LIVIVO - Search results -

Search results

Result 1 - 10 of total 92

Search options

Article ; Online: Untreated sewage outfalls do not promote Trichodesmium blooms in the coasts of the Canary Islands.

Benavides, Mar / Arístegui, Javier

2020 Volume 10, Issue 1, Page(s) 18386

Abstract: During the summer of 2017, recurrent extensive blooms of the diazotrophic cyanobacterium Trichodesmium invaded the beaches and coastal waters of the Canary Islands, causing great social alarm. Some local media and public sectors ascribed, without any ... ...

Abstract	During the summer of 2017, recurrent extensive blooms of the diazotrophic cyanobacterium Trichodesmium invaded the beaches and coastal waters of the Canary Islands, causing great social alarm. Some local media and public sectors ascribed, without any strong scientific evidence, the origin and reactivation of these blooms to untreated sewage outfalls distributed along the coasts. In order to test whether sewage outfalls could have any influence on the metabolic activity of Trichodesmium, we performed
MeSH term(s)	Dust ; Environmental Monitoring ; Eutrophication ; Nitrogen Fixation ; Seasons ; Seawater/microbiology ; Sewage ; Spain ; Temperature ; Trichodesmium/growth & development ; Trichodesmium/metabolism ; Wind
Chemical Substances	Dust ; Sewage
Language	English
Publishing date	2020-10-27
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-020-75447-1
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Article: Activity and distribution of diazotrophic communities across the Cape Verde Frontal Zone in the Northeast Atlantic Ocean

Hallstrøm, Søren / Benavides, Mar / Salamon, Ellen R. / Arístegui, Javier / Riemann, Lasse

Biogeochemistry. 2022 Aug., v. 160, no. 1

2022

Abstract: We investigated dinitrogen (N₂) fixation activity and diazotroph community composition across the Cape Verde Frontal Zone (CVFZ), from photic epipelagic waters (0-200 m) to aphotic meso- (200–1000 m) and bathypelagic (> 1000 m) waters. The highest N₂ ... ...

Abstract	We investigated dinitrogen (N₂) fixation activity and diazotroph community composition across the Cape Verde Frontal Zone (CVFZ), from photic epipelagic waters (0-200 m) to aphotic meso- (200–1000 m) and bathypelagic (> 1000 m) waters. The highest N₂ fixation rates of 4.1 ± 2.2 nmol N l⁻ ¹ day⁻ ¹ and 7.8 ± 2.3 nmol N l⁻ ¹ day⁻ ¹ were in epipelagic waters south of the front. We detected aphotic N₂ fixation in 5 out of 32 samples, primarily south of the front, and sporadically down to 3,000 m, with rates ranging from 0.03 ± 0.01 nmol N l⁻ ¹ day⁻ ¹ to 0.07 ± 0.01 nmol N l⁻ ¹ day⁻ ¹. Cyanobacteria dominated the diazotroph community and nitrogenase gene (nifH) expression profiles in surface waters and, surprisingly, in aphotic waters. The detection of cyanobacterial nifH genes by DNA sequencing and quantitative PCR in the aphotic zone, together with nifH expression in meso- and bathypelagic waters, indicates a downward flux of metabolically active cyanobacteria, and points to a contribution to the observed aphotic N₂ fixation rates. In the photic zone, UCYN-A dominated north of the front, whereas Trichodesmium was mainly found in the southern region. However, our results also show that cross-frontal advection of cyanobacterial diazotrophs can occur via intrusions of surface water. Salinity, temperature, and mixed layer depth were the main determinants of the diazotroph composition and distribution of the key cyanobacteria. Thus, the front appeared to act as a dynamic barrier controlling the distribution of cyanobacterial diazotrophs.
Keywords	DNA ; Trichodesmium ; advection ; biogeochemistry ; community structure ; euphotic zone ; genes ; nitrogen ; nitrogen-fixing bacteria ; nitrogenase ; quantitative polymerase chain reaction ; salinity ; surface water ; temperature ; Atlantic Ocean ; Cabo Verde
Language	English
Dates of publication	2022-08
Size	p. 49-67.
Publishing place	Springer International Publishing
Document type	Article
ZDB-ID	1478541-9
ISSN	1573-515X ; 0168-2563
ISSN (online)	1573-515X
ISSN	0168-2563
DOI	10.1007/s10533-022-00940-w
Database	NAL-Catalogue (AGRICOLA)

Full text online

Accessible to users with ZB MED library card

Order via subito

Details ▾
- Full text online
- Order with fees

Article: Offshore transport of organic carbon by upwelling filaments in the Canary Current System

Santana-Falcón, Yeray / Mason, Evan / Arístegui, Javier

Progress in oceanography. 2020 Apr. 01,

2020

Abstract: A coupled physical-biogeochemical model (ROMS-PISCES) forced by climatological fields is used to examine the role of upwelling filaments in the offshore exchange of particulate (POC) and dissolved (DOC) organic carbon in the Canary Current eastern ... ...

Abstract	A coupled physical-biogeochemical model (ROMS-PISCES) forced by climatological fields is used to examine the role of upwelling filaments in the offshore exchange of particulate (POC) and dissolved (DOC) organic carbon in the Canary Current eastern boundary upwelling system (CanC EBUS). In this region, mesoscale filaments at Capes Ghir (∼30.5 °N) and Juby (∼27.5 °N) have been frequently described using both observational and numerical data. Due to their semi-permanent presence and unique dynamical characteristics, studies focusing on filaments often provide an incomplete picture of the physical and biological processes at work, and their effects on coast-to-ocean export. The present model experiment confirms the complex three-dimensional structure of the filaments that comprises both offshore and onshore flow components. The model shows strong seasonal variability in the offshore transport mediated by the filaments. Recirculation at the edges of the filaments returns water towards the shore, especially in autumn when they are diverted northwards by the large scale boundary circulation. By contrast, offshore transport peaks during late spring - early summer when onshore recirculation is limited. Overall, the estimated net annual offshore flux of excess total organic carbon (e-TOC, the non-refractory pools of DOC and POC) averages 2.0 ×109 kg C y−1, and may increase up to 4.3 ×109 kg C y−1 during the peak upwelling season, each filament contributing to export of up to 22.6% of the organic carbon within the first 100 km from shore along the CanC EBUS (between 9.5 and 32 ° N). These results strongly support the inclusion of offshore transport estimates by coastal filaments in regional carbon budgets.
Keywords	autumn ; biogeochemistry ; seasonal variation ; spring ; summer ; total organic carbon
Language	English
Dates of publication	2020-0401
Publishing place	Elsevier Ltd
Document type	Article
Note	Pre-press version
ISSN	0079-6611
DOI	10.1016/j.pocean.2020.102322
Database	NAL-Catalogue (AGRICOLA)

Full text online

Accessible to users with ZB MED library card

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- Full text online
- Order with fees

Article ; Online: Artificial Upwelling in Singular and Recurring Mode

Ortiz Cortes, Joaquin / Arístegui, Javier / Taucher, Jan / Riebesell, Ulf

Consequences for Net Community Production and Metabolic Balance

2022

Abstract: Artificial upwelling of nutrient-rich waters and the corresponding boost in primary productivity harbor the potential to enhance marine fishery yields and strengthen the biological pump for sequestration of atmospheric CO2. There is increasing urgency to ...

Abstract	Artificial upwelling of nutrient-rich waters and the corresponding boost in primary productivity harbor the potential to enhance marine fishery yields and strengthen the biological pump for sequestration of atmospheric CO2. There is increasing urgency to understand this technology as a “ocean-based solution” for counteracting two major challenges of the 21st century—climate change and overfishing. Yet, little is known about the actual efficacy and/or possible side effects of artificial upwelling. We conducted a large-scale off-shore mesocosm study (∼44 m3) in the oligotrophic waters of the Canary Islands to identify the community-level effects of artificial upwelling on a natural oligotrophic plankton community. Four upwelling intensities were simulated (approx. 1.5/3/5.7/10 μmol L–1 of nitrate plus phosphate and silicate) via two different upwelling modes (a singular deep-water pulse vs. recurring supply every 4 days) for 37 days. Here we present results on the response of net community production (NCP), metabolic balance and phytoplankton community composition (<250 μm). Higher upwelling intensities yielded higher cumulative NCP. Following upwelling onset, the phytoplankton community became dominated by diatoms in all treatments, but other taxa such as Coccolithophores increased later in the experiment. The magnitude of effects on the metabolic balance scaled with the amount of added deep water, leading to (i) a balanced to net-heterotrophic system in the singular and (ii) a net-autotrophic system in the recurring upwelling treatments. Accordingly, the mode in which nutrients are supplied to an oligotrophic system plays a crucial role in the ecosystem response, with recurring upwelling leading to higher long-term positive NCP than singular upwelling. These results highlight the importance of empirically measured local responses to upwelling such as community structure and metabolism, with major implications for the potential employment of artificial upwelling as an ocean-based solution to generate (primary) ...
Subject code	550
Language	English
Publishing date	2022-01-12
Publisher	Frontiers
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Phytoplankton physiology and functional traits under artificial upwelling with varying Si:N

Ortiz Cortes, Joaquin / Aristegui, Javier / Goldenberg, Silvan / Fernandez-Mendez, Mar / Taucher, Jan / Archer, Stephen D. / Baumann, Moritz / Riebesell, Ulf

2024

Abstract: Artificial upwelling has been discussed as a nature-based solution to fertilize currently unproductive areas of the ocean to enhance food web productivity and atmospheric CO2 sequestration. The efficacy of this approach may be closely tied to the ... ...

Abstract	Artificial upwelling has been discussed as a nature-based solution to fertilize currently unproductive areas of the ocean to enhance food web productivity and atmospheric CO2 sequestration. The efficacy of this approach may be closely tied to the nutrient stoichiometry of the upwelled water, as Si-rich water upwelling should benefit the growth of diatoms, who are key players for primary production, carbon export and food web efficiency. With a mesocosm experiment in subtropical waters, we assessed the physiological and functional responses of an oligotrophic phytoplankton community to artificial upwelling under varying Si:N ratios (0.07-1.33). Deep water fertilization led to strongly enhanced primary productivity rates and net autotrophy across Si scenarios. At the community level, Si-rich upwelling temporarily increased primary production and consistently enhanced diatom growth, producing up to 10-fold higher abundances compared to Si-deficient upwelling. At the organism level, contrasting effects were observed. On the one hand, silicification and size of diatom cells remained unaffected by Si:N, which is surprising given the direct dependency of these traits on Si. On the other hand, diatom Chlorophyll a density and carbon density were strongly reduced and particulate matter C:N was elevated under Si-rich upwelling. This suggests a reduced nutritional value for higher trophic levels under high Si:N ratios. Despite these strong qualitative changes under high Si, diatom cells appeared healthy and showed high photosynthetic efficiency. Our findings reveal great physiological plasticity and adaptability in phytoplankton under artificial upwelling, with Si-dependent trade-offs between primary producer quantity and quality.
Subject code	551
Language	English
Publishing date	2024-01-04
Publisher	Frontiers
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Disentangling microbial networks across pelagic zones in the tropical and subtropical global ocean.

Deutschmann, Ina M / Delage, Erwan / Giner, Caterina R / Sebastián, Marta / Poulain, Julie / Arístegui, Javier / Duarte, Carlos M / Acinas, Silvia G / Massana, Ramon / Gasol, Josep M / Eveillard, Damien / Chaffron, Samuel / Logares, Ramiro

Nature communications

2024 Volume 15, Issue 1, Page(s) 126

Abstract: Microbial interactions are vital in maintaining ocean ecosystem function, yet their dynamic nature and complexity remain largely unexplored. Here, we use association networks to investigate possible ecological interactions in the marine microbiome among ... ...

Abstract	Microbial interactions are vital in maintaining ocean ecosystem function, yet their dynamic nature and complexity remain largely unexplored. Here, we use association networks to investigate possible ecological interactions in the marine microbiome among archaea, bacteria, and picoeukaryotes throughout different depths and geographical regions of the tropical and subtropical global ocean. Our findings reveal that potential microbial interactions change with depth and geographical scale, exhibiting highly heterogeneous distributions. A few potential interactions were global, meaning they occurred across regions at the same depth, while 11-36% were regional within specific depths. The bathypelagic zone had the lowest proportion of global associations, and regional associations increased with depth. Moreover, we observed that most surface water associations do not persist in deeper ocean layers despite microbial vertical dispersal. Our work contributes to a deeper understanding of the tropical and subtropical global ocean interactome, which is essential for addressing the challenges posed by global change.
MeSH term(s)	Bacteria/genetics ; Archaea/genetics ; Microbial Consortia ; Microbiota ; Oceans and Seas ; Seawater/microbiology
Language	English
Publishing date	2024-01-02
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-44550-y
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: INT Toxicity over Natural Bacterial Assemblages from Surface Oligotrophic Waters: Implications for the Assessment of Respiratory Activity.

Baños, Isabel / Montero, María F / Benavides, Mar / Arístegui, Javier

Microbial ecology

2020 Volume 80, Issue 1, Page(s) 237–242

Abstract: Plankton community respiration (R) is a major component of the carbon flux in aquatic ecosystems. However, current methods to measure actual respiration from oxygen consumption at relevant spatial scales are not sensitive enough in oligotrophic ... ...

Abstract	Plankton community respiration (R) is a major component of the carbon flux in aquatic ecosystems. However, current methods to measure actual respiration from oxygen consumption at relevant spatial scales are not sensitive enough in oligotrophic environments where respiration rates are very low. To overcome this drawback, more sensitive indirect enzymatic approaches are commonly used as R proxies. The in vivo electron transport system (ETSvivo) assay, which measures the reduction of (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride salt, INT) to INT-formazan in the presence of natural substrate levels, was recently proposed as an indirect reliable estimation of R for natural plankton communities. However, under in vivo conditions, formazan salts could be toxic to the cells. Here, we test the toxicity of 0.2 mM of final INT concentration, widely used for ETSvivo assays, on natural bacterial assemblages collected in coastal and oceanic waters off Gran Canaria (Canary Islands, subtropical North Atlantic), in eight independent experiments. After 0.5 h of incubation, a significant but variable decline in cell viability (14-49%) was observed in all samples inoculated with INT. Moreover, INT also inhibited leucine uptake in less than 90 min of incubation. In the light of these results, we argue that enzymatic respiratory rates obtained with the ETSvivo method need to be interpreted with caution to derive R in oceanic regions where bacteria largely contribute to community respiration. Moreover, the variable toxicity on bacterial assemblages observed in our experiments questions the use of a single R/ETSvivo relationship as a universal proxy for regional studies.
MeSH term(s)	Bacteria/drug effects ; Bacteria/metabolism ; Fresh Water/microbiology ; Oxygen Consumption/drug effects ; Plankton/drug effects ; Plankton/metabolism ; Seawater/microbiology ; Spain ; Tetrazolium Salts/toxicity
Chemical Substances	Tetrazolium Salts ; iodonitrotetrazolium (146-68-9)
Language	English
Publishing date	2020-01-08
Publishing country	United States
Document type	Journal Article
ZDB-ID	1462065-0
ISSN	1432-184X ; 0095-3628
ISSN (online)	1432-184X
ISSN	0095-3628
DOI	10.1007/s00248-019-01479-4
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

Order via subito

Details ▾
- Full text online
- Order with fees

Article: INT Toxicity over Natural Bacterial Assemblages from Surface Oligotrophic Waters: Implications for the Assessment of Respiratory Activity

Baños, Isabel / Montero, María F / Benavides, Mar / Arístegui, Javier

Microbial ecology. 2020 July, v. 80, no. 1

2020

Abstract	Plankton community respiration (R) is a major component of the carbon flux in aquatic ecosystems. However, current methods to measure actual respiration from oxygen consumption at relevant spatial scales are not sensitive enough in oligotrophic environments where respiration rates are very low. To overcome this drawback, more sensitive indirect enzymatic approaches are commonly used as R proxies. The in vivo electron transport system (ETSvivo) assay, which measures the reduction of (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride salt, INT) to INT-formazan in the presence of natural substrate levels, was recently proposed as an indirect reliable estimation of R for natural plankton communities. However, under in vivo conditions, formazan salts could be toxic to the cells. Here, we test the toxicity of 0.2 mM of final INT concentration, widely used for ETSvivo assays, on natural bacterial assemblages collected in coastal and oceanic waters off Gran Canaria (Canary Islands, subtropical North Atlantic), in eight independent experiments. After 0.5 h of incubation, a significant but variable decline in cell viability (14–49%) was observed in all samples inoculated with INT. Moreover, INT also inhibited leucine uptake in less than 90 min of incubation. In the light of these results, we argue that enzymatic respiratory rates obtained with the ETSvivo method need to be interpreted with caution to derive R in oceanic regions where bacteria largely contribute to community respiration. Moreover, the variable toxicity on bacterial assemblages observed in our experiments questions the use of a single R/ETSvivo relationship as a universal proxy for regional studies.
Keywords	aquatic ecosystems ; bacteria ; carbon ; cell respiration ; cell viability ; chlorides ; electron transfer ; enzymatic treatment ; leucine ; oxygen consumption ; plankton ; respiratory rate ; tetrazolium ; toxicity ; Canary Islands
Language	English
Dates of publication	2020-07
Size	p. 237-242.
Publishing place	Springer US
Document type	Article
ZDB-ID	1462065-0
ISSN	1432-184X ; 0095-3628
ISSN (online)	1432-184X
ISSN	0095-3628
DOI	10.1007/s00248-019-01479-4
Database	NAL-Catalogue (AGRICOLA)

Full text online

Accessible to users with ZB MED library card

Order via subito

Details ▾
- Full text online
- Order with fees

Article ; Online: Phytoplankton responses to changing temperature and nutrient availability are consistent across the tropical and subtropical Atlantic.

Fernández-González, Cristina / Tarran, Glen A / Schuback, Nina / Woodward, E Malcolm S / Arístegui, Javier / Marañón, Emilio

Communications biology

2022 Volume 5, Issue 1, Page(s) 1035

Abstract: Temperature and nutrient supply interactively control phytoplankton growth and productivity, yet the role of these drivers together still has not been determined experimentally over large spatial scales in the oligotrophic ocean. We conducted four ... ...

Abstract	Temperature and nutrient supply interactively control phytoplankton growth and productivity, yet the role of these drivers together still has not been determined experimentally over large spatial scales in the oligotrophic ocean. We conducted four microcosm experiments in the tropical and subtropical Atlantic (29°N-27°S) in which surface plankton assemblages were exposed to all combinations of three temperatures (in situ, 3 °C warming and 3 °C cooling) and two nutrient treatments (unamended and enrichment with nitrogen and phosphorus). We found that chlorophyll a concentration and the biomass of picophytoplankton consistently increase in response to nutrient addition, whereas changes in temperature have a smaller and more variable effect. Nutrient enrichment leads to increased picoeukaryote abundance, depressed Prochlorococcus abundance, and increased contribution of small nanophytoplankton to total biomass. Warming and nutrient addition synergistically stimulate light-harvesting capacity, and accordingly the largest biomass response is observed in the warmed, nutrient-enriched treatment at the warmest and least oligotrophic location (12.7°N). While moderate nutrient increases have a much larger impact than varying temperature upon the growth and community structure of tropical phytoplankton, ocean warming may increase their ability to exploit events of enhanced nutrient availability.
MeSH term(s)	Chlorophyll A ; Nitrogen ; Nutrients ; Phosphorus ; Phytoplankton ; Temperature
Chemical Substances	Phosphorus (27YLU75U4W) ; Nitrogen (N762921K75) ; Chlorophyll A (YF5Q9EJC8Y)
Language	English
Publishing date	2022-09-29
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2399-3642
ISSN (online)	2399-3642
DOI	10.1038/s42003-022-03971-z
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Oligotrophic Phytoplankton Community Effectively Adjusts to Artificial Upwelling Regardless of Intensity, but Differently Among Upwelling Modes

Ortiz Cortes, Joaquin / Arístegui, Javier / Hernández-Hernández, Nauzet / Fernandez-Mendez, Mar / Riebesell, Ulf

2022

Abstract: Artificial upwelling has been proposed as a means of enhancing oceanic CO2 sequestration and/or raising fishery yields through an increase in primary production in unproductive parts of the ocean. However, evidence of its efficacy, applicability and side ...

Abstract	Artificial upwelling has been proposed as a means of enhancing oceanic CO2 sequestration and/or raising fishery yields through an increase in primary production in unproductive parts of the ocean. However, evidence of its efficacy, applicability and side effects is scarce. Here we present part of the results of a 37-day mesocosm study conducted in oligotrophic waters off the coast of Gran Canaria. The goal was to assess in situ the effects of artificial upwelling on the pelagic community. Upwelling was simulated via two modes: i) a singular deep-water pulse and ii) a recurring supply every 4 days; each mode at four different intensities defined by the total amount of nitrate added: approx. 1.5, 3, 5.7, and 11 µmol L-1. In this study we focus on the phytoplankton response through size-fractionated 14C primary production rates (PP), Chlorophyll a and biomass. We observed increases in PP, accumulated PP, Chlorophyll a and biomass that scaled linearly with upwelling intensity. Upwelling primarily benefitted larger phytoplankton size fractions, causing a shift from pico- and nano- to nano- and microphytoplankton. Recurring deep-water addition produced more biomass under higher upwelling intensities than a single pulse addition. It also reached significantly higher accumulated PP per unit of added nutrients and showed a stronger reduction in percentage extracellular release with increasing upwelling intensity. These results demonstrate that oligotrophic phytoplankton communities can effectively adjust to artificial upwelling regardless of upwelling intensity, but differently depending on the upwelling mode. Recurring supply of upwelled waters generated higher efficiencies in primary production and biomass build-up than a single pulse of the same volume and nutrient load.
Subject code	551
Language	English
Publishing date	2022-06-20
Publisher	Frontiers
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED