RT journal article
T1 What supports the deep chlorophyll maximum in acidic lakes? The role of the bacterial CO2 production in the hypolimnion
A1 Soria Píriz, Sara
A1 Lara Rallo, Francisco Miguel
A1 Jiménez Arias, Juan Luis
A1 Papaspyrou, Sokratis
A1 Ubeda Sánchez, Bárbara
A1 García Robledo, Emilio Guillermo
A1 Bohórquez Ferrando, Julio
A1 Gálvez Lorente, José Ángel
A1 Revsbech, Niels Peter
A1 Corzo Rodríguez, Alfonso
A2 Biología
AB The interactions between phytoplankton, bacteria and resources, irradiance, and nutrients, leading to the formation of deep chlorophyll maxima (DCMs), are little understood in acid lakes. In “El Sancho” reservoir (Iberian Pyritic belt, Huelva, Spain), an acid mine drainage impacted waterbody (pH 3.5–4.0), a strong DCM forms in the metalimnion during the stratification period. The DCM was located always below the 1% irradiance level, where the decreasing irradiance profile overlapped with a dissolved inorganic carbon concentration (CO2) gradient decreasing upward from the hypolimnion. The DCM was dominated by the chlorophyte Carteria sp. and showed the highest volumetric photosynthetic and dark respiration rates. The DCM, however, only contributed around 20% of water column integrated gross primary production, while it accounted for 54–66% of water column chlorophyll. The total bacterial abundance correlated significantly with the CO2 concentration (r = 0.74). To test the hypothesis of a possible dependence of the formation of the DCM in acid lakes on the production of CO2 by heterotrophic bacteria, a one-dimensional reactive transport model (DCM-CO2) was developed and tested. The DCM-CO2 model simulated the vertical distribution of chlorophyll (R2 > 0.63) and the vertical profile of CO2 rather accurately (R2 > 0.79), the position of DCM depending on both light penetration and an upward flux of CO2 produced by hypolimnetic heterotrophic bacteria. Overall, the results support the hypothesis of microbial degradation of organic matter being a source of CO2 for acid lake primary producers at the DCM.
PB John Wiley & Sons, Inc
SN 1939-5590
YR 2020
FD 2020-06
LK http://hdl.handle.net/10498/36070
UL http://hdl.handle.net/10498/36070
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 06-nov-2026