007 in the Punta de San García, the MV New Flame on August 12 of the same year in Punta Europa, the ships Fedra and Tawe also in Punta Europa and Punta de San García on October 10, 2008, the Ropax I at the Gibraltar-San Roque refinery on December 13, 2008, the Sein I in the port of Gibraltar on September 20, 2009 or the MSC Shenzhen at the CERNAVAL docks on October 28, 2009, place the bay of Algeciras along with the rest of the Strait of Gibraltar in the area with more maritime accidents, especially oil tankers, in the entire Iberian Peninsula.

But fuel spills into the sea do not only come from maritime accidents, many of them have their origin in ship cleaning tasks or leaks during bunkering processes. Bunkering, the transfer of fuel between two ships on the high seas, is a common exercise because refueling ships avoid entering the port and is the source of much criticism. and complaints by environmental groups. Both the ports of Gibraltar and Algeciras carry out bunkering activities, moving quantities of transferred fuel exceeding 4 million tons annually. The facilities intended for the storage of fuel from Gibraltar have also been the cause of polluting discharges both into the waters of the bay and into the air. Thus, the accident that occurred on June 6, 2011, in which two fuel tanks that were being repaired at the North Dock exploded and burned for several hours, resulted in the death of one worker and injuries to another, and the spillage of fuel. to the waters.

The industrial hub of the bay of Algeciras has been among the most important in Spain since the area was declared Preferential industrial location area in 1966. The impact of environmental pollution derived from this industry It varies depending on the entity that carries out the epidemiological studies, with several studies showing an incidence of cancer cases in the population higher than 28% of the average for Spain. Mortality rates higher than the averages for Andalusia and Spain are observed in the population. mainly due to tumors of the trachea, bronchi, lungs, bladder and cirrhosis. Reports on environmental quality carried out by the Government of Andalusia show concentrations higher than those recommended in the emissions of sulfur dioxide, nitrogen dioxide and suspended particles. These emissions peaks appear as specific episodes of pollution, although the average is higher than that of other industrial areas.

The risks of environmental contamination in the bay due to radioactivity are also notable. The presence of nuclear-powered submarines in the port of Gibraltar has been the subject of complaints by citizen associations since in 2000 the submarine H.M.S. Tireless was repaired in said facilities. Even so, the only incident of nuclear contamination in the area took place in May 1998 when scrap metal contaminated by cesium-137 was processed at the Acerinox factory in Los Barrios, giving rise to a radioactive cloud that was detected in Central Europe and 5,198 tons of radioactive ash.

Human environment

Prehistory

The earliest human presence in the Bay of Algeciras has been confirmed by various archaeological finds of lithic tools belonging to the Acheulean technocomplex (or Mode 2), dated to the Middle Pleistocene. This technology, with a very wide temporal distribution (from 600,000 years ago to 125,000 years ago with the beginning of the use of Mousterian technology by Homo neanderthalensis), was used by bands of hunter-gatherers who They used river courses for their movements and areas near the coast. There are several Mode 2 sites that stand out within the geographical context for their abundance of materials, mainly those made on the terraces of the Palmones River (the sites of Calvario de las Tres Marías, Altos de Ringo Rango, Lazareto 1, Huerto Castillo, El Chaparral or Moheda Conejo), in Getares, Cerro del Prado, Punta Mala, the plains of Torrealmirante or Gorham's Cave.

To date, no skeletal remains of the hominids that used this industry associated with the sites have been found either in the bay of Algeciras or in its closest geographical environment, although by equivalence with other remains on the Iberian Peninsula these must correspond with Homo heidelbergensis, currently considered a transitional species between Homo ergaster and Homo neanderthalensis.

Some of these finds of Mode 2 lithic industry, those more modern that present transitional characteristics between this industry and the Mousterian or Mode 3, are already attributable to Homo neanderthalensis although the only remains bones of this species located so far are those corresponding to the site of Forbes Quarry and Devil's Tower on the rock of Gibraltar. Both paleontological sites provided in 1848 (Forbes Quarry) and 1936 (Devil's Tower), two Neanderthal skulls associated with the Mousterian stone industry in the second site. Although they are not very common, they have Mousterian lithic tools also appeared in other sites in the region, Torrealmirante and Palmones, which are usually considered to be typical of Neanderthal populations.

The first representatives of our species (Homo sapiens sapiens) must have arrived in the bay of Algeciras approximately 30,000 years ago during the Solutrean period, as attested by the lithic industry sites associated with them on the plains. from Torrealmirante and Gorham's Cave. From this period onwards, archaeological finds become increasingly scarce. The records corresponding to the Epipaleolithic and the Neolithic are hardly represented in the region with some exceptions such as the presence of ceramics with incised decoration in Gorham's Cave or the remains of a settlement (possibly a village dedicated to agriculture and livestock) in the Huerta de Las Pilas quarry.

Ancient Age

The first human settlement of which there is archaeological evidence in the bay of Algeciras is that of the Phoenician colony of Carteya. This city, with an economy based on fishing and trade among indigenous peoples, was founded on an elevated place next to the mouth of the Guadarranque River in the middle of the century VII a. C. The primitive city, located in the current Cerro del Prado, was abandoned in the IV a. C. and moved to a place closer to the coast, probably due to the clogging of the inlet where it was located and which would have rendered its port facilities unusable.

The economic and structural importance of the city of Carteya in the surroundings of the Bay of Algeciras was maintained with the Roman conquest of the Iberian Peninsula. In the year 171 BC. C. the city acquires the title of Colonia libertinorum after a delegation of children of Roman soldiers and indigenous women requested it before the senate of Rome.

In the middle of the 1st century AD. C. the economic preponderance of the city seems to decrease while another city located in the arc of the bay, Iulia Traducta, takes on greater importance, with an important complex for the production of garum and other products. This city, Located at the mouth of the Miel River, it was founded between the years 33 and 27 BC. C. with part of the population of the North African city of Zilis and veterans of the second civil war of the Roman Republic. With this foundation, Emperor Octavian intended to create a city loyal to him in the face of a Carteia that had supported his adversary Pompey.

The region's economy continues to be based on fishing and the production of products derived from the sea. Apart from the two cities already mentioned of Carteya and Iulia Traducta, there are several settlements on the coast with facilities related to these activities. The presence of potteries is known on the beach of El Chorruelo, El Rinconcillo, Venta del Carmen, Altos de Ringo Rango, Campamento and Punta Mala and factories in Villa Victoria and Getares. The Villa Victoria factory located one kilometer from Carteya and closely linked to this city had a very important activity in the early imperial era, coming to have facilities for the manufacture of dyes in the century IV. The Caetaria factory named by Ptolemy in the II century would be located in Getares. and whose remains of salting pools remain awaiting archaeological interventions.

Middle Ages

With the fall of the Roman Empire, all political organization in the region disappeared. In the year 419, the Silingo vandals crossed the Strait of Gibraltar, and in the year 429 the Asdingo vandals did so with the subsequent destruction of the coastal cities. Due to the lack of Visigoth occupation in the south of the Iberian Peninsula, the bay of Algeciras is severely depressed and its cities suffer a strong loss of population.

Starting in the year 552, the Mediterranean coast was occupied by the Byzantine Empire without this meaning the economic recovery of the bay. A ruralization of the area occurred with the transfer of part of the population to agricultural areas and the abandonment of industrial facilities. The depopulation of the cities of Carteya and Iulia Traducta is not absolute, and the presence of some constructions and burials corresponding to this period in both locations is known.

In the year 711, the Muslim conquest of the Iberian Peninsula took place, with the bay of Algeciras as its main stage. At the beginning of that year, Táriq ibn Ziyad's troops landed on the rock of Gibraltar (since called Jabal Tāriq or Mount of Tariq). After that they conquer the city of Carteya and establish a fixed camp on the island located in front of the city of Iulia Traducta (called Al Yazirat Umm Hakim or island of Humm Hakim) to later move to the city that would become known as Al-Yazirat Al-Hadra or the Green Island.

From the beginning of the Arab presence, the city of Al-Yazirat acted as the administrative center of the entire bay as the capital of a group that encompassed the entire current region of Campo de Gibraltar, Gibraltar and part of the surrounding regions. In the bay of Algeciras, Al-Yazirat appears as the only town of any size, with numerous farmsteads remaining under its administration, including the ancient Carteya (called Turrush Qartayanna) until the founding in the year 1167 of the city of Algeciras. Madina al-Fath or city of Victory in present-day Gibraltar by order of the king of the taifa of Seville Al Mutadid on a castle that had existed a few decades before.

In 1275 the Benimerine troops of Abu al-Hasan landed in Algeciras, taking the territory of the ancient cora. From then on, the area was the scene of the so-called Battle of the Strait of Gibraltar with the attempted conquest of the two cities in the bay by the Crown of Castile. In this way, sieges were established on the city of Algeciras in 1278 and 1309, being definitively conquered by Alfonso Cities were later reconquered by the Nasrid Kingdom of Granada, Algeciras in 1369 and Gibraltar in 1374. Algeciras was completely destroyed in 1379, leaving the entire region controlled by the Kingdom of Granada until the definitive conquest of the square of Gibraltar in 1462 by the troops of Isabel I of the Kingdom of Castile.

Modern Age

After the destruction of Algeciras, its entire municipal area, which included the bay of Algeciras except for the rock, belonged administratively to the cities of Tarifa and Jerez de la Frontera. In 1462 Henry IV granted jurisdiction over the areas of Las Algeciras to the city of Gibraltar, extending the disputes with the councils of Tarifa and Jerez until they definitively became his property in 1514. The bay of Algeciras, now Campo de Gibraltar as it is the municipal area of Gibraltar, remained an agricultural area of this city, sparsely populated and divided into privately owned farmhouses and haciendas.

On August 1, 1704, within the War of the Spanish Succession, an Anglo-Dutch fleet under the command of Admiral George Rooke besieged a sparsely garrisoned city of Gibraltar. The definitive capture of the city on August 4 after the signing of the capitulation by the Gibraltarian council meant the exile of practically the entire population of the city and its provisional establishment on the Campo lands. The new British authorities in Gibraltar encouraged the settlement of the civilian population in the city and although in the first years the number of British was small, there was a strong immigration from Genoa, which had a consulate in the city since 1707, and from Jews from Tetouan..

The rulers of Gibraltar and part of the Gibraltarian bourgeoisie in exile settled around the hermitage of San Roque, in an agricultural area in the interior of the bay. Another group of citizens would do the same in the surroundings of the chapel of the Tinoco farmhouse, another agricultural area in the interior next to the right bank of the Palmones River and a third group settled in the hermitage of San Bernardo, next to the orchards and the small fishing port of Algeciras. Three new population centers were thus populated in the arc of the bay, San Roque, Los Barrios and Algeciras.

In this way the city of San Roque was officially founded in 1706, receiving all the privileges of the lost city of Gibraltar and taking the title of Very Noble and Most Loyal city of San Roque, where the city of Gibraltar resides. The town council was officially established after the meeting of the Gibraltar Council in its Campo y Locko on June 18 of that year, with its first councilor being Rodrigo Muñoz Gallego and deciding to locate the town next to the hermitage of San Roque. After a few first years of uncertainty about the fate of the city of Gibraltar and its citizens in the Campo it was definitively in 1713 when, through the Treaty of Utrecht, Spain ceded to the United Kingdom the Plaza de Gibraltar. After that, in the Campo de Gibraltar the city of San Roque inherited its municipal area from this city, passing the other two population centers to depend on it by Royal Decree of August 14 from 1726.

As a consequence of this concession, the representatives of the city of Algeciras requested the return of its old municipal area to the Council of Castile, receiving the council of San Roque a document for these claims to be fulfilled. With the opposition to complying with this order by the San Roque city council, which considered that the three cities of the Campo represented the city of Gibraltar in exile and therefore were indissoluble, a lawsuit began that ended with a Royal Decree on February 9, 1755. This order, prompted by the claims of the General Commander of the Campo de Gibraltar Francisco de Paula Bucareli y Ursúa, officially constituted the town councils of Los Barrios and Algeciras segregated from that of Gibraltar-San Roque. By Royal Order issued on June 22, 1756, the old areas of Gibraltar would be divided between the three towns of the Campo, although maintaining the joint use of its mountains.

Contemporary Age

The square of Gibraltar suffered three sieges by Spain in 1705, 1727 and 1779. During the last of these sieges, the longest, a large complex of fortifications was created throughout the bay. The main fortification was the so-called Gibraltar Contravalation Line, located on the isthmus of Gibraltar, after which a new town began to be populated, The Gibraltar Line, dependent in these early years on the town council of San Roque. The Spanish War of Independence had as its main consequence in the region the dismantling of the fortifications that dotted its entire coast by British troops in 1810 to prevent them from falling into the hands of Napoleonic troops. The destruction of the Gibraltar Contravallation Line and its subsequent demilitarization and opening led to the establishment of the civilian population in the area favored by the proximity to the British city and the trade possibilities with it. The continuous transfer of workers to one side and the other of the border caused the population of the village of La Línea de Gibraltar to grow rapidly, which would soon request its segregation from San Roque. This segregation was finally approved on the 17th. January 1870. At the first meeting of the new city council it was decided to give the city the name of La Línea de la Concepción because the Virgin of La Concepción was the patron saint of the Spanish Infantry Corps.

The city of Gibraltar was called from its capture The City and garrison of Gibraltar in the Kingdom of Spain (the city and garrison of Gibraltar in the Kingdom of Spain) lacking a specific status until 1830 That year it acquired the status of colony (Crown colony of Gibraltar) with a series of rights for its inhabitants regarding Justice and civil rights. The representatives of the city were not, however, elected by the citizens until December 1, 1921 when, through suffrage limited to men, 4 of the 9 representatives of the City Council were elected (equivalent to a city hall). The Governor of the city, responsible for the entire legislative process, and the Commander of the garrison continued to be appointed by the British Crown. This situation changed in 1946 when the United Kingdom registered Gibraltar with the UN as a non-regional territory. autonomousdependent on the United Kingdom. An Executive Council and a Legislative Council were created that gave greater autonomy to its inhabitants and which would be expanded in 1964 with the creation of the figure of the Chief Minister of Gibraltar. In 1968, following a resolution by the United Nations, the city was included in the list of territories in the process of decolonization, establishing a series of guidelines to resolve the conflict with Spain. On May 30, an Autonomous Statute for Gibraltar, the Constitution of Gibraltar, was approved in a referendum, which recognized the right of its inhabitants to decide on the sovereignty of the territory. The reaction of the Spanish Head of State, Francisco Franco, was to close all communication between the peninsula and the city, eliminating the passage through the border of La Línea de la Concepción and the ferries with Algeciras on June 7, 1969.

The economic and demographic repercussions in the cities around the bay after the closure of the border did not take long, registering a population decrease of 2.72% and losing in just one year (between 1969 and 1970) a total of 8,371 inhabitants in Campo de Gibraltar because a large part of its economy was supported by trade with the city of Gibraltar. A few years earlier, in 1965, the bay of Algeciras had been declared a Preferential Industrial Location Zone after the promulgation on October 28, 1965 of the Regional Plan for the Economic and Social Development of Campo de Gibraltar. This plan, with the aim of promoting the creation of an industrial fabric in the area, allowed the establishment of an important complex of industrial estates and the expansion of the port facilities of Algeciras, La Línea and the industries that would become in the decades later until today the economic engine of the Spanish populations of the Bay of Algeciras. Communication between the cities of the Bay and the city of Gibraltar were reestablished on December 9, 1982 after the promulgation of the Lisbon Declaration on December 10. April 1980 in which the governments of Spain and the United Kingdom undertook to resolve the Gibraltar problem in an atmosphere of cordiality.

Urban centers and port facilities

Currently the entire arc of the bay of Algeciras is occupied by the urban centers of Algeciras, Los Barrios, San Roque, La Línea de la Concepción and Gibraltar with a population of more than 250,000 inhabitants. The Spanish cities in the bay belong administratively to the Campo de Gibraltar region along with the towns of Jimena de la Frontera, Castellar de la Frontera and Tarifa. Together with these same cities they form the Metropolitan Area of the Bay of Algeciras, with 90% of its population (about 235,000 inhabitants) living around the bay. This urban agglomeration is identified in its Territorial Planning Plan (P.O.T.) as a strategic node of Andalusia, mainly for foreign relations, placing it within the first level of the community's city system. Urbanistically it is articulated around the old N roads. -340 and N-351, today A-7 and CA-34. Along this communication route, from south to north and clockwise, in the municipal area of Algeciras the neighborhood of Pelayo and the main nucleus of the city appear, in the municipal area of Los Barrios the main nucleus and the neighborhoods of Puente Romano, Palmones, Los Cortijillos and Guadacorte, in the municipality of San Roque, in addition to its urban center, the neighborhoods of Taraguilla, Estación de San Roque, Miraflores, Guadarranque, La Colonia, Puente Mayorga and Campamento and the city of La Línea of La Concepción. The organization of the territory is polycentric, with the towns of Algeciras and La Línea de la Concepción acting as structural nuclei of greatest importance.

The city of Gibraltar is officially a British Overseas Territory, it has its own government and is not administered by the United Kingdom although it is associated with this country and delegates Defense, Foreign Relations and Commercial Relations to it. It has a population of 29,752 inhabitants in a territory of 6.8 km².

The waters of the bay belong administratively to the Spanish State, although the Government of Gibraltar claims the territoriality of its surrounding waters. This claim contradicts, according to the Spanish government, the Treaty of Utrecht of 1713 by which Spain ceded to Great Britain the city and port of Gibraltar and the internal waters of said port without granting any territoriality over the bay of Algeciras. The government of the United Kingdom argues, for its part, that the transfer of a territory necessarily implies the transfer of its jurisdictional waters. In any case, there are two active ports in the bay of Algeciras, the port of Gibraltar and the port of Algeciras.

The maritime traffic recorded in the area is considered to be one of the most intense in the entire Mediterranean, both in the movement of goods (solid bulk and liquid bulk), fuel and passengers. The port of Gibraltar, managed by the Gibraltar Port Authority since 2005, has as its main activities the transfer of fuel (bunkering) and the docking of tourist cruise ships. Among its facilities, the North Pier stands out, which occupies the front of the historic center of the city, having a length of berths of 2,300 m, and the South Pier, which has almost 1,000 m of berths. Both docks have the capacity to dock cruise ships, freight ships and oil tankers. The main activity of the port of Gibraltar is the transfer of fuel, reaching 4.7 million tons of fuel transferred in 2009. Also noteworthy are the facilities specifically designed for leisure activities, with three marinas. Queensway Quay, Marina Bay on the western face of the rock and Ocean Village on the eastern face.

The ports of Algeciras, La Línea and the Crinavis, Refinery and Camp facilities are grouped under the name of Port of the Bay of Algeciras and are administered by the Port Authority of the Bay of Algeciras. These facilities make up the first port in the Mediterranean in total merchandise traffic, moving a total of 89 million tons in 2012. It also carries out bunkering activities, supplying around 3.06 million tons of fuel in 2012. Its activity in passenger traffic, with regular lines with the cities of Ceuta and Tangier is also notable with a total of close to 5 million passengers during 2012 (next to the port of Tarifa, which also belongs to the Port Authority). Container traffic is carried out at the outer Isla Verde docks (30 hectares). of surface) and Juan Carlos I (with 686,132 m² of surface) from the port of Algeciras. It has facilities in the main industries of the bay, the dock and monobuoy of the Cepsa Refinery, the Acerinox dock, the C.H.S. dock. and the Endesa port that is complemented by the Campamento dock that has shipyards for unique projects. There are two marinas managed by the Port Authority, the Alcaidesa Marina in La Línea de la Concepción with 624 berths for pleasure boats and the Saladillo dock in Algeciras which has 800 berths.