ORCID Profile
0000-0002-8334-9595
Current Organisation
The University of Maine
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Environmental Monitoring | Biological Oceanography | Oceanography
Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Earth Sciences |
Publisher: Elsevier BV
Date: 11-2019
Publisher: Frontiers Media SA
Date: 02-08-2019
Publisher: Copernicus GmbH
Date: 12-04-2022
DOI: 10.5194/ESSD-2022-51
Abstract: Abstract. Marine particles of different nature are found throughout the global Ocean. The term "marine particles" describes detritus aggregates, fecal pellets, but also bacterio-, phyto-, zooplankton and nekton. Here we present a global particle size distribution dataset obtained with several Underwater Vision Profiler 5 (UVP5) camera systems. Overall, within the 64 μm to about 50 mm size range covered by the UVP5, detrital particles are the most abundant component of all marine particles in this size range and thus measurements of the particle size distribution with the UVP5 can yield important information on detrital particle dynamics. During deployment, which is possible down to 6000 m depth, the UVP5 images a volume of about 1 L at a frequency of 6 to 20 Hz. Each image is segmented in real time and size measurements of particles are automatically stored. All UVP5 units used to generate the here presented dataset were inter-calibrated using a UVP5 High Definition unit as reference. Our consistent particle size distribution dataset contains 8805 vertical profiles collected between 2008-06-19 and 2020-11-23. All major ocean basins, as well as the Mediterranean and the Baltic Sea were s led. 19 % of all profiles had a maximum s ling depth shallower than 200 dbar, 80 % had a maximum s ling depth greater than 200 dbar, 38 % s led at least the upper 1000 dbar depth range and 11 % went down to at least 3000 dbar depth. First analysis of the particle size distribution dataset shows that particle abundance is found to be high at high latitudes and in coastal areas where surface productivity or continental inputs are elevated. Lowest values are found in the deeep ocean and in the oceanic gyres. Our dataset should be valuable for more in-depth studies that focus on the analysis of regional, temporal and global patterns of particle size distribution and flux as well as for the development and adjustment of regional and global biogeochemical models. The marineparticle size distribution dataset (Kiko et al., 2021) is available at doi.pangaea.de/10.1594/PANGAEA.924375.
Publisher: American Geophysical Union (AGU)
Date: 2019
DOI: 10.1029/2018JC014059
Publisher: F1000 Research Ltd
Date: 30-05-2023
DOI: 10.12688/OPENRESEUROPE.15047.2
Abstract: Background: Biogeochemical-Argo floats are collecting an unprecedented number of profiles of optical backscattering measurements in the global ocean. Backscattering (BBP) data are crucial to understanding ocean particle dynamics and the biological carbon pump. Yet, so far, no procedures have been agreed upon to quality control BBP data in real time. Methods: Here, we present a new suite of real-time quality-control tests and apply them to the current global BBP Argo dataset. The tests were developed by expert BBP users and Argo data managers and have been implemented on a snapshot of the entire Argo dataset. Results: The new tests are able to automatically flag most of the “bad” BBP profiles from the raw dataset. Conclusions: The proposed tests have been approved by the Biogeochemical-Argo Data Management Team and will be implemented by the Argo Data Assembly Centres to deliver real-time quality-controlled profiles of optical backscattering. Provided they reach a pressure of about 1000 dbar, these tests could also be applied to BBP profiles collected by other platforms.
Publisher: F1000 Research Ltd
Date: 13-10-2022
DOI: 10.12688/OPENRESEUROPE.15047.1
Abstract: Background: Biogeochemical-Argo floats are collecting an unprecedented number of profiles of optical backscattering measurements in the global ocean. Backscattering (BBP) data are crucial to understanding ocean particle dynamics and the biological carbon pump. Yet, so far, no procedures have been agreed upon to quality control BBP data in real time. Methods: Here, we present a new suite of real-time quality-control tests and apply them to the current global BBP Argo dataset. The tests were developed by expert BBP users and Argo data managers and have been implemented on a snapshot of the entire Argo dataset. Results: The new tests are able to automatically flag most of the “bad” BBP profiles from the raw dataset. Conclusions: The proposed tests have been approved by the Biogeochemical-Argo Data Management Team and will be implemented by the Argo Data Assembly Centres to deliver real-time quality-controlled profiles of optical backscattering. Provided they reach a pressure of about 1000 dbar, these tests could also be applied to BBP profiles collected by other platforms.
Publisher: Copernicus GmbH
Date: 22-09-2022
DOI: 10.5194/ESSD-14-4315-2022
Abstract: Abstract. Marine particles of different nature are found throughout the global ocean. The term “marine particles” describes detritus aggregates and fecal pellets as well as bacterioplankton, phytoplankton, zooplankton and nekton. Here, we present a global particle size distribution dataset obtained with several Underwater Vision Profiler 5 (UVP5) camera systems. Overall, within the 64 µm to about 50 mm size range covered by the UVP5, detrital particles are the most abundant component of all marine particles thus, measurements of the particle size distribution with the UVP5 can yield important information on detrital particle dynamics. During deployment, which is possible down to 6000 m depth, the UVP5 images a volume of about 1 L at a frequency of 6 to 20 Hz. Each image is segmented in real time, and size measurements of particles are automatically stored. All UVP5 units used to generate the dataset presented here were inter-calibrated using a UVP5 high-definition unit as reference. Our consistent particle size distribution dataset contains 8805 vertical profiles collected between 19 June 2008 and 23 November 2020. All major ocean basins, as well as the Mediterranean Sea and the Baltic Sea, were s led. A total of 19 % of all profiles had a maximum s ling depth shallower than 200 dbar, 38 % s led at least the upper 1000 dbar depth range and 11 % went down to at least 3000 dbar depth. First analysis of the particle size distribution dataset shows that particle abundance is found to be high at high latitudes and in coastal areas where surface productivity or continental inputs are elevated. The lowest values are found in the deep ocean and in the oceanic gyres. Our dataset should be valuable for more in-depth studies that focus on the analysis of regional, temporal and global patterns of particle size distribution and flux as well as for the development and adjustment of regional and global biogeochemical models. The marine particle size distribution dataset (Kiko et al., 2021) is available at 0.1594/PANGAEA.924375.
Publisher: Scientific Committee on Oceanic Research (SCOR)
Date: 2020
DOI: 10.25607/OBP-718
Publisher: Springer Science and Business Media LLC
Date: 10-02-2016
DOI: 10.1038/NATURE16942
Publisher: Wiley
Date: 06-03-2018
DOI: 10.1002/EAP.1682
Publisher: Frontiers Media SA
Date: 07-08-2019
Publisher: Frontiers Media SA
Date: 27-11-2018
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-13069
Abstract: & & The ocean provides critical services to life on the planet, absorbing 93% of the heat from anthropogenic warming and a quarter of human carbon dioxide (CO& sub& & /sub& ) emissions each year. However, rising ocean temperatures and CO& sub& & /sub& levels also change the marine environment: pH and oxygen levels fall, ocean currents change, and nutrient fluxes and concentrations are shifting, all with large effects on ecosystems and the cycles of oxygen, nitrogen, and carbon throughout the ocean and atmosphere. Observing these biogeochemical (BGC) processes across remote ocean areas with seasonal to interannual resolution has been impractical due to the prohibitive costs associated with ship observations. Yet such observations are essential to understand the natural and perturbed systems.& & & & Profiling floats, proven in the Argo program, with BGC sensors (oxygen, nitrate, pH, bio-optical) provide a transformative solution to this need.& BGC profiling floats are capable of observing chemical and biological properties from 2000 m depth to the surface every 10 days for many years. Based on various OSSE and s ling approaches, global coverage can be achieved with 1000 BGC floats contributing to the core T/S Argo array of about 4000.& & & & The U.S. Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program serves as a major basin-scale pilot for such a global array. Its 141 operating BGC floats, building towards an ultimate 200 floats, demonstrate that the major challenges associated with operating a large-scale, robotic network have been overcome, and that there is a substantial user base for the data. Data have been publicly available in near real-time since the start of SOCCOM. Robust protocols for QC, calibration and validation of BGC float data have been developed, based on GLODAPv2 climatologies and relationships between the observed float variables. Data are being incorporated in BGC state estimation and are being used for comparison/validation of ocean models used for climate. Initial SOCCOM results are already transforming understanding of Southern Ocean biogeochemistry. Annual cycles of air-sea carbon flux are revealing major surprises, including strong outgassing within the Antarctic Circumpolar Current.& Annual net community production in all major regimes of the Southern Ocean has been quantified.& The broad-scale float profiling has validated NASA's satellite algorithms for POC and chlorophyll in the Southern Ocean. As the international community moves forward towards sustained BGC-Argo deployments, SOCCOM can provide its experience in sensors, floats, deployments, calibration, and data management.& & &
Publisher: Elsevier BV
Date: 11-2019
Publisher: Springer Science and Business Media LLC
Date: 12-03-2018
DOI: 10.1038/S41564-018-0128-4
Abstract: Marine phytoplankton account for approximately half of global primary productivity
Publisher: The Oceanography Society
Date: 09-2009
Publisher: University of California Press
Date: 2021
DOI: 10.1525/ELEMENTA.2020.00107
Abstract: The goal of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field c aign is to develop a predictive understanding of the export, fate, and carbon cycle impacts of global ocean net primary production. To accomplish this goal, observations of export flux pathways, plankton community composition, food web processes, and optical, physical, and biogeochemical (BGC) properties are needed over a range of ecosystem states. Here we introduce the first EXPORTS field deployment to Ocean Station Papa in the Northeast Pacific Ocean during summer of 2018, providing context for other papers in this special collection. The experiment was conducted with two ships: a Process Ship, focused on ecological rates, BGC fluxes, temporal changes in food web, and BGC and optical properties, that followed an instrumented Lagrangian float and a Survey Ship that s led BGC and optical properties in spatial patterns around the Process Ship. An array of autonomous underwater assets provided measurements over a range of spatial and temporal scales, and partnering programs and remote sensing observations provided additional observational context. The oceanographic setting was typical of late-summer conditions at Ocean Station Papa: a shallow mixed layer, strong vertical and weak horizontal gradients in hydrographic properties, sluggish sub-inertial currents, elevated macronutrient concentrations and low phytoplankton abundances. Although nutrient concentrations were consistent with previous observations, mixed layer chlorophyll was lower than typically observed, resulting in a deeper euphotic zone. Analyses of surface layer temperature and salinity found three distinct surface water types, allowing for diagnosis of whether observed changes were spatial or temporal. The 2018 EXPORTS field deployment is among the most comprehensive biological pump studies ever conducted. A second deployment to the North Atlantic Ocean occurred in spring 2021, which will be followed by focused work on data synthesis and modeling using the entire EXPORTS data set.
Publisher: American Geophysical Union (AGU)
Date: 03-2019
DOI: 10.1029/2018GB006022
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.CUB.2014.07.046
Abstract: Phytoplankton blooms are ephemeral events of exceptionally high primary productivity that regulate the flux of carbon across marine food webs [1-3]. Quantification of bloom turnover [4] is limited by a fundamental difficulty to decouple between physical and biological processes as observed by ocean color satellite data. This limitation hinders the quantification of bloom demise and its regulation by biological processes [5, 6], which has important consequences on the efficiency of the biological pump of carbon to the deep ocean [7-9]. Here, we address this challenge and quantify algal blooms' turnover using a combination of satellite and in situ data, which allows identification of a relatively stable oceanic patch that is subject to little mixing with its surroundings. Using a newly developed multisatellite Lagrangian diagnostic, we decouple the contributions of physical and biological processes, allowing quantification of a complete life cycle of a mesoscale (∼10-100 km) bloom of coccolithophores in the North Atlantic, from exponential growth to its rapid demise. We estimate the amount of organic carbon produced during the bloom to be in the order of 24,000 tons, of which two-thirds were turned over within 1 week. Complimentary in situ measurements of the same patch area revealed high levels of specific viruses infecting coccolithophore cells, therefore pointing at the importance of viral infection as a possible mortality agent. Application of the newly developed satellite-based approaches opens the way for large-scale quantification of the impact of erse environmental stresses on the fate of phytoplankton blooms and derived carbon in the ocean.
Publisher: The Optical Society
Date: 22-03-2013
DOI: 10.1364/AO.52.002019
Publisher: Elsevier BV
Date: 08-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-05-2015
Abstract: Microbes are dominant drivers of biogeochemical processes, yet drawing a global picture of functional ersity, microbial community structure, and their ecological determinants remains a grand challenge. We analyzed 7.2 terabases of metagenomic data from 243 Tara Oceans s les from 68 locations in epipelagic and mesopelagic waters across the globe to generate an ocean microbial reference gene catalog with million nonredundant, mostly novel sequences from viruses, prokaryotes, and picoeukaryotes. Using 139 prokaryote-enriched s les, containing ,000 species, we show vertical stratification with epipelagic community composition mostly driven by temperature rather than other environmental factors or geography. We identify ocean microbial core functionality and reveal that % of its abundance is shared with the human gut microbiome despite the physicochemical differences between these two ecosystems.
Publisher: Frontiers Media SA
Date: 21-05-2019
Publisher: Springer Science and Business Media LLC
Date: 24-08-2023
DOI: 10.1007/S11229-023-04285-1
Abstract: The distinction between multilevel selection 1 (MLS1) and multilevel selection 2 (MLS2) is classically regarded as a distinction between two multilevel selection processes involving two different kinds of higher-level fitness. It has been invoked to explain evolutionary transitions in in iduality as a shift from an MLS1 to an MLS2 process. In this paper, I argue against the view that the distinction involves two different kinds of processes. I show, starting from the MLS2 version of the Price equation, that it contains the MLS1 version if, following the assumption that a collective constitutively depends (i.e., mereologically supervenes) on its particles, one considers that a necessary map between fitness at two levels exists. I defend the necessity of such a map, making the distinction between MLS1 and MLS2 a matter of perspective and limited knowledge (i.e., epistemic limitations) rather than objective facts. I then provide some reasons why the MLS1/MLS2 distinction nonetheless has some pragmatic value and might be invoked usefully in some contexts, particularly within the context of explaining evolutionary transitions in in iduality.
Publisher: Frontiers Media SA
Date: 25-04-2019
Start Date: 09-2016
End Date: 12-2020
Amount: $454,706.00
Funder: Australian Research Council
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