01789nas a2200145   4500008004100000020001400041245012200055210006900177300001200246490000700258520128800265100002201553700002001575856004801595       2014                        eng d  a1015-162100aPhosphorus loading, transport and concentrations in a lake chain: a probabilistic model to compare management options0 aPhosphorus loading transport and concentrations in a lake chain   a145-1540 v763 aPhosphorus (P) loading, exports and concentrations of the four lakes of the Yahara chain (Wisconsin, USA) were compared under four load-reduction plans using a model calibrated with 29-33 years of annual data. P mitigation goals must balance reductions in P concentrations in the four lakes and the export from the lake chain to downstream waters. Lake Mendota, the uppermost lake, is most responsive to P load reductions, and benefits diminish downstream. Nonetheless, the greatest reductions in export from the lake chain to downstream waters derive from P load reductions to lakes lower in the chain. The effective grazer Daphnia pulicaria causes large improvements in water quality. Management to maintain populations of D. pulicaria has substantial benefits that augment those from reductions in P loading. Model projections show high variability in water quality and exports under all load-reduction plans. This variability is driven by inter-annual variation in runoff. Thus lake managers and the public should expect ongoing year-to-year variability in water quality, even though P load mitigation will improve water quality on average. Because of high variability from year to year, ongoing monitoring is essential to assess the effects of management of this chain of lakes.1 aCarpenter, S., R.1 aLathrop, R., C.  uhttp://dx.doi.org/10.1007/s00027-013-0324-5