Search for dissertations about: "clear-water lakes"

Showing result 1 - 5 of 15 swedish dissertations containing the words clear-water lakes.

2. 1. Carbon metabolism in clear-water and brown-water lakes

   Author : Jenny Ask; Jan Karlsson; Mats Jansson; Rolf Vinebrooke; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clear-water lakes; brown-water lakes; primary production; bacterial production; benthic; pelagic; net ecosystem production; allochthonous organic carbon; CO2; DOC; Physical geography; Naturgeografi; Freshwater ecology; Limnisk ekologi; limnologi; Limnology; naturgeografi; Physical Geography;

   Abstract : The trophic state of lakes is commonly defined by the concentration of nutrients in the water column. High nutrient concentrations generate high phytoplankton production, and lakes with low nutrient concentrations are considered low-productive. READ MORE

4. 2. Food Quality for Zooplankton in Humic Lakes

   Author : Kelly Gutseit; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; limnology; Hydrobiology; marine biology; Clear water lakes; Plankton; Seston; Elements; Fatty acids; Humic lakes; Food quality; Zooplankton; limnologi; akvatisk ekologi; aquatic ecology; Marinbiologi;

   Abstract : Food quality affects growth, reproduction and community structure of zooplankton, and has implications for nutrient cycling and the transfer of energy and matter in aquatic food chains. While the issue of food quality in clear water lakes has received great recent attention, studies on food quality for zooplankton in humic lakes are scarce. READ MORE

5. 3. Role of phagotrophy in freshwater phytoplankton

   Author : Carina Pålsson; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; marine biology; limnology; mixotrophy; phagotrophy; phytoplankton; oligotrophic; clear-water lakes; grazing; competition; nutrient enrichment; autotrophy; heterotrophy; bacterial ingestion; Hydrobiology; Marinbiologi; akvatisk ekologi; limnologi;

   Abstract : Some phytoplankton have the ability to combine phototrophy and heterotrophy within the same individual, which is called mixotrophy. In this thesis, I adress mixotrophy and competitive interactions of mixotrophs and obligate auto- or heterotrophs in relation to the availability of nutrients, light and prey. READ MORE

6. 4. Acidification trends in Swedish lakes : an assessment of past water chemistry conditions using lake sediments

   Author : Tom Korsman; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Palaeolimnology; acidification history; alkalization; acid deposition; land-use; lake sediments; near infrared spectroscopy; diatoms; multivariate calibration; Sweden;

   Abstract : This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented. READ MORE

7. 5. The palaeolimnological record of regime shifts in lakes in response to climate change

   Author : Linda Randsalu Wendrup; Kvartärgeologi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; palaeolimnology; regime shifts; thresholds; alternative stable states; climate change; ecosystem dynamics; diatoms; hydrocarbons; monitoring; lake sediments; shallow lakes; 8.2 ka event;

   Abstract : Regime shifts in lake ecosystems can occur in response to both abrupt and continuous climate change, and the imprints they leave in palaeolimnological records allow us to investigate and better understand patterns and processes governing ecological changes on geological time scales. This thesis aims at investigating palaeolimnological records of regime shifts in lakes during the Holocene to explore how lake ecosystems responded to climate changes and anthropogenic activities and to identify thresholds or tipping points that produced regime shifts. READ MORE