Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland

Insights from imaging variable chlorophyll fluorescence of ice cores

Ian Hawes, Lars Chresten Lund-Hansen, Brian Keith Sorrell, Morten Holtegaard Nielsen, Réka Borzák, Inge Buss

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice–water interface showed the development of ice algae in 0.3–0.4 mm wide brine channels between laminar ice crystals in the lower 4–6 mm of the ice, with a several-fold spatial variation in inferred biomass on cm scales. The maximum quantum yield of photosynthesis, Fv/Fm, was initially low (~0.1), though this increased rapidly to ~0.5 by day 6. Day 6 also saw the onset of biomass increase, the cessation of ice growth and the time at which brine had reached −2 °C. We interpret this as indicating that the establishment of stable brine channels at close to ambient salinity was required to trigger photosynthetically active populations. Maximum relative electron transport rate (rETRmax), saturation irradiance (Ek) and photosynthetic efficiency (α) had also stabilised by day 6 at 5–6 relative units, ~30 μmol photons m−2 s−1 and 0.4–0.5 μmol photons m−2 s−1, respectively. Ek was consistent with under-ice irradiance, which peaked at a similar value, confirming that daytime irradiance was adequate to facilitate photosynthetic activity throughout the study period. Photosynthetic parameters showed no substantial differences with depth within the ice, nor variation between cores or brine channels suggesting that during this early phase of ice algal growth cells were unaffected by gradients of environmental conditions within the ice. Variable chlorophyll fluorescence imaging offers a tool to determine how this situation may change over time and as brine channels and algal populations evolve.

Original languageEnglish
JournalPhotosynthesis Research
Volume112
Issue number2
Pages (from-to)103-115
ISSN0166-8595
DOIs
Publication statusPublished - 2012

Keywords

  • Photosynthesis
  • Diatoms
  • Sea ice
  • Spring bloom
  • Photophysiology
  • Fluorescence
  • Electron transport

Cite this

Hawes, Ian ; Lund-Hansen, Lars Chresten ; Sorrell, Brian Keith ; Nielsen, Morten Holtegaard ; Borzák, Réka ; Buss, Inge. / Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland : Insights from imaging variable chlorophyll fluorescence of ice cores. In: Photosynthesis Research. 2012 ; Vol. 112, No. 2. pp. 103-115.
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abstract = "We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice–water interface showed the development of ice algae in 0.3–0.4 mm wide brine channels between laminar ice crystals in the lower 4–6 mm of the ice, with a several-fold spatial variation in inferred biomass on cm scales. The maximum quantum yield of photosynthesis, Fv/Fm, was initially low (~0.1), though this increased rapidly to ~0.5 by day 6. Day 6 also saw the onset of biomass increase, the cessation of ice growth and the time at which brine had reached −2 °C. We interpret this as indicating that the establishment of stable brine channels at close to ambient salinity was required to trigger photosynthetically active populations. Maximum relative electron transport rate (rETRmax), saturation irradiance (Ek) and photosynthetic efficiency (α) had also stabilised by day 6 at 5–6 relative units, ~30 μmol photons m−2 s−1 and 0.4–0.5 μmol photons m−2 s−1, respectively. Ek was consistent with under-ice irradiance, which peaked at a similar value, confirming that daytime irradiance was adequate to facilitate photosynthetic activity throughout the study period. Photosynthetic parameters showed no substantial differences with depth within the ice, nor variation between cores or brine channels suggesting that during this early phase of ice algal growth cells were unaffected by gradients of environmental conditions within the ice. Variable chlorophyll fluorescence imaging offers a tool to determine how this situation may change over time and as brine channels and algal populations evolve.",
keywords = "Photosynthesis, Diatoms, Sea ice, Spring bloom, Photophysiology, Fluorescence, Electron transport",
author = "Ian Hawes and Lund-Hansen, {Lars Chresten} and Sorrell, {Brian Keith} and Nielsen, {Morten Holtegaard} and R{\'e}ka Borz{\'a}k and Inge Buss",
year = "2012",
doi = "10.1007/s11120-012-9736-7",
language = "English",
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Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland : Insights from imaging variable chlorophyll fluorescence of ice cores. / Hawes, Ian; Lund-Hansen, Lars Chresten; Sorrell, Brian Keith; Nielsen, Morten Holtegaard; Borzák, Réka; Buss, Inge.

In: Photosynthesis Research, Vol. 112, No. 2, 2012, p. 103-115.

Research output: Contribution to journalJournal articleResearchpeer-review

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T1 - Photobiology of sea ice algae during initial spring growth in Kangerlussuaq, West Greenland

T2 - Insights from imaging variable chlorophyll fluorescence of ice cores

AU - Hawes, Ian

AU - Lund-Hansen, Lars Chresten

AU - Sorrell, Brian Keith

AU - Nielsen, Morten Holtegaard

AU - Borzák, Réka

AU - Buss, Inge

PY - 2012

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N2 - We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice–water interface showed the development of ice algae in 0.3–0.4 mm wide brine channels between laminar ice crystals in the lower 4–6 mm of the ice, with a several-fold spatial variation in inferred biomass on cm scales. The maximum quantum yield of photosynthesis, Fv/Fm, was initially low (~0.1), though this increased rapidly to ~0.5 by day 6. Day 6 also saw the onset of biomass increase, the cessation of ice growth and the time at which brine had reached −2 °C. We interpret this as indicating that the establishment of stable brine channels at close to ambient salinity was required to trigger photosynthetically active populations. Maximum relative electron transport rate (rETRmax), saturation irradiance (Ek) and photosynthetic efficiency (α) had also stabilised by day 6 at 5–6 relative units, ~30 μmol photons m−2 s−1 and 0.4–0.5 μmol photons m−2 s−1, respectively. Ek was consistent with under-ice irradiance, which peaked at a similar value, confirming that daytime irradiance was adequate to facilitate photosynthetic activity throughout the study period. Photosynthetic parameters showed no substantial differences with depth within the ice, nor variation between cores or brine channels suggesting that during this early phase of ice algal growth cells were unaffected by gradients of environmental conditions within the ice. Variable chlorophyll fluorescence imaging offers a tool to determine how this situation may change over time and as brine channels and algal populations evolve.

AB - We undertook a series of measurements of photophysiological parameters of sea ice algae over 12 days of early spring growth in a West Greenland Fjord, by variable chlorophyll fluorescence imaging. Imaging of the ice–water interface showed the development of ice algae in 0.3–0.4 mm wide brine channels between laminar ice crystals in the lower 4–6 mm of the ice, with a several-fold spatial variation in inferred biomass on cm scales. The maximum quantum yield of photosynthesis, Fv/Fm, was initially low (~0.1), though this increased rapidly to ~0.5 by day 6. Day 6 also saw the onset of biomass increase, the cessation of ice growth and the time at which brine had reached −2 °C. We interpret this as indicating that the establishment of stable brine channels at close to ambient salinity was required to trigger photosynthetically active populations. Maximum relative electron transport rate (rETRmax), saturation irradiance (Ek) and photosynthetic efficiency (α) had also stabilised by day 6 at 5–6 relative units, ~30 μmol photons m−2 s−1 and 0.4–0.5 μmol photons m−2 s−1, respectively. Ek was consistent with under-ice irradiance, which peaked at a similar value, confirming that daytime irradiance was adequate to facilitate photosynthetic activity throughout the study period. Photosynthetic parameters showed no substantial differences with depth within the ice, nor variation between cores or brine channels suggesting that during this early phase of ice algal growth cells were unaffected by gradients of environmental conditions within the ice. Variable chlorophyll fluorescence imaging offers a tool to determine how this situation may change over time and as brine channels and algal populations evolve.

KW - Photosynthesis

KW - Diatoms

KW - Sea ice

KW - Spring bloom

KW - Photophysiology

KW - Fluorescence

KW - Electron transport

U2 - 10.1007/s11120-012-9736-7

DO - 10.1007/s11120-012-9736-7

M3 - Journal article

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SP - 103

EP - 115

JO - Photosynthesis Research

JF - Photosynthesis Research

SN - 0166-8595

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ER -