Zooplankton structure in interconneted ponds

Istraživanje strukture zooplanktona provedeno je tijekom vegetacijskog razdoblja u pelagičkim postajama na longitudinalnom profilu rukavca rijeke Sutle, koji se sastoji od dva međusobno povezana bazena. Gornji , veće prozirnosti i sa submerznim sastojinama makrofita te Donji bazen, veće mutnoće i bez makrofita. Ciljevi ovog rada bili su utvrditi strukturu zooplanktona s obzirom na: (i) razlike u brojnosti, raznolikosti, veličinskoj strukturi i zastupljenosti funkcionalnih trofičkih skupina; (ii) utjecaj okolišnih čimbenika i izvora hrane; (iii) razlike predacijskog pritiska riba; (iv) ulogu pridnenog sloja vode kao zaklona zooplanktona u plitkim jezerima. Rezultati statističke analize fizičko−kemijskih čimbenika ukazuju na značajno veću prozirnost i količinu izvora hrane u Gornjem bazenu, u odnosu na veću mutnoću i konduktivitet u Donjem bazenu. U Gornjem bazenu, sa submerznim makrofitima u litoralnoj zoni, brojnost i raznolikost zooplanktona u pelagijalu je bila veća u odnosu na Donji bazen, bez makrofita, a prevladavali su detritivorni-mikrofiltratorski (Keratella) i algivorni-makrofiltratorski (Polyartha, Trihocerca) Rotifera. U Donjem bazenu brojnost planktonskih rakova bila je veća u odnosu na Gornji bazen, a prevladavali su mikrofiltratorski Cladocera (Bosmina longirostris) te makrofiltratorski ličinački i adultni stadiji Copepoda (Thermocyclops oithonoides), dok su Rotifera bili zastupljeniji sa sitnijim mikrofiltratorskim vrstama. Predacijski pritisak riba bio je izraženiji u pelagijalu Gornjeg bazena, veće prozirnosti, na što ukazuje manja brojnost Cladocera u površinskom sloju koji su vjerojatno potražili zaklon u makrofitskim sastojinama litorala, ali i u vertikalnom pridnenom sloju gdje je njihova brojnost bila veća. Rezultati istraživanja ukazuju i na migracije planktonskih rakova u vertikalni pridneni sloj gdje je njihova brojnost bila veća. Iako su istraživani bazeni međusobno povezani, rezultati rada ukazuju na značajne razlike u strukturi zooplanktona kao rezultat utjecaja makrofita na promjenu okolišnih uvjeta i predaciju riba.The research of zooplankton structure was conducted during the vegetated period in pelagic stations on the longitudinal profile of the Sutla backwater, which consists of two interconnected basins. The Upper, with higher transparency and submerged macrophytes and Lower basin, turbid and without macrophyte stands. The objectives of this study were to determine zooplankton structure considering: (i) differences in theabundance, diversity, size structure and functional feeding guilds; (ii) the impact of environmental factors and food resources; (iii) differences in fish predatory pressure ; (iv) the role of bottom water layers as a zooplankton shelter in shallow lakes. The results of statistical analysis of physical-chemical factors revealed significantly higher transparency and the amount of available food reources in the Upper basin, as compared to a higher turbidity and conductivity in the Lowerbasin. In the Upper basin with submerged macrophytes in the littoral zone, abundance and diversity of zooplankton in the pelagial was higher compared to the Lower basin, without macrophytes, with prevailance of detritovorous, microfilter-feeders (Keratella) and algivorous, macrofilter-feeder (Polyartha and Trihocerca) Rotifera. In the Lower basin abundance of planktonic Crustacea was higher compared to the Upper basin, and prevailed microfilter-feeders Cladocera (Bosmina longirostris) and macrofilter-feeders larval and adult stages of copepods (Thermocyclops oithonoides), while the Rotifera were presented with smaller, microfilter-feeders species. Fish predation pressure was more pronounced in the pelagial of Upper basin of highertransparency, indicated by smaller number of Cladocera in the surface layer which wee probably shifted in littoral macrophyte stands. The results of this study indicate the migration of planktonic Crustacea in the vertical bottom layer where their abundance were higher. Although the studied basins were interconnected, results indicate significant differences in the zooplankton structure as a result of the macrophytes impact on changing environmental conditions and fish predation pressure

STRUKTURA ZOOPLANKTONA U MEĐUSOBNO POVEZANIM PLITKIM JEZERIMA

The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus Keratella as microfilter-feeder, and genera of Polyartha and Trihocerca as macrofilterfeeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran (Bosmina longirostris) and larval and adult stages of macrofilter-feeder copepod (Macrocyclops albidus) prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05) differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure.Istraživanje raznolikosti, abundancije i trofičke strukture zooplanktona provedeno je tijekom vegetacijskog razdoblja na pelagičkim postajama longitudinalnog profila rukavca rijeke Sutle koji se sastoji od dva međusobno povezana bazena. Gornji bazen veće je prozirnosti i sa submerznim sastojinama makrofita, Donji bazen veće je mutnoće i bez makrofita. U Gornjem bazenu, brojnost i raznolikost zooplanktona u pelagijalu je bila veća u odnosu na Donji bazen, a prevladavali su kolnjaci, detritivorni-mikrofiltratori roda Keratella i algivorni-makrofiltratori rodova Polyartha i Trihocerca. U Donjem bazenu brojnost planktonskih rakova bila je veća u odnosu na Gornji bazen, a prevladavali su mikrofiltratorski rašljoticalci (Bosmina longirostris) te makrofiltratorski ličinački i adultni stadiji veslonožaca (Macrocyclops albidus). Predacijski pritisak riba bio je izraženiji u pelagijalu Gornjeg bazena, na što ukazuje manja brojnost Cladocera u površinskom sloju. Iako su istraživani bazeni međusobno povezani, rezultati rada ukazuju na značajne razlike (Mann-Whitney U test, p < 0.05) u strukturi zooplanktona kao rezultat utjecaja makrofita i predacije riba na promjenu uvjeta okoliša

Algae in diet

U ovom je seminaru istaknuta samo nekolicina algi, one koje su najrasprostranjenije, te koje bi mogle postati bitne u budućnosti zbog nekih svojih značajki ili sastojaka. Diljem svijeta za prehranu ljudi koristi se mnogo više vrsta nego što je ovdje spomenuto. Prednosti algi u prehrani su, osim toga što obiluju hranjivim sastojcima, vitaminima i mineralima, brz ciklus razmnožavanja i neiscrpljivanje okoliša. Usprkos tome kultivacija mnogih vrsta i dalje nije usavršena, te se potrebe najvećim dijelom namiruju iz prirodnih izvora. Usavršavanjem kultivacije i povećanjem globalizacije za očekivati je da će se alge konzumirati u većem broju zemalja i u većim količinama. Također usavršavanjem tehnika obrade i kombiniranjem s većim brojem namirnica alge bi mogle postati hrana za sve slojeve društva, a ne samo primjerice za one koji žele zdravo živjeti ili za astronaute. Iako se danas puno toga zna o hranjivosti i dobrobitima algi još uvijek postoje određene nepoznanice o tome kako pojedini sastojci djeluju na ljudski organizam. Vjerojatno budućnost nosi daljnja istraživanja i spoznaje o navedenim nedoumicama. Za sada se zna da su alge bogate jodom i mogu pomoći u liječenju problema sa štitnom žlijezdom, no i odmoći pa osobe koje imaju upravo tih problema trebaju s oprezom pristupiti konzumiranju algi. Također postoje i druge bolesti koje mogu u kombinaciji sa sastojcima kojima alge obiluju donijeti nepovoljne posljedice. Kao i kod svega i u konzumiranju algi treba biti umjeren. Ni sa čime ne valja pretjerivati pa tako ni sa upotrebom algi u prehrani.In this essay I decided to talk only about those algae that are the most spread around the world or ones that could become useful in the future for their various characteristics. Of course, these are not all the species of algae that people could and do use in their nutrition. The advantage of algae in nutrition are, besides the fact that it contains a lot of nutritious ingredients, vitamins and minerals, their fast reproduction and preservation of nature around it. In spite all of that, the cultivation of many sorts of algae is not perfected yet, and most of human demand for algae is fulfilled direct from nature. By improving the process of cultivation and considering the ever ongoing process of globalization it is normal to expect that algae could become more popular in human diet in years to come. Also, improved processing and combining with other ingreedients algae could become food for all layers of society, not only for those who insist in eating healthy or for astronauts for example. Although today we know a lot about nutrition worth and benefits of algae there still are some undiscovered things about some ingredients and their affects on people. Probably the future will bring more and more experiments and knowledge about algae. So far we know that some algae could be used in medicine but it could also be harmful as useful. When using algae in nutrition, as much as everything, we need to be careful. Nothing is good for you if you overdo it, the same goes for algae

Zooplankton structure in two interconnected ponds: similarities and differences

The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus Keratella as microfilter-feeder, and genera of Polyartha and Trihocerca as macrofilter-feeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran (Bosmina longirostris) and larval and adult stages of macrofilter-feeder copepod (Macrocyclops albidus) prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05) differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure

Zooplankton structure in two interconnected ponds: similarities and differences

The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus Keratella as microfilter-feeder, and genera of Polyartha and Trihocerca as macrofilterfeeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran (Bosmina longirostris) and larval and adult stages of macrofilter-feeder copepod (Macrocyclops albidus) prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05) differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure.Istraživanje raznolikosti, abundancije i trofičke strukture zooplanktona provedeno je tijekom vegetacijskog razdoblja na pelagičkim postajama longitudinalnog profila rukavca rijeke Sutle koji se sastoji od dva međusobno povezana bazena. Gornji bazen veće je prozirnosti i sa submerznim sastojinama makrofita, Donji bazen veće je mutnoće i bez makrofita. U Gornjem bazenu, brojnost i raznolikost zooplanktona u pelagijalu je bila veća u odnosu na Donji bazen, a prevladavali su kolnjaci, detritivorni-mikrofiltratori roda Keratella i algivorni-makrofiltratori rodova Polyartha i Trihocerca. U Donjem bazenu brojnost planktonskih rakova bila je veća u odnosu na Gornji bazen, a prevladavali su mikrofiltratorski rašljoticalci (Bosmina longirostris) te makrofiltratorski ličinački i adultni stadiji veslonožaca (Macrocyclops albidus). Predacijski pritisak riba bio je izraženiji u pelagijalu Gornjeg bazena, na što ukazuje manja brojnost Cladocera u površinskom sloju. Iako su istraživani bazeni međusobno povezani, rezultati rada ukazuju na značajne razlike (Mann-Whitney U test, p < 0.05) u strukturi zooplanktona kao rezultat utjecaja makrofita i predacije riba na promjenu uvjeta okoliša