
A bay is a recessed,
coast
A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...
al body of water that directly connects to a larger main body of water, such as an
ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...
, a
lake
A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...
, or another bay.
[ A large bay is usually called a ''gulf'', '' sea'', ''sound'', or ''bight''. A '']cove
A cove is a small bay or coastal inlet. They usually have narrow, restricted entrances, are often circular or oval, and are often situated within a larger bay. Small, narrow, sheltered bays, inlets, creek (tidal), creeks, or recesses in a coast ...
'' is a small, circular bay with a narrow entrance. A '' fjord'' is an elongated bay formed by glacial action.
The term ''embayment'' is also used for , such as extinct bays or freshwater environments.
A bay can be the estuary of a river, such as the Chesapeake Bay, an estuary of the Susquehanna River. Bays may also be nested within each other; for example, James Bay is an arm of Hudson Bay in northeastern Canada. Some large bays, such as the Bay of Bengal
The Bay of Bengal is the northeastern part of the Indian Ocean. Geographically it is positioned between the Indian subcontinent and the Mainland Southeast Asia, Indochinese peninsula, located below the Bengal region.
Many South Asian and Southe ...
and Hudson Bay, have varied marine geology
Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical, Geochemistry, geochemical, Sedimentology, sedimentological and paleontological investigations of the ocean floor and ...
.
The land surrounding a bay often reduces the strength of winds and blocks waves. Bays may have as wide a variety of shoreline characteristics as other shorelines. In some cases, bays have beaches, which "are usually characterized by a steep upper foreshore with a broad, flat fronting terrace". Bays were significant in the history of human settlement
In geography, statistics and archaeology, a settlement, locality or populated place is a community of people living in a particular location, place. The complexity of a settlement can range from a minuscule number of Dwelling, dwellings gro ...
because they provided easy access to marine resources like fisheries. Later they were important in the development of sea trade
Trade involves the transfer of goods and services from one person or entity to another, often in exchange for money. Economists refer to a system or network that allows trade as a market.
Traders generally negotiate through a medium of cr ...
as the safe anchor
An anchor is a device, normally made of metal, used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ', which itself comes from the Greek ().
Anch ...
age they provide encouraged their selection as port
A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manch ...
s.
Definition
The United Nations Convention on the Law of the Sea
The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international treaty that establishes a legal framework for all marine and maritime activities. , 169 sov ...
defines a bay as a well-marked indentation in the coastline, whose penetration is in such proportion to the width of its mouth as to contain land-locked waters and constitute more than a mere curvature of the coast. An indentation, however, shall not be regarded as a bay unless its area is as large as (or larger than) that of the semi-circle
In mathematics (and more specifically geometry), a semicircle is a one-dimensional locus of points that forms half of a circle. It is a circular arc that measures 180° (equivalently, radians, or a half-turn). It only has one line of symmet ...
whose diameter
In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...
is a line drawn across the mouth of that indentation[United Nations Convention on the Law of the Sea]
/ref> — otherwise it would be referred to as a bight.
Types
* Open bay — a bay that is widest at the mouth, flanked by headland
A headland, also known as a head, is a coastal landform, a point of land usually high and often with a sheer drop, that extends into a body of water. It is a type of promontory. A headland of considerable size often is called a cape.Whittow, Jo ...
s.
* Enclosed bay — a bay whose mouth is narrower than its widest part, flanked by at least one peninsula
A peninsula is a landform that extends from a mainland and is only connected to land on one side. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula.
Etymology
The word ''peninsula'' derives , . T ...
.
* Semi-enclosed bay — an open bay whose exit is made into narrower channels by one or more island
An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been ...
s within its mouth.
** Back-barrier bay — a semi-enclosed bay separated from open water by one or more barrier islands or spits.
* Juridicial bay - A legal distinction defining a bay meeting certain criterion as inland waters, and thus the waters of a state, rather than international waters or the territorial waters of a national government a state may be sovereign to. Foremost among the criteria remains that the area impounded by the bay must be greater than that of a semicircle drawn across its mouth.Confirming Sovereignty in Internal Waters
International Federation of Surveyors (FIG)
:Among the matters impacted by the definition are the right to the seabed and its minerals, control over fishing, the right of seafarers to innocent passage, and whether the affected coast is an international border or not.
Formation
Bays form variously by plate tectonics, coastal erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
by rivers, and glacier
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
s.
The largest bays have developed through plate tectonics. As the Paleozoic/early Mesozoic
The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...
era super-continent Pangaea broke up along curved and indented fault lines, the continents moved apart and left large bays; these include the Gulf of Guinea, the Gulf of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
, and the Bay of Bengal
The Bay of Bengal is the northeastern part of the Indian Ocean. Geographically it is positioned between the Indian subcontinent and the Mainland Southeast Asia, Indochinese peninsula, located below the Bengal region.
Many South Asian and Southe ...
, which is the world's largest bay.
Bays also form through coastal erosion by rivers and glaciers. A bay formed by a glacier is a fjord. Rias are created by rivers and are characterised by more gradual slopes. Deposits of softer rocks erode more rapidly, forming bays, while harder rocks erode less quickly, leaving headland
A headland, also known as a head, is a coastal landform, a point of land usually high and often with a sheer drop, that extends into a body of water. It is a type of promontory. A headland of considerable size often is called a cape.Whittow, Jo ...
s.
See also
*
*
Notes
References
{{Authority control
Bodies of water
Coastal and oceanic landforms
Coastal geography
Oceanographical terminology