{"id":1636,"date":"2017-10-01T02:00:55","date_gmt":"2017-10-01T02:00:55","guid":{"rendered":"https:\/\/himinn.fjarver.is\/mengunsjavar\/?p=1636"},"modified":"2024-08-10T20:15:23","modified_gmt":"2024-08-10T20:15:23","slug":"5-2-naeringarefnaofaudgun","status":"publish","type":"post","link":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/2017\/10\/01\/5-2-naeringarefnaofaudgun\/","title":{"rendered":"5.2 N\u00e6ringarefnaofau\u00f0gun"},"content":{"rendered":"

N\u00e6ringarefnin k\u00f6fnunarefni (N) og fosf\u00f3r (P) eru l\u00edfverum nau\u00f0synleg til vaxtar og vi\u00f0halds, en allt er best \u00ed h\u00f3fi. \u00dear sem n\u00e6ringarefnar\u00edkan sj\u00f3 er a\u00f0 finna eru vaxtarskilyr\u00f0i svif\u00fe\u00f6runga g\u00f3\u00f0. \u00deeir fj\u00f6lga s\u00e9r \u00e1 me\u00f0an n\u00f3g er af n\u00e6ringu \u00ed sj\u00f3num en \u00feegar n\u00e6ringarefnin \u00fer\u00fdtur h\u00e6gir \u00e1 vexti \u00fe\u00f6runganna. Ef st\u00f6\u00f0ugt berast meiri n\u00e6ringarefni \u00ed sj\u00f3inn vegna mannlegra athafna getur \u00fea\u00f0 leitt til offj\u00f6lgunar svif\u00fe\u00f6runga.<\/p>\n

Helstu uppsprettur n\u00e6ringarefna eru notkun \u00e1bur\u00f0ar (b\u00e6\u00f0i tilb\u00fains \u00e1bur\u00f0ar<\/span> og b\u00fafj\u00e1r\u00e1bur\u00f0ar) \u00ed landb\u00fana\u00f0i og losun fr\u00e1veituvatns e\u00f0a sk\u00f3lps \u00ed sj\u00f3inn, b\u00e6\u00f0i h\u00fasask\u00f3lps og i\u00f0na\u00f0arsk\u00f3lps (s\u00e9rstaklega fr\u00e1 matv\u00e6lavinnslu). Fr\u00e1 \u00feessum uppsprettum berast b\u00e6\u00f0i k\u00f6fnunarefni (N) og fosf\u00f3r (P) til sj\u00e1var. \u00de\u00e1 losna einnig k\u00f6fnunarefnisox\u00ed\u00f0 \u00fat \u00ed andr\u00famslofti\u00f0 fr\u00e1 alls kyns i\u00f0na\u00f0i og vegna eldsneytisbrennslu. \u00deetta k\u00f6fnunarefni getur borist me\u00f0 loftstraumum \u2013 jafnvel langar lei\u00f0ir \u2013 og falli\u00f0 til jar\u00f0ar og \u00ed sj\u00f3inn me\u00f0 \u00farkomu e\u00f0a \u00feurri \u00e1komu<\/span>.<\/p>\n

\"\"<\/a>

Mynd 5.2. Uppsprettur n\u00e6ringarefna sem lenda \u00ed hafinu og einf\u00f6ldu\u00f0 mynd af aflei\u00f0ingum n\u00e6ringarefnaofau\u00f0gunar.<\/p><\/div>\n

Me\u00f0 auknu magni n\u00e6ringarefna eykst vaxtarhra\u00f0i \u00fe\u00f6runga (pl\u00f6ntusvif) og \u00fe\u00f6rungabl\u00f3mi myndast. Sumar \u00fe\u00f6rungategundir geta veri\u00f0 eitra\u00f0ar en \u00fe\u00f3 alls ekki allar. Vi\u00f0 aukinn v\u00f6xt \u00fe\u00f6runga vi\u00f0 sj\u00e1varyfirbor\u00f0 dimmir \u00ed sj\u00f3num, \u00fear sem s\u00f3larlj\u00f3si\u00f0 kemst ekki ni\u00f0ur \u00e1 eins miki\u00f0 d\u00fdpi og \u00e1\u00f0ur. L\u00e6kka\u00f0 birtustig getur haft \u00e1hrif \u00e1 botngr\u00f3\u00f0ur sem deyr ef hann f\u00e6r ekki n\u00f3g lj\u00f3s. Hinn aukni v\u00f6xtur pl\u00f6ntusvifs \u00ed yfirbor\u00f0inu veldur \u00fev\u00ed einnig a\u00f0 d\u00fdrasvifi fj\u00f6lgar. \u00deegar svifi\u00f0 (b\u00e6\u00f0i pl\u00f6ntu- og d\u00fdrasvifi\u00f0) deyr fellur \u00fea\u00f0 til botns og \u00fear hefst ni\u00f0urbrot hinna l\u00edfr\u00e6nu leifa fyrir tilstilli botnl\u00e6gra l\u00edfvera (rotvera) sem n\u00fdta s\u00e9r leifarnar til vaxtar og vi\u00f0halds. Rotverurnar nota s\u00farefni vi\u00f0 ni\u00f0urbroti\u00f0 og \u00fear sem miki\u00f0 er um l\u00edfr\u00e6nar leifar \u2013 \u00ed kj\u00f6lfar ofau\u00f0gunar \u2013 kl\u00e1rast s\u00farefni\u00f0 vi\u00f0 botninn. \u00deegar s\u00farefni\u00f0 kl\u00e1rast ver\u00f0ur ni\u00f0urbroti\u00f0 loftfirrt<\/span> og \u00fe\u00e1 myndast eitra\u00f0ar lofttegundir, b\u00e6\u00f0i brennisteinsvetni (H2<\/sub>S) og ammon\u00edak (NH3<\/sub>). \u00deetta er vegna \u00feess a\u00f0 \u00feegar anna\u00f0 s\u00farefni (O2<\/sub>) \u00fer\u00fdtur geta vissar bakter\u00edur n\u00fdtt s\u00e9r s\u00farefni\u00f0 sem bundi\u00f0 er \u00ed s\u00falfati (SO4<\/sub>2-<\/sup>) og n\u00edtrati (NO3<\/sub>–<\/sup>). Vi\u00f0 \u00fea\u00f0 afoxast \u00feessi efnasamb\u00f6nd og hinar fyrrgreindu eitru\u00f0u lofttegundir myndast. S\u00farefnisskorturinn vi\u00f0 botninn ska\u00f0ar botnd\u00fdral\u00edfi\u00f0 og einnig d\u00fdral\u00edfi\u00f0 ofar \u00ed vatnsmassanum ef s\u00farefnisskorturinn n\u00e6r upp \u00ed efri l\u00f6g. Brennisteinsvetni og ammon\u00edak geta stigi\u00f0 upp \u00ed vatnsmassanum og valdi\u00f0 dau\u00f0a b\u00e6\u00f0i fiska og annarra l\u00edfvera. Ofaug\u00f0un veldur \u00fev\u00ed breytingum \u00ed pl\u00f6ntu- og d\u00fdral\u00edfi \u00fear sem \u00fdmsar tegundir vistkerfisins deyja en \u00fe\u00e6r tegundir sem \u00feola s\u00farefnissnautt umhverfi betur fj\u00f6lga s\u00e9r. Vistkerfi\u00f0 ver\u00f0ur \u00fev\u00ed oft einh\u00e6fara.<\/p>\n

\"\"<\/a>

Mynd 5.3. Sk\u00fdringarmynd um n\u00e6ringarefnaofau\u00f0gun og aflei\u00f0ingar hennar.<\/p><\/div>\n

Ofau\u00f0gun \u00ed sj\u00f3 \u00e1 s\u00e9r a\u00f0allega sta\u00f0 vi\u00f0 strendur og \u00e1 sv\u00e6\u00f0um me\u00f0 takm\u00f6rku\u00f0um vatnsskiptum. F\u00e1 d\u00e6mi, ef nokkur, eru um a\u00f0 \u00e1koma n\u00e6ringarefna hafi valdi\u00f0 mengun \u00ed sj\u00f3 h\u00e9r vi\u00f0 land. \u00d6\u00f0ru m\u00e1li gegnir um sunnanver\u00f0an Nor\u00f0ursj\u00f3 og Eystrasalti\u00f0 \u00fear sem miki\u00f0 magn n\u00e6ringarefna berst til sj\u00e1var fr\u00e1 \u00fe\u00e9ttb\u00fdli (fr\u00e1rennsli, b\u00edlaumfer\u00f0) og vegna afrennslis fr\u00e1 landb\u00fana\u00f0arlandi \u00ed kj\u00f6lfar \u00e1bur\u00f0arnotkunar. \u00der\u00e1tt fyrir a\u00f0 \u00e1tak hafi veri\u00f0 gert til a\u00f0 minnka \u00e1komu n\u00e6ringarefna veldur ofau\u00f0gun enn vandam\u00e1lum \u00e1 \u00feessum hafssv\u00e6\u00f0um.<\/p>\n","protected":false},"excerpt":{"rendered":"

N\u00e6ringarefnin k\u00f6fnunarefni (N) og fosf\u00f3r (P) eru l\u00edfverum nau\u00f0synleg til vaxtar og vi\u00f0halds, en allt er best \u00ed h\u00f3fi. \u00dear sem n\u00e6ringarefnar\u00edkan sj\u00f3 er a\u00f0 finna eru vaxtarskilyr\u00f0i svif\u00fe\u00f6runga g\u00f3\u00f0. \u00deeir fj\u00f6lga s\u00e9r \u00e1 me\u00f0an n\u00f3g er af n\u00e6ringu \u00ed Lesa meira…<\/a><\/p>\n","protected":false},"author":2,"featured_media":1749,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25],"tags":[],"class_list":["post-1636","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-5-efnamengun"],"_links":{"self":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/1636","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/comments?post=1636"}],"version-history":[{"count":19,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/1636\/revisions"}],"predecessor-version":[{"id":3914,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/1636\/revisions\/3914"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/media\/1749"}],"wp:attachment":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/media?parent=1636"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/categories?post=1636"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/tags?post=1636"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}