Aluminium, silicon and transition metal dynamics in a non-polluted lake: aquatic concentrations and phytoplankton uptake

Abstract

This study was carried out to monitor and relate seasonal Al, Si and transition metal (Mn, Fe, Ni and Cu) concentrations in lake water and phytoplankton within an unpolluted lake. Lake water concentrations of Al and Mn showed seasonal (high winter-low summer) variation. The clear annual correlation pattern had significant links among transition metals, but not Si-Al. Within phytoplankton biomass, separate analyses of acid (soluble) and carbonate (insoluble) constituents showed that most elements (Si, Ni, Cu and Fe) occurred in bound form, but insoluble Al and Mn concentrations were \50% total. Diatom abundance was characterised by high Si and low Al biomass concentration, with substantial amounts of Si also occurring during phases of bluegreen dominance. The elemental correlation pattern of phytoplankton acid digests (soluble material) was different from carbonate digests, which had significant correlations among the three transition metals (Mn, Ni, and Cu)-but no relationships involving Si, Al and Fe. Data show that phytoplankton biomass accumulates high levels of Al, Si and transition metals, irrespective of taxonomic composition. The different correlation patterns seen for aquatic, soluble biomass and insoluble biomass elemental concentrations indicate that external availability, soluble uptake and insoluble deposition are distinct aspects of the pelagic ecosystem.

Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics

“…Bayley et al (2007) found similar relationships between turbidity and elements in water and reported that turbid shallow lakes had higher concentrations of P and Si compared to clear sites. Si uptake is dominated by diatoms, sponges, and blue-green algae (Fraústo da Silva and Williams 2001; Quiroz-Vazquez et al 2008) and its concentrations in water are primarily controlled by benthic macro-algae (Sigmon and Cahoon 1997). Si might be released or excreted from diatom grazers and decomposing diatom frustules which might explain increased Si concentrations in PP lakes (Parker et al 1977; Ferrante and Parker 1978; Korstad 1983).…”

Variações sazonais e espaciais das concentrações elementares em compartimentos biogeoquímicos de lagoas naturais rasas do Cerrado e suas influências no funcionamento ecossistêmico

“…Grande parte dos estudos realizados em ambientes rasos tropicais aborda questões sobre regime hidrológico (Loverde- Oliveira et al, 2009), papel dos produtores primários na ciclagem de carbono, nitrogênio e fósforo , biomassa e dinâmica do fitoplâncton (Figueredo & Giani, 2009;Rangel et al, 2009; e perifíton (França et al, 2011;Dunck et al, 2013), composição da comunidade de macrófitas aquáticas (Meerhoff et al, 2003;Bando, et al, 2015), estrutura e composição de comunidades de invertebrados e peixes (Rejas et al, 2005). A ocorrência de elementos-traço é importante em todos os níveis tróficos dentro do ecossistema aquático, refletindo a disponibilidade no ambiente e a captação e transferência em relação à demanda metabólica ou tolerância da biota (Quiroz-Vázquez et al, 2008). Estudos ecológicos sobre elementos-traço, normalmente, avaliam a influência da limitação desses elementos no ambiente e o efeito da toxicidade no crescimento, na reprodução e na sobrevivência dos organismos (Munk et al, 2002;Barcarolli & Martinez, 2004) e possibilitam um maior entendimento da mobilidade no ambiente e da tendência de alguns desses elementos biomagnificar por meio da cadeia trófica.…”