Essays about: "silica precipitation"

Showing result 1 - 5 of 8 essays containing the words silica precipitation.

1. 1. Mercury accumulation in lake sediments on different time scales – the influence of algal primary production

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

   Author : Anne Rebotzke; [2023]
   Keywords : mercury; lake sediment; primary productivity; algal scavenging; biogenic silica; diatom proxy; chlorophyll-a; organic matter;

   Abstract : The aim of this work is to test the proposed approach of algal scavenging as a driver of sediment mercury (Hg) on different time scales and to gain a better understanding of the mechanisms of Hg accumulation in lake sediments. A 3000-year sediment record from Nylandssjön in northern Sweden was analysed for this purpose, as well as a 20-year sediment record from the seasonal sediment traps of this lake. READ MORE

3. 2. Polymerized Tubular Silicates in Lower Cambrian Carbonates – Biology or Chemistry?

   University essay from Uppsala universitet/Institutionen för geovetenskaper

   Author : Scott Green; [2022]
   Keywords : biosignature; tubular structures; Lower Cambrian; silica precipitation; bifurcating; biosignatur; rörstrukturer; Kambrium Serie 3; kiseldioxid utfällning; förgrening;

   Abstract : Shallow marine environments from the Lower Cambrian period were very different to shallow marine environments of today. Tubes of what was thought to be silica recovered from a partly dolomitized carbonate sample collected form a site near Indian Springs, Nevada could help further understand the chemistry and characteristics of such environments. READ MORE

4. 3. Records of environmental change and sedimentation processes over the last century in a Baltic coastal inlet

   University essay from Lunds universitet/Geologiska institutionen

   Author : Hanna Nilsson; [2019]
   Keywords : Baltic Sea; eutrophication; coastal areas; archipelago; laminated sediments; nutrient inputs; carbon and nitrogen content; biogenic silica; sedimentation; environmental impact; marine geology; Earth and Environmental Sciences;

   Abstract : The marine ecosystem in the Baltic Sea is affected by multiple stress factors, e.g. eutrophication and deoxygenation, overfishing and anthropogenic pollution. Here we evaluate the short-term trends of dissolved oxygen in bottom waters and changes in the primary productivity within a coastal inlet in the Baltic Sea. READ MORE

5. 4. Estimating soluble arsenic and phosphorus concentrations under Precambrian oceanic conditions

   University essay from Stockholms universitet/Institutionen för geologiska vetenskaper

   Author : Christoffer Hemmingsson; [2014]
   Keywords : Arsenic; Phosphorus; Co-precipitation; Precambrian; Oceanic P levels; Ferrihydrite synthesis; Distribution coefficient; Banded iron formation;

   Abstract : Original estimates of phosphorus (P) concentrations in the Precambrian oceans before 1.9 Ga gave a budget of ~10-25% of modern day levels. READ MORE

6. 5. Synthesis and characterization of superparamagnetic iron oxide nanoparticles coated with silica

   University essay from KTH/Skolan för informations- och kommunikationsteknik (ICT)

   Author : Aleksandr Marinin; [2012]
   Keywords : magnetite; co-precipitation; thermal decomposition; silica; inverse microemulsion; TEOS; biomedical applications; core-shell;

   Abstract : Multifunctional superparamagnetic iron oxide nanoparticles (SPIONs) coated with silica are a promising research field for lots of biomedical applications. The scope of this work is a preparation of SPIONs and coating them with silica to form core-shell structured nanoparticles for nanomedicine applications. READ MORE