Probabilistic Estimate of a Threshold for Eutrophication

Regime shifts, or massive changes in ecosystems, are often associated with thresholds in drivers such as climate, land-use change, nutrient fluxes, or other factors. A frequently studied example is eutrophication, which is a serious environmental problem of lakes and reservoirs associated with phosphorus (P) enrichment above a threshold. We estimated probability distributions of thresholds for eutrophication of Lake Mendota, Wisconsin, USA using 30 years of annual P budgets. Although thresholds were likely to influence eutrophication of the lake (probability 96.6%), the probability distributions of thresholds spanned a wide range of P loading rates. Management recommendations are consistent with simpler models that recommend P load targets near or below the lowest P loads observed in the past 30 years. If loads increase, there is considerable risk of crossing a threshold to sustained eutrophication with high in-lake P concentrations and poor water quality. On the other hand, if loads decrease there is a chance of crossing a mitigation threshold, causing substantial reductions in P concentrations and improvements in water quality. Consideration of these risks will increase estimates of the net economic benefits of lower P loading. Our analysis illustrates a process for estimating probability distributions for thresholds of ecosystem regime shifts. Even though threshold probability distributions may be wide with thick tails, they provide crucial information about potential consequences of alternative policy choices.

[1]  Craig A. Stow,et al.  Phosphorus loading reductions needed to control blue green algal blooms in Lake Mendota , 1998 .

[2]  R. Howarth,et al.  � 2006, by the American Society of Limnology and Oceanography, Inc. Eutrophication of freshwater and marine ecosystems , 2022 .

[3]  A. Pedersen,et al.  An empirical model describing the seasonal dynamics of phosphorus in 16 shallow eutrophic lakes after external loading reduction , 2006 .

[4]  Jennifer L. Weld,et al.  Development of phosphorus indices for nutrient management planning strategies in the United States , 2003 .

[5]  S. Qian,et al.  Long-Term Phosphorus Assimilative Capacity in Freshwater Wetlands: A New Paradigm for Sustaining Ecosystem Structure and Function , 1999 .

[6]  Jan Köhler,et al.  Lake responses to reduced nutrient loading - an analysis of contemporary long-term data from 35 case studies , 2005 .

[7]  A. Wüest,et al.  Is phosphorus retention in autochthonous lake sediments controlled by oxygen or phosphorus? , 2006 .

[8]  David B. Dunson,et al.  Bayesian Data Analysis , 2010 .

[9]  Irena F. Creed,et al.  Frequent regime shifts in trophic states in shallow lakes on the Boreal Plain: Alternative "unstable" states? , 2007 .

[10]  Marten Scheffer,et al.  Slow Recovery from Perturbations as a Generic Indicator of a Nearby Catastrophic Shift , 2007, The American Naturalist.

[11]  B. Walker,et al.  Thresholds in Ecological and Social–Ecological Systems: a Developing Database , 2004 .

[12]  Monica G. Turner,et al.  Cross–Scale Interactions and Changing Pattern–Process Relationships: Consequences for System Dynamics , 2007, Ecosystems.

[13]  S. Carpenter,et al.  A Phosphorus Budget for the Lake Mendota Watershed , 1999, Ecosystems.

[14]  M. Scheffer,et al.  Regime Shifts in Shallow Lakes , 2007, Ecosystems.

[15]  J. Quiggin.  Uncertainty and Climate Change Policy , 2008 .

[16]  James S. Clark,et al.  Models for Ecological Data: An Introduction , 2007 .

[17]  Jan H. Janse.  A model of nutrient dynamics in shallow lakes in relation to multiple stable states , 1997 .

[18]  Richard C. Lathrop,et al.  Internal phosphorus loading in Lake Mendota: response to external loads and weather , 1997 .

[19]  David W. Schindler,et al.  Recent advances in the understanding and management of eutrophication , 2006 .

[20]  Stephen H. Schneider,et al.  Uncertainty and Climate Change Policy , 2002 .

[21]  Stephen H. Schneider,et al.  Climate change policy : a survey , 2003 .

[22]  Gene E. Likens,et al.  A Cross-System Study of Phosphorus Release from Lake Sediments , 1991 .

[23]  S. Carpenter.  Eutrophication of aquatic ecosystems: bistability and soil phosphorus. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[24]  >Gertrud K. Nürnberg.  Prediction of annual and seasonal phosphorus concentrations in stratified and polymictic lakes , 1998 .

[25]  E. Welch,et al.  Restoration and Management of Lakes and Reservoirs , 2005 .

[26]  Stephen R. Carpenter,et al.  UNCERTAINTY AND THE MANAGEMENT OF MULTISTATE ECOSYSTEMS: AN APPARENTLY RATIONAL ROUTE TO COLLAPSE , 2003 .

[27]  Daniel E. Schindler,et al.  TROPHIC CASCADES, NUTRIENTS, AND LAKE PRODUCTIVITY: WHOLE‐LAKE EXPERIMENTS , 2001 .

[28]  G. Ahlgren.  Response of phytoplankton and primary production to reduced nutrient loading in Lake Norrviken: With 5 figures and 2 tables in the text , 1978 .

[29]  Christian Skov,et al.  Lake restoration: successes, failures and long‐term effects , 2007 .

[30]  C. Stow,et al.  Declining threshold for hypoxia in the Gulf of Mexico. , 2005, Environmental science & technology.

[31]  E. Fee,et al.  Phytoplankton Productivity Changes in a Small, Double-Basin Lake in Response to Termination of Experimental Fertilization , 1987 .

[32]  Rainer Brüggemann,et al.  SPIEL—a model for phosphorus diagenesis and its application to lake restoration , 2004 .

[33]  Gertrud K. Nürnberg,et al.  The prediction of internal phosphorus load in lakes with anoxic hypolimnia1 , 1984 .

[34]  Mark E. Borsuk,et al.  A Bayesian network of eutrophication models for synthesis, prediction, and uncertainty analysis , 2004 .

[35]  Stephen R. Carpenter,et al.  Phosphorus Flow in a Watershed-Lake Ecosystem , 2000, Ecosystems.

[36]  Mike Best,et al.  Setting nutrient thresholds to support an ecological assessment based on nutrient enrichment, potential primary production and undesirable disturbance. , 2007, Marine pollution bulletin.

[37]  Erik Jeppesen,et al.  Seasonal response of nutrients to reduced phosphorus loading in 12 Danish lakes , 2005 .

[38]  S. Norton,et al.  Relationship between hypolimnetic phosphorus and iron release from eleven lakes in Maine, USA , 2003 .

[39]  I. Donohue,et al.  Using sediments to assess the resistance of a calcareous lake to diffuse nutrient loading , 2005 .

[40]  B. Ibelings,et al.  Resilience of Alternative Stable States during the Recovery of Shallow Lakes from Eutrophication: Lake Veluwe as a Case Study , 2007, Ecosystems.

[41]  Margaret W. Gitau,et al.  Modeling phosphorus transport in agricultural watersheds: Processes and possibilities , 2002 .

[42]  William A. Brock,et al.  OPTIMAL PHOSPHORUS LOADING FOR A POTENTIALLY EUTROPHIC LAKE , 2003 .

[43]  Monica G. Turner,et al.  Ecological Thresholds: The Key to Successful Environmental Management or an Important Concept with No Practical Application? , 2006, Ecosystems.

[44]  Stephen R. Carpenter,et al.  Summer water clarity responses to phosphorus, Daphnia grazing, and internal mixing in Lake Mendota , 1999 .

[45]  Stephen R. Carpenter,et al.  Regime shifts in lake ecosystems : pattern and variation , 2003 .

[46]  Stephen R. Carpenter,et al.  Management of eutrophication for lakes subject to potentially irreversible change , 1999 .

[47]  Stephen R. Carpenter,et al.  EUTROPHICATION DUE TO PHOSPHORUS RECYCLING IN RELATION TO LAKE MORPHOMETRY, TEMPERATURE, AND MACROPHYTES , 2005 .

[48]  S. Carpenter,et al.  Rising variance: a leading indicator of ecological transition. , 2006, Ecology letters.

[49]  M. Scheffer.  Ecology of Shallow Lakes , 1997, Population and Community Biology Series.

[50]  Michael D Mastrandrea,et al.  Probabilistic Integrated Assessment of "Dangerous" Climate Change , 2004, Science.

[51]  Thomas E. Maloney,et al.  Modeling the eutrophication process , 1973 .

[52]  R. Lathrop.  Perspectives on the eutrophication of the Yahara lakes , 2007 .

[53]  Erik Jeppesen,et al.  The Structuring Role of Submerged Macrophytes in Lakes , 1998, Ecological Studies.

[54]  R. Parsons,et al.  Evaluation of phosphorus-based nutrient management strategies in Pennsylvania , 2002 .

[55]  E. Jeppesen,et al.  Restoration of shallow lakes by nutrient control and biomanipulation—the successful strategy varies with lake size and climate , 2007, Hydrobiologia.

[56]  R. Vollenweider,et al.  Advances in defining critical loading levels for phosphorus in lake eutrophication. , 1976 .

[57]  Erik Jeppesen,et al.  Role of sediment and internal loading of phosphorus in shallow lakes , 2003, Hydrobiologia.

[58]  h-sas-i-ahlgren.  Lake restoration by reduction of nutrient loading: Expectations, experiences, extrapolations , 1989 .

[59]  Modeling phosphorus transport in an agricultural watershed using the WEPP model. , 2010, Journal of environmental quality.

[60]  B. Müller,et al.  Why the phosphorus retention of lakes does not necessarily depend on the oxygen supply to their sediment surface , 2003 .

[61]  Stephen R. Carpenter,et al.  Water clarity in Lake Mendota since 1900 : responses to differing levels of nutrients and herbivory , 1996 .

[62]  U. Aswathanarayana,et al.  Assessing the TMDL Approach to Water Quality Management , 2001 .

[63]  H. Bührer,et al.  Lake Lucerne, Switzerland, a long term study of 1961-1992 , 2001, Aquatic Sciences.

[64]  M. Scheffer,et al.  Alternative equilibria in shallow lakes. , 1993, Trends in ecology & evolution.

[65]  D. Schindler,et al.  Phosphorus, Nitrogen, and Carbon Dynamics of Experimental Lake 303 during Recovery from Eutrophication , 1989 .

[66]  T. Robinson,et al.  Models for Ecological Data: An Introduction , 2008 .

[67]  D. W. Schults,et al.  Summer internal phosphorus supplies in Shagawa Lake, Minnesota , 1981 .

[68]  J. Sickle,et al.  The effect of wastewater phosphorus removal on shagawa lake, Minnesota: phosphorus supplies, lake phosphorus and chlorophyll a , 1979 .

[69]  G. Andersson,et al.  Long-term Patterns of Shifts between Clear and Turbid States in Lake Krankesjön and Lake Tåkern , 2007, Ecosystems.

[70]  S. Carpenter,et al.  Catastrophic shifts in ecosystems , 2001, Nature.

[71]  Erik Jeppesen,et al.  Biomanipulation as an Application of Food-Chain Theory: Constraints, Synthesis, and Recommendations for Temperate Lakes , 1998, Ecosystems.

[72]  Response of northern temperate shallow lakes to reduced nutrient loading, with special emphasis on Danish lakes , 2005 .