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Publications (284)
The 72‐foot sailing yacht Eugen Seibold is a new research platform for contamination‐free sampling of the water column and atmosphere for biological, chemical, and physical properties, and the exchange processes between the two realms. Ultimate goal of the project is a better understanding of the modern and past ocean and climate. Operations starte...
Mesoscale eddies influence the distribution of diazotrophic (nitrogen-fixing) cyanobacteria, impacting marine productivity and carbon export. Non-cyanobacterial diazotrophs (NCDs) are emerging as potential contributors to marine nitrogen fixation, relying on organic matter particles for resources, impacting nitrogen and carbon cycling. However, the...
This study contributes to the inaugural exploration of non-equilibrated Ocean Alkalinity Enhancement (OAE). The manipulation of Total Alkalinity (TA), involving silicate and calcium-based ∆TA gradients ranging from 0 to 600 µmol · L-1, was conducted without prior CO2 sequestration, under natural conditions and at a mesocosm scale (~60 m3). The resu...
Ocean alkalinity enhancement (OAE) is a negative emissions technology (NET) that shows significant potential for climate change mitigation. By increasing the bicarbonate ion concentration in ocean water, OAE could enhance long-term carbon storage and mitigate ocean acidification. However, the side effects and/or potential co-benefits of OAE on natu...
A natural plankton community from oligotrophic subtropical waters of the Atlantic near Gran Canaria, Spain was subjected to varying degrees of ocean alkalinity enhancement (OAE) to assess the potential physiological effects, in the context of the 20 application of ocean carbon dioxide removal (CDR) techniques. We employed 8.3 m 3 mesocosms with a s...
Major coastal upwelling systems are among the most productive marine ecosystems in the world. They contribute disproportionately to the cycling of carbon and nutrients in the ocean and influence marine biogeochemistry beyond their productive regions. Characterized by intense microbial respiration (both aerobic and anaerobic), major coastal upwellin...
Measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) concentrations are used to characterize the dissolved organic matter (DOM) pool and are important components of biogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOM v1; available at 10.1594/PANGAEA.964012, L...
Mesoscale eddies influence the distribution of diazotroph (nitrogen fixing) cyanobacteria, impacting marine primary productivity and carbon export. Recently, non-cyanobacterial diazotrophs (NCDs) have emerged as potentially important contributors to the marine nitrogen fixation. Lacking a photosynthetic apparatus, NCDs are thought to rely on organi...
Introduction
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 upwelling should benefit the grow...
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 th...
Tiny ocean plankton (picoplankton) are fundamental for the functioning of the biosphere, but the ecological mechanisms shaping their biogeography were partially understood. Comprehending whether these microorganisms are structured by niche versus neutral processes is relevant in the context of global change. We investigate the ecological processes...
Ocean Alkalinity Enhancement (OAE) is a Negative Emissions Technology (NET) that shows significant potential for climate change mitigation. By increasing the bicarbonate ion concentration in ocean water, OAE could enhance long-term carbon storage and mitigate ocean acidification. However, the side effects and/or potential co-benefits of OAE on natu...
The measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) are used to characterize the dissolved organic matter (DOM) pool and are important components of biogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOM v1; available at https://figshare.com/s/512289eb43c4f...
The marine biological carbon pump is mainly driven by the interplay between aggregate sinking velocity and remineralization. Sinking velocity of natural marine aggregates is not routinely measured but often calculated using Stokes’ law, which does not consider size-dependent changes in porosity. We analyzed the flow fields around 81 in situ -formed...
The Peruvian upwelling system is a highly productive ecosystem with a large oxygen minimum zone (OMZ) close to the surface. In this work, we carried out a mesocosm experiment off Callao, Peru, with the addition of water masses from the regional OMZ collected at two different sites simulating two different upwelling scenarios. Here, we focus on the...
According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, with the beneficial side effect of counteracting ocean acidification. The real-world application of OAE, however, remains unclear as most basic assumptions are untested. Before large-scale deploymen...
Tiny ocean plankton (picoplankton) are fundamental for the functioning of the biosphere, but the ecological mechanisms shaping their biogeography are partially understood. Comprehending whether these microorganisms are structured by niche vs. neutral processes is highly relevant in the context of global change. The ecological drivers structuring pi...
Prokaryotes represent a major fraction of marine biomass and play a key role in the global carbon cycle. We studied the vertical profiles (0-3500 m) of abundance, viability, and activity of prokaryotic communities along a productivity gradient in the subtropical and tropical Atlantic to assess whether there is a vertical linkage between surface pro...
Upwelling of nutrient-rich waters into the sunlit surface layer of the ocean supports high primary productivity in eastern boundary upwelling systems (EBUSs). However, subsurface waters contain not only macronutrients (N, P, Si) but also micronutrients, organic matter and seed microbial communities that may modify the response to macronutrient inpu...
Artificial upwelling brings nutrient-rich deep water to the sun-lit surface to boost fisheries or carbon sequestration. Deep water sources under consideration range widely in inorganic silicon (Si) relative to nitrogen (N). Yet, little is known about how such differences in nutrient composition may influence the effectiveness of the fertilization....
Distributions of dissolved (DOM) and suspended (POM) organic matter, and their chromophoric (CDOM) and fluorescent (FDOM) fractions, are investigated at high resolution (< 10 km) in the Cape Verde Frontal Zone (CVFZ) during fall 2017. In the epipelagic layer (< 200 m), meso- and submesoscale structures (meanders, eddies) captured by the high resolu...
In the face of climate change there is a need to reduce atmospheric CO2 concentrations. Artificial upwelling of nutrient-rich deep waters has been proposed as a method to enhance the biological carbon pump in oligotrophic oceanic regions in order to increase carbon sequestration. Here we examine the effect of different artificial upwelling intensit...
The eastern North Atlantic region receives large Saharan dust deposition inputs, providing nutrients and trace metals to the surface waters. We assessed the effects of intense dust deposition on phytoplankton and bacteria cell abundances, metabolic activity, and community structure, along a surface productivity gradient in the Mauritanian-Senegales...
The Peruvian upwelling system is a highly productive ecosystem that could be altered by ongoing global changes. We carried out a mesocosm experiment off Peru, with the addition of water masses from the regional oxygen minimum zone (OMZ) collected at two different sites simulating two different upwelling scenarios. Here we focus on pelagic remineral...
Climate change is expected to alter the intensity and frequency of upwelling in high productive coastal regions, thus impacting nutrient fluxes, primary productivity and consequently carbon cycling. However, it is unknown how these changes will impact the planktonic (phytoplankton and bacteria) community structure, which affects community respirati...
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 a...
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...
In the face of climate change there is a need to reduce atmospheric CO 2 concentrations. Artificial upwelling of nutrient-rich deep waters has been proposed as a method to enhance the biological carbon pump in oligotrophic oceanic regions in order to increase carbon sequestration. However, the fate of the newly produced organic matter, and specific...
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...
Prokaryotes represent a major fraction of marine biomass and play a key role in the global carbon cycle. We studied the vertical profiles (from surface down to the bathypelagic realm) of abundance, cytometric signatures, and activity of prokaryotic communities along a productivity gradient in the subtropical and tropical Atlantic to assess whether...
Supplementary information to 'Deep ocean prokaryotes and fluorescent dissolved organic matter reflect the history of the water masses across the Atlantic Ocean'.
According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, and the beneficial side effect of counteracting ocean acidification. The real-world application of OAE, however, remains unclear as most basic assumptions are untested. Before large-scale deployment...
Organic matter is known to influence community composition and metabolism of marine prokaryotes. However, few studies have addressed this linkage in the deep ocean. We studied the relationship between fluorescent dissolved organic matter and prokaryotic community composition in meso- and bathypelagic water masses along a surface productivity gradie...
Upwelling of nutrient rich waters into the sunlit surface layer of the ocean supports high primary productivity in Eastern Boundary Upwelling Systems (EBUS). However, subsurface waters not only contain macronutrients (N, P, Si) but also micronutrients, organic matter, and seed microbial communities that may modify the response to macronutrient inpu...
Phytoplankton growth mainly depends on nutrient and light availability. Highly dynamic oceanic environments are dominated by physical processes that generally alter phytoplankton dynamics by controlling the access to these resources. Mesoscale motions have been considered the most important factor modulating the distribution of biogeochemical prope...
The Cape Verde Frontal Zone (CVFZ) is a highly dynamic region located in the southern boundary of the Canary Current Eastern Boundary Upwelling Ecosystem. Due to the interaction of the Cape Verde Front with the Mauritanian coastal upwelling, the area features large vertical and horizontal export fluxes of organic matter. While the flux, composition...
![Mean NCP [μmol O2 L–1 d–1] of each treatment vs. amount of inorganic N...](publication/357811752/figure/fig3/AS:11431281239586095@1714407647003/Mean-NCP-mmol-O2-L-1-d-1-of-each-treatment-vs-amount-of-inorganic-N-added-mmol-L-1_Q320.jpg)
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 o...
Reduction of anthropogenic CO 2 emissions alone will not sufficiently restrict global warming and enable the 1.5°C goal of the Paris agreement to be met. To effectively counteract climate change, measures to actively remove carbon dioxide from the atmosphere are required. Artificial upwelling has been proposed as one such carbon dioxide removal tec...
The Mediterranean Sea is a miniature ocean divided by the Sicily Strait into two basins with a marked west to east trophic gradient and separated of the nearby eastern Atlantic Ocean by the Strait of Gibraltar. Here, we test the hypothesis that these physical and environmental barriers favor the development of specific prokaryotic assemblages, lead...
Upwelling of nutrient-rich deep waters make eastern boundary upwelling systems (EBUSs), such as the Humboldt Current system, hot spots of marine productivity. Associated settling of organic matter to depth and consecutive aerobic decomposition results in large subsurface water volumes being oxygen depleted. Under these circumstances, organic matter...
Although microbial interactions underpin ocean ecosystem functions, they remain barely known. Different studies have analyzed microbial interactions using static association networks based on omics-data. However, microbial associations are dynamic and can change across physicochemical gradients and spatial scales, which needs to be considered to un...
The circulation patterns in the confluence of the North Atlantic subtropical and tropical gyres delimited by the Cape Verde Front (CVF) were examined during a field cruise in summer 2017. We collected hydrographic data, dissolved oxygen (O2) and inorganic nutrients along the perimeter of a closed box embracing the Cape Verde Frontal Zone (CVFZ). Th...
About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and bi...
The distribution and variability of phytoplankton in the upper layers of the ocean are highly correlated with physical processes at different time and spatial scales. Model simulations have shown that submesoscale features play a pivotal role on plankton distribution, metabolism and carbon fluxes. However, there is a lack of observational studies t...
Upwelling of nutrient-rich deep waters make Eastern Boundary upwelling systems (EBUS), such as the Humboldt Current System, hotspots of marine productivity. Associated settling of organic matter to depth and consecutive aerobic de composition results in large sub-surface water volumes being oxygen-depleted. Under these circumstances organic matter...
The circulation patterns in the confluence of the North Atlantic Subtropical and Tropical gyres delimited by the Cape Verde Frontal Zone (CVFZ) in summer 2017 were examined. Hydrology, dissolved oxygen (O2) and inorganic nutrients data collected in a closed box embracing the CVFZ allowed estimating transports of water masses, O2 and inorganic nutri...
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 sewag...
Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can modify surface production and related biogeochemical processes. Determining the...
Plankton respiration (R) is a key factor governing the ocean carbon cycle. However, although the ocean supports respiratory activity throughout its entire volume, to our knowledge there are no studies that tackle both the spatial and temporal variability of respiration in the dark ocean and its dependence on organic carbon sources. Here, we have st...
Cyclonic and anticyclonic eddies are common mesoscale features in the flow past the Canary Islands throughout the year. While drifting southward, eddy pairs interact among them but also with upwelling filaments and eddies generated at the coastal jet of the nearby African upwelling system. These interactions force the generation of frontal zones wh...
The circulation patterns and the impact of the lateral export of nutrients and organic matter off NW Africa are examined by applying an inverse model to two hydrographic datasets gathered in fall 2002 and spring 2003. These estimates show significant changes in the circulation patterns at central levels from fall to spring, particularly in the sout...
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) an...
