Biological Oceanography
in a Changing Ocean

We have studied the successional dynamics of free-living and particle-associated communities in eight simulated upwelling scenarios of varying intensity and duration (single vs. recurring pulses) by adding nutrient-rich mesopelagic waters into large-scale mesocosms containing oligotrophic surface waters from the subtropical North Atlantic. We observed that despite differences in activity, prokaryotes seemed to be more influenced by processes taking place within the community than by phytoplankton bloom patterns, with similar succession dynamics even under widely distinct blooms. These findings can help advance our understanding on prokaryotic ecology and its relation to organic matter cycling across different upwelling scenarios.

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Read the paper here.

This study contributes to the inaugural exploration of non-equilibrated ocean alkalinity enhancement (OAE). Total alkalinity (TA) was manipulated, with silicate and calcium-based delta TA gradients ranging from 0 to 600 μmol L-1, without prior CO2 sequestration, under natural conditions and at a mesocosm scale (~60m3). Implemented in a neritic system under post-bloom conditions, a midway mixing event was simulated. After the inorganic nutrient addition, mild delays in bloom formation were observed. These delays were related to the delta TA gradient, as indicated by the gross production, net community production, and chlorophyll a  concentrations. Notably, the delay was more pronounced for the calcium treatment set compared to the silicate one, with the low-TA treatments exhibiting earlier responses than the high-TA ones. This delay is likely due to species-specific negative relationships between high pH/low pCO2 conditions and phytoplankton growth rates. It is anticipated that a greater delay in bloom formation would be evident with a larger non-equilibrated TA gradient, highlighting the importance of exploring variations in TA thresholds for a comprehensive understanding of OAE’s impacts.

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Read the paper here.

In this study we investigated the response of a natural plankton community to CO2-equilibrated OAE across a gradient from ambient alkalinity to double.  Abundance and biomass of phytoplankton and microzooplankton were insensitive to OAE across all size classes, nutritional modes  and taxonomic groups These findings suggest a high tolerance of phytoplankton and microzooplankton to CO2-equilibrated OAE in the oligotrophic ocean.

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Read the paper here.

The XXVI Ocean Optics conference was held in the Alfredo Kraus Auditorium in Las Palmas de Gran Canaria from October 6th to 11th, 2024. Our PhD candidate Laura Marín and our postdoc Nauzet Hernández presented their work to the scientific community. Laura shared key results from our eIMPACT project’s research cruises in her talk, “Testing active fluorometry for studying primary production at high spatial resolution across cyclonic and anticyclonic eddies”. Nauzet contributed with a poster from our FLUXES project, “Comparing primary production models in the Canary Boundary Upwelling System”.

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Click here to go to the symposium website.

A new study reveals that mesoscale eddies play a significant role in the distribution of nitrogen-fixing cyanobacteria, which are crucial for marine productivity and carbon cycling. Researchers focused on non-cyanobacterial diazotrophs (NCDs), a less understood group, in the subtropical North Atlantic.

By examining particles collected with a marine snow catcher along a transect of the e-IMPACT2 oceanographical cruise, they found that both cyanobacterial diazotrophs and NCDs were equally abundant. The study highlighted that the diversity of these organisms is influenced by the structure of the eddy. These findings shed light on the ecological roles of NCDs and their impact on ocean biogeochemistry, emphasizing the intricate relationship between marine microorganisms and ocean currents.

This work is part of the e-IMPACT project coordinated by the University of Las Palmas de Gran Canaria (ULPGC) and was carried out by researchers at the Mediterranean Institute of Oceanography (MIO), Instituto de Investigacións Mariñas (CSIC), and the Biological Oceanography Group-IOCAG (ULPGC).

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Read the paper here.

A new paper has been published on ocean based negative emission technologies (NETs): "Assessing the impact of CO2-equilibrated ocean alkalinity enhancement on microbial metabolic rates in an oligotrophic system". The study reveals that ocean alkalinity enhancement, a promising climate mitigation strategy, is safe for phytoplankton—the foundation of marine ecosystems. Also, it highlights a potential benefit: up to a certain threshold, increased ocean alkalinity can enhance photosynthesis in some phytoplankton species. This finding opens new avenues for effective and environmentally safe climate solutions. This publication is part of the research conducted by Laura Marín Samper for her doctoral thesis.

Read the paper here.

In their journey from the surface to the bottom of the ocean, marine particles act as mediators of the biological carbon pump. These particles, also known as marine snow because of their resemblance to falling snowflakes, are the principal mechanisms for sequestering CO2 into the deep ocean, playing a key role in the ocean’s mitigation of climate change.

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An oceanographic cruise aboard the R/V Sarmiento de Gamboa took place during the month of May as part of the project "Microbial Colonization of Ocean Particles (MICOLOR)" led by the Institut de Ciències del Mar (ICM-CSIC, Barcelona, Spain). The objective is to understand how marine particles are colonized by microbes and how the microbial settlers evolve on their long journey to the ocean floor. Furthermore, the project aims to untangle how particles are affected by microbial organisms and the surrounding environment. Our postdoc, Nauzet Hernández, has joined the scientific team to help study microbial respiration associated with these particles.

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Click here to visit the project's blog.

Javier Arístegui, director of the UNESCO Chair of Marine and Coastal Sustainability, one of the 5 UNESCO Chairs of the University of Las Palmas de Gran Canaria (ULPGC), spoke about the work carried out for the project alongside other researchers during the international congress Bridge to Africa, hosted by the University. The conference serves to concentrate all academic initiatives in an african knowledge hub through a service infrastructure that contributes to growth and mutual learning. 

The Canary Region is strategic in the understanding of climate change effects, blue economy initiatives, and the development of interdisciplinary marine sciences. Through our work with the Chair, we contribute to scientific disseminarion, relevant research, and blue skill development opportunities.

The OceanICU's Annual Science Meeting (ASM), which took place this week, provided a robust forum for knowledge sharing, and learning, across disciplines, featuring leading ocean observation experts and renowned modelers. Understanding ocean carbon is key for a sustainable future. The GOB-IOCAG (ULPGC) contributes to the project by co-leading Work Package 4 (WP4) concerning Ecosystem controls of the biological carbon pump, and by leading a task on WP3, regarding the impact of aerosols on surface biogeochemistry and plankton communities under a warming ocean.

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Read about OceanICU here.

Coastal upwelling systems, renowned for their productivity, significantly impact global biogeochemical cycles, particularly in carbon and nutrient cycling. Recent research, contributed to by the Biological Oceanography Group (GOB), highlights their pivotal role in greenhouse gas (GHG) dynamics, notably contributing to atmospheric CO2, N2O, and CH4 levels. While low-latitude systems act as carbon sources, higher latitude ones serve as weak sinks or remain neutral. Despite uncertainties, future changes in upwelling systems due to climate change pose challenges, necessitating a deeper understanding for accurate predictions and mitigation strategies. 

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Read the article here.

A new multi-week mesocosm experiment to explore the potential of ocean alkalinity enhancement in combatting climate change has been launched by GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, as part of the international Ocean Alk-Align project, involving 36 researchers from around the globe. This study is the first to focus on possible seasonal effects using rock powder instead of pre-dissolved alkalinity. By adding rock powder to seawater, they aim to boost its ability to absorb CO2 from the atmosphere, besides mitigating ocean acidification. The findings will inform of crucial insights into this Carbon Dioxde Removal's (CDR) impacts on marine ecosystems and guide future climate strategies. Our PhD student, Laura Marín-Samper, has joined them to help identify impacts on microbial community metabolic rates.

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Read more on GEOMAR's page. 

Photo by: Sarah Kaehlert, GEOMAR

Last week, an oceanographic cruise aboard R/V Sarmiento de Gamboa took place to update and replenish a mooring with sediment traps at the European Oceanic Time Series Station of the Canaries (ESTOC). This mooring is part of the FLUCARO project, funded by the Canarian Agency for Research, Innovation and Information Society (ACIISI) and the European Fund for Regional Development (FEDER) and managed by the University of Las Palmas de Gran Canaria (ULPGC). The cruise was coordinated by the Oceanic Platform of the Canary Islands (PLOCAN) in collaboration with ULPGC. The material collected with the sediment traps will provide crucial information on particle fluxes and carbon sequestration in the ocean, contributing vital knowledge to the evaluation of climate change.

Check out how it happened step by step here, and more here.

We have recently participated in a study led by researchers from the Institut de Ciències del Mar (ICM-CSIC), aimed at evaluating microbial networks across pelagic zones. The study, published in Nature Communications, characterizes microbial ecosystems from the deep ocean in tropical and subtropical regions. This information was previously only available for surface oceans. Results from this study may help assess the effects of climate change on microbial communities.
 

Read more here.