Open AccessClimate Change‐Legacy Phosphorus Synergy Hinders Lake Response to Aggressive Water Policy Targets
Author(s) -
Zia Asim,
Schroth Andrew W.,
Hecht Jory S.,
Isles Peter,
Clemins Patrick J.,
Turnbull Scott,
Bitterman Patrick,
Tsai Yushio,
Mohammed Ibrahim N.,
Bucini Gabriela,
Doran Elizbeth M. B.,
Koliba Christopher,
Bomblies Arne,
Beckage Brian,
Winter Jonathan,
Adair Elizabeth C.,
Rizzo Donna M.,
Gibson William,
Pinder George
Publication year - 2022
Publication title -
earth's future
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.641
H-Index - 39
ISSN - 2328-4277
DOI - 10.1029/2021ef002234
Subject(s) - eutrophication , environmental science , water quality , total maximum daily load , climate change , nutrient , watershed , algal bloom , water resource management , hydrology (agriculture) , phosphorus , ecology , phytoplankton , computer science , materials science , geotechnical engineering , machine learning , engineering , metallurgy , biology
With mounting scientific evidence demonstrating adverse global climate change (GCC) impacts to water quality, water quality policies, such as the Total Maximum Daily Loads (TMDLs) under the U.S. Clean Water Act, have begun accounting for GCC effects in setting nutrient load‐reduction policy targets. These targets generally require nutrient reductions for attaining prescribed water quality standards (WQS) by setting safe levels of nutrient concentrations that curtail potentially harmful cyanobacteria blooms (CyanoHABs). While some governments require WQS to consider climate change, few tools are available to model the complex interactions between climate change and benthic legacy nutrients. We present a novel process‐based integrated assessment model (IAM) that examines the extent to which synergistic relationships between GCC and legacy Phosphorus release could compromise the ability of water quality policies to attain established WQS. The IAM is calibrated for simulating the eutrophic Missisquoi Bay and watershed in Lake Champlain (2001–2050). Water quality impacts of seven P‐reduction scenarios, including the 64.3% reduction specified under the current TMDL, were examined under 17 GCC scenarios. The TMDL WQS of 0.025 mg/L total phosphorus is unlikely to be met by 2035 under the mandated 64.3% reduction for all GCC scenarios. IAM simulations show that the frequency and severity of summer CyanoHABs increased or minimally decreased under most climate and nutrient reduction scenarios. By harnessing IAMs that couple complex process‐based simulation models, the management of water quality in freshwater lakes can become more adaptive through explicit accounting of GCC effects on both the external and internal sources of nutrients.