Ikhwalithi yamanzi omuhle ithonya ukukhula kwezinhlanzi (amanzi amnandi = ukukhula okusheshayo), ukutholakala kwezifo kanye nokunambitheka nombala wezinhlanzi. Imfanelo yamanzi inqunywa yizici ezine eziyinhloko:
Ukushisa kwamanzi
Amazinga e-oksijini emanzini
Amazinga e-Amoniya emanzini
Amanzi pH (izinga le-acidity noma i-alkalinity)
Izinkinga eziningi zekhwalithi yamanzi ezinhlanzi zokudoba ngamanzi ahlanzekile zibangelwa ukuchithwa kwe-oksijeni, amazinga aphezulu e-ammonia noma amazinga aphezulu e-pH. Lezi zinkinga zihlobene kakhulu namazinga ezinhlanganiso ezincane emanzini.
Ukukhula kwalezi zinhlanzi kuncike ekutheni inani lezakhi - i-nitrogen (N) ne-phosphorus (P) - emanzini. Lezi zakhi zifaka idamu nge:
Umthombo wamanzi (ukungena kwamanzi echibini).
Ukuphuma kwezidumbu ngesikhathi semvula enkulu (imvula).
Ukudla kwezinhlanzi phakathi nomjikelezo wokukhiqiza.
Izinga Lokushisa Lamanzi Ekufuyeni Inhlanzi
I-Trout ivame ukukhula kahle phakathi kuka-14 no-18°C (izinga lokushisa elingu-16°C) kodwa izinhlobo ezifudumele ezifana ne-sharptooth catfish zikhula kahle emanzini afudumele (20 - 30°C) futhi i-tilapia ikhetha ngisho namazinga okushisa kwamanzi angama-24 kuya ku-34°C.I-Trout izwela emanzini afudumele. Ukushisa kwama-20°C kuzobangela ukuthi inhlanzi iqhubeke ukukhula futhi iyodala ezinye izinkinga zokukhiqiza, njengengozi enkulu yezifo nezinkinga ze-oksijeni, ichaza umphathi oyinhloko wezobuchwepheshe bezolimo nokufuya: uMnyango WeSayensi yezilwane, eNyuvesi yaseStellenbosch.
Lezi zinkinga (ukwanda kwezinkinga zesifo nokunciphisa oksijini) kubangelwa kakhulu yi-algae eminingi kakhulu emanzini afudumele. Ngokushesha lapho amazinga okushisa afinyelela ku-21°C nangaphezulu, ukunakekelwa okukhethekile kufanele kuthathwe ukuze kuvinjelwe ukufa kwezinhlanzi kanye nokusethwa kwe-algae taint. Ama-algal taints abangelwa ukwanda kwama-blue-green algae izinombolo ezibangelwa ukushisa okuphezulu nokutholakala komsoco. I-algae ikhulula izinhlanganisela zamakhemikhali ezinjengezinto ezihlaba umhlabathi, i-geosmin. Lesi sitho sithandwa yizinhlanzi futhi sishintsha ukunambitheka kwenyama yenhlanzi.
Izinga Le-Oksijeni Ekufuyeni Inhlanzi
Izinkinga ze-oksijeni zibangelwa ikakhulukazi izilwanyana ezincane. Lezi zinyana ezincane zisebenza ngezithombe futhi zenza oksijini. Ngamazinga avamile alawa algae, ngeke kube nezinkinga.
Uma amazinga alawa algae ekhuphuka, amazinga oksijini ngesikhathi sokuhlwa angase abe ngaphansi kuka 5 mg/L futhi kuzoba nezinkinga ze-oxygen emanzini ekuseni olulandelayo.
Okwesibili, uma inani elincane le-algae elincane lifa ngokuzumayo (ngenxa yezimo zezulu ezishisayo noma ukuchithwa kwe-algaecides), amabhaktheriya aerobic azokhula massively ukuze asize ukubola izilwane ezifile. Lezi zingqimba ze-aerobic zisebenzisa i-oksijeni ezokwehlisa amazinga e-oxygen emadamu ngokushesha futhi ibangele ukucindezeleka izinhlanzi.
Amazinga e-Amoniya Emanzini Amasha
I-Amoniya iyenzeka ifomu (i-ammonia mahhala) ne-non-toxic (ionized ammonia) ifomu kodwa ifomu eliyingozi livame ukungaphansi kuka-10% we-concentration yama-ammonia. Emanzini afudumele (+20°C) ane-pH ephezulu (8.5), amazinga ammoniya anobuthi ayanda.
Amazinga e-Amoniya ngeke adale izinkinga emadamu ngaphandle uma engajulile (5 m noma ngaphansi) futhi ngezinga eliphansi lokubuya ngonyaka elingaphansi kwesinye. ('Inzuzo yonyaka' yisilinganiso lapho umthamo wamanzi ogcwele amanzi ugcwaliswa yimvula noma amanzi angene).
I-pH Yamanzi eDamu
Isici esibaluleke kunazo zonke esizokwandisa amazinga e-pH ukukhula kwe-algae encane. Inqwaba yalezi algae ingandisa amazinga e-pH ikakhulukazi amadamu epulazi amancane emazingeni aphakeme kune-pH 9 (ikakhulukazi ntambama). Lokhu kungenxa yokususwa kwe-carbon dioxide ngesikhathi senqubo ye-photosynthesis. Le pH ephezulu izobeka izinhlanzi zicindezelekile.
Ukuze ulungise/uthuthukise la mazinga, kudingeka ushintsho lwamanzi, engeza amanzi ahlanzekile uma kungenzeka. Kungenjalo, engeza utshani webhasi.Translated by Nsika Khoza