@Article{SantosMaAgChSiLa:2017:HyTrSt,
author = "Santos, Jana{\'{\i}}na A. and Marins, Rozane V. and Aguiar,
Jos{\'e} E. and Chalar, Guillermo and Silva, Francisco de Assis
Tavares Ferreira da and Lacerda, Luiz D.",
affiliation = "{Universidade Federal do Cear{\'a} (UFC)} and {Universidade
Federal do Cear{\'a} (UFC)} and {Universidade Federal do
Cear{\'a} (UFC)} and {Universidad de la Republica} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Federal
do Cear{\'a} (UFC)}",
title = "Hydrochemistry and trophic state change in a large reservoir in
the Brazilian northeast region under intense drought conditions",
journal = "Journal of Limnology",
year = "2017",
volume = "76",
number = "1",
pages = "41--51",
keywords = "Reservoir, semiarid, trophic state index, eutrophication.",
abstract = "The study shows changes on physical and chemical water parameters
and of trophic state in a large reservoir in the Brazilian
semiarid region following decreasing reservoir volume due to
rainfall shortage during four consecutive years. The monitoring
period, between November 2011 and May 2014, assessed approximately
50% water volume reduction and 10 meters' decrease of reservoir
water level that degraded water quality. Decrease in reservoir
volume, strong evaporation and the permanent influence of
anthropogenic activities, favored the concentration of salts and
accumulation of nutrients and of increasing pH. Thermal
stratification of the water column occurred when volume was
maximum and lead to a significant reduction in dissolved oxygen in
the hypolimnion (0.07 to 2.62 mg L-1). Diminishing volume resulted
in mixing of the hypolimnion nutrient-rich and oxygen-poor waters
in the entre water column and changed the initial oligotrophic
condition to eutrophic. However, the temporal scale of the
response of the reservoir's trophic state differs in the different
areas of the reservoir. Whereas deeper areas accumulating
nutrients from aquaculture and agriculture progressively became
mesotrophic and eventually eutrophic; shallower regions far from
direct anthropogenic influences, changed their trophic sate much
later, but rapidly turned into super-eutrophic conditions,
probably due to more intense sediment resuspension and water
mixing. Trophic State Index followed nutrient increase during most
of the period. However, it also responded to an increase in
chlorophyll a concentrations when the reservoir achieved its
minimum volume, in particular in the shallower areas. The results
suggest that this type of reservoir systems are vulnerable to
eutrophication during extended drought periods and that a better
assessment of the maximum support capacity for reservoir
activities, particularly aquaculture, must be re-assessed taking
into consideration worst case scenarios forecasted by global
climate change.",
doi = "10.4081/jlimnol.2016.1433",
url = "http://dx.doi.org/10.4081/jlimnol.2016.1433",
issn = "1129-5767",
language = "en",
targetfile = "hydrochemistry.pdf",
urlaccessdate = "27 abr. 2024"
}