Phosphorus Dynamics in a Eutrophic Lagoon: Uptake and Utilization of Nutrient Pulses by Phytoplankton

Berthold, Maximilian; Schumann, Rhena

doi:10.3389/fmars.2020.00281

Cited by 21 publications

(14 citation statements)

References 57 publications

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“…During 2017, high concentrations of seston and pigments caused a constantly low light availability in Grabow with a decreased euphotic zone of 60% in comparison to Vitter Bodden. The phytoplankton in the whole lagoon system of the DZBC is dominated by small-celled cyanobacteria of the Cyanobium clade (Albrecht et al, 2017), which are able to take up available nutrients very efficiently in this system (Berthold and Schumann, 2020), due to their high surface to volume ratio (Friebele and Fasut, 1978;Grillo and Gibson, 1979) resulting in high biomasses and low underwater light availability. Only S. pectinata persisted throughout the year.…”

Section: Low Light Availability In Grabow Efficiently Suppresses Seasonal Development In the Macrophytobenthosmentioning

confidence: 99%

Seasonal Variation in Biomass and Production of the Macrophytobenthos in two Lagoons in the Southern Baltic Sea

et al. 2021

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Baltic coastal lagoons are severely threatened by eutrophication. To evaluate the impact of eutrophication on macrophytobenthos, we compared the seasonal development in macrophytobenthic composition, biomass and production, water column parameters (light, nutrients), phytoplankton biomass and production in one mesotrophic and one eutrophic German coastal lagoon. We hypothesized that light availability is the main driver for primary production, and that net primary production is lower at a higher eutrophication level. In the mesotrophic lagoon, macrophytobenthic biomass was much higher with distinct seasonal succession in species composition. Filamentous algae dominated in spring and late summer and probably caused reduced macrophytobenthic biomass and growth during early summer, thus decreasing vegetation stability. Light attenuation was far higher in the eutrophic lagoon, due to high phytoplankton densities, explaining the low macrophytobenthic biomass and species diversity in every season. Areal net primary production was far lower in the eutrophic lagoon. The “paradox of enrichment” hypothesis predicts lower production at higher trophic levels with increased nutrient concentrations. Our results prove for the first time that this hypothesis may be valid already at the primary producer level in coastal lagoons.

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Section: Low Light Availability In Grabow Efficiently Suppresses Seasonal Development In the Macrophytobenthosmentioning

confidence: 99%

Seasonal Variation in Biomass and Production of the Macrophytobenthos in two Lagoons in the Southern Baltic Sea

et al. 2021

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“…Furthermore, rotifers and ciliates have been described to efficiently graze on small particles and filamentous phytoplankton (Zamora-Terol et al 2020). Especially filamentous cyanobacteria and picocyanobacteria contribute up to 90% of the phytoplankton biovolume in the DZLS (Albrecht et al 2017, Berthold and Schumann 2020) and the Baltic Sea (Celepli et al 2017). Indeed, a variety of studies showed that rotifers and other microzooplankton tend to increase with mesopredator presence (Compte et al, 2011; Compte et al, 2012; Šorf et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…In the case of the DZLS, such a trophic cascade may have been observed, with possible grazing of Eurytemora affinis on eggs and adults of the rotifer Keratella cochlearis (Feike and Heerkloss 2009). However, rotifers such as K. cochlearis are known to graze upon bacterioplankton (Haukka et al 2006), but also on filamentous cyanobacteria (Novotny et al 2021), which provide a large fraction of total biovolume in the DZLS (Albrecht et al 2017, Berthold and Schumann 2020). The DZLS shows a relatively short food web, with a high redundancy (Paar et al 2022), and a dominant energy- and matter flow within the microbial loop (Schiewer et al 1990, Schiewer 2007).…”

Section: Introductionmentioning

confidence: 99%

Mesopredator-mediated trophic cascade can break persistent phytoplankton blooms in coastal waters

Berthold

Schumann

Reiff

et al. 2022

Preprint

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Managing eutrophied systems only bottom-up (nutrient decreases) can be economically and ecologically challenging. Top-down controls (consumption) were sometimes found to effectively control phytoplankton blooms. However, mechanistic insights, especially on possible trophic cascades, are less understood in brackish, species-poor coastal waters, where large cladocera are absent. In this study, we set-up large mesocosms for three consecutive years during growth season. One set of mesocosms was controlled by mesopredator (gobies and shrimp), whereas the other mesocosms had no such mesopredator present. The results were standardized to monitoring data of the ecosystem to denote possible differences between treatments and the system. We found that mesopredator mesocosms showed lower turbidity, phytoplankton biomass, and nutrients compared to no-mesopredator mesocosms and the ecosystem. This decrease allowed macrophytes to colonize water depths only sparsely colonized in the ecosystem. Rotifer biomass increased in mesopredator mesocosms compared to the ecosystem and no-mesopredator mesocosms. Likewise, copepod biomass that potentially grazes upon rotifers and other microzooplankton decreased in mesopredator mesocosms. No-mesopredator mesocosms were colonized by an omnivorous mesograzer (Gammarus tigrinus), potentially creating additional pressure on macrophytes and increasing grazing-mediated nutrient release. Zooplankton was not able to control the non-nutrient limited phytoplankton. We propose a new mechanism, where a higher mesopredator density will increase grazing on phytoplankton by promoting microzooplankton capable of grazing on picophytoplankton. This proposed mechanism would contrast with freshwater systems, where a decrease of zooplanktivorous fish would promote larger phytoplankton grazer like cladocera. Biomanipulation in such species-poor eutrophic coastal waters may be more successful, due to less trophic pathways that can cause complex top-down controls. Stocking eutrophic coastal waters with gobies and shrimps may be an alternative biomanipulative approach rather than selectively remove large piscivorous or omnivorous fish from eutrophic coastal waters.

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“…Dissolved nutrients were always very low (< 0.3 µmol l -1 for DIP, < 6.2 µmol l -1 for DIN) within the mesocosms as well as the lagoon (see supplement table 1). The low availability of dissolved inorganic nutrients is a special feature of the DZLS, probably caused by its cyanobacterial dominance [20], which were described to rapidly take up occurring nutrient pulses [31]. Water circulation by water pumps simulated the permanently mixed shallow areas of the lagoon system.…”

Section: Methodological Annotationsmentioning

confidence: 99%

Dynamics of primary productivity in relation to submerged vegetation of a shallow, eutrophic lagoon: a field and mesocosm study

Berthold

Paar

2021

Preprint

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Aquatic ecosystems nowadays are under constant pressure, either from recent or historical events. In most systems with increased nutrient supply, submerged macrophytes got replaced by another stable state, dominated by phytoplankton as main primary producer. Yet, reducing the nutrient supply did not yield the aimed goal of restored habitats for submerged macrophytes in systems worldwide. The question arises, why submerged macrophytes do not re-colonize, and if they are actually competitive. Therefore, primary production assays were conducted in ex-situ bentho-pelagic mesocosms and compared to the actual ecosystem, a turbid brackish lagoon of the southern Baltic Sea. Mesocosm were either manipulated to be colonized by macrophytes, or stayed phytoplankton dominated. Oxygen evolution was monitored over a period of five months in 5 min (mesocosms) to 10 min (ecosystem) intervals. Surface and depth-integrated production was calculated to analyse seasonal and areal resolved production patterns. It was found that macrophyte mesocosms were more stable, when considering only surface O 2 production. However, calculating depth-integrated production resulted in net-heterotrophy in both shallow mesocosms approaches and the actual ecosystem. This heterotrophy is likely mediated by sediment respiration and POC accumulation in mesocosms, and a low share of productive to respiring water column in the actual ecosystem. Therefore, it seems unlikely that macrophytes will re-settle, as constant net-heterotrophy may allow for high-nutrient turnover at sediment-water interfaces and within the water column, favouring phytoplankton. Changes within the ecosystem cannot be expected without further restoration measures within and in the systems proximity.

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Phosphorus Dynamics in a Eutrophic Lagoon: Uptake and Utilization of Nutrient Pulses by Phytoplankton

Cited by 21 publications

References 57 publications

Seasonal Variation in Biomass and Production of the Macrophytobenthos in two Lagoons in the Southern Baltic Sea

Seasonal Variation in Biomass and Production of the Macrophytobenthos in two Lagoons in the Southern Baltic Sea

Mesopredator-mediated trophic cascade can break persistent phytoplankton blooms in coastal waters

Dynamics of primary productivity in relation to submerged vegetation of a shallow, eutrophic lagoon: a field and mesocosm study

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