High food availability linked to dominance of small zooplankton in a subtropical floodplain

Abstract

Zooplankton body size is fundamentally affecting productivity, ecosystem respiration, nutrient cycling, and energy transfer and may be controlled by food availability but also water physical and chemical characteristics. However, the differences in control of water physical and chemical characteristics and food availability on zooplankton body size have rarely been investigated in subtropical systems. We tested the hypotheses that: (i) the type of environment, food availability, and water physical and chemical characteristics would influence body size distribution in the Upper Paraná River floodplain and nearby subsystems and (ii) in environments with higher food availability, small‐sized organisms would predominate showing higher abundance, whereas the opposite would occur in environments with lower food availability. To test these hypotheses, we performed partial redundancy and redundancy analyses (RDA). Our results showed that food availability, Secchi depth, and suspended inorganic matter influenced the body size structure of rotifers and cladocerans. Additionally, we observed that greater food availability was related to greater abundance of organisms, which were dominated by small‐sized zooplankton (size classes C2 and C1 in rotifers, and class C2′ in cladocerans). It was possible to associate different zooplankton body size spectra with phytoplankton biovolume and planktonic ciliate abundance. We suggest that large‐bodied cladocerans could have a competitive advantage over rotifers and small‐sized cladocerans when resources are scarce, because the large‐sized group could explore a wider range of resource types.

The Effect of Hydrological Connectivity on the Zooplankton Structure in Floodplain Lakes of a Regulated Large River (the Lower Vistula, Poland)

“…The river water carried mineral and organic suspension into the connected lakes, thus providing food for detritivorous rotifera, such as K. tecta or B. angularis. Similar phenomena are observed by Bomfim et al [53].…”

“…According to Mitrovic et al [52] organic matter supply from inundation could stimulate heterotrophic bacterioplankton and affect zooplankton density and structure. High food availability is related to greater density of zooplankton, which is dominated by small-sized rotifers [53], e.g., K. tecta (Table 3, Figure 4B). Rotifers preferred the transitional floodplain lake ( Figure 5A).…”

Temporal dynamics of rotifers' feeding guilds shaped by chlorophyll‐a, nitrate, and environmental heterogeneity in subtropical floodplain lakes

“…This was probably because each guild encompasses different feeding strategies and habitat preferences (Oh et al, 2017). For example, filter feeders (trophi: malleate, malleoramate, and ramate) represent smaller bodied rotifers, ingest multiple food items (but no larger than ∼15-20 μm), are predominantly planktonic (Karabin, 1985;Obertegger & Manca, 2011), and good competitors under high food availability (Bomfim et al, 2018;Obertegger & Manca, 2011).…”

“…The species identification followed Koste (1978) and Segers (1995). We also obtained the body length of each species from the literature (Bomfim et al, 2018;Koste, 1978;de Souza Magalhães Braghin, 2018). We found 8 types of trophi among the 234 species identified such as malleate, malleoramate, ramate, virgate, uncinate, cardate, incudate, and forcipate (Figure 3).…”

Influence of the chlorophyll-a gradient on the community structure of plankton microcrustaceans (Cladocera and Copepoda) in a Neotropical reservoir

“…According to Sampaio et al (2002) and Rietzler et al (2002) these species, of large size, can be used as indicators of trophic state in freshwater ecosystems. Studies have demonstrated a relationship between body size of aquatic organisms and availability of feeding resources (Jeppesen et al 2010, Bomfim et al 2018, Mantovano et al 2019. Habitats with high productivity have a higher quantity of available energetic resources (Ortega-Mayagoitia et al 2011).…”