Lithological controls on lake water biogeochemistry in Maritime Antarctica

• Published in: The Science of the total environment Vol. 912; p. 168562
• Main Authors: Olgun, Nazlı, Tarı, Ufuk, Balcı, Nurgül, Altunkaynak, Şafak, Gürarslan, Işıl, Yakan, Sevil Deniz, Thalasso, Frederic, Astorga-España, María Soledad, Cabrol, Léa, Lavergne, Céline, Hoffmann, Linn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.02.2024; Elsevier
• Subjects: Antarctica; Environmental Sciences; King George Island; Lake; Leaching; Lithology; Nutrients; Phytoplankton; Lithology; Phytoplankton; Nutrients; Antarctica; Lake; Leaching; King George Island
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.168562

Although the Antarctic lakes are of great importance for the climate and the carbon cycle, the lithological influences on the input of elements that are necessary for phytoplankton in lakes have so far been insufficiently investigated. To address this issue, we analyzed phytoplankton cell concentrations and chemical compositions of water samples from lakes, ponds and a stream on Fildes and Ardley Islands of King George Island in the South Shetland Archipelago. Furthermore, lake sediments, as well as soil and rock samples collected from the littoral zone were analyzed for their mineralogical/petrographic composition and pollutant contents of polycyclic aromatic hydrocarbons (PAHs). In addition, leaching experiments were carried out to with the lithologic samples to investigate the possible changes in pH, alkalinity, macronutrients (N, P, Si), micronutrients (e.g. Fe, Zn, Cu, Mn), anions (S, F, Br), and other cations (e.g. Na, K, Mg, Ca, Al, Ti, V, Cr, Co, Ni, As, Se, Pb, Sb, Mo, Ag, Cd, Sn, Ba, Tl, B). Our results showed that phytoplankton levels varied between 15 and 206 cells/mL. Chlorophyll-a concentrations showed high correlations with NH4, NO3. The low levels of PO4 (<0.001 mg/L) indicated a possible P-limitation in the studied lakes. The composition of rock samples ranged from basalt to trachybasalt with variable major oxide (e.g. SiO2, Na2O and K2O) contents and consist mainly quartz, albite, calcite, dolomite and zeolite minerals. The concentrations of total PAHs were below the toxic threshold levels (9.55–131.25 ng g−1 dw). Leaching experiments with lithologic samples indicated major increase in pH (up to 9.77 ± 0.02) and nutrients, especially PO4 (1.03 ± 0.04 mg/L), indicating a strong P-fertilization impact in increased melting scenarios. Whereas, toxic elements such as Pb, Cu, Cd, Al and As were also released from the lithology, which may reduce the phytoplankton growth. [Display omitted] •Biogeochemical properties of lakes, ponds and one stream in Maritime Antarctica were characterized.•Significant differences in terms of phytoplankton populations were observed in the Fildes Peninsula and Ardley Islands•P-limitation is very likely in lakes in King George Island•Input of N, P, Si and Fe from sediments, soils and rocks were shown by the leaching experiments.•Climate warming can increase in input of bio-relevant elements from the lithology into the lakes