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Carbon Uptake in Surface Water Food Webs Fed by Palaeogroundwater
Author(s) -
Mazumder Debashish,
Saintilan Neil,
Hollins Suzanne,
Meredith Karina,
Jacobsen Geraldine,
Kobayashi Tsuyoshi,
Wen Li
Publication year - 2019
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2018jg004925
Subject(s) - trophic level , food chain , wetland , environmental science , artesian aquifer , groundwater , ecology , surface water , ecosystem , isotopes of carbon , food web , stable isotope ratio , isotope analysis , radiocarbon dating , algae , structural basin , carbon fibers , total organic carbon , geography , aquifer , biology , geology , environmental engineering , paleontology , physics , geotechnical engineering , archaeology , quantum mechanics , composite material , materials science , composite number
The use of 14 C to elucidate sources of carbon within freshwater aquatic ecosystems is challenging the assumption that modern autochthonous carbon dominates energy flows. We measured the uptake of old carbon through several trophic levels of a wetland fed by groundwater of the Great Artesian Basin, Australia, the largest artesian basin in the world. Stable isotopes (δ 13 C and δ 15 N) and radiocarbon ( 14 C) were used to quantify food chain links and connection between groundwater and surface water food webs. Our results suggest that old groundwater was the dominant carbon source even at the highest trophic levels, with predatory fish returning apparent carbon ages of up to 11 ka. Stable isotope analysis (δ 13 C and δ 15 N) identified trophic links between fish, aquatic insects, and algae with smaller contributions from particulate organic matter to the food webs. As natural mound springs and associated wetlands are the only source of reliable water during dry periods over vast areas of the western Great Artesian Basin, the result has potential implications for the interpretation of archaeological artifacts associated with indigenous passage within the interior.