Meta tags:

Headings (most frequently used words):

on, of, eutrophication, effects, estuarine, classification, based, implications, human, type, mixed, america, estuary, contents, definition, ecosystems, geomorphology, water, circulation, physiochemical, variation, estuaries, for, marine, life, impact, examples, see, also, references, external, links, ecosystem, services, drowned, river, valleys, lagoon, or, bar, built, fjord, tectonically, produced, salt, wedge, partially, well, inverse, intermittent, biogeochemical, cycles, plants, animals, activities, africa, asia, europe, north, oceania, south,

Text of the page (most frequently used words):
the (258), and (200), estuaries (86), #estuary (74), river (73), marine (58), water (57), coastal (45), from (42), are (38), edit (36), with (33), #eutrophication (31), estuarine (31), can (31), freshwater (30), bay (30), that (27), fish (26), marsh (25), salt (24), for (24), sea (24), this (21), zone (21), ecosystem (21), doi (21), which (21), also (20), ecosystems (19), united (18), aquatic (17), tidal (17), bibcode (17), ecology (16), bog (16), effects (16), wetland (15), sediment (15), these (15), type (13), have (13), such (13), life (12), human (12), many (12), where (12), list (11), beach (11), mouth (11), 978 (11), isbn (11), kingdom (11), wetlands (10), rivers (10), bar (10), habitats (10), ocean (10), new (10), issn (10), species (10), salinity (10), nutrients (10), land (10), oxygen (10), they (10), portal (9), processes (9), intertidal (9), gulf (9), examples (9), science (9), within (9), their (9), nitrogen (9), into (9), wikipedia (8), may (8), retrieved (8), erosion (8), level (8), lake (8), beaches (8), lagoon (8), shelf (8), barrier (8), based (8), along (8), toggle (7), oceanic (7), fishing (7), states (7), national (7), delta (7), off (7), classification (7), pool (7), swamp (7), mangrove (7), flow (7), large (7), coast (7), sound (7), food (7), africa (7), productivity (7), waters (7), has (7), s2cid (7), between (7), habitat (7), nutrient (7), depth (7), animals (7), environment (7), south (7), formed (7), including (7), well (7), more (7), not (7), there (7), seawater (7), circulation (7), valleys (7), definition (7), link (6), fen (6), plants (6), meadow (6), forest (6), brackish (6), natural (6), current (6), physical (6), wave (6), tide (6), reef (6), coral (6), fisheries (6), deep (6), archived (6), original (6), impacts (6), one (6), areas (6), systems (6), see (6), countries (6), been (6), activities (6), lead (6), move (6), main (6), partially (6), both (6), mixing (6), wedge (6), page (5), category (5), short (5), articles (5), 2012 (5), 2020 (5), all (5), different (5), bodies (5), impact (5), other (5), republic (5), body (5), bangladesh (5), system (5), australia (5), high (5), stream (5), geomorphology (5), plain (5), coastline (5), island (5), fjord (5), firth (5), ecological (5), ground (5), primary (5), web (5), san (5), north (5), america (5), biomass (5), plant (5), chesapeake (5), 2006 (5), 2019 (5), seasonal (5), hdl (5), 1016 (5), york (5), commercial (5), causes (5), rise (5), cycles (5), inverse (5), india (5), some (5), populations (5), environments (5), organisms (5), tides (5), however (5), levels (5), implications (5), during (5), increase (5), than (5), less (5), most (5), mixed (5), shaped (5), built (5), subsection (5), contents (4), search (4), about (4), commons (4), pages (4), environmental (4), control (4), drainage (4), related (4), conservation (4), ramsar (4), important (4), mudflat (4), deposition (4), channel (4), migration (4), scale (4), region (4), influence (4), oceanography (4), littoral (4), management (4), shoreline (4), bays (4), top (4), continental (4), lakes (4), pollution (4), community (4), production (4), general (4), state (4), column (4), hypoxia (4), dissolved (4), links (4), university (4), press (4), hudson (4), 1007 (4), 2008 (4), springer (4), 2017 (4), composition (4), 2016 (4), migratory (4), pmid (4), pdf (4), communities (4), shallow (4), whitefish (4), movement (4), biogeochemical (4), spencer (4), volume (4), information (4), because (4), brazil (4), run (4), example (4), but (4), excess (4), overfishing (4), pollutants (4), small (4), bottom (4), cause (4), zones (4), sediments (4), two (4), services (4), often (4), variation (4), cycle (4), industry (4), biodiversity (4), death (4), vegetation (4), phosphorus (4), input (4), only (4), tectonically (4), typically (4), sills (4), bars (4), spits (4), lagoons (4), open (4), enclosed (4), hide (4), sidebar (4), mobile (3), view (3), contact (3), available (3), under (3), wikimedia (3), use (3), was (3), wikidata (3), displaying (3), descriptions (3), redirect (3), targets (3), december (3), landforms (3), biological (3), research (3), soil (3), tropical (3), peat (3), pools (3), pond (3), low (3), valley (3), upland (3), raised (3), direction (3), geology (3), point (3), cut (3), number (3), sand (3), engineering (3), wind (3), mouths (3), evolution (3), inlet (3), mangroves (3), seagrass (3), oyster (3), pelagic (3), saltwater (3), turbidity (3), process (3), biology (3), ratio (3), vertical (3), layer (3), francisco (3), ecoregions (3), limnology (3), quality (3), stable (3), phytoplankton (3), microbial (3), effect (3), population (3), animal (3), anoxic (3), algal (3), 2009 (3), free (3), john (3), ecss (3), 2001 (3), plata (3), 1038 (3), nature (3), three (3), scott (3), robert (3), economic (3), carbon (3), world (3), temperate (3), over (3), history (3), evaporation (3), tampa (3), used (3), help (3), washington (3), what (3), growth (3), word (3), inlets (3), puget (3), banks (3), jersey (3), canada (3), delaware (3), russia (3), china (3), myanmar (3), senegal (3), gabon (3), congo (3), historically (3), forests (3), now (3), result (3), out (3), year (3), algae (3), impacted (3), time (3), changes (3), sewage (3), located (3), further (3), found (3), very (3), resulting (3), conditions (3), dynamic (3), productive (3), variety (3), anadromous (3), affect (3), decrease (3), across (3), any (3), making (3), greatly (3), could (3), causing (3), above (3), lower (3), marshes (3), form (3), range (3), limit (3), varies (3), riverine (3), surface (3), seaward (3), exceed (3), output (3), due (3), reaches (3), here (3), include (3), forming (3), intrusion (3), produced (3), glacial (3), coasts (3), 000 (3), action (3), ridges (3), semi (3), drowned (3), article (3), connection (3), derived (3), tools (3), languages (2), table (2), privacy (2), policy (2), terms (2), using (2), site (2), organization (2), foundation (2), inc (2), last (2), categories (2), clarification (2), unsourced (2), statements (2), cs1 (2), maint (2), location (2), missing (2), publisher (2), description (2), geography (2), index (2), czech (2), france (2), international (2), will (2), riparian (2), basin (2), wood (2), iron (2), society (2), peatland (2), convention (2), gas (2), mechanics (2), garden (2), pannes (2), bed (2), flooded (2), flood (2), rich (2), poor (2), carr (2), types (2), law (2), dune (2), canyon (2), meander (2), pattern (2), morphology (2), avulsion (2), alluvial (2), silt (2), shingle (2), size (2), integrated (2), shoaling (2), surf (2), steep (2), shoal (2), rocky (2), shore (2), longshore (2), drift (2), flat (2), biogeomorphology (2), wash (2), margin (2), storm (2), shell (2), ria (2), liman (2), cliff (2), oceans (2), protected (2), area (2), change (2), values (2), sponge (2), biomes (2), hydrothermal (2), kelp (2), cold (2), demersal (2), mammal (2), plankton (2), wildlife (2), invertebrates (2), fertilization (2), components (2), specific (2), pacific (2), subtropical (2), latin (2), trophic (2), stratification (2), biome (2), underwater (2), macrobenthos (2), ecohydrology (2), dead (2), predation (2), bird (2), bloom (2), experience (2), www (2), characteristics (2), external (2), amazon (2), jeffrey (2), spatial (2), distribution (2), feeding (2), naf (2), 10072 (2), journal (2), meghna (2), dawei (2), atmospheric (2), administration (2), reefs (2), importance (2), 1981 (2), elemental (2), biofilm (2), río (2), 187 (2), buffer (2), birds (2), 412 (2), 247 (2), evidence (2), juvenile (2), abundance (2), upper (2), newport (2), california (2), katherine (2), northern (2), frontiers (2), sciences (2), shellfish (2), recreational (2), value (2), protect (2), jensen (2), martin (2), down (2), netherlands (2), 106729 (2), 0272 (2), 7714 (2), 2005 (2), pmc (2), increases (2), cordgrass (2), response (2), sergio (2), 490 (2), williams (2), extreme (2), howarth (2), marino (2), roxanne (2), oxford (2), saloum (2), sow (2), jean (2), pierre (2), 2014 (2), geological (2), wolanski (2), 1986 (2), driven (2), maximum (2), chemical (2), 2010 (2), epa (2), basic (2), mitra (2), abhijit (2), zaman (2), sufia (2), basics (2), 102 (2), navigation (2), fishes (2), lampreys (2), pritchard (2), 1967 (2), threats (2), cite (2), references (2), mean (2), narrow (2), term (2), various (2), acidification (2), uruguay (2), complex (2), zealand (2), oceania (2), carolina (2), outer (2), harbor (2), narragansett (2), mississippi (2), long (2), laguna (2), mexico (2), great (2), galveston (2), columbia (2), western (2), germany (2), severn (2), exe (2), europe (2), thailand (2), asia (2), cameroon (2), mozambique (2), guinea (2), gambia (2), through (2), had (2), reduced (2), tend (2), naturally (2), includes (2), chemicals (2), waste (2), occurs (2), almost (2), oysters (2), filter (2), them (2), deposited (2), entire (2), four (2), problems (2), local (2), runoff (2), accumulate (2), shift (2), benthic (2), settlement (2), much (2), events (2), far (2), materials (2), domestic (2), heavy (2), metals (2), early (2), were (2), sedimentation (2), bacteria (2), upon (2), abundant (2), variability (2), highly (2), make (2), difficult (2), survive (2), provide (2), critical (2), rely (2), known (2), eggs (2), corridors (2), catch (2), significant (2), leads (2), being (2), wide (2), structure (2), greater (2), seen (2), negatively (2), rates (2), below (2), similar (2), root (2), seasons (2), swamps (2), amount (2), while (2), creating (2), unbalanced (2), harmful (2), hypoxic (2), limitation (2), silica (2), availability (2), near (2), exist (2), special (2), leading (2), develop (2), needed (2), physiochemical (2), changing (2), intermittent (2), climates (2), exceeds (2), inflow (2), landward (2), forces (2), vertically (2), moves (2), waves (2), formation (2), inundation (2), epoch (2), holocene (2), eroded (2), rock (2), width (2), sill (2), exchange (2), glaciers (2), fjords (2), existing (2), cross (2), developed (2), years (2), ago (2), flooding (2), atlantic (2), islands (2), rising (2), common (2), part (2), supporting (2), diluted (2), streams (2), meaning (2), yachats (2), classified (2), saline (2), appearance (2), upload (2), file (2), read (2), english (2), norsk (2), bahasa (2), беларуская (2), log (2), create (2), account (2), donate (2), menu (2), add, topic, cookie, statement, statistics, developers, code, conduct, legal, safety, contacts, disclaimers, text, additional, apply, you, agree, registered, trademark, non, profit, creative, attribution, sharealike, license, rendered, parsoid, edited, september, 2026, utc, hidden, via, module, annotated, needing, june, geodesy, https, org, php, title, oldid, 1374247076, yale, lux, israel, spain, bnf, data, gnd, authority, databases, wisp, turbary, telmatology, bogs, butter, wildfowl, trust, scientists, meadowview, station, irish, council, ducks, unlimited, waterfowl, haor, development, board, organizations, indicator, status, die, organ, greenhouse, emissions, clean, act, inventory, directory, classifications, dieback, paludification, hydrosere, halosere, ombrotrophic, hydric, sapric, muck, histosol, acrotelm, sphagnum, swale, converted, constructed, artificial, yaéré, whitewater, vernal, várzea, wet, shrub, myristica, coniferous, slough, reed, pothole, pocosin, mire, quagmire, palustrine, palsa, pakihi, oasis, muskeg, moorland, misse, mere, inland, lagg, kettle, interdunal, ings, igapó, hamun, guelta, grass, grasslands, savannas, flark, dambo, cypress, dome, clearwater, ciénega, alder, callows, string, polygonal, plateau, kermi, cataract, blanket, bofedales, blackwater, bayou, backswamp, reversed, transport, playfair, helicoidal, hack, exner, equation, rejuvenation, tectonics, degradation, base, aggradation, regional, ripple, antidune, ait, bedforms, plunge, knickpoint, bedrock, thalweg, slip, slope, bifurcation, rapids, riffle, oxbow, cutoff, floodplain, bank, braided, anabranch, sinuosity, strahler, order, features, plume, pebble, gravel, granule, cobble, clay, boulder, grain, bulkhead, line, submersion, accretion, fetch, platform, volcanic, arc, undertow, swash, surge, break, submergent, peresyp, foam, cave, rip, transgression, regression, behaviour, ingression, graded, feeder, bluff, emergent, discordant, cuspate, foreland, concordant, cliffed, blowhole, regressive, mega, debouch, recession, pocket, morphodynamics, beachrock, wrack, ridge, cusps, windwatt, waituna, tombolo, tied, submarine, strand, strait, stack, spit, skerry, peninsula, arch, machair, isthmus, islet, headland, hapua, gut, geo, gat, fundus, fjard, cove, waterfall, cape, bodden, bight, ayre, atoll, archipelago, anchialine, activism, hermione, climate, bleaching, vent, davidson, seamount, seep, mud, seabird, reptile, vertebrates, paradox, viruses, protists, prokaryotes, bacteriophage, microorganisms, wild, seashore, larval, fungi, census, whale, fall, viral, shunt, upwelling, thorson, rule, photophore, snow, chemistry, diel, scattering, gyre, maharashtra, everglades, caribbean, madagascar, wwf, lowland, rheotaxis, macrophyte, hyporheic, parameters, zooplankton, camouflage, thermal, substrate, metabolism, isotope, analysis, spawn, siltation, schooling, semiaquatic, trap, pleuston, photic, particle, neuston, nekton, mycoloop, loop, meiobenthos, hydrobiology, gis, chain, colored, organic, matter, cascade, bioluminescence, benthos, toxicology, respiration, dynamics, biomonitoring, insect, adaptation, acoustic, guide, onr, navy, mil, noaa, animated, documentary, look, wiktionary, dictionary, media, etai, levinton, waldman, cambridge, 521, 20798, onep, พื้นที่ชุ่มน้ำในประเทศไทย, noman, abu, mamunur, rashid, islam, shahanul, hossain, belal, 2018, functional, guilds, 1023, 92734488, 426555, s00343, 019, 8063, 2019jol, 1010n, 1010, oceanology, jakobsen, azam, mahboob, kabir, 2002, residual, 597, 1006, 0929, 2002ecss, 587j, 587, dmcr, สัณฐานชายฝั่ง, ระบบฐานข้อมูลทรัพยากรทางทะเลและชายฝั่ง, กรมทรัพยากรทางทะเลและชายฝั่ง, myanmarholiday, com, tavoy, october, gerlach, sebastian, berlin, 387, 10940, diagnosis, therapy, garcía, alonso, lercari, araujo, almeida, rezende, total, extractable, disentangling, anthropogenic, influences, 018, 2017ecss, 53g, branch, george, 1999, vulnerability, 499, s0169, 5347, 01732, trends, ross, 1995, harper, collins, college, publishers, 673, 46938, introduction, gill, jennifer, norris, ken, potts, peter, gunnarsson, tómas, grétar, atkinson, philip, sutherland, william, regulation, 6845, 438, 4308197, 11473317, 35086568, 2001natur, 436g, 436, gillanders, able, brown, eggleston, sheridan, 2003, 295, 24866466, jstor, 2440, 1877, 3354, meps247281, 2003meps, 281g, 281, progress, series, connectivity, adult, fauna, component, nurseries, allen, larry, 1982, 790, 769, fishery, bulletin, assemblage, osborn, thesis, humboldt, invertebrate, fay, gavin, depiper, geret, steinback, gamble, jason, 133, 2296, 7745, 3389, fmars, 00133, 2019frmas, 133f, northeast, gao, yang, lee, jeong, yeol, 311, 2234, 1749, 5657, fas, 0305, 305, compensatory, responses, nile, tilapia, oreochromis, niloticus, feed, deprivation, regimes, lellis, dibble, incentive, restore, jeppesen, erik, peder, jens, søndergaard, lauridsen, torben, junge, pedersen, leif, lars, 1997, role, submerged, macrophytes, dordrecht, 164, 010, 6382, 011, 5648, 6_17, 151, vonlanthen, bittner, speciation, reversal, adaptive, radiations, 482, 337, 362, nature0824, waltham, nathan, mccann, jack, power, trent, moore, matt, buelow, christina, 216460098, 398049, 2020ecss, 23806729w, 238, patterns, urban, maintenance, schedules, broader, seascape, guest, michaela, connolly, rod, fine, assimilation, saltmarsh, resident, 609, 20771999, 1386, 2588, s10452, 005, 0442, 2005aqeco, 599g, 599, lovelock, catherine, ball, marilyn, feller, ilka, e5600, 19440554, 2679148, 1932, 6203, 1371, pone, 0005600, 2009ploso, 5600l, plos, enrichment, mortality, donnelly, bertness, mark, 14223, 11724926, 64662, 0027, 8424, 1073, pnas, 251209298, 2001pnas, 9814218d, 14218, proceedings, academy, rapid, shoreward, encroachment, accelerated, deegan, linda, johnson, david, samuel, warren, peterson, bruce, fleeger, fagherazzi, wollheim, wilfred, driver, loss, 7420, 392, 4414196, 23075989, 0028, 0836, nature11533, 2012natur, 388d, 388, selman, mindy, sugg, zachary, greenhalgh, suzie, resources, institute, 56973, 681, morales, ana, wanamaker, alan, clayton, downing, 2021, 450, 220856626, 1432, 9840, s10021, 020, 00527, 2021ecosy, 434m, 434, drives, flux, chan, francis, conley, daniel, garnier, josette, doney, billen, gilles, 2011, 1540, 9295, 1813, 60819, 1890, 100008, 2011free, 18h, coupled, 1part2, 376, 18144068, 0024, 3590, 4319, 1_part_2, 0364, 2006limoc, 364h, 364, limiting, evolving, views, decades, kaiser, 924975, day, rotterdam, balkema, 6191, 205, tomczak, 2000, november, notes, descroix, luc, sané, yancouba, thior, mamadou, manga, sylvie, paméla, boubacar, demba, mingou, joseph, mendy, victor, coly, dièye, arame, badiane, alexandre, senghor, marie, jeanne, diedhiou, ange, bouramanding, djiby, bouaita, yasmin, soumaré, safietou, diop, awa, faty, bakary, bamol, ali, machu, eric, montoroi, andrieu, julien, vandervaere, 647, 3390, w12030647, 2020water, 647d, west, rainfall, recovery, hall, setting, royal, 9780959662764, gostin, australian, 424, 90065, 1986ecss, 415w, 415, kennish, boca, raton, crc, 8493, 5892, aspects, kunneke, palik, 1984, january, wildl, serv, biol, rep, atlas, 2015, 2025, gov, rose, simon, av2, weigl, silva, lowry, maran, macaya, solis, consuelo, byatt, barry, lucas, martyn, 302, ecoleng, 027, 2017eceng, 291s, 291, locks, swimming, performance, pass, barrages, test, lauff, american, association, advancement, publication, aaas, stand, 2007, amsterdam, elsevier, 444, 53066, mclusky, elliott, 2004, 852508, book, viewpoint, lauf, publ, vol, 1969, 24383, saturated, prism, traveling, incoming, bore, aspect, landform, network, reserve, waterways, england, russian, sandbar, scottish, straits, inhabit, edge, reducing, nonprofit, federation, argentina, rio, mearim, mirim, lagoa, dos, patos, iguape, cananéia, paranaguá, peru, ecuador, colombia, bolivia, port, jackson, gippsland, avon, heathcote, sarasota, billy, frank, nisqually, refuge, pamlico, back, pontchartrain, miramichi, mackenzie, merritt, borgne, madre, términos, indian, fraser, saint, lawrence, east, drake, estero, coos, hampton, roads, buzzards, albemarle, scheldt, unterelbe, thames, portugal, tagus, southampton, solway, ireland, shannon, poland, oder, humber, turkey, golden, horn, gironde, forth, clyde, ukraine, dnieper, bug, dee, yenisei, yangtze, waeru, chanthaburi, province, philippines, puerto, princesa, underground, narmada, kraburi, vietnam, hàn, hangzhou, adyar, amur, wouri, zimbabwe, pungwe, namibia, lesotho, orange, lucia, bissau, geba, estuário, espírito, santo, zambia, tanzania, rwanda, democratic, central, african, burundi, angola, major, deserts, vast, expansive, fraction, former, dams, diversions, covered, marshlands, essentially, colorado, discharges, fertilizers, agriculture, livestock, humans, depleting, creation, reductions, once, flourishing, wiped, either, eat, shape, packets, harmless, filtered, every, days, today, takes, eutrophic, toxins, tissues, called, record, century, reflect, reversible, irreversible, abiotic, biotic, parts, muds, bioaccumulation, threat, threatened, clearance, affected, upstream, concentrate, industrial, agricultural, enter, discharged, contaminants, introduced, disintegrate, rapidly, phenols, dioxins, furans, pesticides, plastics, thirty, largest, cities, 1990s, twenty, service, source, detritus, key, producers, flushed, largely, dependent, present, dinoflagellates, diatoms, challenges, methods, conform, shifts, concentrations, termed, avoid, live, sedimental, numbers, demand, reduces, exacerbated, limited, burrow, osmoregulators, osmoconformers, incredibly, temperature, daily, dynamism, makes, round, strong, winter, dominated, hardy, residents, summer, capitalizing, completion, herring, lay, surfperch, give, birth, flatfish, rockfish, migrate, rear, black, tailed, godwit, salmonids, clupea, pallasii, consequences, relies, approximately, percent, fishermen, noticed, quantity, sudden, spikes, utilized, continued, deoxygenation, then, decline, begin, surrounding, turn, sales, country, contributes, billions, dollars, gross, product, gdp, million, people, employs, yearly, boat, results, end, alters, afflicted, hotspots, containing, majority, feel, strongly, others, extinctions, carnivorous, enriched

Text of the page (random words):
lation and vertical stratification and system energetics 5 they can have many different names such as bays harbors lagoons inlets or sounds although some of these water bodies do not strictly meet the above definition of an estuary and could be fully saline many estuaries suffer degeneration from a variety of factors including soil erosion deforestation overgrazing overfishing and the filling of wetlands eutrophication may lead to excessive nutrients from nitrogen run off sewage and animal wastes pollutants including heavy metals polychlorinated biphenyls radionuclides and hydrocarbons from sewage inputs and diking or damming for flood control or water diversion 4 6 definition edit new york new jersey harbor estuary river exe estuary estuary mouth located in darwin northern territory australia a crowded estuary mouth in paravur near the city of kollam india estuary mouth of the yachats river in yachats oregon the word estuary is derived from the latin word aestuarium meaning tidal inlet of the sea which in itself is derived from the term aestus meaning tide there have been many definitions proposed to describe an estuary the most widely accepted definition is a semi enclosed coastal body of water which has a free connection with the open sea and within which seawater is measurably diluted with freshwater derived from land drainage 1 however this definition excludes a number of coastal water bodies such as coastal lagoons and brackish seas a more comprehensive definition of an estuary is a semi enclosed body of water connected to the sea as far as the tidal limit or the salt intrusion limit and receiving freshwater runoff however the freshwater inflow may not be perennial the connection to the sea may be closed for part of the year and tidal influence may be negligible 4 this broad definition also includes fjords lagoons river mouths and tidal creeks overall an estuary is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides the effects of tides on estuaries can show nonlinear effects on the movement of water which can have important impacts on the ecosystem and waterflow the seawater entering the estuary is diluted by the fresh water flowing from rivers and streams the pattern of dilution varies between different estuaries and depends on the volume of freshwater the tidal range and the extent of evaporation of the water in the estuary 2 estuarine ecosystems edit estuaries are dynamic coastal ecosystems shaped by the interaction of riverine and marine processes the mixing of freshwater inflows with oceanic waters creates constantly changing physical and chemical conditions that influence habitat structure nutrient availability and biological productivity this transitional environment supports a diverse and highly interconnected community of organisms species from freshwater marine and terrestrial systems coexist and interact within estuaries forming complex food webs and nutrient cycles together these interactions make estuaries essential ecosystems that maintain biodiversity regulate environmental processes and link land freshwater and marine environments into a single integrated system 7 ecosystem services edit estuaries provide a wide range of ecosystem services that sustain both ecological productivity and human well being they function as nursery habitats supporting the early life stages of many marine fish and shellfish while also maintaining mangroves seagrasses salt marshes and seaweeds that recycle nutrients and support productive fisheries these ecosystems serve as critical migration corridors for anadromous and catadromous fish in addition estuaries offer habitat for migratory birds and endangered species enhancing biodiversity and supporting ecotourism opportunities water draining from upland areas carries sediments nutrients and pollutants into estuaries where wetlands such as swamps and salt marshes naturally filter these materials improving water clarity and quality for both marine organisms and coastal communities vegetation such as salt marsh grasses also stabilize shorelines and help reduce erosion providing a natural buffer against storm impacts and sea level rise thereby protecting coastal environments and human infrastructure 8 9 classification based on geomorphology edit drowned river valleys edit main article ria drowned river valleys are also known as coastal plain estuaries in places where the sea level is rising relative to the land sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley this is the most common type of estuary in temperate climates well studied estuaries include the severn estuary in the united kingdom and the ems dollard along the dutch german border the width to depth ratio of these estuaries is typically large appearing wedge shaped in cross section in the inner part and broadening and deepening seaward water depths rarely exceed 30 m 100 ft examples of this type of estuary in the u s are the hudson river chesapeake bay and delaware bay along the mid atlantic coast and galveston bay and tampa bay along the gulf coast 10 lagoon type or bar built edit see also mouth bar bar built estuaries are found in a place where the deposition of sediment has kept pace with rising sea levels so that the estuaries are shallow and separated from the sea by sand spits or barrier islands they are relatively common in tropical and subtropical locations these estuaries are semi isolated from ocean waters by barrier beaches barrier islands and barrier spits formation of barrier beaches partially encloses the estuary with only narrow inlets allowing contact with the ocean waters bar built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts they are extensive along the atlantic and gulf coasts of the u s in areas with active coastal deposition of sediments and where tidal ranges are less than 4 m 13 ft the barrier beaches that enclose bar built estuaries have been developed in several ways building up of offshore bars by wave action in which sand from the seafloor is deposited in elongated bars parallel to the shoreline reworking of sediment discharge from rivers by a wave current and wind action into beaches overwash flats and dunes engulfment of mainland beach ridges ridges developed from the erosion of coastal plain sediments around 5000 years ago due to sea level rise and resulting in the breaching of the ridges and flooding of the coastal lowlands forming shallow lagoons elongation of barrier spits from the erosion of headlands due to the action of longshore currents with the spits growing in the direction of the littoral drift citation needed fjord type edit fjords were formed where pleistocene glaciers deepened and widened existing river valleys so that they become u shaped in cross sections at their mouths there are typically rocks bars or sills of glacial deposits which have the effects of modifying the estuarine circulation fjord type estuaries are formed in deeply eroded valleys formed by glaciers these u shaped estuaries typically have steep sides rock bottoms and underwater sills contoured by glacial movement the estuary is shallowest at its mouth where terminal glacial moraines or rock bars form sills that restrict water flow in the upper reaches of the estuary the depth can exceed 300 m 1 000 ft the width to depth ratio is generally small in estuaries with very shallow sills tidal oscillations only affect the water down to the depth of the sill and the waters deeper than that may remain stagnant for a very long time so there is only an occasional exchange of the deep water of the estuary with the ocean if the sill depth is deep water circulation is less restricted and there is a slow but steady exchange of water between the estuary and the ocean fjord type estuaries can be found along the coasts of alaska the puget sound region of western washington state british columbia eastern canada greenland iceland new zealand chile and norway tectonically produced edit these estuaries are formed by subsidence or land cut off from the ocean by land movement associated with faulting volcanoes and landslides inundation from eustatic sea level rise during the holocene epoch has also contributed to the formation of these estuaries there are only a small number of tectonically produced estuaries one example is the san francisco bay which was formed by the crustal movements of the san andreas fault system causing the inundation of the lower reaches of the sacramento and san joaquin rivers 11 classification based on water circulation edit see also estuarine water circulation salt wedge edit salt wedge redirects here not to be confused with salt wedging geology see also saltwater intrusion in this type of estuary river output greatly exceeds marine input and tidal effects have minor importance freshwater floats on top of the seawater in a layer that gradually thins as it moves seaward the denser seawater moves landward along the bottom of the estuary forming a wedge shaped layer that is thinner as it approaches land as a velocity difference develops between the two layers shear forces generate internal waves at the interface mixing the seawater upward with the freshwater examples of salt wedge estuaries are the mississippi river 11 and the mandovi estuary in goa during the monsoon period partially mixed edit as tidal forcing increases river output becomes less than the marine input here current induced turbulence causes mixing of the whole water column such that salinity varies more longitudinally rather than vertically leading to a moderately stratified condition examples include the chesapeake bay and narragansett bay 11 well mixed edit tidal mixing forces exceed river output resulting in a well mixed water column and the disappearance of the vertical salinity gradient the freshwater seawater boundary is eliminated due to the intense turbulent mixing and eddy effects the lower reaches of delaware bay and the raritan river in new jersey are examples of vertically homogeneous estuaries 11 inverse edit inverse estuaries occur in dry climates where evaporation greatly exceeds the inflow of freshwater a salinity maximum zone is formed and both riverine and oceanic water flow close to the surface towards this zone 12 this water is pushed downward and spreads along the bottom in both the seaward and landward direction 4 examples of an inverse estuary are spencer gulf south australia 13 saloum river and casamance river senegal 14 intermittent edit estuary type varies dramatically depending on freshwater input and is capable of changing from a wholly marine embayment to any of the other estuary types 15 16 physiochemical variation edit the most important variable characteristics of estuary water are the concentration of dissolved oxygen salinity and sediment load there is extreme spatial variability in salinity with a range of near zero at the tidal limit of tributary rivers to 3 4 at the estuary mouth at any one point the salinity will vary considerably over time and seasons making it a harsh environment for organisms sediment often settles in intertidal mudflats which are extremely difficult to colonize no points of attachment exist for algae so vegetation based habitat is not established clarification needed sediment can also clog feeding and respiratory structures of species and special adaptations exist within mudflat species to cope with this problem lastly dissolved oxygen variation can cause problems for life forms nutrient rich sediment from human made sources can promote primary production life cycles perhaps leading to eventual decay removing the dissolved oxygen from the water thus hypoxic or anoxic zones can develop 17 implications of eutrophication on estuaries edit further information eutrophication coastal waters effects of eutrophication on biogeochemical cycles edit processes that nitrogen undergo in estuarine systems nitrogen is often the lead cause of eutrophication in estuaries in temperate zones 18 during a eutrophication event biogeochemical feedback decreases the amount of available silica 19 these feedbacks also increase the supply of nitrogen and phosphorus creating conditions where harmful algal blooms can persist given the now off balance nitrogen cycle estuaries can be driven to phosphorus limitation instead of nitrogen limitation estuaries can be severely impacted by an unbalanced phosphorus cycle as phosphorus interacts with nitrogen and silica availability with an abundance of nutrients in the ecosystem plants and algae overgrow and eventually decompose which produce a significant amount of carbon dioxide 20 while releasing co 2 into the water and atmosphere these organisms are also intaking all or nearly all of the available oxygen creating a hypoxic environment and unbalanced oxygen cycle 21 the excess carbon in the form of co 2 can lead to low ph levels and ocean acidification which is more harmful for vulnerable coastal regions like estuaries effects of eutrophication on estuarine plants edit a salt marsh with wood storks wading eutrophication has been seen to negatively impact many plant communities in estuarine ecosystems 22 salt marshes are a type of ecosystem in some estuaries that have been negatively impacted by eutrophication 22 cordgrass vegetation dominates the salt marsh landscape 23 excess nutrients allow the plants to grow at greater rates in above ground biomass however less energy is allocated to the roots since nutrients is abundant 22 24 this leads to a lower biomass in the vegetation below ground which destabilizes the banks of the marsh causing increased rates of erosion 22 a similar phenomenon occurs in mangrove swamps which are another potential ecosystem in estuaries 24 25 an increase in nitrogen causes an increase in shoot growth and a decrease in root growth 24 weaker root systems cause a mangrove tree to be less resilient in seasons of drought which can lead to the death of the mangrove 24 this shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems 22 24 effects of eutrophication on estuarine animals edit example of a whitefish across all biomes eutrophication often results in plant death but the impacts do not end there plant death alters the entire food web structure which can result in the death of animals within the afflicted biome estuaries are hotspots for biodiversity containing a majority of commercial fish catch making the impacts of eutrophication that much greater within estuaries 26 some specific estuarine animals feel the effects of eutrophication more strongly than others one example is the whitefish species from the european alps 27 eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive causing l...