Changing biogeochemistry of the Southern Ocean and its ecosystem implications
The datasets published here apply only to unpublished nutrient data from the wintertime trans-Southern Ocean sections WOCE line IO6 (2017) and A12 (2019) and one summertime surface ocean A12 ammonium dataset. Nutrient concentrations are in units micromole per liter. Variables measured from the CTD (...
Main Authors: | , , , , , , , , , , , , |
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Format: | Dataset |
Language: | English |
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Zenodo
2020
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Online Access: | https://dx.doi.org/10.5281/zenodo.3883618 https://zenodo.org/record/3883618 |
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ftdatacite:10.5281/zenodo.3883618 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Southern Ocean, biogeochemistry, macronutrient concentrations, ammonium concentrations, nutrient ratios, N*, DIN*, Si* |
spellingShingle |
Southern Ocean, biogeochemistry, macronutrient concentrations, ammonium concentrations, nutrient ratios, N*, DIN*, Si* Henley, Sian Frances Cavan, Emma Louise Fawcett, Sarah E. Kerr, Rodrigo Monteiro, Thiago Sherrell, Robert Bowie, Andrew Ross Boyd, Philip W. Barnes, David K. A. Schloss, Irene R. Marshall, Tanya Flynn, Raquel Smith, Shantelle Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
topic_facet |
Southern Ocean, biogeochemistry, macronutrient concentrations, ammonium concentrations, nutrient ratios, N*, DIN*, Si* |
description |
The datasets published here apply only to unpublished nutrient data from the wintertime trans-Southern Ocean sections WOCE line IO6 (2017) and A12 (2019) and one summertime surface ocean A12 ammonium dataset. Nutrient concentrations are in units micromole per liter. Variables measured from the CTD (pressure, temperature and salinity) for the two wintertime datasets are provided at 1 m resolution. Winter nutrient sampling was conducted aboard the R/V SA Agulhas II in 2017 (WC-17; 28 June – 13 July 2017) along WOCE line IO6 (Indian sector) and in 2019 (SCALE; 18 July – 12 August 2019) along WOCE line A12 (the GoodHope repeat hydrographic line; Atlantic sector). Seawater was collected at regular depth intervals in 12-L Niskin bottles attached to a CTD rosette. Samples for the analysis of nitrate, nitrite, dissolved silicon and phosphate concentrations were decanted into replicate 50 mL HDPE tubes that were copiously rinsed prior to filling. Duplicate tubes were immediately frozen at -20°C for later measurement of nitrate and dissolved silicon, whilst nitrite and phosphate samples that were to be measured shipboard within a few hours were stored in the fridge. Duplicate samples of unfiltered seawater (~40 mL) were also collected at each depth between the surface and 500 m for the analysis of ammonium concentrations in 50 mL HDPE Nalgene bottles that had been stored (“aged”) with orthophthaldialdehyde working reagent (OPA-WR) prior to sample collection. The OPA-WR was decanted just prior to sample collection and bottles were rinsed three times with sample seawater prior to filling. Phosphate and nitrite concentrations were analysed manually according to the methods described by Grasshoff et al. (1983), with absorbance measured using a Thermo Scientific Genesis 30 Visible spectrophotometer. Aliquots of a certified reference material (CRM; JAMSTEC) were analysed with each sample run to ensure data quality. Nitrate+nitrite and dissolved silicon were measured in the Marine Biogeochemistry Lab at the University of Cape Town (MBL-UCT) using a Lachat Quick-Chem flow injection autoanalyser (Wolters, 2002;Egan, 2008). Standards of varying concentration were run after every ten samples to monitor instrument performance and allow for correction of any drift, and a CRM was measured at the beginning and end of each run to ensure measurement accuracy. The precision of the nitrate+nitrite, dissolved silicon, phosphate, and nitrite measurements was ± 0.4 µmol L-1, ± 0.2 µmol L-1, ± 0.06 µmol L-1, and ± 0.05 µmol L-1, respectively, and the detection limit was 0.1 µmol L-1, 0.2 µmol L-1, 0.05 µmol L-1, and 0.05 µmol L-1, respectively. Ammonium concentrations were measured shipboard via the fluorometric method of Holmes et al. (1999) using a UV module in a Turner Designs Trilogy Fluorometer 7500-000. Standards were made daily using Type-1 ultrapure Milli-Q water, and samples and standards were measured in duplicate. Precision was ± 0.01 µmol L-1 and the detection limit was <0.02 µmol L-1. The matrix effect resulting from the calibration of seawater samples to Milli-Q standards was calculated according to the standard addition method (Saxberg and Kowalski, 1979). All samples were corrected for the matrix effect (Holmes et al., 1999), which was always <10% and typically <5%. No ammonium concentration data are available for the summer in the WOCE database. However, we collected triplicate samples of unfiltered seawater (~40 mL) from the underway system (~7 m intake depth) of the R/V SA Agulhas II every ~0.25 degrees of latitude during the 2018/2019 resupply voyage along WOCE line A12 between Cape Town and Antarctica (SANAE 58; 7 – 17 December 2018). These samples were measured shipboard as described above. Although not collected at the same time as the other summertime nutrient data from WOCE line A12, the SANAE 58 ammonium concentrations provide an indication of typical summertime conditions. N* is a quasi-conservative tracer used to track the changes in dissolved inorganic nitrogen (DIN) relative to phosphate, thereby providing information as to whether fixed nitrogen is being added to or lost from an ecosystem relative to phosphorus (Gruber and Sarmiento, 1997). N* was originally defined as N* (µmol L-1) = [NO3-] – 16 x [PO43-]. Here, we further derive N*DIN = [NO3-+NO2-+NH4+] – 16 x [PO43-] where DIN is the sum of nitrate, nitrite and ammonium, and 16 is the average stoichiometric N:P ratio observed during the autotrophic production and heterotrophic remineralisation of organic matter (Redfield et al., 1963;Anderson and Sarmiento, 1994). The tracer Si* was initially developed to track SAMW from its formation region into the lower latitude ocean (Sarmiento et al., 2004). It is also an indicator of the nutrient status of diatoms. Si* leverages the general observation that under favourable conditions, diatoms consume dissolved silicon and nitrate in a ratio of ~1:1 (Hutchins and Bruland, 1998;Takeda, 1998;Ragueneau et al., 2000), but that under conditions of limitation (e.g. of low iron), the ratio of dissolved silicon-to-nitrate uptake changes (e.g. Franck et al., 2000;Brzezinski et al., 2003). Si* was computed from measurements of nitrate and dissolved silicon concentrations following Sarmiento et al. (2004) as Si* (µmol L-1) = [Si(OH)4] – [NO3-]. : The biogeochemical data from the Rothera Time Series program in northern Marguerite Bay (2013-2016) presented in Section 4 are available through the British Oceanographic Data Centre (BODC) at https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/98cc0722-e337-029ce0536c86abc02029/ (Henley and Venables, 2019). Summer nutrient data for IO6 and A12 are accessible from the WOCE Hydrographic Program data repository (weblink:https://doi.org/10.21976/C6RP4Z). : {"references": ["Anderson, L.A., and Sarmiento, J.L. (1994). Redfield ratios of remineralization determined by nutrient data analysis. Global Biogeochemical Cycles 8, 65-80. Brzezinski, M.A., Dickson, M.L., Nelson, D.M., and Sambrotto, R. (2003). Ratios of Si, C and N uptake by microplankton in the Southern Ocean. Deep-Sea Research Part II-Topical Studies in Oceanography 50, 619-633. Egan, L. (2008). Determination of nitrate and/or nitrite in brackish or seawater by flow injection analysis. Quickchem method\u00ae 31-107-04-1-C. Lachat Instruments, USA. Franck, V.M., Brzezinski, M.A., Coale, K.H., and Nelson, D.M. (2000). Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean. Deep-Sea Research Part II-Topical Studies in Oceanography 47, 3315-3338. Grasshoff, K., Kremling, K., and Ehrhardt, M. (1983). Methods of Seawater Analysis. Verlag Chemie, Weinheim, Germany. Gruber, N., and Sarmiento, J.L. (1997). Global patterns of marine nitrogen fixation and denitrification. Global Biogeochemical Cycles 11, 235-266. Holmes, R.M., Aminot, A., Kerouel, R., Hooker, B.A., and Peterson, B.J. (1999). A simple and precise method for measuring ammonium in marine and freshwater ecosystems. Canadian Journal of Fisheries and Aquatic Sciences 56, 1801-1808. Hutchins, D.A., and Bruland, K.W. (1998). Iron-limited diatom growth and Si : N uptake ratios in a coastal upwelling regime. Nature 393, 561-564. Ragueneau, O., Tr\u00e9guer, P., Leynaert, A., Anderson, R.F., Brzezinski, M.A., Demaster, D.J., Dugdale, R.C., Dymond, J., Fischer, G., Fran\u00e7ois, R., Heinze, C., Maier-Reimer, E., Martin-J\u00e9z\u00e9quel, V., Nelson, D.M., and Qu\u00e9guiner, B. (2000). A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy. Global and Planetary Change 26, 317-365. Redfield, A.C., Ketchum, B.H., and Richards, F.A. (1963). \"The influence of organisms on the composition of sea water,\" in The Sea, ed. M.N. Hill. (New York: Interscience Publishers), 26-77. Sarmiento, J.L., Gruber, N., Brzezinski, M.A., and Dunne, J.P. (2004). High-latitude controls of thermocline nutrients and low latitude biological productivity. Nature 427, 56-60. Saxberg, B.E.H., and Kowalski, B.R. (1979). Generalized standard addition method. Analytical Chemistry 51, 1031-1038. Takeda, S. (1998). Influence of iron availability on nutrient consumption ratio of diatoms in oceanic waters. Nature 393, 774-777. Wolters, M. (2002). Determination of silicate in brackish or seawater by flow injection analysis. QuickChem\u00ae method 31-114-24-1-D. Lachat Instruments, USA."]} |
format |
Dataset |
author |
Henley, Sian Frances Cavan, Emma Louise Fawcett, Sarah E. Kerr, Rodrigo Monteiro, Thiago Sherrell, Robert Bowie, Andrew Ross Boyd, Philip W. Barnes, David K. A. Schloss, Irene R. Marshall, Tanya Flynn, Raquel Smith, Shantelle |
author_facet |
Henley, Sian Frances Cavan, Emma Louise Fawcett, Sarah E. Kerr, Rodrigo Monteiro, Thiago Sherrell, Robert Bowie, Andrew Ross Boyd, Philip W. Barnes, David K. A. Schloss, Irene R. Marshall, Tanya Flynn, Raquel Smith, Shantelle |
author_sort |
Henley, Sian Frances |
title |
Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
title_short |
Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
title_full |
Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
title_fullStr |
Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
title_full_unstemmed |
Changing biogeochemistry of the Southern Ocean and its ecosystem implications |
title_sort |
changing biogeochemistry of the southern ocean and its ecosystem implications |
publisher |
Zenodo |
publishDate |
2020 |
url |
https://dx.doi.org/10.5281/zenodo.3883618 https://zenodo.org/record/3883618 |
long_lat |
ENVELOPE(141.378,141.378,-66.787,-66.787) ENVELOPE(-68.130,-68.130,-67.568,-67.568) ENVELOPE(-68.000,-68.000,-68.500,-68.500) ENVELOPE(-86.200,-86.200,-77.800,-77.800) ENVELOPE(-62.050,-62.050,-63.283,-63.283) ENVELOPE(-2.850,-2.850,-71.667,-71.667) ENVELOPE(-68.000,-68.000,-72.000,-72.000) ENVELOPE(15.262,15.262,68.757,68.757) |
geographic |
Southern Ocean Pacific Indian Marguerite Rothera Marguerite Bay Reimer Hooker SANAE Sarmiento Bruland |
geographic_facet |
Southern Ocean Pacific Indian Marguerite Rothera Marguerite Bay Reimer Hooker SANAE Sarmiento Bruland |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_relation |
https://dx.doi.org/10.3389/fmars.2020.00581 https://dx.doi.org/10.5281/zenodo.3883617 |
op_rights |
Open Access Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5281/zenodo.3883618 https://doi.org/10.3389/fmars.2020.00581 https://doi.org/10.5281/zenodo.3883617 |
_version_ |
1766193100213977088 |
spelling |
ftdatacite:10.5281/zenodo.3883618 2023-05-15T13:43:47+02:00 Changing biogeochemistry of the Southern Ocean and its ecosystem implications Henley, Sian Frances Cavan, Emma Louise Fawcett, Sarah E. Kerr, Rodrigo Monteiro, Thiago Sherrell, Robert Bowie, Andrew Ross Boyd, Philip W. Barnes, David K. A. Schloss, Irene R. Marshall, Tanya Flynn, Raquel Smith, Shantelle 2020 https://dx.doi.org/10.5281/zenodo.3883618 https://zenodo.org/record/3883618 en eng Zenodo https://dx.doi.org/10.3389/fmars.2020.00581 https://dx.doi.org/10.5281/zenodo.3883617 Open Access Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 info:eu-repo/semantics/openAccess CC-BY Southern Ocean, biogeochemistry, macronutrient concentrations, ammonium concentrations, nutrient ratios, N*, DIN*, Si* dataset Dataset 2020 ftdatacite https://doi.org/10.5281/zenodo.3883618 https://doi.org/10.3389/fmars.2020.00581 https://doi.org/10.5281/zenodo.3883617 2021-11-05T12:55:41Z The datasets published here apply only to unpublished nutrient data from the wintertime trans-Southern Ocean sections WOCE line IO6 (2017) and A12 (2019) and one summertime surface ocean A12 ammonium dataset. Nutrient concentrations are in units micromole per liter. Variables measured from the CTD (pressure, temperature and salinity) for the two wintertime datasets are provided at 1 m resolution. Winter nutrient sampling was conducted aboard the R/V SA Agulhas II in 2017 (WC-17; 28 June – 13 July 2017) along WOCE line IO6 (Indian sector) and in 2019 (SCALE; 18 July – 12 August 2019) along WOCE line A12 (the GoodHope repeat hydrographic line; Atlantic sector). Seawater was collected at regular depth intervals in 12-L Niskin bottles attached to a CTD rosette. Samples for the analysis of nitrate, nitrite, dissolved silicon and phosphate concentrations were decanted into replicate 50 mL HDPE tubes that were copiously rinsed prior to filling. Duplicate tubes were immediately frozen at -20°C for later measurement of nitrate and dissolved silicon, whilst nitrite and phosphate samples that were to be measured shipboard within a few hours were stored in the fridge. Duplicate samples of unfiltered seawater (~40 mL) were also collected at each depth between the surface and 500 m for the analysis of ammonium concentrations in 50 mL HDPE Nalgene bottles that had been stored (“aged”) with orthophthaldialdehyde working reagent (OPA-WR) prior to sample collection. The OPA-WR was decanted just prior to sample collection and bottles were rinsed three times with sample seawater prior to filling. Phosphate and nitrite concentrations were analysed manually according to the methods described by Grasshoff et al. (1983), with absorbance measured using a Thermo Scientific Genesis 30 Visible spectrophotometer. Aliquots of a certified reference material (CRM; JAMSTEC) were analysed with each sample run to ensure data quality. Nitrate+nitrite and dissolved silicon were measured in the Marine Biogeochemistry Lab at the University of Cape Town (MBL-UCT) using a Lachat Quick-Chem flow injection autoanalyser (Wolters, 2002;Egan, 2008). Standards of varying concentration were run after every ten samples to monitor instrument performance and allow for correction of any drift, and a CRM was measured at the beginning and end of each run to ensure measurement accuracy. The precision of the nitrate+nitrite, dissolved silicon, phosphate, and nitrite measurements was ± 0.4 µmol L-1, ± 0.2 µmol L-1, ± 0.06 µmol L-1, and ± 0.05 µmol L-1, respectively, and the detection limit was 0.1 µmol L-1, 0.2 µmol L-1, 0.05 µmol L-1, and 0.05 µmol L-1, respectively. Ammonium concentrations were measured shipboard via the fluorometric method of Holmes et al. (1999) using a UV module in a Turner Designs Trilogy Fluorometer 7500-000. Standards were made daily using Type-1 ultrapure Milli-Q water, and samples and standards were measured in duplicate. Precision was ± 0.01 µmol L-1 and the detection limit was <0.02 µmol L-1. The matrix effect resulting from the calibration of seawater samples to Milli-Q standards was calculated according to the standard addition method (Saxberg and Kowalski, 1979). All samples were corrected for the matrix effect (Holmes et al., 1999), which was always <10% and typically <5%. No ammonium concentration data are available for the summer in the WOCE database. However, we collected triplicate samples of unfiltered seawater (~40 mL) from the underway system (~7 m intake depth) of the R/V SA Agulhas II every ~0.25 degrees of latitude during the 2018/2019 resupply voyage along WOCE line A12 between Cape Town and Antarctica (SANAE 58; 7 – 17 December 2018). These samples were measured shipboard as described above. Although not collected at the same time as the other summertime nutrient data from WOCE line A12, the SANAE 58 ammonium concentrations provide an indication of typical summertime conditions. N* is a quasi-conservative tracer used to track the changes in dissolved inorganic nitrogen (DIN) relative to phosphate, thereby providing information as to whether fixed nitrogen is being added to or lost from an ecosystem relative to phosphorus (Gruber and Sarmiento, 1997). N* was originally defined as N* (µmol L-1) = [NO3-] – 16 x [PO43-]. Here, we further derive N*DIN = [NO3-+NO2-+NH4+] – 16 x [PO43-] where DIN is the sum of nitrate, nitrite and ammonium, and 16 is the average stoichiometric N:P ratio observed during the autotrophic production and heterotrophic remineralisation of organic matter (Redfield et al., 1963;Anderson and Sarmiento, 1994). The tracer Si* was initially developed to track SAMW from its formation region into the lower latitude ocean (Sarmiento et al., 2004). It is also an indicator of the nutrient status of diatoms. Si* leverages the general observation that under favourable conditions, diatoms consume dissolved silicon and nitrate in a ratio of ~1:1 (Hutchins and Bruland, 1998;Takeda, 1998;Ragueneau et al., 2000), but that under conditions of limitation (e.g. of low iron), the ratio of dissolved silicon-to-nitrate uptake changes (e.g. Franck et al., 2000;Brzezinski et al., 2003). Si* was computed from measurements of nitrate and dissolved silicon concentrations following Sarmiento et al. (2004) as Si* (µmol L-1) = [Si(OH)4] – [NO3-]. : The biogeochemical data from the Rothera Time Series program in northern Marguerite Bay (2013-2016) presented in Section 4 are available through the British Oceanographic Data Centre (BODC) at https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/98cc0722-e337-029ce0536c86abc02029/ (Henley and Venables, 2019). Summer nutrient data for IO6 and A12 are accessible from the WOCE Hydrographic Program data repository (weblink:https://doi.org/10.21976/C6RP4Z). : {"references": ["Anderson, L.A., and Sarmiento, J.L. (1994). Redfield ratios of remineralization determined by nutrient data analysis. Global Biogeochemical Cycles 8, 65-80. Brzezinski, M.A., Dickson, M.L., Nelson, D.M., and Sambrotto, R. (2003). Ratios of Si, C and N uptake by microplankton in the Southern Ocean. Deep-Sea Research Part II-Topical Studies in Oceanography 50, 619-633. Egan, L. (2008). Determination of nitrate and/or nitrite in brackish or seawater by flow injection analysis. Quickchem method\u00ae 31-107-04-1-C. Lachat Instruments, USA. Franck, V.M., Brzezinski, M.A., Coale, K.H., and Nelson, D.M. (2000). Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean. Deep-Sea Research Part II-Topical Studies in Oceanography 47, 3315-3338. Grasshoff, K., Kremling, K., and Ehrhardt, M. (1983). Methods of Seawater Analysis. Verlag Chemie, Weinheim, Germany. Gruber, N., and Sarmiento, J.L. (1997). Global patterns of marine nitrogen fixation and denitrification. Global Biogeochemical Cycles 11, 235-266. Holmes, R.M., Aminot, A., Kerouel, R., Hooker, B.A., and Peterson, B.J. (1999). A simple and precise method for measuring ammonium in marine and freshwater ecosystems. Canadian Journal of Fisheries and Aquatic Sciences 56, 1801-1808. Hutchins, D.A., and Bruland, K.W. (1998). Iron-limited diatom growth and Si : N uptake ratios in a coastal upwelling regime. Nature 393, 561-564. Ragueneau, O., Tr\u00e9guer, P., Leynaert, A., Anderson, R.F., Brzezinski, M.A., Demaster, D.J., Dugdale, R.C., Dymond, J., Fischer, G., Fran\u00e7ois, R., Heinze, C., Maier-Reimer, E., Martin-J\u00e9z\u00e9quel, V., Nelson, D.M., and Qu\u00e9guiner, B. (2000). A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy. Global and Planetary Change 26, 317-365. Redfield, A.C., Ketchum, B.H., and Richards, F.A. (1963). \"The influence of organisms on the composition of sea water,\" in The Sea, ed. M.N. Hill. (New York: Interscience Publishers), 26-77. Sarmiento, J.L., Gruber, N., Brzezinski, M.A., and Dunne, J.P. (2004). High-latitude controls of thermocline nutrients and low latitude biological productivity. Nature 427, 56-60. Saxberg, B.E.H., and Kowalski, B.R. (1979). Generalized standard addition method. Analytical Chemistry 51, 1031-1038. Takeda, S. (1998). Influence of iron availability on nutrient consumption ratio of diatoms in oceanic waters. Nature 393, 774-777. Wolters, M. (2002). Determination of silicate in brackish or seawater by flow injection analysis. QuickChem\u00ae method 31-114-24-1-D. Lachat Instruments, USA."]} Dataset Antarc* Antarctica Southern Ocean DataCite Metadata Store (German National Library of Science and Technology) Southern Ocean Pacific Indian Marguerite ENVELOPE(141.378,141.378,-66.787,-66.787) Rothera ENVELOPE(-68.130,-68.130,-67.568,-67.568) Marguerite Bay ENVELOPE(-68.000,-68.000,-68.500,-68.500) Reimer ENVELOPE(-86.200,-86.200,-77.800,-77.800) Hooker ENVELOPE(-62.050,-62.050,-63.283,-63.283) SANAE ENVELOPE(-2.850,-2.850,-71.667,-71.667) Sarmiento ENVELOPE(-68.000,-68.000,-72.000,-72.000) Bruland ENVELOPE(15.262,15.262,68.757,68.757) |