Izinguquko ezibangelwa yisimo sezulu ekufakweni kwamanzi ahlanzekile ziboniswe ukuthi zithinta isakhiwo kanye nomsebenzi wezindawo zemvelo zasogwini. Sihlole izinguquko ethonyeni lokugeleza kwemifula ezinhlelweni zasogwini zaseNorthwestern Patagonia (NWP) emashumini eminyaka amuva nje (1993–2021) ngokuhlaziywa okuhlangene kochungechunge lwesikhathi sokugeleza kwemifula yesikhathi eside, ukulingisa kwamanzi, idatha etholakala ngesathelayithi kanye nokuhlaziywa kabusha kwezimo zobuso bolwandle (izinga lokushisa, ukudungeka kwamanzi, kanye nosawoti). Ukwehla okukhulu kokugeleza kwemifula okuncane endaweni ehlanganisa izigodi eziyisithupha ezinkulu zemifula kwabonakala ezikalini zamasonto onke, zanyanga zonke, kanye nezezinkathi zonyaka. Lezi zinguquko ziye zabonakala kakhulu ezigodini zasenyakatho ezixubile (isib. uMfula iPuelo) kodwa kubonakala sengathi ziya ngaseningizimu ziye emifuleni ephawulwa yisimiso se-nival. Olwandle olungaphakathi olunezingqimba ezimbili oluseduze, ukungena kwamanzi ahlanzekile okuncishisiwe kuhambisana ne-halocline engajulile kanye namazinga okushisa aphezulu olwandle olusenyakatho yePatagonia. Imiphumela yethu igcizelela ithonya elishintsha ngokushesha lemifula emanzini ase-estuarine aseduze kanye nasogwini e-NWP. Sigcizelela isidingo sokubuka, ukubikezela, ukunciphisa kanye namasu okuzivumelanisa nezimo esimweni sezulu esishintshayo, kanye nokuphathwa kwezinhlelo ezihambisanayo ezihlinzeka ngamanzi ageleza olwandle olusogwini.
Imifula iwumthombo oyinhloko wokungenisa amanzi ahlanzekile ezwekazini olwandle1. Ezinhlelweni zasogwini ezivalekile kancane, imifula iyisishukumisi esibalulekile sezinqubo zokujikeleza2 kanye nebhuloho phakathi kwezindawo zemvelo zomhlaba nezasolwandle, ukuthutha izakhamzimba, izinto eziphilayo, kanye nenhlabathi enezela lezo ezivela olwandle olusogwini noluvulekile3. Izifundo zakamuva zibike izinguquko kumthamo nesikhathi sokufakwa kwamanzi ahlanzekile olwandle olusogwini4. Ukuhlaziywa kochungechunge lwesikhathi kanye namamodeli amanzi ahlanzekile kubonisa amaphethini ahlukene endawo nesikhathi5, kusukela, isibonelo, ekukhuleni okunamandla kokukhishwa kwamanzi ahlanzekile ezindaweni eziphakeme6—ngenxa yokwanda kokuncibilika kweqhwa—kuya ekuncipheni kwezindlela eziphakathi nendawo ngenxa yokwanda kwesomiso samanzi7. Kungakhathaliseki ukuthi isiqondiso nobukhulu bezindlela ezisanda kubikwa, ushintsho lwesimo sezulu lubonwe njengosishukumisi esikhulu sezinhlelo zamanzi ezishintshiwe8, kuyilapho imiphumela emanzini asogwini kanye nezindawo zemvelo ezisekelayo ingakahlolwa futhi iqondwe ngokugcwele9. Izinguquko zesikhashana ekugelezeni kwamanzi, ezithonywa ukushintsha kwesimo sezulu (ukushintsha kwamaphethini emvula kanye nokwenyuka kwamazinga okushisa) kanye nezingcindezi zabantu ezifana namadamu kagesi noma amadamu okugcina amanzi10,11, ukuchelela, kanye nezinguquko zokusetshenziswa komhlaba12, ziyinselele ekuhlaziyeni izitayela zokufakwa kwamanzi ahlanzekile13,14. Isibonelo, izifundo eziningana zibonise ukuthi izindawo ezinezinhlobonhlobo eziningi zamahlathi zibonisa ukuqina okukhulu kwemvelo ngesikhathi sesomiso kunalezo ezibuswa amasimu amahlathi noma ezolimo15,16. Ezindaweni eziphakathi nendawo, ukuqonda imiphumela yokushintsha kwesimo sezulu esikhathini esizayo olwandle olusogwini ngokuhlukanisa imiphumela yokushintsha kwesimo sezulu kanye nokuphazamiseka kwabantu bendawo kudinga ukubonwa okuvela ezinhlelweni zokubhekisela ezinoshintsho olulinganiselwe ukuze izinguquko ohlelweni lwamanzi zihlukaniswe nokuphazamiseka kwabantu bendawo.
I-Western Patagonia (> 41°S ogwini lwasePacific eNingizimu Melika) ivela njengenye yalezi zifunda ezigcinwe kahle, lapho ucwaningo oluqhubekayo lubalulekile khona ukuqapha nokuvikela lezi zindawo zemvelo. Kulesi sifunda, imifula egeleza ngokukhululeka ixhumana ne-geomorphology eyinkimbinkimbi yogu lolwandle ukuze yakhe enye yezindawo ezinkulu kakhulu emhlabeni. Ngenxa yokuba kude kwazo, izigodi zemifula yasePatagonia aziphazanyiswa ngokuphawulekayo, zimbozwe amahlathi amaningi endawo19, ubuningi babantu obuphansi, futhi ngokuvamile azinawo amadamu, amachibi, kanye nengqalasizinda yokunisela. Ukubekeka engozini kwalezi zindawo zemvelo zasogwini ezinguqukweni zemvelo kuncike kakhulu, ngokwengeziwe, ekusebenzisaneni kwazo nemithombo yamanzi ahlanzekile. Amanzi ahlanzekile angena emanzini asogwini lwaseNorthwestern Patagonia (NWP; 41–46 ºS), okuhlanganisa imvula eqondile kanye nokugeleza kwemifula, axhumana nezinqwaba zamanzi olwandle, ikakhulukazi i-Subantarctic Water (SAAW) enosawoti omningi. Lokhu, nakho, kuthonya amaphethini okujikeleza kwegazi, ukuvuselelwa kwamanzi, kanye nokuphefumula20 ngokudalwa kwe-gradient enamandla kasawoti, enezinga eliphezulu lokushintshashintsha kwesizini kanye nokungafani kwendawo ku-halocline21. Ukusebenzisana phakathi kwale mithombo emibili yamanzi nakho kuthinta ukwakheka kwemiphakathi ye-planktonic22, kuthinta ukuncishiswa kokukhanya23, futhi kuholela ekunciphisweni kokugcwala kwe-nitrogen ne-Phosphorus ku-SAAW24 kanye nokuhlinzekwa kwe-orthosilicate okuthuthukisiwe kungqimba olungaphezulu25,26. Ngaphezu kwalokho, ukufakwa kwamanzi ahlanzekile kuphumela ku-gradient eqinile ye-oxygen encibilikisiwe (DO) kulawa manzi ase-estuarine, kanti ungqimba olungaphezulu luvame ukubonisa ukugcwala okuphezulu kwe-DO (6–8 mL L−1)27.
Ukungenelela okulinganiselwe okubonisa izizinda zasePatagonia zezwekazi kuyahluka ekusetshenzisweni kakhulu kogu lolwandle, ikakhulukazi embonini yezolimo zasemanzini, umkhakha obalulekile wezomnotho eChile. Njengamanje ibalwa phakathi kwabakhiqizi bezolimo zasemanzini abaphambili emhlabeni, iChile ingumthumeli wesibili ngobukhulu we-salmon ne-trout, futhi ingumthengisi omkhulu wezinhlanzi zasemanzini. Ukufuywa kwezinhlanzi zasemanzini nezimbaza, okwamanje okuhlala ezindaweni ezingaba ngu-2300 ezinendawo engamahektha angu-24,000 esifundeni, kukhiqiza inani elikhulu lezomnotho eningizimu yeChile. Lokhu kuthuthukiswa akunawo umthelela wezemvelo, ikakhulukazi endabeni yokufuywa kwezinhlanzi zasemanzini, umsebenzi ofaka isandla ngezakhamzimba zangaphandle kulezi zindawo zemvelo. Kuye kwabonakala futhi ukuthi isengozini enkulu yezinguquko ezihlobene nesimo sezulu.
Emashumini eminyaka amuva nje, izifundo ezenziwe ku-NWP zibike ukwehla kokufakwa kwamanzi ahlanzekile33 futhi zibikezele ukwehla kokugeleza kwamanzi ngesikhathi sasehlobo nasekwindla34, kanye nokwelulwa kwesikhathi sesomiso samanzi35. Lezi zinguquko kokufakwa kwamanzi ahlanzekile zithinta imingcele yezemvelo esheshayo futhi zinemiphumela eholela ekuguqukeni kwemvelo okubanzi. Isibonelo, izimo ezimbi kakhulu emanzini asogwini ngesikhathi sesomiso sasehlobo nasekwindla ziye zaba ziningi, futhi, kwezinye izimo, ziye zathinta imboni yezolimo zasemanzini nge-hypoxia36, ukwanda kwama-parasitism, kanye nezimbali ze-algal eziyingozi32,37,38 (ama-HAB).
Emashumini eminyaka amuva nje, izifundo ezenziwe ku-NWP zibike ukwehla kokufakwa kwamanzi ahlanzekile33 futhi zibikezele ukwehla kokugeleza kwamanzi ngesikhathi sasehlobo nasekwindla34, kanye nokwelulwa kwesikhathi sesomiso samanzi35. Lezi zinguquko kokufakwa kwamanzi ahlanzekile zithinta imingcele yezemvelo esheshayo futhi zinemiphumela eholela ekuguqukeni kwemvelo okubanzi. Isibonelo, izimo ezimbi kakhulu emanzini asogwini ngesikhathi sesomiso sasehlobo nasekwindla ziye zaba ziningi, futhi, kwezinye izimo, ziye zathinta imboni yezolimo zasemanzini nge-hypoxia36, ukwanda kwama-parasitism, kanye nezimbali ze-algal eziyingozi32,37,38 (ama-HAB).
Ulwazi lwamanje mayelana nokwehla kokufakwa kwamanzi ahlanzekile kulo lonke i-NWP lusekelwe ekuhlaziyweni kwezilinganiso zamanzi39, ezichaza izakhiwo zezibalo noma eziguquguqukayo zochungechunge lwedatha yamanzi oluvela enanini elilinganiselwe lamarekhodi esikhathi eside kanye nokumbozwa okuncane kwendawo. Ngokuphathelene nezimo zamanzi ezihambisanayo emanzini ase-NWP noma olwandle oluseduze nolwandle, awekho amarekhodi atholakalayo esikhathi eside. Njengoba kusengozini yemisebenzi yezenhlalo nezomnotho yasogwini emiphumeleni yokushintsha kwesimo sezulu, ukwamukela indlela ephelele yokuxhumana komhlaba nolwandle ekuphathweni nasekuzivumelaniseni nokushintsha kwesimo sezulu kubalulekile40. Ukuze sibhekane nale nselele, sihlanganise imodeli yamanzi (1990-2020) nedatha ethathwe ngesathelayithi kanye nokuhlaziywa kabusha kwezimo zolwandle (1993-2020). Le ndlela inezinhloso ezimbili eziyinhloko: (1) ukuhlola izitayela zomlando zezilinganiso zamanzi esikalini sesifunda kanye (2) ukuhlola imiphumela yalezi zinguquko ohlelweni oluseduze nolwandle, ikakhulukazi maqondana nosawoti wolwandle, izinga lokushisa, kanye nokugcwala kwamanzi.
Singahlinzeka ngezinhlobo ezahlukene zezinzwa ezihlakaniphile zokuqapha i-hydrology kanye nekhwalithi yamanzi, wamukelekile ukubonisana.
Isikhathi sokuthunyelwe: Septhemba 18-2024