Lagoon Mirim (Portuguese, ) or Merín (Spanish, ) is a large
estuarine
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...
lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons ...
which extends from southern
Rio Grande do Sul
Rio Grande do Sul (, , ; "Great River of the South") is a state in the southern region of Brazil. It is the fifth-most-populous state and the ninth largest by area. Located in the southernmost part of the country, Rio Grande do Sul is border ...
state in
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
into eastern
Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
. Lagoa Mirim is separated from 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 ...
by a sandy, partially barren
isthmus
An isthmus (; ; ) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea counterpart of an isthmus ...
.
The
Jaguarão/Yaguarón,
Tacuarí and
Cebollatí Rivers empty into Lagoon Mirim, while the
São Gonçalo Channel connects it with
Lagoa dos Patos to the north.
Location
Lagoon Mirim is about long by wide and in area. It is more irregular in outline than its larger neighbor to the north,
Lagoa dos Patos, and discharges into the latter through
São Gonçalo Channel, which is navigable by small boats. Lagoa Mirim has no direct connection to the Atlantic, but the Rio Grande, a tidal channel about long which connects Lagoon dos Patos to the Atlantic, affords an entrance to the navigable inland waters of both lagoons and several small ports.
Both lagoons are the remains of an ancient depression in the coastline shut in by sand beaches built up by the combined action of
wind
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ...
and
oceanic current
An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, ...
s. They are at the same level as the ocean, but their waters are affected by the tides and are
brackish
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estua ...
only a short distance above the Rio Grande outlet.
The
Taim Ecological Station lies to the east of the lagoon, in the narrow land strip between it and the Atlantic Ocean.
The
Jaguarão/Yaguarón River, which forms part of the Brazil-Uruguay boundary line, empties into Lagoon Mirim, and is navigable up to and beyond the twin towns of
Jaguarão (Brazil) and
Rio Branco (Uruguay).
On the Uruguayan side apart from the Yaguarón River, the Cebollatí River and the Tacuarí River empty into the Lagoon Mirim. The amount of water received by the lagoon is greater from the Uruguayan side.
See also
*
Topography and hydrography of Uruguay
*
1851 Boundary Treaty (Brazil–Uruguay)
*
Jaguar%C3%A3o River#Navigability
Sources
External links
Mirim
Mirim
Landforms of Rio Grande do Sul
Brazil–Uruguay border
Mirim
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