The impact of climate change and eutrophication on phosphorus forms in sediment: Results from a long-term lake mesocosm experiment


Saar K., Noges P., Sondergaard M., Jensen M., Jorgensen C., Reitzel K., ...More

SCIENCE OF THE TOTAL ENVIRONMENT, vol.825, 2022 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 825
  • Publication Date: 2022
  • Doi Number: 10.1016/j.scitotenv.2022.153751
  • Journal Name: SCIENCE OF THE TOTAL ENVIRONMENT
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, PASCAL, Aerospace Database, Analytical Abstracts, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chimica, Communication Abstracts, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, Greenfile, MEDLINE, Metadex, Pollution Abstracts, Public Affairs Index, Veterinary Science Database, Civil Engineering Abstracts
  • Keywords: Shallow lake, Sediment accumulation, Temperature gradient, Nutrient load, Macrophytes, P-31 NMR, Sequential extraction, P-pools, SHALLOW, RELEASE, TEMPERATURE, PHOSPHATE, IRON, PH, MACROPHYTES, NUTRIENTS, RATES, COPRECIPITATION

Abstract

Characteristics of bottom sediments in lake mesocosms 11 years after starting the experiment were studied in order to determine the effects of nutrient loading, temperature increase and vegetation type on concentration and vertical distribution of phosphorus (P) forms. The experimental setup consisted of 24 outdoor flow-through mesocosms with two nutrient treatments - low (L) and high (H) and 3 temperature levels - ambient (T0), heated by 2-4 degrees C (T1) and 3-6 degrees C (T2) in four replicates. Thickness of the organic sediment was measured and the sediment analysed for dry weight, organic matter, and P fractions (according to a sequential extraction scheme) and organic P compounds (by P-31 nuclear magnetic resonance spectroscopy). Higher nutrient loading led to increased sediment accumulation and higher concentration of total P and most P fractions, except P bound to aluminium and humic matter. The dominant vegetation type covaried with nutrient levels. Vertical gradients in Ca bound P and mobile P in low nutrient mesocosms was perhaps a result of P coprecipitation with calcite on macrophytes and P uptake by roots indicating that in macrophyte-rich lakes, plants can be important modifiers of early P diagenesis. Temperature alone did not significantly affect sediment accumulation rate but the interaction effect between nutrient and temperature treatments was significant. At high nutrient loading, sediment thickness decreased with increasing temperature, but at low nutrient loading, it increased with warming. The effect of warming on sediment composition became obvious only in nutrient enriched mesocosms showing that eutrophication makes shallow lake ecosystems more susceptible to climate change.