scholarly journals Viral infection switches the balance between bacterial and eukaryotic recyclers of organic matter during algal blooms

2021 ◽  
Author(s):  
Flora VINCENT ◽  
Matti Gralka ◽  
Guy Schleyer ◽  
Daniella Schatz ◽  
Miguel Cabrera-Brufau ◽  
...  
Keyword(s):  
Organic Matter ◽  
Viral Infection ◽  
Algal Blooms ◽  
Large Scale ◽  
Deep Ocean ◽  
Trophic Levels ◽  
Microbiome Composition ◽  
Carbon Release ◽  
Open Question ◽  
The Impact

Abstract Algal blooms are hotspots of marine primary production and play central roles in microbial ecology and global nutrient cycling. When blooms collapse, organic carbon is transferred to higher trophic levels, microbial respiration or sinking in proportions that depend on the dominant mortality agent. Viral infection can lead to bloom termination, but its impact on the fate of carbon remains an open question. Here, we characterized the consequences of viral infection on the microbiome composition and biogeochemical landscape of marine ecosystems by conducting a large-scale mesocosm experiment. Moniroting of seven induced coccolithophore blooms, which showed different degrees of viral infection, revealed that only high levels of viral infection caused significant shifts in the composition of free-living bacterial and eukaryotic assemblages. Intriguingly, viral infection favored the growth of eukaryotic heterotrophs (thraustochytrids) over bacteria as potential recyclers of organic matter. By combining modeling and quantification of active viral infection at a single-cell resolution, we estimate that viral infection can increase per-cell rates of extracellular carbon release by 2-4.5 fold. This happened via production of acidic polysaccharides and particulate inorganic carbon, two major contributors to carbon sinking into the deep ocean. These results reveal the impact of viral infection on the fate of carbon through microbial recyclers of organic matter in large-scale coccolithophore blooms.

scholarly journals Viral infection switches the balance between bacterial and eukaryotic recyclers of organic matter during algal blooms

2021 ◽  
Author(s):  
Flora Vincent ◽  
Matti Gralka ◽  
Guy Schleyer ◽  
Daniella J Schatz ◽  
Miguel Cabrera-Brudau ◽  
...  
Keyword(s):  
Organic Matter ◽  
Viral Infection ◽  
Algal Blooms ◽  
Large Scale ◽  
Deep Ocean ◽  
Trophic Levels ◽  
Microbiome Composition ◽  
Carbon Release ◽  
Open Question ◽  
The Impact

Algal blooms are hotspots of marine primary production and play central roles in microbial ecology and global nutrient cycling. When blooms collapse, organic carbon is transferred to higher trophic levels, microbial respiration or sinking in proportions that depend on the dominant mortality agent. Viral infection can lead to bloom termination, but its impact on the fate of carbon remains an open question. Here, we characterized the consequences of viral infection on the microbiome composition and biogeochemical landscape of marine ecosystems by conducting a large-scale mesocosm experiment. Moniroting of seven induced coccolithophore blooms, which showed different degrees of viral infection, revealed that only high levels of viral infection caused significant shifts in the composition of free-living bacterial and eukaryotic assemblages. Intriguingly, viral infection favored the growth of eukaryotic heterotrophs (thraustochytrids) over bacteria as potential recyclers of organic matter. By combining modeling and quantification of active viral infection at a single-cell resolution, we estimate that viral infection can increase per-cell rates of extracellular carbon release by 2-4.5 fold. This happened via production of acidic polysaccharides and particulate inorganic carbon, two major contributors to carbon sinking into the deep ocean. These results reveal the impact of viral infection on the fate of carbon through microbial recyclers of organic matter in large-scale coccolithophore blooms.

Anoxic metabolism after the 21st century in oxygen minimum zones

2020 ◽  
Author(s):  
Wolfgang Koeve ◽  
Angela Landolfi
Keyword(s):  
Organic Matter ◽  
Ocean Circulation ◽  
Large Scale ◽  
Deep Ocean ◽  
Sulphate Reduction ◽  
Oxygen Minimum Zones ◽  
The Future ◽  
Ocean Models ◽  
The Impact ◽  
Oxygen Minimum

<p>Global models project a decrease of marine oxygen over the course of the 21th century. The future of marine oxygen becomes increasingly uncertain further into the future after yr 2100 , partly because ocean models differ in the way organic matter remineralisation continues under oxygen- and nitrate-free conditions. Using an Earth system model of intermediate complexity we found that under a business-as-usual CO2-emission scenario ocean deoxygenation further intensifies for several centuries until eventually ocean circulation re-establishes and marine oxygen increases again. (Oschlies et al. 2019, DOI 10.1038/s41467-019-10813-w).</p><p>In the Pacific Ocean the deoxygenation after yr 2100 goes along with the large scale loss of nitrate from oxygen minimum zones. Here we explore the impact on simulated ocean biogeochemistry of three different process formulation of anoxic metabolism, which have been used in other ocean models: (1) implicit sulphate reduction (organic matter degradation continues without oxidant), (2) no sulphidic metabolism (organic matter is not degraded under anoxic conditions), and (3) explicit sulphate reduction (with H2S as explicit model tracer). The model with explicit sulfphate reduction supports larger regional organic matter fluxed into the deep ocean and an increase in respired carbon storage, compared with the model applying implicit sulphate. We discuss the impact of anoxic metabolism on the coupling between export production and respired carbon stored in the ocean interior.</p>

scholarly journals Viral infection of algal blooms leaves a halogenated footprint on the dissolved organic matter in the ocean

2020 ◽  
Author(s):  
Constanze Kuhlisch ◽  
Guy Schleyer ◽  
Nir Shahaf ◽  
Flora Vincent ◽  
Daniella Schatz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Viral Infection ◽  
Natural Environment ◽  
Algal Blooms ◽  
Algal Bloom ◽  
Trophic Levels ◽  
Viral Gene ◽  
Gene Marker ◽  
Market Place

AbstractAlgal blooms are important hotspots of primary production in the ocean, forming the basis of the marine food web and fueling the pool of dissolved organic matter (DOM)1, which is the largest global inventory of reduced carbon and a market place for metabolic exchange in the ocean2. Marine viruses are key players in controlling algal bloom demise and act as major biogeochemical drivers of nutrient cycling and metabolic fluxes by shunting algal biomass from higher trophic levels to the DOM pool, a process termed the ‘viral shunt’3,4. Nevertheless, the metabolic composition of virus-induced DOM (vDOM) in the marine environment is unknown. To decode the metabolic footprint of the ‘viral shunt’, we induced a bloom of the ecologically important alga Emiliania huxleyi in the natural environment, and followed its succession using an untargeted exometabolomics approach. Here we show that algal bloom succession induces extensive and dynamic changes in the exometabolic landscape, especially during bloom demise. By correlating to a specific viral gene marker, we discovered a set of novel chlorine-iodine-containing metabolites that were induced by viral infection and copiously released during bloom demise. We further detected several of these chloro-iodo metabolites in virus-infected open ocean blooms of E. huxleyi, supporting their use as sensitive biomarkers for virus-induced demise in the natural environment. Therefore, we propose halogenation to be a hallmark of the E. huxleyi vDOM, providing insights into the profound metabolic consequences of viral infection for the marine DOM pool.

scholarly journals Viral infection of algal blooms leaves a unique metabolic footprint on the dissolved organic matter in the ocean

2021 ◽  
Vol 7 (25) ◽  
pp. eabf4680
Author(s):  
Constanze Kuhlisch ◽  
Guy Schleyer ◽  
Nir Shahaf ◽  
Flora Vincent ◽  
Daniella Schatz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Primary Production ◽  
Viral Infection ◽  
Algal Blooms ◽  
Trophic Levels ◽  
Dynamic Changes ◽  
Marine Food Web ◽  
Key Players ◽  
Marine Food

Algal blooms are hotspots of primary production in the ocean, forming the basis of the marine food web and fueling the dissolved organic matter (DOM) pool. Viruses are key players in controlling algal demise, thereby diverting biomass from higher trophic levels to the DOM pool, a process termed the “viral shunt.” To decode the metabolic footprint of the viral shunt in the environment, we induced a bloom of Emiliania huxleyi and followed its succession using untargeted exometabolomics. We show that bloom succession induces dynamic changes in the exometabolic landscape. We found a set of chlorine-iodine–containing metabolites that were induced by viral infection and released during bloom demise. These metabolites were further detected in virus-infected oceanic E. huxleyi blooms. Therefore, we propose that halogenation with both chlorine and iodine is a distinct hallmark of the virus-induced DOM of E. huxleyi, providing insights into the metabolic consequences of the viral shunt.

scholarly journals BPOP-v1 model: exploring the impact of changes in the biological pump on the shelf sea and ocean nutrient and redox state

2019 ◽  
Author(s):  
Elisa Lovecchio ◽  
Timothy M. Lenton
Keyword(s):  
Organic Matter ◽  
Deep Ocean ◽  
Biological Pump ◽  
Promising Tool ◽  
Biogeochemical Fluxes ◽  
Structure Changes ◽  
Large Particles ◽  
Shelf Sea ◽  
Slope Sediment ◽  
The Impact

Abstract. The ocean’s biological pump has changed over Earth history from one dominated by prokaryotes, to one involving a mixture of prokaryotes and eukaryotes with trophic structure. Changes in the biological pump are in turn hypothesised to have caused important changes in the ocean’s nutrient and redox properties. To explore these hypotheses, we present here a new box model including oxygen (O), phosphorus (P) and a dynamical biological pump. Our Biological Pump, Oxygen and Phosphorus (BPOP) model accounts for two – small and large – organic matter species generated by production and coagulation, respectively. Export and burial of these particles are regulated by a remineralization length (zrem) scheme. We independently vary zrem of small and large particles in order to study how changes in sinking speeds and remineralization rates affect the major biogeochemical fluxes, and O and P ocean concentrations. Modelled O and P budgets and fluxes lay close to present estimates for zrem in the range of currently measured values. Our results highlight that relatively small changes in zrem of the large particles can have important impacts on the O and P ocean availability and support the idea that an early ocean dominated by small particles was nutrient rich due to inefficient removal to sediments. The results also highlight that shelf ocean anoxia can coexist with an oxygenated deep open ocean for realistic values of zrem, especially for large values of the small particle zrem. This could challenge conventional interpretations that the Proterozoic deep ocean was anoxic, which are derived from shelf and slope sediment redox data. This simple and computationally inexpensive model is a promising tool to investigate the impact of changes in the organic matter sinking and remineralization rates as well as changes in physical processes coupled to the biological pump in a variety of case studies.

scholarly journals Linking Terrestrial and Aquatic Biodiversity to Ecosystem Function Across Scales, Trophic Levels, and Realms

2021 ◽  
Vol 9 ◽  
Author(s):  
Kyla M. Dahlin ◽  
Phoebe L. Zarnetske ◽  
Quentin D. Read ◽  
Laura A. Twardochleb ◽  
Aaron G. Kamoske ◽  
...  
Keyword(s):  
Ecosystem Function ◽  
Large Scale ◽  
Information Science ◽  
Spatial Scales ◽  
Biodiversity Loss ◽  
Relative Strength ◽  
Trophic Levels ◽  
Aquatic Biodiversity ◽  
Patterns And Processes ◽  
The Impact

Global declines in biodiversity have the potential to affect ecosystem function, and vice versa, in both terrestrial and aquatic ecological realms. While many studies have considered biodiversity-ecosystem function (BEF) relationships at local scales within single realms, there is a critical need for more studies examining BEF linkages among ecological realms, across scales, and across trophic levels. We present a framework linking abiotic attributes, productivity, and biodiversity across terrestrial and inland aquatic realms. We review examples of the major ways that BEF linkages form across realms–cross-system subsidies, ecosystem engineering, and hydrology. We then formulate testable hypotheses about the relative strength of these connections across spatial scales, realms, and trophic levels. While some studies have addressed these hypotheses individually, to holistically understand and predict the impact of biodiversity loss on ecosystem function, researchers need to move beyond local and simplified systems and explicitly investigate cross-realm and trophic interactions and large-scale patterns and processes. Recent advances in computational power, data synthesis, and geographic information science can facilitate studies spanning multiple ecological realms that will lead to a more comprehensive understanding of BEF connections.

scholarly journals Environmental Considerations for the Management of the Bivalve Fisheries of Bahía Magdalena (Mexico), a Coastal Lagoon at the Southern End of the California Current

2021 ◽  
Vol 8 ◽  
Author(s):  
María del Carmen Jiménez-Quiroz ◽  
Francisco Javier Barrón-Barraza ◽  
Rafael Cervantes-Duarte ◽  
René Funes-Rodríguez
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Large Scale ◽  
Environmental Variability ◽  
Southern Oscillation ◽  
Warming Trend ◽  
Regional Warming ◽  
Biological Variables ◽  
The Impact ◽  
Bahia Magdalena

This study presents an overview of bivalve assemblages in Bahia Magdalena (BM, México) and the possible impact of environmental variability on these populations, constantly stressed by fishing. This lagoon is responsible for a high proportion of harvest of regional bivalves. First, we list the bivalve species reported in public biogeographic databases. Based on eight commercially exploited species, we described the composition of the bivalve assemblage and its biological characteristics, the history of fishery, and environmental variability in the marine area adjacent to the lagoon (1970–2019) and the habitat of bivalves (2002–2020). Sources of data were public databases and published literature. The enlisted species (n = 184) belong to six orders, and most are small and infaunal, but the structure of the assemblage is unknown. The fisheries began at different times and focused on the most valuable resources. Almost all harvest of bivalves had wide variations because of intensive fishing and a weak regulation frame. After 2015, the main resources were the Pacific wing-oyster (a new resource since 2017) and the geoduck clam due to the declining abundance of other resources (e.g., pen shells, Pacific calico scallop). There was a warming trend in the region since the 1970's, but the strongest El Niño-Southern Oscillation (ENSO) phases caused the most notable changes before 2013; after that year, a combination of large-scale phenomena increased the temperature significantly. The trend of chlorophyll-a abundance negatively correlated with temperature, but there was an almost constant supply of particulate organic matter in the interior of Bahia Magdalena (BM). After 2015, the quality of lagoon water gradually deteriorated, and in 2017 and 2019, harmful algal blooms developed, but the impact was not fully assessed. The challenges faced by the fishery are multiple (institutional weakness and regional warming); however, permanent monitoring programs of environmental conditions and critical biological variables should be implemented to design scenarios that allow fishery sustainability.

Factors controlling primary productivity in a wet–dry tropical river

2013 ◽  
Vol 64 (7) ◽  
pp. 585 ◽  
Author(s):  
S. J. Faggotter ◽  
I. T. Webster ◽  
M. A. Burford
Keyword(s):  
Algal Blooms ◽  
Algal Biomass ◽  
Arid Zone ◽  
River System ◽  
Dry Season ◽  
Trophic Levels ◽  
Nutrient Inputs ◽  
Tropical River ◽  
Algal Production ◽  
The Impact

Algal production in rivers fuels foodwebs, and factors controlling this production ultimately affect food availability. Conversely, excessive algal production can have negative effects on higher trophic levels. The present study examined permanent waterholes in a disconnected wet–dry tropical river to determine the controls on algal production. Primary production in this river system was high compared with arid-zone and perennially flowing tropical rivers. Phytoplankton biomass increased over the dry season but this appeared to be because waterhole volume decreased, due to evaporation. Nitrogen (N) was the key limiting nutrient for phytoplankton, with rapid N turnover times, depletion of particulate 15N-nitrogen reflecting increasing N fixationover the dry season, and N stimulation in phytoplankton bioassays. The waterholes were shallow, providing sufficient light for accumulation of benthic algal biomass. Exclosure experiments were also conducted to determine the impact of top–down control on benthic algal biomass, with no evidence that exclusion of fish and crustaceans increased benthic algal biomass. The shallow off-channel waterhole in our study had substantially higher concentrations of nutrients and chlorophyll a than did the on-channel waterholes. This suggests that future anthropogenic changes, such as increased water extraction and increased nutrient inputs, could make the waterholes more vulnerable to deteriorating water quality, such as e.g. algal blooms, low concentrations of dissolved oxygen.

scholarly journals Functional Landscape of SARS-CoV-2 Cellular Restriction

2020 ◽  
Author(s):  
Laura Martin-Sancho ◽  
Mary K. Lewinski ◽  
Lars Pache ◽  
Charlotte A. Stoneham ◽  
Xin Yin ◽  
...  
Keyword(s):  
Viral Infection ◽  
Viral Entry ◽  
Large Scale ◽  
Function Analysis ◽  
Integral Membrane Protein ◽  
Interferon Response ◽  
Human Interferon ◽  
Nucleic Acid Binding ◽  
Host Determinants ◽  
The Impact

SUMMARYA deficient interferon response to SARS-CoV-2 infection has been implicated as a determinant of severe COVID-19. To identify the molecular effectors that govern interferon control of SARS-CoV-2 infection, we conducted a large-scale gain-of-function analysis that evaluated the impact of human interferon stimulated genes (ISGs) on viral replication. A limited subset of ISGs were found to control viral infection, including endosomal factors that inhibited viral entry, nucleic acid binding proteins that suppressed viral RNA synthesis, and a highly enriched cluster of ER and Golgi-resident ISGs that inhibited viral translation and egress. These included the type II integral membrane protein BST2/tetherin, which was found to impede viral release, and is targeted for immune evasion by SARS-CoV-2 Orf7a protein. Overall, these data define the molecular basis of early innate immune control of viral infection, which will facilitate the understanding of host determinants that impact disease severity and offer potential therapeutic strategies for COVID-19.

scholarly journals What ocean biogeochemical models can tell us about bottom-up control of ecosystem variability

2011 ◽  
Vol 68 (6) ◽  
pp. 1030-1044 ◽  
Author(s):  
A. Gnanadesikan ◽  
J. P. Dunne ◽  
J. John
Keyword(s):  
Interannual Variability ◽  
Phytoplankton Biomass ◽  
Large Scale ◽  
Trophic Levels ◽  
Areal Extent ◽  
Bottom Up ◽  
High Productivity ◽  
Biogeochemical Models ◽  
Ocean Reanalyses ◽  
The Impact

Abstract Gnanadesikan, A., Dunne, J. P., and John, J. 2011. What ocean biogeochemical models can tell us about bottom-up control of ecosystem variability. – ICES Journal of Marine Science, 68: 1030–1044. Processes included in earth system models amplify the impact of climate variability on phytoplankton biomass and, therefore, on upper trophic levels. Models predict much larger relative interannual variability in large phytoplankton biomass than in total phytoplankton biomass, supporting the goal of better constraining size-structured primary production and biomass from remote sensing. The largest modelled variability in annually averaged large phytoplankton biomass is associated with changes in the areal extent of relatively productive regions. Near the equator, changes in the areal extent of the high-productivity zone are driven by large-scale shifts in nutrient fields, as well as by changes in currents. Along the poleward edge of the Subtropical Gyres, changes in physical mixing dominate. Finally, models indicate that high-latitude interannual variability in large phytoplankton biomass is greatest during spring. Mechanisms for producing such variability differ across biomes with internal ocean processes, such as convection complicating efforts to link ecosystem variability to climate modes defined using sea surface temperature alone. In salinity-stratified subpolar regions, changes in bloom timing driven by salinity can produce correlations between low surface temperatures and high productivity, supporting the potential importance of using coupled atmosphere–ocean reanalyses, rather than simple forced ocean reanalyses, for attributing past ecosystem shifts.

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