Mary Allen
Nyanja ndi madzi opangidwa ndi madzi amchere. Mbali yaikulu ya dziko lapansi ili ndi madzi a m’nyanja, oposa magawo awiri pa atatu alionse. Pali magawo amodzi, koma onse amalumikizana. Izi zimatchedwa "Nyanja Yapadziko Lonse". Nthawi zambiri imagawidwa m'nyanja zisanu.
Kuphatikiza apo, mbali zina zanyanja zimakhalanso ndi mayina apadera, monga nyanja zolumikizana ndi magombe. Nyanja ya Mediterranean ndi chitsanzo cha izi kapena Caribbean. Nyanja Yofiira pakati pa Igupto ndi Arabia ndi nyanja yam'mbali yomwe ili pafupi ndi malire.
Pamwamba pa dziko lapansi makamaka ndi nyanja: Ndi pafupifupi 71 peresenti, mwachitsanzo, pafupifupi atatu mwa anayi. Malo ozama kwambiri ali mumtsinje wa Mariana ku Pacific Ocean. Ndi pafupi mamita zikwi khumi ndi chimodzi kuya pamenepo.
Kodi nyanja ndi chiyani kwenikweni, ndipo imatchedwa chiyani motero?
Ngati madzi azunguliridwa ndi nthaka, ndiye kuti si nyanja koma nyanja. Nyanja zina zimatchedwabe nyanja. Izi zitha kukhala ndi zifukwa ziwiri zosiyana.
Nyanja ya Caspian kwenikweni ndi nyanja yamchere. Izi zikugwiranso ntchito ku Nyanja Yakufa. Iwo anatenga dzina lawo chifukwa cha kukula kwawo: kwa anthu, iwo ankawoneka aakulu ngati nyanja.
Ku Germany, pali chifukwa china, chachindunji. Mu Chijeremani, nthawi zambiri timati Meer ku mbali ya nyanja ndi See poyimirira madzi akumtunda. Mu Low German, komabe, ndi njira ina. Izi zapeza njira yake mu chilankhulo cha Chijeremani chokhazikika.
Ndicho chifukwa chake timatinso "nyanja" ya nyanja: Nyanja ya Kumpoto, Nyanja ya Baltic, Nyanja ya Kumwera, ndi zina zotero. Palinso nyanja zina kumpoto kwa Germany zomwe zili ndi mawu akuti "nyanja" m'maina awo. Chodziwika bwino mwina ndi Steinhuder Meer ku Lower Saxony, nyanja yayikulu kwambiri kumpoto.
Kodi pali nyanja ziti?
Nyanja yapadziko lonse nthawi zambiri imagawidwa m'nyanja zisanu. Chachikulu kwambiri ndi Pacific Ocean pakati pa America ndi Asia. Imatchedwanso kuti Pacific. Yachiwiri yaikulu ndi nyanja ya Atlantic kapena nyanja ya Atlantic pakati pa Ulaya ndi Africa kummawa ndi America kumadzulo. Chachitatu chachikulu kwambiri ndi Nyanja ya Indian pakati pa Africa, India, ndi Australia.
Chachinayi chachikulu ndi Southern Ocean. Awa ndi malo ozungulira nyanja ya Antarctica. Chaching'ono kwambiri mwa zisanu ndi nyanja ya Arctic. Imakhala pansi pa ayezi ndipo imafika ku Canada ndi Russia.
Anthu ena amanena za nyanja zisanu ndi ziwiri. Kuwonjezera pa nyanja zisanu, amawonjezera nyanja ziwiri zomwe zili pafupi ndi iwo kapena kuti nthawi zambiri amayenda pa sitima. Zitsanzo zodziwika bwino ndi Nyanja ya Mediterranean ndi Caribbean.
Kalekale, anthu ankawerengeranso nyanja zisanu ndi ziwiri. Izi zinali mbali zisanu ndi imodzi za nyanja ya Mediterranean monga nyanja ya Adriatic kuphatikiza ndi Black Sea. Nyengo iliyonse inali ndi njira yakeyake yowerengera. Izi zinali zogwirizana kwambiri ndi nyanja zomwe zinkadziwika konse.
N’chifukwa chiyani nyanja zili zofunika kwambiri?
Anthu ambiri amakhala m’mphepete mwa nyanja: amapha nsomba kumeneko, amalandila alendo odzaona malo, kapena amayenda panyanja kukanyamula katundu. M'munsi mwa nyanja muli zinthu monga mafuta osapsa, omwe amachotsedwa.
Pomaliza, nyanja ndi yofunika kwambiri pa nyengo ya dziko lathu lapansili. Nyanja zimasunga kutentha, kumazigawa kudzera mu mafunde, komanso kutenga mpweya wowonjezera kutentha monga carbon dioxide. Choncho popanda iwo, tikadakhala ndi kutentha kwa dziko.
Komabe, carbon dioxide yambiri ndi yoipa kwa nyanja. M'madzi a m'nyanja, imakhala carbonic acid. Izi zimapangitsa nyanja kukhala acidic, zomwe sizoyipa m'madzi ambiri.
Akatswiri a zachilengedwe nawonso akuda nkhawa kuti zinyalala zochulukirachulukira zikutha m’nyanja. Pulasitiki makamaka imawonongeka pang'onopang'ono. Komabe, amawola kukhala tiziduswa tating'ono kwambiri, ma microplastics. Izi zimapangitsa kuti zitheke m'matupi a nyama ndikuwononga pamenepo.
Kodi mcherewo umalowa bwanji m’nyanja?
Palibe kulikonse padziko lapansi kumene kuli madzi ochuluka ngati a m’nyanja: 97 peresenti. Komabe, madzi a m’nyanjayi sangamwe. M'mphepete mwa nyanja, pali zomera zochotsa mchere m'madzi a m'nyanja, zomwe zimawasandutsa madzi akumwa.
Mchere umapezeka m’miyala padziko lonse lapansi. Pokhudzana ndi nyanja, nthawi zambiri munthu amalankhula za mchere wa tebulo kapena mchere wamba, womwe timagwiritsa ntchito kukhitchini. Mchere wa patebulo umasungunuka bwino kwambiri m'madzi. Ngakhale zochepa zimaloŵa m’nyanja kudzera m’mitsinje.
Pansi pa nyanja palinso mchere. Nayonso ikumira m’madzi pang’onopang’ono. Mapiri ophulika pansi pa nyanja amathanso kutulutsa mchere. Zivomezi zomwe zili pansi pa nyanja zimapangitsanso mchere kulowa m’madzi.
Kuzungulira kwa madzi kumapangitsa kuti madzi ambiri alowe m'nyanja. Komabe, imatha kungochokanso m’nyanja chifukwa cha nthunzi. Mcherewo supita nawo. Mchere, ukakhala m'nyanja, umakhala momwemo. Madzi akamasanduka nthunzi, m’pamenenso nyanjayi imakhala ya mchere wambiri. Choncho, mcherewu suli wofanana ndendende m’nyanja iliyonse.
Lita imodzi yamadzi am'nyanja nthawi zambiri imakhala ndi pafupifupi magalamu 35 a mchere. Ndiye pafupifupi supuni imodzi ndi theka. Nthawi zambiri timadzaza madzi okwana malita 150 m’bafa. Choncho munkafunika kuthira mchere wokwana makilogalamu asanu kuti mupeze madzi a m’nyanja.