The structuring role of macrophytes on plankton community composition and bacterial metabolism in a large subtropical shallow lake

Abstract

Aim We aimed at investigating changes in major groups of plankton (bacterioplankton, phytoplankton and zooplankton) and bacterioplankton metabolism along a transect covering a littoral, macrophyte dominated zone to a pelagic, phytoplankton dominated zone in the large subtropical shallow lake Mangueira, Rio Grande do Sul State, Brazil. Methods The 3.2 km littoral-pelagic transect (7 points) was sampled in October 2007 in the southern section of the lake. Major taxonomic groups of phytoplankton and zooplankton were counted and identified by optic microscopy. The bacterioplankton was identified by FISH (Fluorescent in situ Hybridization), and bacterial abundance, biovolume and biomass were quantified by epifluorescence microscopy. Primary and bacterial productions were measured by incorporation of radioactive bicarbonate and leucine, respectively. Bacterial respiration was measured by experiments of oxygen consumption, and an extensive data set of limnological variables were measured through standard methods. Results Sharp changes in chemical/physical variables, as well as in bacterial density, biovolume, biomass and bacterial growth efficiency occurred on average at 30% of macrophyte coverage, with most of them increasing towards pelagic zones. The composition of major groups of zooplankton, phytoplankton, bacterial morphotypes and phylotypes indicated that different planktonic assemblies live apart in these two zones. Conclusions Our results demonstrate that macrophytes are a structuring driver of the plankton community and bacterial metabolism in this large subtropical shallow lake.

Association Between the Distributions and Chemical Composition of Aquatic Macrophytes and Bacterial Community Structure in Some Irrigation Canals (Rayahs) of the Nile River, Egypt

“…The quality of water is typically determined by monitoring bacterial presence especially feacal coliform bacteria, which are used as microbiological indicator of the pollution. Bacteria are the major users of dissolved organic matter and therefore of central importance for carbon cycle in aquatic systems (They and Marques, 2019). The availability of fixed inorganic nitrogen often plays a fundamental role in regulating primary production in both aquatic and terrestrial ecosystems.…”

Horizontal variability and regulation of bacterial production in Lake Biwa, Japan

“…gradients (Scavia and Laird 1987;Güde 1990;Filippini et al 2008), while there were no systematic horizontal patterns or clear correlations to environmental variables in some cases (Reichart and Simon 1996;They and Marques 2019). Horizontal variability, shown as ratios of maximum to minimum BP within a horizontal sampling, varies among seasons and lakes (1.6-19.5, Table 1) and reaches the order level.…”

Bacterial decomposition of allochthonous organic matter in shallow subtropical lakes

“…Increased aquatic macrophyte cover in lentic environments inhibit the algae community through shading, promoting competition for nutrients, and releasing allelopathic substances (Scheffer & Jeppesen, 2007;van Donk & van Bund, 2002). The presence of macrophytes has a significant capacity to alter the composition and metabolism of bacterioplankton (They & Marques, 2019). Despite consistent evidence supporting the effects of macrophytes on algae and planktonic bacteria, their effect on bacteria associated with the decomposition process is largely unknown (Hempel et al, 2008;Mentes et al, 2018;They & Marques, 2019;Torremorell et al, 2015).…”

“…The presence of macrophytes has a significant capacity to alter the composition and metabolism of bacterioplankton (They & Marques, 2019). Despite consistent evidence supporting the effects of macrophytes on algae and planktonic bacteria, their effect on bacteria associated with the decomposition process is largely unknown (Hempel et al, 2008;Mentes et al, 2018;They & Marques, 2019;Torremorell et al, 2015).…”