@article{BrothersHiltMeyeretal.2013,
  author    = {Brothers, Soren M. and Hilt, Sabine and Meyer, Stephanie and K{\"o}hler, Jan},
  title     = {Plant community structure determines primary productivity in shallow, eutrophic lakes},
  series = {Freshwater biology},
  volume    = {58},
  journal   = {Freshwater biology},
  number    = {11},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0046-5070},
  doi       = {10.1111/fwb.12207},
  pages     = {2264 -- 2276},
  year      = {2013},
  abstract  = {Regime shifts are commonly associated with the loss of submerged macrophytes in shallow lakes; yet, the effects of this on whole-lake primary productivity remain poorly understood. This study compares the annual gross primary production (GPP) of two shallow, eutrophic lakes with different plant community structures but similar nutrient concentrations. Daily GPP rates were substantially higher in the lake containing submerged macrophytes (58623gCm(-2)year(-1)) than in the lake featuring only phytoplankton and periphyton (40823gCm(-2)year(-1); P<0.0001). Comparing lake-centre diel oxygen curves to compartmental estimates of GPP confirmed that single-site oxygen curves may provide unreliable estimates of whole-lake GPP. The discrepancy between approaches was greatest in the macrophyte-dominated lake during the summer, with a high proportion of GPP occurring in the littoral zone. Our empirical results were used to construct a simple conceptual model relating GPP to nutrient availability for these alternative ecological regimes. This model predicted that lakes featuring submerged macrophytes may commonly support higher rates of GPP than phytoplankton-dominated lakes, but only within a moderate range of nutrient availability (total phosphorus ranging from 30 to 100gL(-1)) and with mean lake depths shallower than 3 or 4m. We conclude that shallow lakes with a submerged macrophyte-epiphyton complex may frequently support a higher annual primary production than comparable lakes that contain only phytoplankton and periphyton. We thus suggest that a regime shift involving the loss of submerged macrophytes may decrease the primary productivity of many lakes, with potential consequences for the entire food webs of these ecosystems.},
  language  = {en}
}
@article{BrothersHiltAttermeyeretal.2013,
  author    = {Brothers, Soren M. and Hilt, Sabine and Attermeyer, Katrin and Grossart, Hans-Peter and Kosten, Sarian and Lischke, Betty and Mehner, Thomas and Meyer, Nils and Scharnweber, Inga Kristin and K{\"o}hler, Jan},
  title     = {A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake},
  series = {Ecosphere : the magazine of the International Ecology University},
  volume    = {4},
  journal   = {Ecosphere : the magazine of the International Ecology University},
  number    = {11},
  publisher = {Wiley},
  address   = {Washington},
  issn      = {2150-8925},
  doi       = {10.1890/ES13-00247.1},
  pages     = {17},
  year      = {2013},
  abstract  = {Ecological regime shifts and carbon cycling in aquatic systems have both been subject to increasing attention in recent years, yet the direct connection between these topics has remained poorly understood. A four-fold increase in sedimentation rates was observed within the past 50 years in a shallow eutrophic lake with no surface in-or outflows. This change coincided with an ecological regime shift involving the complete loss of submerged macrophytes, leading to a more turbid, phytoplankton-dominated state. To determine whether the increase in carbon (C) burial resulted from a comprehensive transformation of C cycling pathways in parallel to this regime shift, we compared the annual C balances (mass balance and ecosystem budget) of this turbid lake to a similar nearby lake with submerged macrophytes, a higher transparency, and similar nutrient concentrations. C balances indicated that roughly 80\% of the C input was permanently buried in the turbid lake sediments, compared to 40\% in the clearer macrophyte-dominated lake. This was due to a higher measured C burial efficiency in the turbid lake, which could be explained by lower benthic C mineralization rates. These lower mineralization rates were associated with a decrease in benthic oxygen availability coinciding with the loss of submerged macrophytes. In contrast to previous assumptions that a regime shift to phytoplankton dominance decreases lake heterotrophy by boosting whole-lake primary production, our results suggest that an equivalent net metabolic shift may also result from lower C mineralization rates in a shallow, turbid lake. The widespread occurrence of such shifts may thus fundamentally alter the role of shallow lakes in the global C cycle, away from channeling terrestrial C to the atmosphere and towards burying an increasing amount of C.},
  language  = {en}
}