Juan Höfer

Juan Höfer
Pontificia Universidad Católica de Valparaíso | PUCV · School of Ocean Sciences

PhD

About

45
Publications
9,529
Reads
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517
Citations
Citations since 2017
34 Research Items
482 Citations
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2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Additional affiliations
June 2016 - March 2019
Universidad Austral de Chile
Position
  • PostDoc Position
February 2016 - May 2016
University of Oviedo
Position
  • Researcher
January 2013 - June 2014
University of Oviedo
Position
  • PhD Student

Publications

Publications (45)
Article
Oceans are the largest source of biogenic emissions to the atmosphere, including aerosol precursors like marine halocarbons and dimethyl sulfide (DMS). During the last decade, the CAMS-GLOB-OCE dataset has developed an analysis of daily emissions of tribromomethane (CHBr3), dibromomethane (CH2Br2), iodomethane (CH3I), and DMS, due to its increasing...
Article
Full-text available
Background Multi-omics technology provides a good tool to analyze the protein toxin composition and search for the potential pathogenic factors of Solenopsis invicta, under the great harm of the accelerated invasion in southern China. Methods Species collection, functional annotation, toxin screening, and 3D modeling construction of three interest...
Article
Full-text available
The Chilean Patagonia is a complex puzzle of numerous fjords, channels, bays, estuaries, and islands. The largest part of it is very remote, hampering the generation of scientific knowledge and effective management planning that could balance conservation of the marine resources with the increasing development of aquaculture activities. The present...
Technical Report
Full-text available
The Southern Ocean plays a central role in the Earth System by connecting the Earth’s ocean basins, and it is a crucial link between the deep ocean, surface ocean and atmosphere. Hence, the ongoing changes in the Southern Ocean impact global climate, rates of sea level rise, biogeochemical cycles and ecological systems. Yet, understanding of the ca...
Article
Full-text available
In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass and abundance and their roles in maintaining food webs and ecosystem structure and function, including the provision of globally important ecosystem services. These groups are consumers of microbes, primary a...
Article
Background The application of multi-omics technologies provides a new perspective to solve three main problems including species identification, toxin screening and effective antagonist conformation in the studies of marine toxic jellyfish. Methods A series of transcriptome-proteome based analysis accompanied with toxicity evaluations were perform...
Article
Background The incidents of Aurelia sp. stinging have recently increased because of a bloom in offshore area. However, their symptoms are much milder than those from another scyphozoan jellyfish, Stomolophus meleagris. Methods The molecular composition of the medusa and polyp of Aurelia coerulea was analyzed by sequencing the transcriptome and pro...
Article
Full-text available
Comau Fjord is a stratified Chilean Patagonian Fjord characterized by a shallow brackish surface layer and a >400 m layer of aragonite-depleted subsurface waters. Despite the energetic burden of low aragonite saturation levels to calcification, Comau Fjord harbours dense populations of cold-water corals (CWC). While this paradox has been attributed...
Article
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The Beagle Channel (BC) is a long and narrow interoceanic passage (∼270 km long and 1–12 km wide) with west-east orientation and complex bathymetry connecting the Pacific and Atlantic oceans at latitude 55°S. This study is the first integrated assessment of the main oceanographic features of the BC, using recent oceanographic observations from crui...
Article
Full-text available
Around the Greenlandic and Antarctic coastlines, sediment plumes associated with glaciers are significant sources of lithogenic material to the ocean. These plumes contain elevated concentrations of a range of trace metals, especially in particle bound phases, but it is not clear how these particles affect dissolved (<0.2 µm) metal distributions in...
Article
Full-text available
Southern Ocean ecosystems are globally important. Processes in the Antarctic atmosphere, cryosphere, and the Southern Ocean directly influence global atmospheric and oceanic systems. Southern Ocean biogeochemistry has also been shown to have global importance. In contrast, ocean ecological processes are often seen as largely separate from the rest...
Presentation
Cold-water corals (CWC) face an uncertain future under climate change. They seem to grow successfully under low pH conditions but physiological mechanisms and the role of energy efficiency in sustaining metabolic rates are largely unknown. The solitary, pseudo-colonial CWC Desmophyllum dianthus thrives in Comau Fjord (Northern Patagonia, Chile) des...
Article
Despite the recent increase in knowledge concerning microorganisms, the processes determining their global distribution and functioning have not been disentangled. Microbial dormant stages are adapted to endure specific adverse conditions related to their dispersion path, suggesting that dispersion is not entirely a stochastic process. Long-term do...
Article
Full-text available
Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around Antarctica and parts of northern Greenland, this freshwater then experiences prolonged residence ti...
Article
Full-text available
Within the framework of the Marine Ecosystem Assessment for the Southern Ocean (MEASO), this paper brings together analyses of recent trends in phytoplankton biomass, primary production and irradiance at the base of the mixed layer in the Southern Ocean and summarises future projections. Satellite observations suggest that phytoplankton biomass in...
Article
Full-text available
The Chilean fjord region includes many remote and poorly known areas where management plans for the marine living resources and conservation strategies are urgently needed. Few data are available about the spatial distribution of its marine invertebrate fauna, prevalently influenced by complex interactions between biotic and abiotic factors, animal...
Article
Full-text available
Here, we present radiative forcing (RF) estimates by snow algae in the Antarctic Peninsula (AP) region from multi-year measurements of solar radiation and ground-based hyperspectral characterization of red and green snow algae collected during a brief field expedition in austral summer 2018. Our analysis includes pigment content from samples at thr...
Article
Full-text available
This work describes a robust and powerful method for wide-scope target and non-target analysis of xenobiotics in biota samples based on bead beating tissuelyser extraction, solid phase extraction (SPE) clean-up and further detection by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). Unlike target methodologies, non-tar...
Article
Full-text available
The manuscript assesses the current and expected future global drivers of Southern Ocean (SO) ecosystems. Atmospheric ozone depletion over the Antarctic since the 1970s, has been a key driver, resulting in springtime cooling of the stratosphere and intensification of the polar vortex, increasing the frequency of positive phases of the Southern Annu...
Preprint
Full-text available
Here, we present radiative forcing (RF) estimates by snow algae in the Antarctic Peninsula (AP) region from multi-year measurements of solar radiation and ground-based hyperspectral characterization of red and green snow algae collected during a brief field expedition in austral summer 2018. Our analysis includes pigment content from samples at thr...
Article
Full-text available
Pressure in academia and science is rapidly increasing and early career researchers (ECRs) have a lot to gain from being involved in research initiatives such as large international projects. But just how inclusive are they? Here we discuss experiences of ECRs directly involved in the Marine Ecosystem Assessment for the Southern Ocean (MEASO), an A...
Article
Full-text available
Seasonal dynamics of ocean prokaryotic communities in the free-living fraction have been widely described, but less is known about the seasonality of prokaryotes inhabiting marine particles. We describe the seasonality of bacterial communities in the particulate matter continuum by sampling monthly over two years in a temperate oligotrophic coastal...
Article
Full-text available
Scientific meetings, conferences, field schools and workshops provide essential networking and training opportunities for early career researchers, but in highly international fields like polar sciences, attending these events can involve extensive travel. We surveyed Association of Polar Early Career Scientists members and other early career membe...
Poster
In our collective endeavour towards global sustainability, there is now a broad appreciation that producing scientifically robust knowledge requires new forms of engagement between scientists, stakeholders and society. But what is the role of Early Career Scientists (ECS) in these processes that are closing the gap between science and policy? Becau...
Article
Full-text available
Marine phytoplankton growth at high latitudes is extensively limited by iron availability. Icebergs are a vector transporting the bioessential micronutrient iron into polar oceans. Therefore, increasing iceberg fluxes due to global warming have the potential to increase marine productivity and carbon export, creating a negative climate feedback. Ho...
Technical Report
Full-text available
The primary objective for this krill research activity was twofold 1) to conduct a survey that provides updated estimates of the biomass and distribution of krill which are used in models to estimate sustainable yield in CCAMLR Area 48 and 2) to develop knowledge on the marine environment essential for the implementation of a Feed-Back Management (...
Article
During January and February 2017 massive phytoplankton blooms (chlorophyll > 15 mg m-3) were registered in surface waters within two bays in the Western Antarctic Peninsula (WAP). Reflecting these intense blooms, surface waters exhibited high pH (up to 8.4), low pCO2 (< 175 µatm) and low nitrate concentrations (down to 1.5 µM). These summer phytopl...
Article
Full-text available
The feeding behavior of the cosmopolitan cold-water coral (CWC) Desmophyllum dianthus (Cnidaria: Scleractinia) is still poorly known. Its usual deep distribution restricts direct observations, and manipulative experiments are so far limited to prey that do not occur in CWC natural habitat. During a series of replicated incubations, we assessed the...
Article
Glacial retreat at high latitudes has increased significantly in recent decades associated with global warming. Along Chile's Patagonian fjords, this has promoted increases in freshwater discharge, vertical stratification, and the input of organic and inorganic particles to fjords. In addition, it has modified the water chemistry [i. e. nutrient st...
Article
Disentangling the bottom-up controls of natural ecosystems is key to understanding the capacity of local communities to resist natural and anthropogenic disturbances. Here, we used carbon and nitrogen stable isotope ratios with a Bayesian multiple source mixing model to trace diverse food sources supporting the benthic trophic network in Fildes Bay...
Article
Full-text available
The pelagic phases of the commercially important stalked barnacle, Pollicipes pollicipes (Cirripedia: Scalpellomorpha), still remain a knowledge gap due to the extreme paucity of these larvae in the plankton. During four cruises at the Nalón River mouth (Spain, Southern Bay of Biscay) high densities of these larvae were consistently found inside th...
Article
The transport and fate of organic matter (OM) sources within the Avilés submarine canyon (Cantabrian Sea, Southern Bay of Biscay) were studied using carbon and nitrogen stable isotope ratios. The isotopic composition of settling particles and deep bottom sediments closely resembled that of surface particulate OM, and there were no marked difference...
Article
Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based trophic structure of a deep-sea ecosystem, the Avilés submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), ta...
Article
Full-text available
River plumes are important features in coastal ecosystems and more studies are necessary to improve our knowledge about their influence on the distribution and dispersion of plankton, especially at small scales. Four surveys were conducted in the Nalo´n River mouth (Spain, southern Bay of Biscay) to study the effect of the river plume front on the...
Article
Full-text available
Long-term studies are necessary to gain insight into the influence of external climate forcing on zooplankton dynamics. Using monthly time series (1993–2010) collected in the Cantabrian Sea (southern Bay of Biscay), we studied long-term trends and seasonal cycles of zooplankton abundance and biomass along a coastal-ocean gradient. We also analysed...
Technical Report
Full-text available
Long-term studies are necessary to gain insight into the influence of external climate forcing on zooplankton dynamics. Using monthly time series (1993–2010) collected in the Cantabrian Sea (southern Bay of Biscay), we studied long-term trends and seasonal cycles of zooplankton abundance and biomass along a coastal-ocean gradient. We also analysed...
Article
Full-text available
Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm) and five depths, allowing us to characterize...
Article
Full-text available
The effect of 1918 influenza pandemic is studied in different sex and age classes in Oviedo, Gijón and Avilés. The pandemic is a mortality crisis in the three cities. Mortality rates are affected by both city and age class, but there is no sex effect according to log-linear models.

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Projects

Projects (3)
Project
CoastCarb is an international Research Network that follows an interdisciplinary approach to understanding the consequences of Climate Change in the Beagle Channel and the coastal Western Antarctic, a region of recent rapid aerial warming. The CoastCarb Network for Staff Exchange and Training is funded by the Marie Curie Action RISE (Research and Innovation Staff Exchange) of the Horizon 2020 Framework Programme of the European Union (H2020-MCSA-RISE 872690). Climate change and intensifying human resource use are causing massive changes to Subantarctic coastal systems and carbon cycling. At the same time, these systems house benthic communities of the highest biomass and biodiversity, which sustain important ecosystem services and require strategic observation and management plans. The multidisciplinary network CoastCarb joins experts in Subantarctic coastal system ecology and ecological modelling to create a knowledge information system with open access data portal and produce dynamic ecosystem models for fjordic and estuarine environments. CoastCarb has five specific objectives that will be pursued by five work-packages (WP): Obj 1 - Data and Information System (DIS): Compile a geo-referenced data information system for Souuth Patagonia (SP) and West Antarctic Peninsula (WAP) coastal change, including abiotic environmental factors, disturbance levels, and mapping coastal biosphere (WP1). Obj 2 - Ecosystem Modelling: Develop a carbon flux model for SP/WAP coastal fjords and estuaries, considering different ecosystem processes such as carbon sequestration (production, coastal runoff fluxes, deposition and burial) and mobilization (bioturbation, remineralization, transport processes) (WP2). Obj 3 – Species Metrics & Multiple Stressors: Parameterise the response of coastal biosphere (key species, groups, key communities) to environmental change for different focal areas along SP and the WAP. Identify and fill present data gaps (WP3). Obj 4 - Ecosystem Change and Carbon Storage: Develop a coastal status classification scheme (dynamic mapping of carbon sink and source areas) (WP4). Obj 5 - Ecosystem Services, Food Security and Public Engagement: Contribute to the analysis of ecosystem service changes, sustainable management and public engagement (WP5). Obj 6 - Managment and Ethichs, plus Science Communication (WP6). www.coastcarb.eu
Project
This project has the following activities: -The WRF-SMOKE-CMAQ models will be applied to simulate the transport to the ocean of the air pollutants generated during wildfires in Chile. -The CAMS Global dataset and the local registries of wildfire emissions will be used as main inputs. Its comparison would be part of the analysis in this study. -The deposition of the air pollutants will be correlated with the phytoplankton activity in the ocean, by using satellite data. More details (in Spanish) link here (http://www.eiq.cl/estudio-de-los-efectos-de-los-incendios-forestales-en-los-ecosistemas-marinos/)
Project
The Southern Ocean is considered a major sink of anthropogenic carbon, which would help to mitigate global climate change. However, recent findings have evidenced the existence of some key gaps on how models depict the role played by the Southern Ocean in Earth Climate System. The production of marine aerosols by phytoplankton activity may likely promote negative climate feedbacks (i.e. decreasing the impacts and trends of climate change) by boosting cloud formation and increasing cloud albedo (i.e. enhancing upward short wave radiative flux at the top of the atmosphere). Despite current evidences indicate the influence of oceanic biota on the optical characteristics of the atmosphere and, thus, the Earth radiative budget, there are too many uncertainties to assess and model this process accurately. The atmospheric data collected at different heights by the SouthTrack project would allow us to improve the parametrization of the role of the Southern Ocean on Earth Climate System, as well as refine the adjustment of air quality models (e.g. CMAQ) that normally cannot be constrained due to the lack of actual data at levels higher than Earth surface.