Lead Organizer: Claudia Feijoo, Universidad Nacional de Luján (clasife@yahoo.com.ar)
Co-organizers:
Olena Bilous, University of Natural Resources and Life Sciences (bilous_olena@ukr.net)
Presentations
08:30 AM
PHYTOPLANKTON METACOMMUNITIES IN ALTERED RIVERINE LANDSCAPES (5105)
Primary Presenter: Olena Bilous, University of Natural Resources and Life Sciences (olena.bilous@boku.ac.at)
Phytoplankton metacommunities are intensely studied for ponds and lakes, less studies are found for riverine landscapes and their hydrological dynamics. Evidently, phytoplankton metacommunities are impacted by hydrological dynamics and local and regional factors. Thus, to gain a deeper insight into the role of mentioned factors driving phytoplankton community composition, its diversity and functioning, we investigated metacommunity patterns of phytoplankton in riverine landscapes. We hypothesized that the exchange of phytoplankton species between hydrologically connected waterbodies is higher than the distribution and diversity patterns formed by local habitat conditions in riverine landscapes. We studied the spatial complexity and the similarity of the communities of phytoplankton with regard to hydrologically connected waterbodies emphasising habitat diversity in the floodplain area according to temporal (seasonal) scale. Twenty-four sites from different water bodies along the Danube River, including floodplain sites and main channel sites, were studied for one year under different hydrological conditions. Plankton samples were collected to define algal species distribution and associated local habitat factors and regional factors related to different connectivity and network properties were included. The result of the study will complement existing ecological models in riverine landscapes applied to species occurrence and distribution.
08:45 AM
A functional perspective on the factors underpinning carbon storage in coastal plant communities (5357)
Primary Presenter: Roel Lammerant, University of Helsinki (roel.lammerant@helsinki.fi)
Coastal vegetated ecosystems have received global interest for their possible role in climate change mitigation. To date, studies on aquatic plants have mainly focused on the role of mono-specific seagrass stands, typically ignoring that the coastal zone can be heterogeneous, where multiple species with a range of trait characteristics may influence carbon storage differently across seasons. With few studies having assessed how functional traits link to carbon storage in aquatic plant communities, we sought to explore (i) the relationship between functional community composition and biomass-bound carbon stocks, and (ii) seasonal fluctuations of non-structural carbohydrates in different plant species. We conducted multiple field surveys (i.e., October, March, June and August) in the Baltic Sea, Finland, where we sampled six soft-bottom communities dominated by aquatic vascular plants and measured nine traits that capture the key variation in plant life-history strategies. We found that functional composition was associated with plant carbon stocks and this relationship was mediated by seasonality. Non-structural carbohydrates varied significantly through time, with the amount stored in leaf tissue throughout winter being tied to functional characteristics of the leaves. Our results indicate that the underlying biological mechanisms influencing carbon storage are affected by community trait composition, underlining the importance of using functional traits as a tool to assess the role of aquatic plant biodiversity for ecosystem functioning.
09:00 AM
ARE “LAKEMOUNTS” BIODIVERSITY HOTSPOTS? (5831)
Primary Presenter: Bianca Possamai, University of Vermont (biancapossamai@hotmail.com)
Seamounts modify water flow and create nutrient-enriched upwelling zones that support increased productivity and biodiversity. However, similar systems are largely unstudied in lakes. We hypothesized that steep reefs in deep lakes (“lakemounts”) act as seamounts. In a preliminary study, we monitored water temperature and compared fish and benthic invertebrate diversity nearshore (NS) and around a lakemount (LM) in Lake Champlain, US. In a 20-day period, the thermocline oscillated around 15 m depth. We observed two seiche events that upwelled cold water, both with 4 days duration. Temperature was positively related to NE winds (t=1.95, p=0.05) and negatively related to SSW winds (t=-5.14, p<0.001), indicating formation of a wind-driven seiche. Taxonomic richness was higher at the NS than LM site (12 vs 11 fish species, and 25 vs 20 benthic taxa, respectively). Shannon-Weiner diversity (H) and Evenness (evar) indices showed that NS benthos had higher diversity and evenness compared to the LM benthic community (H=2.2 vs 1.7; evar=0.7 vs 0.6; NS vs LM, respectively), while the fish diversity and evenness were higher in the LM (H=1.5 vs 1.8; evar 0.6 vs 0.7; NS vs LM, respectively). Salmonids were present only at the LM and insects were exclusively in the NS, while other taxonomic groups were similar between the habitats. Zooplankton samples remain to be processed. Our early results suggest the diversity of benthic invertebrates and fishes were comparable between lakemount and nearshore habitats, suggesting lakemounts may act as a biological hotspot in the offshore habitat.
09:15 AM
An abundant future for quagga mussels in deep European lakes (7095)
Primary Presenter: Benjamin Kraemer, University of Konstanz (ben.m.kraemer@gmail.com)
The range of the quagga mussel has expanded rapidly across the northern hemisphere in recent decades owing to its dispersal abilities, prolific reproduction rates, and broad ecological tolerances. Their rapid spread is matched by a remarkable capacity to filter particulates from the water column with profound effects on local ecosystems. In the North American Great Lakes, quagga mussel populations have increased inexorably since the late 1980’s, but it remains unclear whether quagga mussels will follow a similar trajectory in Europe where they have appeared more recently. Here we apply knowledge from a 34-year quagga population monitoring effort in the North American Great Lakes to predict future quagga populations in deep European lakes, where quaggas are quickly becoming a conspicuous part of the underwater landscape. We predict that quagga mussel biomass in Lakes Biel, Constance, and Geneva may increase by a factor of 9 – 20 by 2045. Like in North America, this increase will likely be characterized by a shift to larger individuals and deeper depths as the population matures. If realized, this rapid expansion of quagga mussels would likely drive the largest aquatic ecosystem change in deep European lakes since the eutrophication period of the mid-20th century.
09:30 AM
Influence of macrophyte complexity on phosphorus retention in artificial stream mesocosms (5379)
Primary Presenter: Claudia Feijoó, Institute of Ecology and Sustainable Development (INEDES) (clasife@yahoo.com.ar)
Macrophytes have a key structuring role in aquatic environments, increasing habitat heterogeneity and promoting nutrient uptake when present in multispecific communities. Here, we experimentally investigated the effect of different submerged macrophyte species, with similar or distinct complexity, on phosphorus (P) retention in recirculating artificial streams. Two experiments were performed in 12 artificial channels during 3 days each. Macrophyte complexity was estimated by the fractal dimension at patch scale (FD), and P retention (k) was calculated as the slope of the relationship between P concentration (in ln) and time, and standardized by macrophyte biomass. In the first experiment, we estimated P retention in two macrophyte species (Egeria densa and Stuckenia striata) of similar complexity, alone or combined. We observed no significant differences neither in k nor in FD among treatments. In the second experiment, we compared P retention in 3 species with different complexities (Ceratophyllum demersum, Egeria densa and Elodea ernstae). We found that k differed significantly among treatments, being higher in Elodea (the species with the highest FD), intermediate in Ceratophyllum, and lower in Egeria (k = 0.0098, 0.0065, and 0.0049 1/h, respectively). Our results suggest that species that are more complex may show higher P retention when comparing with simple species. However, physiological characteristics of each species should also influence P uptake.
CS024 Biodiversity
Description
Time: 8:30 AM
Date: 5/6/2023
Room: Sala Portixol 1