{"id":5921,"date":"2019-02-12T12:16:45","date_gmt":"2019-02-12T11:16:45","guid":{"rendered":"https:\/\/www.vtei.cz\/?p=5921"},"modified":"2024-07-16T14:53:00","modified_gmt":"2024-07-16T13:53:00","slug":"vliv-rybniku-na-kvalitu-vody-vn-jordan-v-tabore","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2019\/02\/vliv-rybniku-na-kvalitu-vody-vn-jordan-v-tabore\/","title":{"rendered":"Impact of fishponds on water quality of the Jord\u00e1n water reservoir in T\u00e1bor"},"content":{"rendered":"

This article is available in Czech only. For translation or more information on this topic, please contact author.<\/h4>\n

 <\/p>\n

Souhrn<\/h2>\n

M\u00edra eutrofizace vodn\u00ed n\u00e1dr\u017ee Jord\u00e1n v\u00a0T\u00e1bo\u0159e dos\u00e1hla na p\u0159elomu mil\u00e9nia velmi vysok\u00e9 \u00farovn\u011b. To v\u00fdznamn\u011b omezilo jej\u00ed vod\u00e1rensk\u00e9 i\u00a0rekrea\u010dn\u00ed vyu\u017eit\u00ed. V\u00a0letech 2011\u20132014 prob\u011bhlo na n\u00e1dr\u017ei pom\u011brn\u011b rozs\u00e1hl\u00e9 odbahn\u011bn\u00ed, v\u00a0jeho\u017e pr\u016fb\u011bhu bylo odstran\u011bno t\u00e9m\u011b\u0159 270\u2008tis. m3<\/sup> sediment\u016f. Od roku 2015 prov\u00e1d\u00ed st\u00e1tn\u00ed podnik Povod\u00ed Vltavy komplexn\u00ed monitoring kvality vody VN\u00a0Jord\u00e1n a\u00a0bl\u00edzk\u00e9ho povod\u00ed. V\u00a0roce 2017 bylo sou\u010d\u00e1st\u00ed tohoto monitoringu tak\u00e9 sledov\u00e1n\u00ed 11 rybn\u00edk\u016f, kter\u00e9 byly vyhodnoceny jako potenci\u00e1ln\u011b rizikov\u00e9 z\u00a0pohledu eutrofizace VN\u00a0Jord\u00e1n. C\u00edlem tohoto monitoringu je zjistit, zdali se realizovan\u00e1 a\u00a0pl\u00e1novan\u00e1 opat\u0159en\u00ed projev\u00ed ve zlep\u0161en\u00ed kvality vody v\u00a0t\u00e9to vodn\u00ed n\u00e1dr\u017ei. Doposud po\u0159\u00edzen\u00e9 v\u00fdsledky potvrzuj\u00ed, \u017ee pro zachov\u00e1n\u00ed dobr\u00e9 kvality vody v\u00a0n\u00e1dr\u017ei i\u00a0v\u00a0budouc\u00edch letech je nezbytn\u00e9 v\u00fdrazn\u011b sn\u00ed\u017eit vstup fosforu p\u0159\u00edtoky. Aktu\u00e1ln\u011b by tento po\u017eadavek m\u011blo vy\u0159e\u0161it vybudov\u00e1n\u00ed centr\u00e1ln\u00ed sr\u00e1\u017eec\u00ed stanice pro fosfor um\u00edst\u011bn\u00e9 na hlavn\u00edm p\u0159\u00edtoku VN\u00a0Jord\u00e1n. Z\u00edskan\u00e9 v\u00fdsledky d\u00e1le potvrdily, \u017ee v\u011bt\u0161ina vzorkovan\u00fdch rybn\u00edk\u016f je rizikov\u00fdch nejen jako potencion\u00e1ln\u00ed zdroje fosforu, ale obsahuj\u00ed tak\u00e9 v\u00fdznamn\u00e9 inokulum fytoplanktonu. Rybn\u00edky jsou tak\u00e9 zdrojem drobn\u00fdch planktonof\u00e1gn\u00edch druh\u016f ryb, kter\u00e9 zhor\u0161uj\u00ed celkov\u00fd efekt biomanipula\u010dn\u00edch opat\u0159en\u00ed, kter\u00e1 jsou realizov\u00e1na v\u00a0n\u00e1dr\u017ei Jord\u00e1n.<\/p>\n\"\"<\/a>\n

\u00davod<\/h2>\n

Postupn\u00e1 eutrofizace vodn\u00edch ekosyst\u00e9m\u016f, projevuj\u00edc\u00ed se zejm\u00e9na od druh\u00e9 poloviny dvac\u00e1t\u00e9ho stolet\u00ed, neu\u0161et\u0159ila ani vodn\u00ed n\u00e1dr\u017e Jord\u00e1n v\u00a0T\u00e1bo\u0159e [1]. M\u00edra eutrofizace t\u00e9to n\u00e1dr\u017ee dos\u00e1hla na p\u0159elomu mil\u00e9nia velmi vysok\u00e9 \u00farovn\u011b, co\u017e v\u00fdznamn\u011b omezilo jej\u00ed vod\u00e1rensk\u00e9 vyu\u017eit\u00ed [2]. Projevy eutrofizace, zejm\u00e9na pak v\u00fdskyt hladinov\u00fdch vodn\u00edch kv\u011bt\u016f sinic, tak\u00e9 negativn\u011b ovlivnily i\u00a0vodn\u00ed rekreaci. P\u0159\u00ed\u010dinou t\u011bchto negativn\u00edch zm\u011bn byl nadm\u011brn\u00fd p\u0159\u00edsun \u017eivin, zejm\u00e9na pak fosforu, z\u00a0povod\u00ed Ko\u0161\u00ednsk\u00e9ho potoka [3]. Hlavn\u00ed pod\u00edl na celkov\u00e9m p\u0159\u00edsunu fosforu z\u00a0tohoto povod\u00ed maj\u00ed bodov\u00e9 zdroje komun\u00e1ln\u00edho zne\u010di\u0161t\u011bn\u00ed. Rizikov\u00e9 jsou zejm\u00e9na proto, \u017ee hlavn\u00ed \u010d\u00e1st celkov\u00e9ho fosforu p\u0159ich\u00e1zej\u00edc\u00edho t\u011bmito zdroji je ve form\u011b fosfore\u010dnanov\u00e9ho fosforu, kter\u00fd je p\u0159\u00edmo dostupn\u00fd pro r\u016fst fytoplanktonu (\u0159as a\u00a0sinic). Nezanedbateln\u00e9 mno\u017estv\u00ed fosforu se do Ko\u0161\u00ednsk\u00e9ho potoka dost\u00e1v\u00e1 tak\u00e9 z\u00a0\u010detn\u00fdch hospod\u00e1\u0159sky vyu\u017e\u00edvan\u00fdch rybn\u00edk\u016f [4]. Ty v\u00a0pr\u016fb\u011bhu vegeta\u010dn\u00ed sezony generuj\u00ed zna\u010dnou biomasu fytoplanktonu, ve kter\u00e9 je v\u00e1z\u00e1no i\u00a0v\u00fdznamn\u00e9 mno\u017estv\u00ed fosforu. Tento fosfor je relativn\u011b dob\u0159e uvolniteln\u00fd (rozklad biomasy) a\u00a0mus\u00edme ho tedy pova\u017eovat za prakticky stejn\u011b rizikov\u00fd jako fosfor poch\u00e1zej\u00edc\u00ed z\u00a0bodov\u00fdch zdroj\u016f zne\u010dist\u011bn\u00ed.<\/p>\n

V\u00a0letech 2011\u20132014 prob\u011bhlo na n\u00e1dr\u017ei pom\u011brn\u011b rozs\u00e1hl\u00e9 odbahn\u011bn\u00ed, v\u00a0jeho\u017e pr\u016fb\u011bhu bylo odstran\u011bno t\u00e9m\u011b\u0159 270\u2008tis. m3<\/sup> sediment\u016f. Sou\u010d\u00e1st\u00ed odbahn\u011bn\u00ed byla i\u00a0v\u00fdstavba nov\u00e9 spodn\u00ed v\u00fdpusti, kter\u00e1 krom\u011b regulace hladiny v\u00a0pr\u016fb\u011bhu povodn\u00ed m\u016f\u017ee slou\u017eit i\u00a0ke zlep\u0161ov\u00e1n\u00ed kysl\u00edkov\u00fdch pom\u011br\u016f v\u00a0hypolimniu n\u00e1dr\u017ee. Z\u00a0publikovan\u00fdch prac\u00ed vypl\u00fdv\u00e1, \u017ee p\u0159ed odbahn\u011bn\u00edm se koncentrace celkov\u00e9ho fosforu v\u00a0horn\u00edch vrstv\u00e1ch sedimentu (0\u20135\u2008cm) pohybovala v\u00a0rozp\u011bt\u00ed od 1,5 do 2,2\u2008mg.g-1 <\/sup>su\u0161iny [5, 6]. Sou\u010dasn\u011b bylo potvrzeno riziko uvol\u0148ov\u00e1n\u00ed tohoto fosforu ze sedimentu [7]. Je tedy z\u0159ejm\u00e9, \u017ee odbahn\u011bn\u00edm do\u0161lo i\u00a0k\u00a0odstran\u011bn\u00ed nemal\u00e9ho mno\u017estv\u00ed rizikov\u00e9ho fosforu.<\/p>\n

Dal\u0161\u00edm pl\u00e1novan\u00fdm opat\u0159en\u00edm, kter\u00e9 by v\u00a0bl\u00edzk\u00e9 budoucnosti m\u011blo \u0159e\u0161it ot\u00e1zku nadm\u011brn\u00e9ho p\u0159\u00edsunu fosforu z\u00a0povod\u00ed, je vybudov\u00e1n\u00ed sr\u00e1\u017eec\u00ed stanice pro fosfor na hlavn\u00edm p\u0159\u00edtoku VN\u00a0Jord\u00e1n [8].<\/p>\n

Na ot\u00e1zku, zdali se realizovan\u00e1 a\u00a0pl\u00e1novan\u00e1 opat\u0159en\u00ed projev\u00ed na zlep\u0161ov\u00e1n\u00ed kvality vody, m\u00e1 odpov\u011bd\u011bt hydrochemick\u00fd a\u00a0hydrobiologick\u00fd monitoring n\u00e1dr\u017ee a\u00a0jej\u00edho bl\u00edzk\u00e9ho povod\u00ed, kter\u00fd prov\u00e1d\u00ed od roku 2015 st\u00e1tn\u00ed podnik Povod\u00ed Vltavy. V\u00a0roce 2017 bylo sou\u010d\u00e1st\u00ed tohoto monitoringu tak\u00e9 sledov\u00e1n\u00ed 11\u00a0rybn\u00edk\u016f, kter\u00e9 byly vyhodnoceny jako potenci\u00e1ln\u011b rizikov\u00e9 z\u00a0pohledu eutrofizace VN\u00a0Jord\u00e1n. Hlavn\u00edm c\u00edlem tohoto p\u0159\u00edsp\u011bvku je p\u0159edstavit nejd\u016fle\u017eit\u011bj\u0161\u00ed v\u00fdsledky z\u00edskan\u00e9 v\u00a0pr\u016fb\u011bhu monitoringu t\u011bchto rybn\u00edk\u016f.<\/p>\n

Materi\u00e1l a\u00a0metody<\/h2>\n

V\u00a0uplynul\u00fdch letech prob\u00edhaly odb\u011bry vzork\u016f na VN\u00a0Jord\u00e1n v\u017edy od dubna do listopadu pravideln\u011b ve \u010dtrn\u00e1ctidenn\u00edch intervalech. Odb\u011br byl realizov\u00e1n na t\u0159ech odb\u011brov\u00fdch profilech, v\u00a0doln\u00ed \u010d\u00e1sti n\u00e1dr\u017ee v\u00a0prostoru u\u00a0hr\u00e1ze a\u00a0d\u00e1le pak ve st\u0159edu n\u00e1dr\u017ee a\u00a0v\u00a0p\u0159\u00edtokov\u00e9 \u010d\u00e1sti (obr. 1<\/em>). V\u00a0r\u00e1mci vzorkov\u00e1n\u00ed bylo na ka\u017ed\u00e9m odb\u011brov\u00e9m profilu prov\u00e1d\u011bno zona\u010dn\u00ed m\u011b\u0159en\u00ed hlavn\u00edch fyzik\u00e1ln\u011b-chemick\u00fdch parametr\u016f vody (teplota vody, koncentrace a\u00a0nasycen\u00ed vody kysl\u00edkem, konduktivita, pH a\u00a0oxidoreduk\u010dn\u00ed potenci\u00e1l). Odb\u011br hydrochemick\u00fdch vzork\u016f byl realizov\u00e1n tak, aby reprezentativn\u011b postihl vertik\u00e1ln\u00ed gradient sledovan\u00fdch parametr\u016f ve v\u00fd\u0161e uveden\u00fdch odb\u011brov\u00fdch profilech. V\u00a0pr\u016fb\u011bhu odb\u011br\u016f byla m\u011b\u0159ena pr\u016fhlednost vody pomoc\u00ed Secchiho desky. Hydrochemick\u00e1 anal\u00fdza byla zam\u011b\u0159ena zejm\u00e9na na slou\u010deniny fosforu, dus\u00edku, \u017eeleza, nerozpu\u0161t\u011bn\u00fdch a\u00a0organick\u00fdch l\u00e1tek. V\u00a0r\u00e1mci monitoringu byla sledov\u00e1na tak\u00e9 sezonn\u00ed dynamika fytoplanktonu a\u00a0zooplanktonu v\u00a0epilimnetick\u00e9 \u010d\u00e1sti vodn\u00edho sloupce.<\/p>\n\"\"<\/a>\n

Obr. 1. Sch\u00e9ma zn\u00e1zor\u0148uj\u00edc\u00ed um\u00edst\u011bn\u00ed odb\u011brov\u00fdch profil\u016f na VN\u00a0Jord\u00e1n a\u00a0jeho povod\u00ed v\u00a0roce 2017; 1. Ko\u0161\u00ednsk\u00fd potok pod VN Mal\u00fd Jord\u00e1n, 2. Ko\u0161\u00ednsk\u00fd potok nad VN Mal\u00fd Jord\u00e1n, 3. Radimovick\u00fd potok, 4. Svrabovsk\u00fd potok, 5. bezejmenn\u00fd p\u0159\u00edtok od Stoklasn\u00e9 Lhoty, 6. bezejmenn\u00fd p\u0159\u00edtok od Chotovin, 7. Hejlov Doln\u00ed rybn\u00edk, 8. Hejlov Prost\u0159edn\u00ed rybn\u00edk, 9. Hejlov Horn\u00ed rybn\u00edk, 10. Nasavrky rybn\u00edk u\u00a0zast\u00e1vky, 11. Nasavrky Doln\u00ed rybn\u00edk, 12. Nasavrky Velk\u00fd rybn\u00edk, 13. Ko\u0161\u00edn, 14. Ko\u0161\u00edn 2, 15. Liderovice N\u00e1vesn\u00ed rybn\u00edk, 16. Dl\u00e1\u017ed\u011bn\u00fd rybn\u00edk, 17. rybn\u00edk Homolka
\nFig. 1. The scheme of water quality monitoring of reservoir Jord\u00e1n and nearby catchment in 2017; 1. Ko\u0161\u00ednsk\u00fd stream under VN Mal\u00fd Jord\u00e1n, 2. Ko\u0161\u00ednsk\u00fd stream above VN\u00a0Mal\u00fd Jord\u00e1n, 3. Radimovick\u00fd stream, 4. Svrabovsk\u00fd stream, 5. nameless tributary from Stoklasn\u00e9 Lhoty, 6. nameless tributary from Chotovin, 7. Hejlov Doln\u00ed pond, 8.\u00a0Hejlov Prost\u0159edn\u00ed pond, 9. Hejlov Horn\u00ed pond, 10. Nasavrky pond at the stop, 11. Nasavrky Doln\u00ed pond, 12. Nasavrky Velk\u00fd pond, 13. Ko\u0161\u00edn, 14. Ko\u0161\u00edn 2, 15. Liderovice N\u00e1vesn\u00ed pond, 16.\u00a0Dl\u00e1\u017ed\u011bn\u00fd pond, 17. Homolka pond<\/h6>\n

Monitoring bl\u00edzk\u00e9ho povod\u00ed VN\u00a0Jord\u00e1n byl zam\u011b\u0159en zejm\u00e9na na vzorkov\u00e1n\u00ed hlavn\u00edho p\u0159\u00edtoku (Ko\u0161\u00ednsk\u00fd potok) nad a\u00a0pod n\u00e1dr\u017e\u00ed Mal\u00fd Jord\u00e1n a\u00a0d\u00e1le pak na vzorkov\u00e1n\u00ed dal\u0161\u00edch v\u00fdznamn\u00fdch p\u0159\u00edtok\u016f (Radimovick\u00fd, Svrabovsk\u00fd potok a\u00a0n\u011bkolik drobn\u00fdch bezejmenn\u00fdch p\u0159\u00edtok\u016f) v\u00a0\u00faseku mezi n\u00e1dr\u017e\u00ed Mal\u00fd Jord\u00e1n a\u00a0n\u00e1dr\u017e\u00ed Ko\u0161\u00edn. Od roku 2017 bylo do monitoringu za\u0159azeno tak\u00e9 sledov\u00e1n\u00ed jeden\u00e1cti rybn\u00edk\u016f v\u00a0povod\u00ed Ko\u0161\u00ednsk\u00e9ho potoka (obr. 1<\/em>). Monitoring rybn\u00edk\u016f byl v\u00a0roce 2017 realizov\u00e1n t\u0159ikr\u00e1t b\u011bhem vegeta\u010dn\u00ed sezony (odb\u011br sm\u011bsn\u00e9ho vzorku v\u00a0prostoru u\u00a0hr\u00e1ze). Rozsah sledovan\u00fdch parametr\u016f byl zac\u00edlen zejm\u00e9na na m\u011b\u0159en\u00ed z\u00e1kladn\u00edch fyzik\u00e1ln\u011b-chemick\u00fdch parametr\u016f vody a\u00a0stanoven\u00ed obsahu slou\u010denin fosforu, dus\u00edku, \u017eeleza, nerozpu\u0161t\u011bn\u00fdch a\u00a0organick\u00fdch l\u00e1tek, chlorofylu-a<\/em>\u00a0a\u00a0pr\u016fhlednosti vody. Dopl\u0148kov\u011b se odeb\u00edraly vzorky fytoplanktonu a\u00a0zooplanktonu. Pro odhad l\u00e1tkov\u00fdch vstup\u016f do VN\u00a0Jord\u00e1n byl odb\u011br vzork\u016f dopln\u011bn o\u00a0m\u011b\u0159en\u00ed aktu\u00e1ln\u00edho pr\u016ftoku vody p\u0159\u00edstrojem FlowTracker (SonTek).<\/p>\n\"\"<\/a>\n

Obr. 2. Pr\u016fm\u011brn\u00e9, minim\u00e1ln\u00ed a\u00a0maxim\u00e1ln\u00ed koncentrace celkov\u00e9ho fosforu (Pc) za vegeta\u010dn\u00ed sezonu (duben\u2013\u0159\u00edjen) v\u00a0Ko\u0161\u00ednsk\u00e9m potoce na p\u0159\u00edtoku do VN\u00a0Jord\u00e1n za obdob\u00ed 2009\u20132017
\nFig. 2. Average, minimal and maximal concentration of total phosphorus (Pc) during the vegetation season (April\u2013October) 2009\u20132017; Ko\u0161\u00ednsk\u00fd stream\u00a0\u2013 inflow of reservoir Jord\u00e1n<\/h6>\n

V\u00fdsledky a\u00a0diskuse<\/h2>\n

Hlavn\u00ed riziko pro eutrofizaci VN\u00a0Jord\u00e1n p\u0159edstavuje p\u0159\u00edsun fosforu z\u00a0povod\u00ed Ko\u0161\u00ednsk\u00e9ho potoka. Z\u00a0porovn\u00e1n\u00ed pr\u016fm\u011brn\u00fdch a\u00a0maxim\u00e1ln\u00edch koncentrac\u00ed celkov\u00e9ho fosforu v\u00a0Ko\u0161\u00ednsk\u00e9m potoce na p\u0159\u00edtoku do VN\u00a0Jord\u00e1n za uplynul\u00fdch dev\u011bt let (2009\u20132017) je patrn\u00e9, \u017ee koncentrace se dr\u017e\u00ed na st\u00e1le velmi vysok\u00e9 \u00farovni.\u00a0Pr\u016fm\u011brn\u00e9 koncentrace celkov\u00e9ho fosforu (Pc) za vegeta\u010dn\u00ed sezonu jsou p\u0159inejmen\u0161\u00edm 5\u00d7 a\u017e 10\u00d7 vy\u0161\u0161\u00ed, ne\u017e je z\u00a0pohledu dobr\u00e9 kvality vody ve VN\u00a0Jord\u00e1n p\u0159ijateln\u00e9 (c\u00edlov\u00e1 pr\u016fm\u011brn\u00e1 koncentrace Pc za vegeta\u010dn\u00ed sezonu <\u20090,020\u2008mg.l-1<\/sup>) (obr. 2<\/em>).<\/p>\n

Hlavn\u00edm zdrojem tohoto fosforu z\u016fst\u00e1vaj\u00ed komun\u00e1ln\u00ed odpadn\u00ed vody. Nemal\u00e9 riziko v\u0161ak mohou p\u0159edstavovat i\u00a0v\u00a0povod\u00ed hojn\u00e9 hospod\u00e1\u0159sky vyu\u017e\u00edvan\u00e9 rybn\u00edky.<\/p>\n

V\u00a0povod\u00ed prvn\u00ed n\u00e1dr\u017e\u00ed rybni\u010dn\u00edho typu je n\u00e1dr\u017e Mal\u00fd Jord\u00e1n. Jedn\u00e1 se o\u00a0m\u011blkou, pr\u016fto\u010dnou n\u00e1dr\u017e (teoretick\u00e1 doba zdr\u017een\u00ed ~ 4\u20135\u00a0dn\u00ed) le\u017e\u00edc\u00ed na hlavn\u00edm p\u0159\u00edtoku VN\u00a0Jord\u00e1n (Ko\u0161\u00ednsk\u00fd potok). Do konce roku 2014 slou\u017eila tato n\u00e1dr\u017e k\u00a0chovu ryb. Hospoda\u0159\u00edc\u00edm subjektem byla spole\u010dnost ESOX, s. r. o. V\u00a0roce 2015 bylo Radou m\u011bsta T\u00e1bor schv\u00e1leno odkoupen\u00ed t\u00e9to n\u00e1dr\u017ee s\u00a0c\u00edlem jej\u00edho vyu\u017eit\u00ed pro zlep\u0161ov\u00e1n\u00ed kvality p\u0159it\u00e9kaj\u00edc\u00ed vody do VN\u00a0Jord\u00e1n.<\/p>\n

Od roku 2016 je na n\u00e1dr\u017ei Mal\u00fd Jord\u00e1n realizov\u00e1n \u017eivinov\u011b bilan\u010dn\u00ed monitoring s\u00a0c\u00edlem zjistit potenci\u00e1l t\u00e9to n\u00e1dr\u017ee k\u00a0zadr\u017eov\u00e1n\u00ed fosforu. Doposud vyhodnocen\u00e9 v\u00fdsledky uk\u00e1zaly, \u017ee v\u00a0hydrologick\u00fdch podm\u00ednk\u00e1ch roku 2016 (relativn\u011b such\u00fd rok s\u00a0podpr\u016fm\u011brn\u00fdmi sr\u00e1\u017ekami) byla tato n\u00e1dr\u017e schopn\u00e1 zadr\u017eet ~ 16\u00a0% celkov\u00e9ho fosforu (za obdob\u00ed duben\u2013\u0159\u00edjen). Ve vztahu k\u00a0teoretick\u00e9 dob\u011b zdr\u017een\u00ed se jej\u00ed potenci\u00e1ln\u00ed retence v\u0161ak m\u011bla pohybovat na \u00farovni 27\u00a0%. Naopak v\u00a0hydrologick\u00fdch podm\u00ednk\u00e1ch roku 2017 (relativn\u011b such\u00e1 prvn\u00ed polovina l\u00e9ta, od srpna intenzivn\u00ed sr\u00e1\u017ekov\u00e1 \u010dinnost) vyk\u00e1zala tato n\u00e1dr\u017e za vegeta\u010dn\u00ed sezonu prakticky nulovou retenci celkov\u00e9ho fosforu. Z\u00a0porovn\u00e1n\u00ed v\u00fdsledk\u016f z\u00edskan\u00fdch v\u00a0uplynul\u00fdch dvou letech je tedy z\u0159ejm\u00e9, \u017ee v\u00fdznam t\u00e9to n\u00e1dr\u017ee z\u00a0pohledu retence P vzr\u016fst\u00e1 v\u00a0hydrologicky podpr\u016fm\u011brn\u00fdch letech. N\u00e1dr\u017e Mal\u00fd Jord\u00e1n v\u0161ak i\u00a0p\u0159es p\u0159\u00edpadn\u00e9 budouc\u00ed snahy o\u00a0nastolen\u00ed vhodn\u00e9ho \u201eprotieutrofiza\u010dn\u00edho\u201c managementu sama o\u00a0sob\u011b k\u00a0v\u00fdrazn\u00e9mu sn\u00ed\u017een\u00ed vstupu fosforu Ko\u0161\u00ednsk\u00fdm potokem do VN\u00a0Jord\u00e1n sta\u010dit nebude. Role n\u00e1dr\u017ee Mal\u00fd Jord\u00e1n bude tedy zejm\u00e9na v\u00a0tom, \u017ee by v\u00a0budoucnu m\u011bla slou\u017eit jako \u201ez\u00e1chytn\u00e9 m\u00edsto\u201c, umo\u017e\u0148uj\u00edc\u00ed sedimentaci \u010d\u00e1stic vyflokulovan\u00e9ho materi\u00e1lu poch\u00e1zej\u00edc\u00edho z\u00a0procesu sr\u00e1\u017een\u00ed fosforu v\u00a0Ko\u0161\u00ednsk\u00e9m potoce.<\/p>\n\"\"<\/a>\n

Obr. 3. Pr\u016fm\u011brn\u00e9 a\u00a0maxim\u00e1ln\u00ed koncentrace celkov\u00e9ho fosforu (Pc) a\u00a0chlorofylu-a<\/em>\u00a0(Chl_a) v\u00a0rybn\u00edc\u00edch sledovan\u00fdch v\u00a0pr\u016fb\u011bhu vegeta\u010dn\u00ed sezony 2017
\nFig. 3. Average and maximal concentration of total phosphorus (Pc) and chlorophyll-a<\/em> a\u00a0(Chl_a) in investigated fishponds during the vegetation season 2017<\/h6>\n

Krom\u011b Mal\u00e9ho Jord\u00e1nu jsme v\u00a0roce 2017 v\u00a0r\u00e1mci pr\u016fzkumn\u00e9ho monitoringu odvzorkovali tak\u00e9 11 vybran\u00fdch hospod\u00e1\u0159sky vyu\u017e\u00edvan\u00fdch rybn\u00edk\u016f v\u00a0povod\u00ed Ko\u0161\u00ednsk\u00e9ho potoka, o\u00a0kter\u00fdch jsme se domn\u00edvali, \u017ee mohou p\u0159edstavovat p\u0159\u00edm\u00e9 eutrofiza\u010dn\u00ed riziko pro Ko\u0161\u00ednsk\u00fd potok a\u00a0n\u00e1sledn\u011b pak pro vlastn\u00ed VN\u00a0Jord\u00e1n. Z\u00edskan\u00e9 v\u00fdsledky potvrdily, \u017ee v\u011bt\u0161ina t\u011bchto rybn\u00edk\u016f se nach\u00e1z\u00ed v\u00a0siln\u011b eutrofn\u00edm a\u017e hypertrofn\u00edm stavu, kdy\u00a0pr\u016fm\u011brn\u00e9 koncentrace celkov\u00e9ho fosforu v\u00fdrazn\u011b p\u0159esahuj\u00ed 0,2\u2008mg.l-1<\/sup>. Nadm\u011brn\u00e9 mno\u017estv\u00ed \u017eivin se odr\u00e1\u017e\u00ed v\u00a0celkov\u00e9 biomase fytoplanktonu. Pr\u016fm\u011brn\u00e9 koncentrace chlorofylu-a<\/em>\u00a0u\u00a0v\u00edce ne\u017e 72\u00a0% rybn\u00edk\u016f p\u0159esahovaly 100 \u00b5g.l-1<\/sup> (obr. 3<\/em>). Nejhor\u0161\u00ed situace panovala na rybn\u00edc\u00edch u\u00a0obce Hejlov a\u00a0na rybn\u00edce Dl\u00e1\u017ed\u011bn\u00fd u\u00a0obce Vr\u00e1\u017en\u00e1. Rybn\u00edky u\u00a0obce Hejlov jsou m\u00e1lo pr\u016fto\u010dn\u00e9, organick\u00fdmi l\u00e1tkami a\u00a0\u017eivinami p\u0159et\u00ed\u017een\u00e9 rybn\u00edky, kter\u00e9 v\u00a0p\u0159\u00edpad\u011b intenzivn\u00ed sr\u00e1\u017ekov\u00e9 \u010dinnosti (vypl\u00e1chnut\u00ed velk\u00e9ho objemu vody z\u00a0rybn\u00edka) p\u0159edstavuj\u00ed nemal\u00e9 eutrofiza\u010dn\u00ed riziko pro VN\u00a0Jord\u00e1n. Hlavn\u00ed m\u00edra p\u0159et\u00ed\u017een\u00ed je d\u00e1na zejm\u00e9na vstupem komun\u00e1ln\u00edch odpadn\u00edch vod z\u00a0obce Hejlov. Tyto rybn\u00edky nejsou p\u0159\u00edmo vyu\u017e\u00edv\u00e1ny k\u00a0produk\u010dn\u00edmu chovu ryb. Naopak v\u00a0pozitivn\u00edm sv\u011btle se uk\u00e1zal vlastn\u00ed rybn\u00edk Ko\u0161\u00edn a\u00a0nad n\u00edm le\u017e\u00edc\u00ed rybn\u00edk Ko\u0161\u00edn 2. Ten vykazoval ze v\u0161ech sledovan\u00fdch rybn\u00edk\u016f v\u00a0pr\u016fm\u011bru nejni\u017e\u0161\u00ed koncentrace celkov\u00e9ho fosforu i\u00a0chlorofylu-a<\/em>\u00a0(obr. 3<\/em>).<\/p>\n

Krom\u011b nezanedbateln\u00e9ho mno\u017estv\u00ed fosforu p\u0159edstavuj\u00ed tyto rybn\u00edky tak\u00e9 v\u00fdznamn\u00e9 inokulum fytoplanktonu pro VN\u00a0Jord\u00e1n. Abychom z\u00edskali alespo\u0148 orienta\u010dn\u00ed p\u0159edstavu o\u00a0druhov\u00e9m slo\u017een\u00ed fytoplanktonu ve sledovan\u00fdch rybn\u00edc\u00edch, bylo v\u00a0letn\u00edm a\u00a0pozdn\u011b letn\u00edm odb\u011brov\u00e9m term\u00ednu ve sm\u011bsn\u00fdch vzorc\u00edch stanoveno procentu\u00e1ln\u00ed zastoupen\u00ed biomasy hlavn\u00edch taxonomick\u00fdch skupin fytoplanktonu (fluorescen\u010dn\u00ed sonda FluoroProbe (bbe-Moldaenke)). Nejhojn\u011bj\u0161\u00ed skupinou fytoplanktonu se uk\u00e1zaly b\u00fdt zelen\u00e9 \u0159asy. Ty dominovaly na v\u00edce ne\u017e 60\u00a0% sledovan\u00fdch rybn\u00edk\u016f. Sinice a\u00a0rozsivky byly dominantou shodn\u011b na 20\u00a0% rybn\u00edk\u016f.<\/p>\n

Z\u00edskan\u00e9 v\u00fdsledky potvrdily, \u017ee v\u011bt\u0161ina vzorkovan\u00fdch rybn\u00edk\u016f je rizikov\u00fdch nejen jako potencion\u00e1ln\u00ed zdroje fosforu, ale obsahuj\u00ed tak\u00e9 v\u00fdznamn\u00e9 inokulum fytoplanktonu pro n\u00ed\u017ee le\u017e\u00edc\u00ed VN\u00a0Jord\u00e1n. D\u016fkazem je situace, kter\u00e1 nastala na Ko\u0161\u00ednsk\u00e9m rybn\u00edce v\u00a0srpnu 2017. Dne 13. 8. 2017 do\u0161lo k\u00a0poru\u0161e na v\u00fdpustn\u00edm objektu rybn\u00edka Ko\u0161\u00edn a\u00a0n\u00e1sledkem toho k\u00a0nekontrolovateln\u00e9mu odtoku vody z\u00a0t\u00e9to n\u00e1dr\u017ee do VN\u00a0Jord\u00e1n. Odtok vody se poda\u0159ilo zastavit a\u017e 15. 8. 2017. B\u011bhem t\u0159\u00ed dn\u016f v\u0161ak odteklo z\u00a0Ko\u0161\u00edna bezm\u00e1la 400\u00a0tis. m3<\/sup> vody. Na tento neo\u010dek\u00e1van\u00fd p\u0159\u00edsun vody reagoval provozovatel VN\u00a0Jord\u00e1n odpou\u0161t\u011bn\u00edm vody spodn\u00ed v\u00fdpust\u00ed (cca 1,5\u2008m3<\/sup>.s-1<\/sup>). Tento manipula\u010dn\u00ed z\u00e1sah m\u011bl na jednu stranu pozitivn\u00ed vliv na zlep\u0161en\u00ed oxidoreduk\u010dn\u00edch podm\u00ednek u\u00a0dna n\u00e1dr\u017ee Jord\u00e1n. Na druhou stranu v\u0161ak do n\u00e1dr\u017ee p\u0159iteklo nemal\u00e9 mno\u017estv\u00ed vody bohat\u00e9 na fosfor (pr\u016fm\u011brn\u00e1 koncentrace Pcelk<\/sub> v\u00a0epilimniu Ko\u0161\u00edna se v\u00a0pr\u016fb\u011bhu srpna pohybovala kolem 0,2\u2008mg.l-1<\/sup>) i\u00a0na biomasu fytoplanktonu. Z\u00a0pr\u016fb\u011bhu sezonn\u00ed dynamiky fytoplanktonu v\u00a0roce 2017 je patrn\u00e9, \u017ee tato jednor\u00e1zov\u00e1 \u201e\u017eivinov\u00e1 infuze\u201c v\u00fdrazn\u011b podpo\u0159ila rozvoj planktonn\u00edch sinic, kter\u00e9 na konci pr\u00e1zdnin tvo\u0159ily dominantn\u00ed slo\u017eku fytoplanktonu v\u00a0pod\u00e9ln\u00e9m profilu VN\u00a0Jord\u00e1n (obr. 4<\/em>).<\/p>\n\"\"<\/a>\n

Obr. 4. Sezonn\u00ed dynamika biomasy planktonn\u00edch sinic (mg.l-1<\/sup>) a\u00a0procentu\u00e1ln\u00edho zastoupen\u00ed planktonn\u00edch sinic v\u00a0biomase fytoplanktonu
\nFig. 4. Seasonal dynamic of the planktonic cyanobacteria biomass (mg.l-1<\/sup>) and their frequency (%) in the phytoplankton biomass<\/h6>\n

Z\u00e1v\u011br<\/h2>\n

Rybn\u00edky obecn\u011b mohou b\u00fdt p\u0159\u00ednosn\u00e9 z\u00a0pohledu retence \u017eivin, zejm\u00e9na pak fosforu. Pokud jsou v\u0161ak dlouhodob\u011b p\u0159et\u011b\u017eov\u00e1ny, d\u00edlem ze strany komun\u00e1ln\u00edch odpadn\u00edch vod nebo ze strany ne\u00fam\u011brn\u011b intenzivn\u00edho ryb\u00e1\u0159sk\u00e9ho obhospoda\u0159ov\u00e1n\u00ed, chovaj\u00ed se p\u0159esn\u011b opa\u010dn\u011b a\u00a0jsou t\u00edm p\u00e1dem rizikov\u00e9 pro eutrofizaci n\u00ed\u017ee le\u017e\u00edc\u00edch vodn\u00edch ekosyst\u00e9m\u016f. I\u00a0p\u0159esto\u017ee \u0159ada rybn\u00edk\u016f v\u00a0povod\u00ed nen\u00ed p\u0159\u00edli\u0161 pr\u016fto\u010dn\u00e1, mohou p\u0159edstavovat v\u00fdznamn\u00e9 riziko pro n\u00e1dr\u017e Jord\u00e1n. Jedn\u00e1 se zejm\u00e9na o\u00a0obdob\u00ed intenzivn\u00ed letn\u00ed sr\u00e1\u017ekov\u00e9 \u010dinnosti, kdy m\u016f\u017ee doj\u00edt k\u00a0propl\u00e1chnut\u00ed velk\u00e9ho objemu vody t\u011bchto rybn\u00edk\u016f, kter\u00e9 jsou v\u00a0t\u00e9 dob\u011b bohat\u00e9 na \u017eiviny i\u00a0na biomasu fytoplanktonu, a\u00a0tedy ke zna\u010dn\u00e9 jednor\u00e1zov\u00e9 dotaci Jord\u00e1nu \u017eivinami vyu\u017eiteln\u00fdmi pro r\u016fst \u0159as a\u00a0sinic. To m\u00e1 za n\u00e1sledek zhor\u0161en\u00ed kvality vody a\u00a0zhor\u0161en\u00ed podm\u00ednek pro vodn\u00ed rekreaci.<\/p>\n

V\u00fdsledky po\u0159\u00edzen\u00e9 od roku 2015 potvrzuj\u00ed, \u017ee pro zachov\u00e1n\u00ed dobr\u00e9 kvality vody ve VN\u00a0Jord\u00e1n i\u00a0v\u00a0budouc\u00edch letech je nezbytn\u00e9 v\u00fdrazn\u011b sn\u00ed\u017eit vstup fosforu p\u0159\u00edtoky. Aktu\u00e1ln\u011b by tento po\u017eadavek m\u011blo vy\u0159e\u0161it vybudov\u00e1n\u00ed centr\u00e1ln\u00ed sr\u00e1\u017eec\u00ed stanice pro fosfor um\u00edst\u011bn\u00e9 na hlavn\u00edm p\u0159\u00edtoku pod hr\u00e1z\u00ed rybn\u00edka Ko\u0161\u00edn. D\u016fle\u017eit\u00e9 bude vyzkou\u0161et a\u00a0n\u00e1sledn\u011b navrhnout optim\u00e1ln\u00ed d\u00e1vku koagul\u00e1tu (s\u00edran \u017eelezit\u00fd) s\u00a0ohledem na v\u00fdznamn\u00e9 mno\u017estv\u00ed fosforu, kter\u00e9 se do VN\u00a0Jord\u00e1n dost\u00e1v\u00e1 z\u00a0v\u00fd\u0161e polo\u017een\u00fdch rybn\u00edk\u016f ve form\u011b partikulovan\u00e9, v\u00e1zan\u00e9 v\u00a0biomase fytoplanktonu. Vybudov\u00e1n\u00ed sr\u00e1\u017eec\u00ed stanice v\u0161ak neznamen\u00e1, \u017ee nen\u00ed nutn\u00e9 problematiku rybn\u00edk\u016f v\u00a0povod\u00ed VN\u00a0Jord\u00e1n i\u00a0nad\u00e1le \u0159e\u0161it. D\u016fle\u017eit\u00e9 bude prov\u00e9st zejm\u00e9na revizi st\u00e1vaj\u00edc\u00edho zp\u016fsobu ryb\u00e1\u0159sk\u00e9ho obhospoda\u0159ov\u00e1n\u00ed. Samostatnou kapitolou je minimalizace odnosu fosforu a\u00a0nerozpu\u0161t\u011bn\u00fdch l\u00e1tek v\u00a0pr\u016fb\u011bhu v\u00fdlov\u016f. D\u016fraz by m\u011bl b\u00fdt tak\u00e9 kladen na omezen\u00ed rozvoje a\u00a0n\u00e1sledn\u00e9ho nekontrolovateln\u00e9ho transportu drobn\u00fdch planktonof\u00e1gn\u00edch druh\u016f ryb z\u00a0v\u00fd\u0161e le\u017e\u00edc\u00edch rybn\u00edk\u016f, kter\u00fd m\u016f\u017ee zhor\u0161it celkov\u00fd efekt biomanipula\u010dn\u00edch opat\u0159en\u00ed, kter\u00e1 jsou realizov\u00e1na ve vlastn\u00ed n\u00e1dr\u017ei Jord\u00e1n. V\u00a0posledn\u00edch letech se ukazuje tak\u00e9 jako velk\u00fd probl\u00e9m \u0161\u00ed\u0159en\u00ed a\u00a0v\u00fdskyt nep\u016fvodn\u00edch druh\u016f ryb (nap\u0159. st\u0159evli\u010dka v\u00fdchodn\u00ed, sume\u010dek americk\u00fd) v\u00a0povod\u00ed Ko\u0161\u00ednsk\u00e9ho potoka.<\/p>\n

P\u016fvodn\u00ed p\u0159\u00edsp\u011bvek byl publikov\u00e1n ve sborn\u00edku Rybn\u00edky 2018, ISBN 978-80-01-06452-8.<\/p>\n","protected":false},"excerpt":{"rendered":"

M\u00edra eutrofizace vodn\u00ed n\u00e1dr\u017ee Jord\u00e1n v T\u00e1bo\u0159e dos\u00e1hla na p\u0159elomu mil\u00e9nia velmi vysok\u00e9 \u00farovn\u011b. To v\u00fdznamn\u011b omezilo jej\u00ed vod\u00e1rensk\u00e9 i rekrea\u010dn\u00ed vyu\u017eit\u00ed. V letech 2011\u20132014 prob\u011bhlo na n\u00e1dr\u017ei pom\u011brn\u011b rozs\u00e1hl\u00e9 odbahn\u011bn\u00ed, v jeho\u017e pr\u016fb\u011bhu bylo odstran\u011bno t\u00e9m\u011b\u0159 270\u2008tis. m3 sediment\u016f.<\/p>\n","protected":false},"author":8,"featured_media":5846,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[91,87],"tags":[413,1503,520,1504],"coauthors":[1493,1494,1495,1496],"class_list":["post-5921","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-applied-ecology","category-hydrochemistry-radioecology-microbiology","tag-fosfor","tag-kvalita-vod","tag-povodi","tag-rybnik"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5921","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=5921"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5921\/revisions"}],"predecessor-version":[{"id":30493,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/5921\/revisions\/30493"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/5846"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=5921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=5921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=5921"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=5921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}