Water volume reduction increases eutrophication risk in tropical semi-arid reservoirs

Becker, Vanessa; Rocha Junior, Carlos Alberto Nascimento da; Costa, Mariana Rodrigues Amaral da; Menezes, Rosemberg Fernandes; Attayde, José Luiz

Water volume reduction increases eutrophication risk in tropical semi-arid reservoirs

Página do item simplificado Estatísticas

dc.contributor.author	Becker, Vanessa
dc.contributor.author	Rocha Junior, Carlos Alberto Nascimento da
dc.contributor.author	Costa, Mariana Rodrigues Amaral da
dc.contributor.author	Menezes, Rosemberg Fernandes
dc.contributor.author	Attayde, José Luiz
dc.date.accessioned	2020-12-07T13:33:43Z
dc.date.available	2020-12-07T13:33:43Z
dc.date.issued	2018-04-05
dc.description.resumo	Global patterns of temperature and precipitation have significantly changed over the last century and nearly all predictions point to even greater changes by the end of 2100. Long periods of drought in semi-arid regions generally reduce reservoirs and lakes water level, increasing the nutrients concentrations in the water. Our principal hypothesis is that water volume reduction, driven by prolonged droughts, will increase reservoirs susceptibility to eutrophication and accordingly an increase in trophic state. To test this hypothesis, we used a comparative analysis of ecosystems in a space-for-time substitution approach, in a Brazilian semi-arid region, to predict the consequences of reservoirs water volume reduction on key limnological variables. Methods: We sampled 16 reservoirs located in two sub-basins with contrasting rainfall regimes, inserted on Piranhas-Açu watershed. The Seridó River basin (SB) is dry and the Piancó River basin (SB) is humid, with annual mean precipitation of 500 and 700 mm, respectively. Linear regressions analyzes were performed to assess whether the percentage of maximum volume stored (%MVS) is a good predictor for total phosphorus (TP), total nitrogen (TN) and chlorophyll-a (CHLA). In addition, a two factorial analysis of variance (two-way ANOVA) was performed to test for period (dry, very dry and extremely dry), basin (SB and PB) and their interactions effects on TP, TN, CHLA, conductivity, turbidity, and Secchi depth. Results: The results showed a reduction in the reservoirs %MVS both for PB and SB regions. At the extremely dry period, all reservoirs were classified as eutrophic, but TP concentrations reached much higher values in SB than in PB. The linear regressions analyses showed that the TP and TN were negatively related to %MVS during all periods sampled. The two-way ANOVA showed that there were significant basin and period effects on TP, TN, Secchi depth and turbidity, whereas for CHLA and conductivity only basin effects were observed. In addition, we found significant interaction effects between period and basin on TP, TN and turbidity. Conclusions: We conclude that the contrasting levels of rainfall observed between the two basins affect the water quality and trophic state of the reservoirs and these effects are magnified by water volume reduction. Therefore, our findings might help to predict the consequences of rainfall reductions on freshwater ecosystems of Brazilian drylands	pt_BR
dc.identifier.citation	ROCHA JUNIOR, Carlos Alberto Nascimento da; COSTA, Mariana Rodrigues Amaral da; MENEZES, Rosemberg Fernandes; ATTAYDE, José Luiz; BECKER, Vanessa. Water volume reduction increases eutrophication risk in tropical semi-arid reservoirs. Acta Limnologica Brasiliensia, [S.L.], v. 30, p. 1-10, 5 abr. 2018. FapUNIFESP (SciELO). Disponível em <https://www.scielo.br/scielo.php?script=sci_arttext&pid=S2179-975X2018000100802&lng=en&tlng=en>. Acesso em 20 out 2020.http://dx.doi.org/10.1590/s2179-975x2117.	pt_BR
dc.identifier.doi	10.1590/S2179-975X2117
dc.identifier.issn	2179-975X
dc.identifier.uri	https://repositorio.ufrn.br/handle/123456789/30856
dc.language	en	pt_BR
dc.publisher	Associação Brasileira de Limnologia	pt_BR
dc.rights	Attribution 3.0 Brazil	*
dc.rights.uri	http://creativecommons.org/licenses/by/3.0/br/	*
dc.subject	Drought	pt_BR
dc.subject	Climate change	pt_BR
dc.subject	Phosphorous	pt_BR
dc.subject	Water shortage	pt_BR
dc.subject	Water quality	pt_BR
dc.title	Water volume reduction increases eutrophication risk in tropical semi-arid reservoirs	pt_BR
dc.type	article	pt_BR