Water Quality Indicators in Three Surface Hydraulic Connection Conditions in Tropical Floodplain Lakes

Abstract

Water quality indicators have been tied to natural or man-made surface hydraulic connection (SHC) conditions. Among these, temporally connected lakes (TCL) are hydraulic intermediates between isolated (IL) and permanently connected lakes (PCL). Therefore, the aim of this study is to answer if water quality indicators can estimate the possible overlap between the two opposed conditions of SHC (IL and PCL) with the intermediate one (TCL) in lakes with similar modifications in the water level regulation at the basin level. Among nine water variables sampled in six lakes with the three SHC conditions mentioned, chlorophyll a (Chl-a), Secchi disk (SD), and total phosphorus (TP) were identified as quality water indicators through principal component analysis. Furthermore, said indicators were used to measure their overlap and trophic state index deviations. The Chl-a, SD, and TP values in TCL showed a 0.72 overlap of PCL and IL. TP surplus measured in all the lakes was meaningful in urbanized ILs and lessened in a rural lake (PCL6) with submerged rooted macrophytes. The estimated overlap of trophic indicators between TCL, IL, and PCL in this study must be verified at a global representative scale for predictive and preventive use in the conservation of tropical coastal plain lakes.

Lipid Prospection Based on the Cellular Size of Phytoplankton Communities from Tropical Freshwater Ecosystems: A Systematic Literature Review

“…With respect to review present, the topics registered were microalgal isolation, exopolysaccharide production, total lipid accumulation, microalgal fatty acids and biomass for feed, supplemental nutrients, pharmaceuticals, and biodiesel, which occur with low frequency in the tropical freshwater phytoplankton literature according to cell size. Consequently, studies on the lipids of phytoplankton communities by cell size in eutrophic and hypereutrophic tropical freshwater ecosystems are lacking, especially in peri-urban and urban lakes with surface hydraulic disconnection [3].…”

“…Freshwater phytoplankton include oxygenic photoautotrophs represented by microalgae and cyanobacteria of different cell sizes that can form extensive colonies and mixed communities with specialized and economically exploitable ecological functions in tropical regions [1]. Tropical aquatic ecosystems have shown a high diversity of phytoplankton species that provide ecosystem services [2] but are highly vulnerable [3]. One of the reasons for this is the uptake of organic matter into the ecosystem, which alters the phytoplankton community through changes in trophic cascades [4].…”

“…One of the reasons for this is the uptake of organic matter into the ecosystem, which alters the phytoplankton community through changes in trophic cascades [4]. In the case of hypereutrophic ecosystems that have a trophic dynamic dominated by an exacerbated phytoplankton biomass due to the oversupply of phosphorus and nitrogen [3][4][5][6], the actions required to prevent organic photoautotrophic production or to restore environmental services are sometimes contradictory to basic human needs [2,[6][7][8]. In this sense, the high biomass and persistence of phytoplankton in hypereutrophic ecosystems reflect the possibility of applying a technological approach to harness the metabolic raw materials generated from the surplus of phytoplankton biomass in stressed environmental conditions [9] for the well-being of Water 2023, 15, 3774 2 of 14 local human populations, such as the extraction of valuable lipid biomolecules [10][11][12].…”