TY - JOUR
T1 - Increasing depth distribution of Arctic kelp with increasing number of open water days with light
AU - De La Guardia, Laura Castro
AU - Filbee-Dexter, Karen
AU - Reimer, Jillian
AU - MacGregor, Kathleen A.
AU - Garrido, Ignacio
AU - Singh, Rakesh K.
AU - Bélanger, Simon
AU - Konar, Brenda
AU - Iken, Katrin
AU - Johnson, Ladd E.
AU - Archambault, Philippe
AU - Sejr, Mikael K.
AU - Søreide, Janne E.
AU - Mundy, C. J.
N1 - Funding Information:
This research was funded through: the Marine Environmental Observation, Prediction and Response Network of Centres of Excellence (MEOPAR-NCE), Polar Knowledge Canada, and National Science and Engineering Research Council of Canada (NSERC) ship time grants for the Southampton Island Marine Ecosystem Project (SIMEP, https://doi.org/10.34992/dc0p-kf56 , to CJM); the 2017–2018 Belmont Forum and BiodivERsA joint call for research proposals under the BiodivScen ERA-Net COFUND programme to the project ACCES: De-icing of Arctic coasts: Critical or new opportunities for marine biodiversity and ecosystem services? with funding organizations National Science Foundation (NSF; project nr. 1906726 to KI and BK), Natural Science and Engineering Research Council of Canada (NSERC; project nr. RGPBB 523763-2018 to CJM and project nr. RGPIN-2019-06070 to SB), Fonds de recherche du Québec -Nature et technologies (FRQNT; project nr. 270860 to SB) and Research Council of Norway (RCN; project nr. 296836 to JES); NSERC Discovery Grant and Northern Research Supplements to SB, PA, CJM; ArcticNet (project nr. P101 ArcticKelp, htts://www.arctickelp.ca , to PA, KFD, and LEJ); NSERC Postdoctoral Fellowship program (NSERC-PDF; project nr. 516938-2018 to KFD) and Australian Research Council DECRA (project nr. DE1901006192 to KFD). Furthermore, this study was supported in part by the Churchill Marine Observatory (CMO), which was funded by the Canada Foundation for Innovation and other partners, including the Arctic Research Foundation (ARF). This work represents a contribution to the Canada Excellence Research Chair (CERC) unit at the University of Manitoba.
Funding Information:
This research was funded through: the Marine Environmental Observation, Prediction and Response Network of Centres of Excellence (MEOPAR-NCE), Polar Knowledge Canada, and National Science and Engineering Research Council of Canada (NSERC) ship time grants for the Southampton Island Marine Ecosystem Project (SIMEP, https:// doi.org/10.34992/dc0p-kf56, to CJM); the 2017-2018 Belmont Forum and BiodivERsA joint call for research proposals under the BiodivScen ERA-Net COFUND programme to the project ACCES: De-icing of Arctic coasts: Critical or new opportunities for marine biodiversity and ecosystem services? with funding organizations National Science Foundation (NSF; project nr. 1906726 to KI and BK), Natural Science and Engineering Research Council of Canada (NSERC; project nr. RGPBB 523763-2018 to CJM and project nr. RGPIN-2019-06070 to SB), Fonds de recherche du Québec -Nature et technologies (FRQNT; project nr. 270860 to SB) and Research Council of Norway (RCN; project nr. 296836 to JES); NSERC Discovery Grant and Northern Research Supplements to SB, PA, CJM; ArcticNet (project nr. P101 ArcticKelp, htts://www.arctickelp. ca, to PA, KFD, and LEJ); NSERC Postdoctoral Fellowship program (NSERC-PDF; project nr. 516938-2018 to KFD) and Australian Research Council DECRA (project nr. DE1901006192 to KFD). Furthermore, this study was supported in part by the Churchill Marine Observatory (CMO), which was funded by the Canada Foundation for Innovation and other partners, including the Arctic Research Foundation (ARF). This work represents a contribution to the Canada Excellence Research Chair (CERC) unit at the University of Manitoba.
Publisher Copyright:
© 2023 The Author(s).
PY - 2023/3/2
Y1 - 2023/3/2
N2 - Kelps are a dominant macrophyte group and primary producer in Arctic nearshore waters that provide significant services to the coastal ecosystem. The quantification of these services in the Arctic is constrained, however, by limited estimates of kelp depth extent, which creates uncertainties in the area covered by kelp. Here, we test the environmental drivers of the depth extent of Arctic kelp. We used Southampton Island (SI), Nunavut, Canada, as an example region after an initial survey found deep Arctic kelp (at depths to at least 50 m) with relatively low grazing pressure within diverse hydrographic conditions. We found abundant rocky substrata, but no influence of substratum type on kelp cover. The kelp cover increased with depth until 20 m and then decreased (the median maximum depth for all stations was 37 m). The best predictor of kelp depth extent was the number of annual open (ice-free) water days with light (r2 = 44-52%); combining depth extent data from SI with published data from Greenland strengthened this relationship (r2 = 58-71%). Using these relationships we estimated the maximum kelp-covered area around SI to be 27;000-28;000 km2, yielding potential primary production between 0.6 and 1.9 Tg Cyr-1. Water transparency was a key determinant of the underwater light environment and was essential for explaining cross-regional differences in kelp depth extent in SI and Greenland. Around SI the minimum underwater light required by kelp was 49 mol photons m-2 yr-1, or 1.4% of annual integrated incident irradiance. Future consideration of seasonal variation in water transparency can improve these underwater light estimations, while future research seeking to understand the kelp depth extent relationship with nutrients and ocean dynamics can further advance estimates of their vertical distribution. Improving our understanding of the drivers of kelp depth extent can reduce uncertainties around the role of kelp in Arctic marine ecosystems.
AB - Kelps are a dominant macrophyte group and primary producer in Arctic nearshore waters that provide significant services to the coastal ecosystem. The quantification of these services in the Arctic is constrained, however, by limited estimates of kelp depth extent, which creates uncertainties in the area covered by kelp. Here, we test the environmental drivers of the depth extent of Arctic kelp. We used Southampton Island (SI), Nunavut, Canada, as an example region after an initial survey found deep Arctic kelp (at depths to at least 50 m) with relatively low grazing pressure within diverse hydrographic conditions. We found abundant rocky substrata, but no influence of substratum type on kelp cover. The kelp cover increased with depth until 20 m and then decreased (the median maximum depth for all stations was 37 m). The best predictor of kelp depth extent was the number of annual open (ice-free) water days with light (r2 = 44-52%); combining depth extent data from SI with published data from Greenland strengthened this relationship (r2 = 58-71%). Using these relationships we estimated the maximum kelp-covered area around SI to be 27;000-28;000 km2, yielding potential primary production between 0.6 and 1.9 Tg Cyr-1. Water transparency was a key determinant of the underwater light environment and was essential for explaining cross-regional differences in kelp depth extent in SI and Greenland. Around SI the minimum underwater light required by kelp was 49 mol photons m-2 yr-1, or 1.4% of annual integrated incident irradiance. Future consideration of seasonal variation in water transparency can improve these underwater light estimations, while future research seeking to understand the kelp depth extent relationship with nutrients and ocean dynamics can further advance estimates of their vertical distribution. Improving our understanding of the drivers of kelp depth extent can reduce uncertainties around the role of kelp in Arctic marine ecosystems.
KW - Arctic coastal regions
KW - Depth extent
KW - Kelp
KW - Minimum light
KW - Open water days
KW - Water transparency
UR - http://www.scopus.com/inward/record.url?scp=85150526515&partnerID=8YFLogxK
U2 - 10.1525/elementa.2022.00051
DO - 10.1525/elementa.2022.00051
M3 - Article
AN - SCOPUS:85150526515
VL - 11
JO - Elementa
JF - Elementa
IS - 1
M1 - 11
ER -