Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean
The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to exa...
Published in: | Atmospheric Chemistry and Physics |
---|---|
Main Authors: | , , , |
Format: | Text |
Language: | English |
Published: |
2018
|
Subjects: | |
Online Access: | https://doi.org/10.5194/acp-11-2487-2011 https://www.atmos-chem-phys.net/11/2487/2011/ |
id |
ftcopernicus:oai:publications.copernicus.org:acp8754 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:acp8754 2023-05-15T13:45:55+02:00 Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean Johnson, M. S. Meskhidze, N. Kiliyanpilakkil, V. P. Gassó, S. 2018-01-15 application/pdf https://doi.org/10.5194/acp-11-2487-2011 https://www.atmos-chem-phys.net/11/2487/2011/ eng eng doi:10.5194/acp-11-2487-2011 https://www.atmos-chem-phys.net/11/2487/2011/ eISSN: 1680-7324 Text 2018 ftcopernicus https://doi.org/10.5194/acp-11-2487-2011 2019-12-24T09:56:57Z The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system) elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem), implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble iron, while a dust/biota assessment tool (Boyd et al., 2010) is applied to evaluate the amount of bioavailable iron formed through the slow and sustained leaching of dust in the ocean mixed layer. The effect of iron-laden mineral dust supply on surface ocean biomass is investigated by comparing predicted surface chlorophyll- a concentration ([Chl- a ]) to remotely-sensed data. As the dust transport episodes examined here represent large summertime outflows of mineral dust from South American continental sources, this study suggests that (1) atmospheric fluxes of mineral dust from Patagonia are not likely to be the major source of bioavailable iron to ocean regions characterized by high primary productivity; (2) even if Patagonian dust plumes may not cause visible algae blooms, they could still influence background [Chl- a ] in the South Atlantic sector of the Southern Ocean. Text Antarc* Antarctica South Atlantic Ocean Southern Ocean Copernicus Publications: E-Journals Austral Patagonia Southern Ocean Atmospheric Chemistry and Physics 11 6 2487 2502 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system) elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem), implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble iron, while a dust/biota assessment tool (Boyd et al., 2010) is applied to evaluate the amount of bioavailable iron formed through the slow and sustained leaching of dust in the ocean mixed layer. The effect of iron-laden mineral dust supply on surface ocean biomass is investigated by comparing predicted surface chlorophyll- a concentration ([Chl- a ]) to remotely-sensed data. As the dust transport episodes examined here represent large summertime outflows of mineral dust from South American continental sources, this study suggests that (1) atmospheric fluxes of mineral dust from Patagonia are not likely to be the major source of bioavailable iron to ocean regions characterized by high primary productivity; (2) even if Patagonian dust plumes may not cause visible algae blooms, they could still influence background [Chl- a ] in the South Atlantic sector of the Southern Ocean. |
format |
Text |
author |
Johnson, M. S. Meskhidze, N. Kiliyanpilakkil, V. P. Gassó, S. |
spellingShingle |
Johnson, M. S. Meskhidze, N. Kiliyanpilakkil, V. P. Gassó, S. Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
author_facet |
Johnson, M. S. Meskhidze, N. Kiliyanpilakkil, V. P. Gassó, S. |
author_sort |
Johnson, M. S. |
title |
Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
title_short |
Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
title_full |
Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
title_fullStr |
Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
title_full_unstemmed |
Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean |
title_sort |
understanding the transport of patagonian dust and its influence on marine biological activity in the south atlantic ocean |
publishDate |
2018 |
url |
https://doi.org/10.5194/acp-11-2487-2011 https://www.atmos-chem-phys.net/11/2487/2011/ |
geographic |
Austral Patagonia Southern Ocean |
geographic_facet |
Austral Patagonia Southern Ocean |
genre |
Antarc* Antarctica South Atlantic Ocean Southern Ocean |
genre_facet |
Antarc* Antarctica South Atlantic Ocean Southern Ocean |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-11-2487-2011 https://www.atmos-chem-phys.net/11/2487/2011/ |
op_doi |
https://doi.org/10.5194/acp-11-2487-2011 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
11 |
container_issue |
6 |
container_start_page |
2487 |
op_container_end_page |
2502 |
_version_ |
1766232544466960384 |