Essays about: "food webs"

Showing result 16 - 20 of 31 essays containing the words food webs.

  1. 16. Analysis of Per- and Polyfluoroalkyl Substances (PFASs) in African Darter (Anhinga rufa) Eggs along Vaal River, South Africa : Comparison of Homologue and Isomer Profiles

    University essay from Örebro universitet/Institutionen för naturvetenskap och teknik

    Author : Felicia Fredriksson; [2016]
    Keywords : Per- and polyfluoroalkyl substances PFASs ; Perfluorooctane sulfonate PFOS ; linear and branched isomers; African Darter; Vaal River; bird eggs; Per- och polyfluoralkylerade substanser PFASs ; perfluoroktansulfonat PFOS ; linjära och grenade isomerer; African Darter; Vaal River; fågelägg;

    Abstract : Per- and polyfluoroalkyl substances (PFASs) are a group of toxic and persistent organic compounds. Their properties make them extremely resistant and they have been shown to have bioaccumulation and toxic properties in the environment and also to biomagnify in both aquatic and terrestrial food webs. READ MORE

  2. 17. Spring ice melt effect on benthic oxygen production

    University essay from Umeå universitet/Institutionen för ekologi, miljö och geovetenskap

    Author : Tommy Karlsson; [2015]
    Keywords : Benthic; Oxygen; Ice release; Ecology;

    Abstract : In biology, the winter season is less studied than other seasons partly due to technical and logistical difficulties. The Arctic region is undergoing rapid changes with shorter and warmer winters, shorter snow duration and considerable changes in snow and ice cover as a result. READ MORE

  3. 18. Resource use by macroinvertebrates within boreal stream food webs

    University essay from Umeå universitet/Institutionen för ekologi, miljö och geovetenskap

    Author : Emelie Landström; [2015]
    Keywords : Allochthonous; Autochthonous; Food webs; Boreal; Streams; Deuterium; Carbon;

    Abstract : Stream food webs are supported by carbon produced within the stream (autochthonous) and from terrestrial environments (allochthonous). Allochthonous carbon (C) inputs are assumed to be the dominant C source supporting food webs within small streams, but few direct estimates of resource use in small streams have been made, especially in boreal streams. READ MORE

  4. 19. Ecotoxicological effects on a food-web exposed to pharmaceuticals : Uptake and effects of oxazepam, fexofenadine and a mixture of both in algae, zooplankton and sticklebacks.

    University essay from Umeå universitet/Institutionen för ekologi, miljö och geovetenskap

    Author : Anna Sundelin; [2015]
    Keywords : Bioconcentration; Bioaccumulation; Behaviour; Pharmaceutical mixtures.;

    Abstract : Complex mixtures of biologically active pharmaceutical residues continuously enter aquatic environments via wastewater, where it can affect species through preserved human drug targets or cause unexpected effects in non-target species. Benzodiazepines and antihistamines are two highly consumed groups of pharmaceuticals that have been shown to bioconcentrate in aquatic organisms and induce behavioural alterations affecting individual fitness. READ MORE

  5. 20. How does nutrients and light affect algal growth in Swedish headwater streams? : A study using nutrient diffusing substrate and natural gradients of light

    University essay from Umeå universitet/Institutionen för ekologi, miljö och geovetenskap

    Author : Jannika Andersson; [2014]
    Keywords : : boreal streams; algal productivity; N limitation; nutrient diffusing substrate; incident light;

    Abstract : Gaining knowledge about what factors determine benthic algal biomass and productivity is vital for understanding food webs in aquatic systems, especially in woodland streams with naturally low rates of primary productivity. The aim of this study was to investigate what factors determine algal growth in Swedish headwater streams. READ MORE