A submerged forest is the in situ remains of trees, especially tree stumps, that lie submerged beneath a bay, sea, ocean, lake, or other body of water. These remains have usually been buried in mud, peat, or sand for several thousand years before being uncovered by sea level change and erosion and have been preserved in the compacted sediment by the exclusion of oxygen. [2] A forest can become submerged as the result of a lake or sea level rise that results in a lacustrine or marine transgression and in-place drowning of the forest. A submerged forest that lies beneath a lake can also be formed by the blockage of a river valley by either a landslide or manmade dam.
The examples and perspective in this section deal primarily with the Anglophone countries and Europe and do not represent a worldwide view of the subject.(August 2019) |
Marine submerged forests may be regularly exposed at low tide; examples of these can be found at low tide on the fringes of the submerged landmass known as Doggerland, [3] around the coast of England and the coasts of Wales, [4] the Channel Islands, [3] north-west France and Denmark. One of the first recorded encounters with submerged forests was in 1892 off of the coast of Mablethorpe. [5] In some places, such as Blackpool Sands, Dartmouth, the remains are normally covered by sand and only rarely exposed. [6] During the storms of 1974 (see Penparcau) [7] [8] and the winter storms of 2013–14 in the United Kingdom extensive remains of submerged forests were revealed in a number of places around the coast of Britain. [9] [10] For example, researchers discovered a 10,000 year old submerged forest that used to be part of Doggerland following the storm of 2013. [11] There is also evidence that some submerged forests have disappeared over time as back in 1933, there were reports of a disappearing submerged forest off of the coast of Cheshire and Lancashire. [12]
As the North American Laurentide Ice Sheet began receding for the last time some 10,000 years ago, water levels in the future Great Lakes were sometimes much lower than at present. Forests once covered the southern end of what is now Lake Huron but as the glaciers melted and waters rose these forests were inundated and drowned. Today their remnants, well preserved logs and stumps, have been discovered in waters over 200 feet deep. [13] [14]
A submerged forest was found in Nantucket Sound, off the coast of Massachusetts. [15] In 2012 a submerged bald cypress forest, which has been dated at around 60,000 years old, was discovered in the Gulf of Mexico off the coast of Alabama. [2] There have been attempts to make it into a marine sanctuary. [16]
Submerged forests host a whole variety of flora and fauna. The submerged forest located off of the coast of Alabama near Dauphin Island has the bald cypress tree (Taxodium distichum). [17] Mantis shrimp, crabs, anemones, grouper, and red snappers are commonly found at this submerged forest, and of particular interest, due to their practical use in drug discovery, are shipworms. [18] [19]
Maritime archaeology is a discipline within archaeology as a whole that specifically studies human interaction with the sea, lakes and rivers through the study of associated physical remains, be they vessels, shore-side facilities, port-related structures, cargoes, human remains and submerged landscapes. A specialty within maritime archaeology is nautical archaeology, which studies ship construction and use.
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as Lake Michigan, to which it is connected by the 5-mile-wide (8.0 km), 20-fathom-deep Straits of Mackinac. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French explorers who named it for the indigenous people they knew as Huron (Wyandot) inhabiting the region.
A lightvessel, or lightship, is a ship that acts as a lighthouse. They are used in waters that are too deep or otherwise unsuitable for lighthouse construction. Although some records exist of fire beacons being placed on ships in Roman times, the first modern lightvessel was off the Nore sandbank at the mouth of the River Thames in London, England, placed there by its inventor Robert Hamblin in 1734. The type has become largely obsolete; lighthouses replaced some stations as the construction techniques for lighthouses advanced, while large, automated buoys replaced others.
The Strait of Dover or Dover Strait, is the strait at the narrowest part of the English Channel, marking the boundary between the Channel and the North Sea, and separating Great Britain from continental Europe. The shortest distance across the strait, at approximately 20 miles, is from the South Foreland, northeast of Dover in the English county of Kent, to Cap Gris Nez, a cape near to Calais in the French département of Pas-de-Calais. Between these points lies the most popular route for cross-channel swimmers. The entire strait is within the territorial waters of France and the United Kingdom, but a right of transit passage under the United Nations Convention on the Law of the Sea allows vessels of other nations to move freely through the strait.
The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent 26,000 and 20,000 years ago. Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing a major expansion of deserts, along with a large drop in sea levels.
The three Storegga Slides are amongst the largest known submarine landslides. They occurred at the edge of Norway's continental shelf in the Norwegian Sea, approximately 6225–6170 BCE. The collapse involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km3 (840 cu mi) of debris, which caused a paleotsunami in the North Atlantic Ocean.
The Older Dryas was a stadial (cold) period between the Bølling and Allerød interstadials, about 14,000 years Before Present, towards the end of the Pleistocene. Its date range is not well defined, with estimates varying by 400 years, but its duration is agreed to have been around two centuries.
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems. Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides. Other near-shore (neritic) zones can include mudflats, seagrass meadows, mangroves, rocky intertidal systems, salt marshes, coral reefs, lagoons. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.
Totten Glacier is a large glacier draining a major portion of the East Antarctic Ice Sheet, through the Budd Coast of Wilkes Land in the Australian Antarctic Territory. The catchment drained by the glacier is estimated at 538,000 km2 (208,000 sq mi), extending approximately 1,100 km (680 mi) into the interior and holds the potential to raise sea level by at least 3.5 m (11 ft). Totten drains northeastward from the continental ice but turns northwestward at the coast where it terminates in a prominent tongue close east of Cape Waldron. It was first delineated from aerial photographs taken by USN Operation Highjump (1946–47), and named by Advisory Committee on Antarctic Names (US-ACAN) for George M. Totten, midshipman on USS Vincennes of the United States Exploring Expedition (1838–42), who assisted Lieutenant Charles Wilkes with correction of the survey data obtained by the expedition.
Doggerland was an area of land in Northern Europe, now submerged beneath the North Sea, that connected Britain to continental Europe. It was repeatedly exposed at various times during the Pleistocene epoch due to the lowering of sea levels during glacial periods. It was last flooded by rising sea levels around 6500–6200 BCE. The flooded land is known as the Dogger Littoral. Geological surveys have suggested that it stretched from what is now the east coast of Great Britain to what is now the Netherlands, the western coast of Germany and the Danish peninsula of Jutland. It was probably a rich habitat with human habitation in the Mesolithic period, although rising sea levels gradually reduced it to low-lying islands before its final submergence, possibly following a tsunami caused by the Storegga Slide. Doggerland was named after the Dogger Bank, which in turn was named after 17th-century Dutch fishing boats called doggers.
Tsunamis affecting Britain and Ireland are extremely uncommon, and there have only been two confirmed cases in recorded history. Meteotsunamis are somewhat more common, especially on the southern coasts of England around the English and Bristol Channels.
The Whitefish Point Underwater Preserve was established in 1987 to protect and conserve shipwrecks and historical resources on 376 square miles (970 km2) of Lake Superior bottomlands in Whitefish Bay and around Whitefish Point, Michigan. The formation of the Michigan Underwater Preserves helped stop controversy over artifact removal from shipwrecks of this area. The preserve is now known for deep, well preserved shipwrecks in clear water accessible to scuba divers with technical skill and experience. The preserve is one of the last places in the Great Lakes to observe shipwrecks without zebra mussel encrustation.
The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude and moves toward Northwest Europe as the North Atlantic Current. The process of western intensification causes the Gulf Stream to be a northward-accelerating current off the east coast of North America. Around 40°0′N30°0′W, it splits in two, with the northern stream, the North Atlantic Drift, crossing to Northern Europe and the southern stream, the Canary Current, recirculating off West Africa.
David Jay Julius is an American physiologist and Nobel Prize laureate known for his work on molecular mechanisms of pain sensation and heat, including the characterization of the TRPV1 and TRPM8 receptors that detect capsaicin, menthol, and temperature. He is a professor at the University of California, San Francisco.
Vintana sertichi is an early gondwanatherian mammal dating from the Late Cretaceous, approximately 66 million years ago. Scientists found the lone fossil, a skull, on Madagascar's west coast in the Maastrichtian Maevarano Formation.
Parmastega is an extinct genus of stem tetrapod from the Devonian, dated to the earliest Famennian age, in contrast to later fossils known from late Famennian. These later fossils are considerably younger, by about 30 million years, than the earliest recorded tetrapod footprints, which presented a mystery that Parmastega's more recently described morphology from a three dimensional reconstruction has helped provide light on.
Nicole Boury-Esnault is a retired French researcher of sponges, formerly at Centre d'Océanologie de Marseille, Aix-Marseille University.
A paleoshoreline is a shoreline that existed in the geologic past. A perched coastline is an ancient (fossil) shoreline positioned above the present shoreline.