Synergistic effects of warming and internal nutrient loading interfere with the long-term stability of lake restoration and induce sudden re-eutrophication

This repository contains the dataset linked to the following publication:

Article title: Synergistic effects of warming and internal nutrient loading interfere with the long-term stability of lake restoration and induce sudden re-eutrophication

Journal: Environmental Science & Technology

DOI: 10.1021/acs.est.2c07181

Abstract: Phosphorus (P) precipitation is among the most effective treatments to mitigate lake eutrophication. However, after a period of high effectiveness, studies have shown possible re-eutrophication and the return of harmful algal blooms. While such abrupt ecological changes were attributed to the internal P loading, the role of lake warming and its potential synergistic effects with internal loading, thus far, has been understudied. Here, in a eutrophic lake in central Germany, we quantified the driving mechanisms of the abrupt re-eutrophication and cyanobacterial blooms in 2016 (30 years after the first P precipitation). A process-based lake ecosystem model (GOTM-WET) was established using a high-frequency monitoring dataset covering contrasting trophic states. Model analyses suggested that the internal P release accounted for 68% of the cyanobacterial biomass proliferation, while lake warming contributed to 32%, including direct effects via promoting growth (18%) and synergistic effects via intensifying internal P loading (14%). The model further showed that the synergy was attributed to prolonged lake hypolimnion warming and oxygen depletion. Our study unravels the substantial role of lake warming in promoting cyanobacterial blooms in re-eutrophicated lakes. The warming effects on cyanobacteria via promoting internal loading need more attention in lake management, particularly for urban lakes.

SYNOPSIS: Warming synergistically promotes re-eutrophication with internal nutrient loading and exacerbates cyanobacterial blooms in urban lakes 30 years after phosphorus mitigation.

Data description by Xiangzhen Kong (xzkong@niglas.ac.cn), 2023-02-20

---Wet chemical analysis on water samples taken at five depths (0.5, 2.5, 5.0, 7.0 and 9.0 m) from the deepest point in the lake (BA1) at biweekly intervals from 2018.5-2021.8.

        File name:

• BAB_BA1_TN_mgL.obs (total nitrogen concentration)
• BAB_BA1_NH4_mgL.obs (ammonium nitrogen concentration)
• BAB_BA1_NO3_mgL.obs (nitrate nitrogen concentration)
• BAB_BA1_TP_mgL.obs (total phosphorus concentration)
• BAB_BA1_SRP_mgL.obs (Soluble reactive phosphorus concentration)
• BAB_BA1_DP_mgL.obs (dissolved P concentration)
• BAB_BA1_DOC_mgL.obs (Dissolved organic carbon concentration)
• BAB_BA1_Si_mgL.obs (dissolved silicon concentration)
• BAB_BA1_Chla_HPLC_DIN_mgL.obs (Chl-a concentration)

---CTD probe profile data from the deepest point in the lake (BA1) from 2017.8 to 2021.8 at biweekly basis with approximately 0.1 m vertical resolution

       File name:

• t_prof_file_barleber_ctm644.obs (water temperature)
• oxy_prof_file_barleber_ctm644 (Dissolved oxygen)
• turb_prof_file_barleber_ctm644.obs (Turbidity)
• chla_prof_file_barleber_ctm644.obs (Chl-a concentration)

---BBE probe profile data from the deepest point in the lake (BA1) from 2017.8 to 2021.8 at biweekly basis with approximately 0.1 m vertical resolution

       File name:

• totalChla_prof_file_barleber_FP2101.obs (Chl-a concentration)
• bluegreen_prof_file_barleber_FP2101.obs (Blue-green algae Chl-a concentration)
• green_prof_file_barleber_FP2101.obs (Green algae Chl-a concentration)
• diatom_prof_file_barleber_FP2101.obs (Diatom Chl-a concentration)