Articles | Volume 14, issue 5
https://doi.org/10.5194/os-14-1185-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-14-1185-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Oct 2018
Research article |
| 09 Oct 2018
| 09 Oct 2018
Turbulence and hypoxia contribute to dense biological scattering layers in a Patagonian fjord system
Centro i-mar, Universidad de Los Lagos, Camino a
Chinquihue km 6, Puerto Montt, Chile
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Leonardo Castro
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Departamento de Oceanografía, Universidad de Concepción,
Campus Concepción, Víctor Lamas 1290, Casilla 160-C, código
postal: 4070043, Concepción, Chile
Centro de Investigaciones de Altas Latitudes (IDEAL), Universidad
Austral de Chile, Valdivia, Chile
Lauren Ross
Department of Civil and Environmental Engineering, University of
Maine, 5711 Boardman Hall, Orono, ME 04469-5711, USA
Edwin Niklitschek
Centro i-mar, Universidad de Los Lagos, Camino a
Chinquihue km 6, Puerto Montt, Chile
Nicolás Mayorga
Centro i-mar, Universidad de Los Lagos, Camino a
Chinquihue km 6, Puerto Montt, Chile
Luis Cubillos
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Departamento de Oceanografía, Universidad de Concepción,
Campus Concepción, Víctor Lamas 1290, Casilla 160-C, código
postal: 4070043, Concepción, Chile
Mariano Gutierrez
Universidad Nacional Federico Villareal, Facultad de
Oceanografía, Pesquerías y Ciencias Alimentarias, Calle Francia
726, Miraflores, Lima, Peru
Eduardo Escalona
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Departamento de Oceanografía, Universidad de Concepción,
Campus Concepción, Víctor Lamas 1290, Casilla 160-C, código
postal: 4070043, Concepción, Chile
Manuel Castillo
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Centro de Observación Marino para Estudios de Riesgo en Ambientes
Costeros, Facultad de Ciencias del Mar y de Recursos Naturales, Universidad
de Valparaíso, Valparaiso, Chile
Nicolás Alegría
Instituto de Investigaciones Pesqueras, Talcahuano, Chile
Giovanni Daneri
Centro COPAS Sur-Austral, Universidad de Concepción, Campus
Concepción, Víctor Lamas 1290, Casilla 160-C, código postal:
4070043, Concepción, Chile
Centro de Investigaciones en Ecosistemas de la Patagonia (CIEP),
Coyhaique, Chile
Related authors
Iván Pérez-Santos, Pamela Linford, Luis Rozas, Osvaldo Artal, Elías Pinilla, Lauren Ross, Patricio Díaz, Marcela Rojas, Guido Mancilla-Gutiérrez, Gabriel Soto, and Ivonne Montes
EGUsphere, https://doi.org/10.5194/egusphere-2026-2889, https://doi.org/10.5194/egusphere-2026-2889, 2026
Short summary
Short summary
The ocean deoxygenation has accelerated globally, driven by warming and diminishing deep-water ventilation. The objective of this work is to quantify the contributions of turbulent and diapycnal mixing to water ventilation, as evidenced by upward oxygen transport from deep to subsurface layers in the northern Patagonian fjords. Our results highlight the importance of incorporating turbulence measurements into fjord studies to understand sensitivity to significant oxygen variability.
Maibelin Castillo-Alvarez, Oscar Pizarro, Alain Muñoz-Caravaca, Iván Pérez-Santos, David Carrasco, David Francisco Bustos-Usta, and Laura Castellanos-Torres
Ocean Sci., 22, 1409–1427, https://doi.org/10.5194/os-22-1409-2026, https://doi.org/10.5194/os-22-1409-2026, 2026
Short summary
Short summary
We examine 2003–2022 sea-surface temperature (SST) in Cuba's Jardines de la Reina National Park. Using standard marine heatwave metrics and climate-mode indices, we show how large-scale patterns drive SST changes at different scales and in marine heatwave frequency, duration, and intensity. Findings help explain recent extremes and support reef conservation and early-warning efforts in the Caribbean.
Camila Sola-Hidalgo, Iván Pérez-Santos, Manuel Castillo, Marcela Cornejo, Ángela Baldrich, and Maibelin Castillo-Álvarez
EGUsphere, https://doi.org/10.5194/egusphere-2026-2329, https://doi.org/10.5194/egusphere-2026-2329, 2026
Short summary
Short summary
This study investigates the influence of climate change and physical drivers on dissolved oxygen (DO) renewal in northern Patagonian fjords. The research identifies two distinct scales of oxygen recovery: seasonal ventilation periods and synoptic-scale ventilation pulses. Key drivers, including onshore Ekman transport and wind-driven downwelling, were found to be the primary mechanisms delivering oxygen-rich water to deeper layers, especially from winter to spring.
Cécile Pujol, Alexander Barth, Iván Pérez-Santos, Pamela Linford, and Aida Alvera-Azcárate
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2026-42, https://doi.org/10.5194/essd-2026-42, 2026
Preprint under review for ESSD
Short summary
Short summary
In this study, we present the first high-resolution, four-dimensional temperature climatology for Northern Chilean Patagonia, a region characterised by a complex network of fjords and channels. The climatology win based on approximately three million in situ observations collected over the past 75 years and interpolated into continuous temperature fields with a horizontal resolution of about 900 m and 32 vertical levels, providing monthly and daily fields from the surface to 400 m depth.
Marcela Rojas-Celis, Manuel I. Castillo, Iván Pérez-Santos, Carmen Barrios-Guzmán, José Garcés-Vargas, Alicia Guerrero, Mauricio F. Landaeta, Andrea Piñones, and Maritza Sepúlveda
EGUsphere, https://doi.org/10.5194/egusphere-2025-5846, https://doi.org/10.5194/egusphere-2025-5846, 2025
Preprint archived
Short summary
Short summary
The turbulent kinetic energy dissipation rates (ε) in Chilean Patagonia spanning 10-9 to 10-5 W kg⁻2 was maxima at sills and constrictions. The northern fjords had strong seasonal stratification by freshwater input, while southern regions are mixed by tidal forcing. These results underscore the critical control of topography and tidal forcing on mixing heterogeneity, providing a framework for projecting the response of these ecosystems to climate-driven changes.
Pilar Aparicio-Rizzo, Dagoberto Poblete-Caballero, Cristian Vera-Bastidas, Iván Pérez-Santos, and Daniel Varela
Ocean Sci., 21, 2379–2395, https://doi.org/10.5194/os-21-2379-2025, https://doi.org/10.5194/os-21-2379-2025, 2025
Short summary
Short summary
This work combines a hyperspectral sensor and an unmanned aerial vehicle to detect and differentiate phytoplankton species from optical data in Patagonian fjords at local scale. The results show differences between in situ spectral signals, especially in the blue, green and red near-infrared spectra, distinguishing between diatom and dinoflagellate. These tools are useful especially in coastal areas where cloud cover and geographical heterogeneity make satellite data acquisition difficult.
Macarena Díaz-Astudillo, Manuel I. Castillo, Pedro A. Figueroa, Leonardo R. Castro, Ramiro Riquelme-Bugueño, Iván Pérez-Santos, Oscar Pizarro, and Gonzalo S. Saldías
Ocean Sci., 21, 1833–1848, https://doi.org/10.5194/os-21-1833-2025, https://doi.org/10.5194/os-21-1833-2025, 2025
Short summary
Short summary
Submarine canyons are known hotspots of marine productivity and biodiversity, but we do not fully understand why. We studied a submarine canyon located in central Chile and found that it is a highly dynamic environment in both space and time. We think that the alternating currents and the contrasting distribution of zooplankton within the canyon might interact to promote zooplankton retention. Our results help to explain why submarine canyons host such high zooplankton diversity and abundance.
Cécile Pujol, Alexander Barth, Iván Pérez-Santos, Pamela Muñoz-Linford, and Aida Alvera-Azcárate
EGUsphere, https://doi.org/10.5194/egusphere-2025-1421, https://doi.org/10.5194/egusphere-2025-1421, 2025
Preprint archived
Short summary
Short summary
Marine heatwaves and cold spells are periods of extreme sea temperatures. This study focuses on Chilean Northern Patagonia, a fjord region vulnerable due to its aquaculture. It aims to understand these events' distribution and identify the most affected basins. Results show higher intensity in enclosed areas like Reloncaví Sound and Puyuhuapi Fjord. Marine heatwaves are becoming more frequent over time, while cold spells are decreasing.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
Short summary
Short summary
The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Manuel I. Castillo, Constanza Zuñiga, Carmen Barrios-Guzmán, Natalia Cisternas, José Garcés-Vargas, Mauricio F. Landaeta, Andrea Piñones, Marcela Rojas, Alicia I. Guerrero, and Maritza Sepúlveda
Ocean Sci., 22, 2221–2247, https://doi.org/10.5194/os-22-2221-2026, https://doi.org/10.5194/os-22-2221-2026, 2026
Short summary
Short summary
The study use Conductivity, Temperature and Depth (CTD) measurement (including seals-borne CTD) to describe the seasonality of the stratification and mixing of one of the southernmost Fjords of Patagonia: The Almirantazgo Fjord. The region, typically tidal was indicated as the most important forcing for mixing the inner-sea of Tierra del Fuego, here the study shows that the persistent an episodic strong along-fjord winds could perturb the pynoclyne and rivals to the estuarine circulation.
Iván Pérez-Santos, Pamela Linford, Luis Rozas, Osvaldo Artal, Elías Pinilla, Lauren Ross, Patricio Díaz, Marcela Rojas, Guido Mancilla-Gutiérrez, Gabriel Soto, and Ivonne Montes
EGUsphere, https://doi.org/10.5194/egusphere-2026-2889, https://doi.org/10.5194/egusphere-2026-2889, 2026
Short summary
Short summary
The ocean deoxygenation has accelerated globally, driven by warming and diminishing deep-water ventilation. The objective of this work is to quantify the contributions of turbulent and diapycnal mixing to water ventilation, as evidenced by upward oxygen transport from deep to subsurface layers in the northern Patagonian fjords. Our results highlight the importance of incorporating turbulence measurements into fjord studies to understand sensitivity to significant oxygen variability.
Maibelin Castillo-Alvarez, Oscar Pizarro, Alain Muñoz-Caravaca, Iván Pérez-Santos, David Carrasco, David Francisco Bustos-Usta, and Laura Castellanos-Torres
Ocean Sci., 22, 1409–1427, https://doi.org/10.5194/os-22-1409-2026, https://doi.org/10.5194/os-22-1409-2026, 2026
Short summary
Short summary
We examine 2003–2022 sea-surface temperature (SST) in Cuba's Jardines de la Reina National Park. Using standard marine heatwave metrics and climate-mode indices, we show how large-scale patterns drive SST changes at different scales and in marine heatwave frequency, duration, and intensity. Findings help explain recent extremes and support reef conservation and early-warning efforts in the Caribbean.
Camila Sola-Hidalgo, Iván Pérez-Santos, Manuel Castillo, Marcela Cornejo, Ángela Baldrich, and Maibelin Castillo-Álvarez
EGUsphere, https://doi.org/10.5194/egusphere-2026-2329, https://doi.org/10.5194/egusphere-2026-2329, 2026
Short summary
Short summary
This study investigates the influence of climate change and physical drivers on dissolved oxygen (DO) renewal in northern Patagonian fjords. The research identifies two distinct scales of oxygen recovery: seasonal ventilation periods and synoptic-scale ventilation pulses. Key drivers, including onshore Ekman transport and wind-driven downwelling, were found to be the primary mechanisms delivering oxygen-rich water to deeper layers, especially from winter to spring.
Cristian M. Rojas, Lauren Ross, Betty John Kaimathuruthy, Isabel Jalón-Rojas, Aldo Sottolichio, and Nicolas Huybrechts
Ocean Sci., 22, 1311–1327, https://doi.org/10.5194/os-22-1311-2026, https://doi.org/10.5194/os-22-1311-2026, 2026
Short summary
Short summary
Although estuaries typically exhibit high suspended sediment concentrations (SSC), only a few studies have investigated how the impact of SSC on density can affect the exchange between rivers and coastal waters. Here, we use numerical models to quantify the impact of SSC on water exchange based on an estuary with large SSC and tidal range. We found that the non-consideration of SSC leads to large differences in the exchange of water that could lead to the over-quantification of water transport.
Débora Barros, Lauren Ross, and Carlos A. F. Schettini
EGUsphere, https://doi.org/10.5194/egusphere-2026-1840, https://doi.org/10.5194/egusphere-2026-1840, 2026
Short summary
Short summary
Coastal waters often show vertical stratification because lighter freshwater overlies denser seawater. Mixing requires kinetic energy, generating turbulence that is difficult to quantify. We investigate the transition from a confined channel to the adjacent coast, where outflow spreads over denser water. Measurements of velocity, salinity, and turbulence show that small geometric changes enhance mixing, especially near the mouth, reaching levels comparable to tide-dominated systems.
Cécile Pujol, Alexander Barth, Iván Pérez-Santos, Pamela Linford, and Aida Alvera-Azcárate
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2026-42, https://doi.org/10.5194/essd-2026-42, 2026
Preprint under review for ESSD
Short summary
Short summary
In this study, we present the first high-resolution, four-dimensional temperature climatology for Northern Chilean Patagonia, a region characterised by a complex network of fjords and channels. The climatology win based on approximately three million in situ observations collected over the past 75 years and interpolated into continuous temperature fields with a horizontal resolution of about 900 m and 32 vertical levels, providing monthly and daily fields from the surface to 400 m depth.
Marcela Rojas-Celis, Manuel I. Castillo, Iván Pérez-Santos, Carmen Barrios-Guzmán, José Garcés-Vargas, Alicia Guerrero, Mauricio F. Landaeta, Andrea Piñones, and Maritza Sepúlveda
EGUsphere, https://doi.org/10.5194/egusphere-2025-5846, https://doi.org/10.5194/egusphere-2025-5846, 2025
Preprint archived
Short summary
Short summary
The turbulent kinetic energy dissipation rates (ε) in Chilean Patagonia spanning 10-9 to 10-5 W kg⁻2 was maxima at sills and constrictions. The northern fjords had strong seasonal stratification by freshwater input, while southern regions are mixed by tidal forcing. These results underscore the critical control of topography and tidal forcing on mixing heterogeneity, providing a framework for projecting the response of these ecosystems to climate-driven changes.
Elias Pinilla and Lauren Ross
EGUsphere, https://doi.org/10.5194/egusphere-2025-4893, https://doi.org/10.5194/egusphere-2025-4893, 2025
Short summary
Short summary
Fjords connect land and ocean, exchanging nutrients and oxygen that sustain ecosystems. As climate shifts alter rainfall and winds, we probed what drives water renewal in Patagonian fjords. Using computer models that switched rivers, wind, and tides on and off, we measured their roles in exchange. Rivers provide about half of the circulation, while winds and tides modulate this baseline. As rainfall and winds change, these patterns help predict renewal failures and low-oxygen risk.
Pilar Aparicio-Rizzo, Dagoberto Poblete-Caballero, Cristian Vera-Bastidas, Iván Pérez-Santos, and Daniel Varela
Ocean Sci., 21, 2379–2395, https://doi.org/10.5194/os-21-2379-2025, https://doi.org/10.5194/os-21-2379-2025, 2025
Short summary
Short summary
This work combines a hyperspectral sensor and an unmanned aerial vehicle to detect and differentiate phytoplankton species from optical data in Patagonian fjords at local scale. The results show differences between in situ spectral signals, especially in the blue, green and red near-infrared spectra, distinguishing between diatom and dinoflagellate. These tools are useful especially in coastal areas where cloud cover and geographical heterogeneity make satellite data acquisition difficult.
Macarena Díaz-Astudillo, Manuel I. Castillo, Pedro A. Figueroa, Leonardo R. Castro, Ramiro Riquelme-Bugueño, Iván Pérez-Santos, Oscar Pizarro, and Gonzalo S. Saldías
Ocean Sci., 21, 1833–1848, https://doi.org/10.5194/os-21-1833-2025, https://doi.org/10.5194/os-21-1833-2025, 2025
Short summary
Short summary
Submarine canyons are known hotspots of marine productivity and biodiversity, but we do not fully understand why. We studied a submarine canyon located in central Chile and found that it is a highly dynamic environment in both space and time. We think that the alternating currents and the contrasting distribution of zooplankton within the canyon might interact to promote zooplankton retention. Our results help to explain why submarine canyons host such high zooplankton diversity and abundance.
Cécile Pujol, Alexander Barth, Iván Pérez-Santos, Pamela Muñoz-Linford, and Aida Alvera-Azcárate
EGUsphere, https://doi.org/10.5194/egusphere-2025-1421, https://doi.org/10.5194/egusphere-2025-1421, 2025
Preprint archived
Short summary
Short summary
Marine heatwaves and cold spells are periods of extreme sea temperatures. This study focuses on Chilean Northern Patagonia, a fjord region vulnerable due to its aquaculture. It aims to understand these events' distribution and identify the most affected basins. Results show higher intensity in enclosed areas like Reloncaví Sound and Puyuhuapi Fjord. Marine heatwaves are becoming more frequent over time, while cold spells are decreasing.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
Short summary
Short summary
The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Julio Salcedo-Castro, Antonio Olita, Freddy Saavedra, Gonzalo S. Saldías, Raúl C. Cruz-Gómez, and Cristian D. De la Torre Martínez
Ocean Sci., 19, 1687–1703, https://doi.org/10.5194/os-19-1687-2023, https://doi.org/10.5194/os-19-1687-2023, 2023
Short summary
Short summary
Considering the relevance and impact of river discharges on the coastal environment, it is necessary to understand the processes associated with river plume dynamics in different regions and at different scales. Modeling studies focused on the eastern Pacific coast under the influence of the Humboldt Current are scarce. Here, we conduct for the first time an interannual modeling study of two river plumes off central Chile and discuss their characteristics.
Dirk S. van Maren, Christian Maushake, Jan-Willem Mol, Daan van Keulen, Jens Jürges, Julia Vroom, Henk Schuttelaars, Theo Gerkema, Kirstin Schulz, Thomas H. Badewien, Michaela Gerriets, Andreas Engels, Andreas Wurpts, Dennis Oberrecht, Andrew J. Manning, Taylor Bailey, Lauren Ross, Volker Mohrholz, Dante M. L. Horemans, Marius Becker, Dirk Post, Charlotte Schmidt, and Petra J. T. Dankers
Earth Syst. Sci. Data, 15, 53–73, https://doi.org/10.5194/essd-15-53-2023, https://doi.org/10.5194/essd-15-53-2023, 2023
Short summary
Short summary
This paper reports on the main findings of a large measurement campaign aiming to better understand how an exposed estuary (the Ems Estuary on the Dutch–German border) interacts with a tidal river (the lower Ems River). Eight simultaneously deployed ships measuring a tidal cycle and 10 moorings collecting data throughout a spring–neap tidal cycle have produced a dataset providing valuable insight into processes determining exchange of water and sediment between the two systems.
Cited articles
Ariza, A., Landeira, J. M., Escánez, A., Wienerroither, R., Aguilar de
Soto, N., Røstad, A., Kaartvedt, S., and Hernández-León, S.: Vertical
distribution, composition and migratory patterns of acoustic scattering
layers in the Canary Islands, J. Mar. Syst, 157, 82–91, 2016.
Ayón, P., Criales-Hernandez, M. I., Schwamborn, R., and Hirche, H. J.:
Zooplankton research off Peru: a review, Prog. Oceanogr., 79, 238–255, 2008.
Ballón, M.: Acoustic study of macrozooplankton off Peru: biomass
estimation, spatial patterns, impact of physical forcing and effect on
forage fish distribution, Thesis, Universite Montpellier II, 205 pp., Montpellier, France, 2010.
Ballón, M., Bertrand, A., Lebourges-Dhaussy, A., Gutiérrez, M.,
Ayón, P., Grados, D., and Gerlotto, F.: Is there enough zooplankton to feed
forage fish populations off Peru? An acoustic (positive) answer, Prog.
Oceanogr., 91, 360–381, 2011.
Basedow, S. L., Eliane, K., Tverberg, V., and Spindler, M.: Advection of
zooplankton in an Arctic fjord (Kongsfjorden, Svalbard), Estuar. Coast. Shelf S., 60, 113–124, 2004.
Bearman, G.: Waves, tides and
shallow water processes, Butterworth-Heinemann, Oxford, 187 pp., 1989.
Berge, J., Cottier, F., Last, K., Varpe, Ø., Leu, E., Søreide,
J., Eiane, K., Falk-Petersen, S., Willis, K., Nygård, H., Vogedes,
D., Griffiths, C., Johnsen, G., Lorentzen, D., and Brierley, A.: Diel vertical migration of Arctic
zooplankton during the polar night, Biol. Lett., 5 69–72, 2009.
Buchholz, F., Buchholz, C., Reppin, J., and Fischer, J.: Diel vertical migrations of
Meganyctiphanes norvegica in the Kattegat: Comparison of net catches and measurements with Acoustic
Doppler Current Profilers, Helgolander Meeresun., 49, 849–866, 1995.
Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M.,. Chavez, F. P.,
Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K.,
Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W., Pitcher, G. C.,
Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M.,
Yasuhara, M., and Zhang, J.: : Declining oxygen in the global ocean and
coastal waters, Science, 359, 1–11, 2018.
Brierley, A., Saunders, R. A., Bone, D. G., Murphy, E. J., Enderlein, P.,
Conti, S. G., and Demer, D. A.: Use of moored acoustic instruments to measure short-term
variability in abundance of Antarctic krill, Limnol. Oceanogr.-Meth., 4, 18–29, 2006.
Cade, D. E. and Benoit-Bird, K. J.: Depths, migration rates and environmental
associations of acoustic scattering layers in the Gulf of California, Deep-Sea Res. Pt. I, 102, 78–89, 2015.
Castillo, M. I., Cifuentes, U., Pizarro, O., Djurfeldt, L., and Caceres, M.:
Seasonal hydrography and surface outflow in a fjord with a deep sill: the
Reloncaví fjord, Chile, Ocean Sci., 12, 533–544,
https://doi.org/10.5194/os-12-533-2016, 2016.
Castro, L. R., Bernal, P. A., and Troncoso, V. A.: Coastal intrusion of copepods:
mechanisms and consequences in the population biology of Rhincalanus nasutus, J. Plankton Res., 15, 501–515, 1993.
Castro, L. R. and Troncoso, V. A.: Fine-scale vertical distribution of coastal
and offshore copepods in the Golfo de Arauco, central Chile, during the
upwelling season, Prog. Oceanogr., 75, 486–500, 2007.
Castro, L. R., Caceres, M. A., Silva, N., Muñoz, M. I., León, R., Landaeta,
M. F., and Soto Mendoza, S.: Short-term variations in mesozooplankton,
ichthyoplankton, and nutrients associated with semi-diurnal tides in a
Patagonian Gulf, Cont. Shelf Res., 31, 282–292, 2014.
Cloern, J.: Tidal stirring and phytoplankton bloom dynamics in an estuary, J.
Mar. Res., 49, 203–221, 1991.
Cuypers, Y., Bouruet-Aubertot, P., Marec, C., and Fuda, J.-L.:
Characterization of turbulence from a fine-scale parameterization and
microstructure measurements in the Mediterranean Sea during the BOUM
experiment, Biogeosciences, 9, 3131–3149,
https://doi.org/10.5194/bg-9-3131-2012, 2012.
Daneri, G., Montero, P., Lizárraga, L., Torres, R., Iriarte, J. L., Jacob,
B., González, H. E., and Tapia, F. J.: Primary Productivity and heterotrophic
activity in an enclosed marine area of central Patagonia (Puyuhuapi channel;
44∘ S, 73∘ W), Biogeosciences Discuss., 9, 5929–5968,
https://doi.org/10.5194/bgd-9-5929-2012, 2012.
Díaz, R. J.: Overview of hypoxia around the world, J. Environ. Qual.,
30, 275–281, 2001
Díaz-Astudillo, M., Cáceres, M., and Landaeta, M.: Zooplankton structure
and vertical migration: Using acoustics and biomass to compare stratified and
mixed fjord systems, Cont. Shelf Res., 148, 208–218, 2017.
Dyer, K. R.: Estuaries: A physical introduction, John Wiley & Sons, West
Sussex, England, 1997.
Ekau, W., Auel, H., Pörtner, H.-O., and Gilbert, D.: Impacts of hypoxia on
the structure and processes in pelagic communities (zooplankton,
macro-invertebrates and fish), Biogeosciences, 7, 1669–1699,
https://doi.org/10.5194/bg-7-1669-2010, 2010.
Escribano, R., Hidalgo, P., and Krautz, C.: Zooplankton associated with the
oxygen minimum zone system in the northern upwelling region of Chile during
March 2000, Deep-Sea Res. Pt. II, 56, 1083–1094, 2009.
Farmer, D. M. and Freeland, H. J.: The physical oceanography of fjords,
Prog. Oceanogr., 12, 147–194, 1983.
Fielding, S., Griffiths, G., and Roe, H. S. J.: The biological validation of
ADCP acoustic backscatter through direct comparison with net samples and
model predictions based on acoustic-scattering models, J. Mar. Sci., 61,
184–200, 2004.
Foreman, M. G. G.: Manual for Tidal Heights Analysis and Prediction, Pacific
Marine Science Report 77–10, Sidney, Canada, 1977.
Foreman, M. G. G.: Manual for Tidal Currents Analysis and Prediction, Pacific
Marine Science Report 78-6, Sidney, Canada, 1978.
Foote, K. G., Knudsen, H. P., Vestnes, G., MacLennan, D. N., and Simmonds, E.
J.: Calibration of acoustic instruments for fish density estimation: a
practical guide. ICES cooperative research report N∘ 144,
International Council for the Exploration of the Sea, Copenhaguen, Denmark,
1987.
Fuenzalida, R., Schneider, W., Garcés-Vargas, J., Bravo, L., and Lange,
C.: Vertical and horizontal extension of the oxygen mínimum zone in the
eastern South Pacific Ocean, Deep-Sea Res. Pt. II, 56, 1027–1038, 2009.
Gattuso, J., Frankingnoulle, M., and Wollast, R.: Carbon and carbonate
metabolism in coastal aquatic ecosystems, Annu. Rev. Ecol. Syst., 29,
405–434, 1998.
Giesecke, R. and González, H. E.: Feeding of Sagitta enflata and
vertical distribution of chaetognaths in relation to low oxygen
concentrations, J. Plankton Res., 26, 475–486, 2005.
González, H. E., Calderon, M. J., Castro, L., Clement, A., Cuevas, L. A.,
Daneri, G., Iriarte, J. L., Lizárraga, L., Martinez, R., Menschel, E.,
Silva, N., Carrasco, C., Valenzuela, C., Vargas, C. A., and Molinet, C.:
Primary Production and plankton dynamics in the Reloncavi Fjord and the
Interior Sea of Chiloe, Northern Patagonia, Chile, Mar. Ecol. Prog. Ser.,
402, 13–30, 2010.
González, H. E., Castro, L., Daneri, G., Iriarte, J. L., Silva, N.,
Vargas, C., Giesecke, R., and Sánchez, N.: Seasonal plankton variability
in Chilean Patagonia Fjords: carbon flow through the pelagic foodweb of the
Aysen Fjord and plankton dynamics in the Moraleda Channel basin, Cont. Shelf
Res. 31, 225–243, 2011.
González, H. E., Castro, L. R., Daneri, G., Iriarte, J. L., Silva, N.,
Tapia, F., Teca, E., and Vargas, C. A.: Land-ocean gradient in haline
stratification and its effects on plankton dynamics and trophic carbon fluxes
in Chilean Patagonian fjords (47–50∘ S), Prog. Oceanogr., 119,
32–47, 2013.
González, H. E, Graeve, M., Kattner, G., Silva, N., Castro, L., Iriarte,
J. L., Osmán, L., Daneri, G., and Vargas, C. A.: Carbon flow through the
pelagic food web in southern Chilean Patagonia: relevance of
Euphausia vallentini as key species, Mar. Ecol. Prog. Ser., 557,
91–110, 2016.
Godin, G.: The Analysis of Tides, University of Toronto Press, Toronto, 1972.
Govani, J. J., Hoss, D. E., and Colby, D. R.: The spatial distribution of
larval fishes about the Mississippi River plume, Limnol. Oceanogr., 34,
178–187, 1989.
Greene, C. H. and Peter, H. W.: Bioacoustical oceanography: New tools for
zooplankton and micronekton research in the 1990s, Oceanography, 3, 12–17,
1990.
Van Haren, H. and Compton, T. J.: Diel Vertical Migration in Deep Sea
Plankton Is Finely Tuned to Latitudinal and Seasonal Day Length, PLoS ONE, 8,
e64435, https://doi.org/10.1371/journal.pone.0064435, 2013.
Haury, L. R., Yamazaki, H., and Itsweire, E. C.: Effects of turbulent shear
flow on zooplankton distribution, Deep-Sea Res., 37, 447–461, 1990.
Hauss, H., Christiansen, S., Schütte, F., Kiko, R., Edvam Lima, M.,
Rodrigues, E., Karstensen, J., Löscher, C. R., Körtzinger, A., and
Fiedler, B.: Dead zone or oasis in the open ocean? Zooplankton distribution
and migration in low-oxygen modewater eddies, Biogeosciences, 13, 1977–1989,
https://doi.org/10.5194/bg-13-1977-2016, 2016.
Heywood, K.: Diel vertical migration of zooplankton in the Northeast Atlantic,
J. Plankton Res., 18, 163–184, 1996.
Horne, J. K. and Jech, J. M.: Multi-frequency estimates of fish abundance:
constraints of rather high frequencies, J. Marine Sci., 56, 184–199, 1999.
Holliday, D. V. and Pieper, R. E.: Bioacoustical oceanography at high
frequencies, J. Marine Sci., 52, 279–296, 1995.
Inall, M. E. and Gillibrand, P. A.: The physics of mid-latitude fjords: a
review, Geological Society, Special Publications, London, UK, 344, 17–33,
2010.
IOC, SCOR and IAPSO: The international thermodynamic equation of seawater –
2010: Calculation and use of thermodynamic properties, Intergovernmental
Oceanographic Commission, Manuals and Guides No. 56, UNESCO, 196 pp.,
available at: http://www.teos-10.org/ (last access: 2 October 2018), 2010.
Iriarte, J. L., Pantoja, S., and Daneri, G.: Oceanographic Processes in
Chilean Fjords of Patagonia: From small to large-scale studies, Prog.
Oceanogr., 129, Part A, 1–7, https://doi.org/10.1016/j.pocean.2014.10.004, 2014
Kloser, R. J., Ryan, T., Sakov, P., Willliams, A., and Koslow, J. A.: Species
identification in deep water using multiple acoustic frequencies, Can. J. Fish Aquat. Sci., 59, 1065–1077,
2016.
Klymak, J. M. and Gregg, M. C.: Tidally Generated Turbulence over the Knight
Inlet Sill, American Meteorological Society,
https://doi.org/10.1175/1520-0485(2004)034<1135:TGTOTK>2.0.CO;2, 1–17, 2004.
Koseff, J., Holen, J., Monismith, S., and Cloern, J.: Coupled effects of
vertical mixing and benthic grazing on phytoplankton populations in shallow,
turbid estuaries, J. Mar. Res., 51, 843–868, 1993.
Landaeta, M., Martínez, R., Bustos, C., and Castro L.: Distribution of microplankton and fish larvae
related to sharp clines in a Patagonian fjord, Rev. Biol. Mar. Oceanog., 48, 401–407, 2013.
Lee, K., Mukai, T., Kang, D., and Iida, K.: Application of acoustic Doppler current
profiler combined with a scientific echo-sounder for krill Euphausia
pacifica density estimation, Fisheries Sci., 70, 1051–1060, 2004.
Lee, O., Nash, R. D. M., and Danilowicz, B. S.: Small-scale spatio-temporal
variability in ichthyoplankton and zooplankton distribution in relation to a
tidal-mixing front in the Irish Sea, J. Mar. Sci., 62, 1021—1036, https://doi.org/10.1016/j.icesjms.2005.04.016, 2005.
Lewis, D. and Pedley, T.: The Infuence of Turbulence on Plankton Predation
Strategies, J. Theor. Biol., 210, 347–365, 2001.
Logerwell, E. A. and Wilson, C.: Species discrimination of fish using
frequencydependent acoustic backscatter, J. Marine Sci., 61, 1004–1013,
2004.
Lough, R. G. and Manning, J. P.: Tidal-front entrainment and retention of
fish larvae on the southern flank of Georges Bank, Deep-Sea Res., 48, Suppl.
2, 631–644, 2001.
MacCready, P., Hetland, R., and Geyer, R.: Long-term isohaline salt balance in
an estuary, Cont. Shelf Res., 22, 1591–1601, 2002.
Maas, A. M., Frazar, S. L., Outram, D. M., Seibel, B. A., and Wishner, K. F.:
Fine-scale vertical distribution of macroplankton andmicronekton in
the Eastern Tropical North Pacific inassociation with
an oxygen minimum zone, J. Plankton Res., 36, 1557–1575, 2014.
Mair, A., Fernandes, P., Lebourges-Dhaussy, A., and Brierley, A.: An investigation
into the zooplankton composition of a prominent 38-khz scattering layer in
the North Sea, J. Plankton Res., 27, 623–633, 2005.
Meerhoff, E., Castro, L., and Tapia, F.: Influence of freshwater discharges and
tides on the abundance and distribution of larval and juvenile Munida
gregaria in then Baker river estuary, Chilean Patagonia, Cont. Shelf Res., 61–62, 1–11, 2013.
Meerhoff, E., Tapia, F. J., Sobarzo, M., and Castro, L.: Influence of
estuarine and secondary circulation on crustacean larval fluxes: a case study
from a Patagonian fjord, J. Plankton Res., 37, 168–182,
https://doi.org/10.1093/plankt/fbu106, 2015.
Montero, P., Pérez-Santos, I., Daneri, G., Gutiérrez, M., Igor, G.,
Seguel, R., Crawford, D., and Duncan, P.: A winter dinoflagellate bloom drives high
rates of primary production in a Patagonian fjord ecosystem, Estuar. Coast. Shelf S., 199, 105–116, 2017a.
Montero, P., Daneri, G., Tapia, F., Iriarte, J. L., and Crawford, D.: Diatom blooms
and primary production in a channel ecosystem of central Patagonia, Lat. Am.
J. Aquat. Res., 45, 999–1016, 2017b.
Mosteiro, A., Fernandes, P. G., Armstrong, F., and Greenstreet, S. P. R.: A
Dual Frequency Algorithm for the Identification of Sandeel School Echotraces,
ICES Document CM 2004/R: 12, 13 pp., 2004.
Munk, P., Wright, P. J., and Pihl, N. J.: Distribution of the early larval stages
of Cod, Plaice and Lesser Sandeel across haline fronts in the North Sea,
Estuar. Coast. Shelf S., 55, 139–149, 2002.
North, E. W. and Houde, E. D.: Retention of white perch and striped bass larvae:
biological-physical interactions in Chesapeake Bay estuarine turbidity
maximum, Estuaries, 24, 756–769, 2001.
North, E. W. and Houde, E. D.: Distribution and transport of bay anchovy (Anchoa
mitchilli) eggs and larvae in Chesapeake Bay, Estuar. Coast. Shelf S., 60, 409–429, 2004.
Osborn, T. R.: Estimates of the local rate of vertical diffusion from dissipation measurements, J. Phys. Oceanogr., 10, 83–89, 1980.
Oviatt, C. A.: Effects of different mixing schedules on phytoplankton,
zooplankton and nutrients in marine microcosms, Mar. Ecol. Prog. Ser., 4,
57–67, 1981.
Pagés, F., González, H. E., Ramon, M., Sobarzo, M., and Gili, J. M.:
Gelatinous zooplankton assemblages associated with wáter masses in the
Humboldt Current System, and potential predatory impact by Bassia bassensis (Siphonophora;
Calycophorae), Mar. Ecol. Prog. Ser., 210, 13–24, 2001.
Palma, S.: Zooplankton distribution and abundance in the austral Chilean
channels and fjords. Progress in the oceanographic knowledge of Chilean inner
waters, from Puerto Montt to Cape Horn, Comité Oceanográfico Nacional
– Pontificia Universidad Católica de Valparaíso, Valparaíso,
Chile, 107–113, available at: http://www.cona.cl/ (last access: 2 October 2018), 2008.
Paulmier, A. and Ruiz-Pino, D.: Oxygen minimum zones (OMZs) in the modern
ocean, Prog. Oceanogr., 80, 113–128, 2009.
Pawlowicz, R., Beardsley, B., and Lentz, S.: Classical tidal harmonic analysis including error
estimates in MATLAB using T_TIDE, Comput. Geosci., 28, 929–937, 2002.
Pantoja, S., Iriarte, L., and Daneri, G.: Oceanography of the Chilean
Patagonia, Cont. Shelf Res., 31, 149–153, 2011.
Pérez-Santos, I., Garcés-Vargas, J., Schneider, W., Ross, L., Parra, S.,
and Valle-Levinson, A.: Double-diffusive layering and mixing in Patagonia fjords,
Prog. Oceanogr., 129, 35–49, 2014.
Pérez-Santos, I.: Deep ventilation event during fall and winter of 2015
in Puyuhuapi fjord (44.6∘ S), Lajar, 45, 223–225, 2017.
Peters, H. and Bokhorst, R.: Microstructure observations of turbulent mixing in
a partially mixed estuary. Part II: Salt flux and stress, J. Phys.
Oceanogr., 31, 1105–1119, 2001.
Ressler, P. H.: Acoustic backscatter measurements with a 153 kHz ADCP in the
northeastern Gulf of Mexico: determination of dominant zooplankton and
micronekton scatterers, Deep-Sea Res. Pt. I, 49, 2035–2051, 2002.
Rodriguez, J. M., Hernandez-Leon, S., and Barton, E. D.: Mesoscale distribution of
fish larvae in relation to an upwelling filament off northwest Africa, Deep-Sea Res. Pt. I, 46, 1969–1984, 1999.
Robinson, C. and Gómez-Gutiérrez, J.: Daily vertical migration of
dense deep scattering layers to the shelf-break along the northwest coast of
Baja California, Mexico, J. Plankton Res., 20, 1679–1697, 1998.
Ross, L., Pérez-Santos, I., Valle-levinson, A., and Schneider, W.: Semidiurnal
internal tides in a Patagonian fjord, Prog. Oceanogr., 129, 19–34,
2014.
Røstad, A. and Kaartvedt, S.: Seasonal and diel patterns in sedimentary
flux of krill fecal pellets recorded by an echo-sounder, Limnol. Oceanogr.,
58, 1985–1997, 2013.
Sato, M.: Variability in Diel Vertical Migration of Zooplankton and Physical
Properties in Saanich Inlet, British Columbia, a dissertation submitted in
partial fulfillment of the requirements for the degree of doctor of
philosophy in the School of Earth and Ocean Sciences, University of Victoria,
Canada, 2013.
Sato, M., Horne, J., Parker-Stetter, S., Essington, T., Keister, J.,
Moriarty, P., Li, L., and Newton, J.: Impacts of moderate hypoxia on fish and zooplankton
prey distributions in a coastal fjord, Mar. Ecol. Prog. Ser., 560, 57–72, 2016.
Seibel, B. A., Schneider, J. L., Kaartvedt, S., Wishner, K. F., and Daly, K. L.:
Hypoxia Tolerance and Metabolic Suppression in Oxygen Minimum Zone
Euphausiids: Implications for Ocean Deoxygenation and Biogeochemical Cycles,
Integr. Comp. Biol., 56, 510–523, 2016.
Shih, L. H., Koseff, J. R., Ivey, G. N., and Ferziger, J.: Parameterization
of turbulent fluxes and scales using homogeneous sheared stably stratified
turbulence simulations, J. Fluid Mech., 525, 193–214, 2005.
Silva, N. and Calvete, C.: Physical and chemical oceanographic features of
southern Chilean inlets between Penas Gulf and Magellan Strait (Cimar-Fiordo
2 cruise), Ciencias y Tecnología del Mar, 25, 23–88, 2002.
Silva, N., Rojas, N., and Fedele, A.: Water masses in the Humboldt Current
System: Properties, distribution, and the nitrate deficit as a chemical water
mass tracer for Equatorial Subsurface Water off Chile, Deep-Sea Res. Pt. II,
56, 1004–1020, https://doi.org/10.1016/j.dsr2.2008.12.013, 2009.
Silva, N. and Vargas, C.: Hypoxia in Chilean Patagonia fjords, Prog. Oceanogr., 129,
62–74, 2014.
Sievers, A. H. and Silva, N.: Water masses and circulation in austral Chilean
channels and fjords, in: Progress in the oceanographic knowledge of Chilean
inner waters, from Puerto Montt to Cape Horn, edited by: Silva, N. and Palma,
S., Comité Oceanográfico Nacional – Pontificia Universidad
Católica de Valparaíso, Valparaíso, Chile, 53–58, available
at: http://www.cona.cl/ (last access: 2 October 2018), 2008.
Simmonds, E. J. and MacLennan, D. N.: Fisheries Acoustics: Theory and
Practice, 2nd edn., Blackwell Science, London, 456, 2005.
Schneider, W., Pérez-Santos, I., Ross, L., Bravo, L., Seguel, R.,
and Hernández, F.: On the hydrography of Puyuhuapi Channel, Chilean
Patagonia, Prog. Oceanogr., 128, 8–18, 2014.
Strickland, J. D. H. and Parsons, T. R.: A Practical Handbook of Seawater
Analysis, B. Fish. Res. Board Can., 167, 293 pp., 1968.
Valle-Levinson, A., Castro, L., Cáceres, M., and Pizarro, O.: Twilight vertical
migrations of zooplankton in a Chilean fjord, Prog. Oceanogr., 129, 114–124,
2014.
Visser, A. and Stips, A.: Turbulence and zooplankton production: insights from
PROVESS, J. Sea Res., 47, 317–329, 2002.
Visser, A., Mariani, P., and Pigolotti, S.: Swimming in turbulence: zooplankton
fitness in terms of foraging efficiency and predation risk, J. Plankton Res.,
31, 121–133, 2009.
Whitney, M., Jia, Y., McManus, P. M., and Kunz, C. J.: Sill effects on
physical dynamics in eastern Long Island Sound, Ocean Dynam., 64, 443–458,
https://doi.org/10.1007/s10236-013-0681-6, 2014.
Zhou, M. and Dorland, R.: Aggregation and verticalmigration behavior of
Euphausia superba, Deep-Sea Res. Pt. II, 51, 2119–2137, 2004.
Short summary
Fjord systems play an important role in primary production and carbon export. Acoustic, hydrographic and in situ abundance measurements were used to study macrozooplankton assemblages at 44.7° S. Diel vertical migration of zooplankton stopped at the hypoxic boundary layer and apparently did not tolerate the hypoxic conditions. Turbulence appears to be the oceanographic process that contributes to vertical mixing around the sill, helping the interchange of nutrients, feeding and carbon export.
Fjord systems play an important role in primary production and carbon export. Acoustic,...
