The Underwater Photic Environment of Two Subarctic Icelandic Lakes
The underwater light fields of two Icelandic lakes of volcanic origin and differing trophic status, Thingvallavatn (oligotrophic) and Myvatn (eutrophic), were investigated. Gilvin and turbidity depth profiles were also measured. Diurnal variation in photosynthetically active radiation (PAR) reached...
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The Arctic Institute of North America
1993
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ftunivcalgaryojs:oai:journalhosting.ucalgary.ca:article/64372 2023-05-15T14:19:11+02:00 The Underwater Photic Environment of Two Subarctic Icelandic Lakes Heinermann, P.H. Ali, M.A. 1993-01-01 application/pdf https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372 eng eng The Arctic Institute of North America https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372/48307 https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372 ARCTIC; Vol. 46 No. 1 (1993): March: 1–96; 17-26 1923-1245 0004-0843 Adaptation (Biology) Arctic char Chlorophyll Diurnal variations Eutrophic lakes Fresh-water biology Fresh-water ecology Light Oligotrophic lakes Optical properties Phytoplankton Water masses Water quality Iceland info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion research-article 1993 ftunivcalgaryojs 2022-03-22T21:21:38Z The underwater light fields of two Icelandic lakes of volcanic origin and differing trophic status, Thingvallavatn (oligotrophic) and Myvatn (eutrophic), were investigated. Gilvin and turbidity depth profiles were also measured. Diurnal variation in photosynthetically active radiation (PAR) reached almost 3 orders or magnitude. Downward irradiance spectra were variable near the surface, but with increases in depth transmission peaks at 510, 560 and 570 nanometres (nm) became apparent in Thingvallavatn, Myvatn-East Basin and Myvatn-South Basin respectively. Upward irradiance transmission maxima shifted from 480 to 500 nm with depth in Thingvallavatn, while in Myvatn they remained near 570 nm. An irradiance trough at 520 nm was noted in both the upward and downward spectra of Thingvallavatn. The importance of phytoplankton (chlorophyll) and gilvin in modifying the underwater light climate of Myvatn is clearly demonstrated. The mean downwelling and upwelling irradiance curves for Thingvallavatn coincide very well with the spectral sensitivities of resident adult arctic charr. This provides support for the sensitivity hypothesis.Key words: subarctic, limnology, imdiance, underwater light, arctic charr, spectral sensitivitjr, Iceland L'environnement photique sous-marin de deux lacs islandais, le Thingvallavatn (oligotrophe) et le Myvatn (eutrophe), d'origine volcanique et présentant un état trophique différent, ont été étudiés. La quantité de matière organique dissoute (gilvin) et la turbidité ont été mesurées en fonction de la profondeur dans chaque lac. La radiation disponible pour la photosynthèse (PAR) pouvait varier quotidiennement jusqu'à trois ordres de grandeur. Alors que les spectres de l'irradiance descendante variaient près de la surface, ils augmentaient avec la profondeur aux pics de transmission de 510, 560 et 570 nanomètres (nm) respectivement dans le Thingvallavatn et le bassin est du Myvatn et le bassin sud du Myvatn. Les maxima dans la transmission de l'irradiance ascendante ont été décalés avec la profondeur de 480 à 500 nm dans le Thingvallavatn tandis que dans le Myvatn ils sont demeurés près de 570 nm. Une zone d'absorption à 520 nm a également été observée dans les spectres descendants et ascendants du Thingvallavatn. L'importance du phytoplancton (chlorophylle) et de la matière organique dissoute (gilvin) dans la modification de l'environnement photique sous-marin du Myvatn a été nettement démontrée. Les spectres moyens de l'irradiance descendante et ascendante coïncident très étroitement avec les sensibilités spectrales chez les ombles-chevaliers adultes indigènes. Ceci appuie l'hypothèse de la sensibilité chez ces poissons.Mots clés: subarctique, limnologie, irradiance, lumière sous-marine, omble-chevalier, sensibilite spectrale, Islande Article in Journal/Newspaper Arctic Arctic charr Arctic Iceland Islande Omble chevalier Phytoplankton Subarctic subarctique* University of Calgary Journal Hosting Arctic Chevalier ENVELOPE(-57.831,-57.831,51.500,51.500) ARCTIC 46 1 |
institution |
Open Polar |
collection |
University of Calgary Journal Hosting |
op_collection_id |
ftunivcalgaryojs |
language |
English |
topic |
Adaptation (Biology) Arctic char Chlorophyll Diurnal variations Eutrophic lakes Fresh-water biology Fresh-water ecology Light Oligotrophic lakes Optical properties Phytoplankton Water masses Water quality Iceland |
spellingShingle |
Adaptation (Biology) Arctic char Chlorophyll Diurnal variations Eutrophic lakes Fresh-water biology Fresh-water ecology Light Oligotrophic lakes Optical properties Phytoplankton Water masses Water quality Iceland Heinermann, P.H. Ali, M.A. The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
topic_facet |
Adaptation (Biology) Arctic char Chlorophyll Diurnal variations Eutrophic lakes Fresh-water biology Fresh-water ecology Light Oligotrophic lakes Optical properties Phytoplankton Water masses Water quality Iceland |
description |
The underwater light fields of two Icelandic lakes of volcanic origin and differing trophic status, Thingvallavatn (oligotrophic) and Myvatn (eutrophic), were investigated. Gilvin and turbidity depth profiles were also measured. Diurnal variation in photosynthetically active radiation (PAR) reached almost 3 orders or magnitude. Downward irradiance spectra were variable near the surface, but with increases in depth transmission peaks at 510, 560 and 570 nanometres (nm) became apparent in Thingvallavatn, Myvatn-East Basin and Myvatn-South Basin respectively. Upward irradiance transmission maxima shifted from 480 to 500 nm with depth in Thingvallavatn, while in Myvatn they remained near 570 nm. An irradiance trough at 520 nm was noted in both the upward and downward spectra of Thingvallavatn. The importance of phytoplankton (chlorophyll) and gilvin in modifying the underwater light climate of Myvatn is clearly demonstrated. The mean downwelling and upwelling irradiance curves for Thingvallavatn coincide very well with the spectral sensitivities of resident adult arctic charr. This provides support for the sensitivity hypothesis.Key words: subarctic, limnology, imdiance, underwater light, arctic charr, spectral sensitivitjr, Iceland L'environnement photique sous-marin de deux lacs islandais, le Thingvallavatn (oligotrophe) et le Myvatn (eutrophe), d'origine volcanique et présentant un état trophique différent, ont été étudiés. La quantité de matière organique dissoute (gilvin) et la turbidité ont été mesurées en fonction de la profondeur dans chaque lac. La radiation disponible pour la photosynthèse (PAR) pouvait varier quotidiennement jusqu'à trois ordres de grandeur. Alors que les spectres de l'irradiance descendante variaient près de la surface, ils augmentaient avec la profondeur aux pics de transmission de 510, 560 et 570 nanomètres (nm) respectivement dans le Thingvallavatn et le bassin est du Myvatn et le bassin sud du Myvatn. Les maxima dans la transmission de l'irradiance ascendante ont été décalés avec la profondeur de 480 à 500 nm dans le Thingvallavatn tandis que dans le Myvatn ils sont demeurés près de 570 nm. Une zone d'absorption à 520 nm a également été observée dans les spectres descendants et ascendants du Thingvallavatn. L'importance du phytoplancton (chlorophylle) et de la matière organique dissoute (gilvin) dans la modification de l'environnement photique sous-marin du Myvatn a été nettement démontrée. Les spectres moyens de l'irradiance descendante et ascendante coïncident très étroitement avec les sensibilités spectrales chez les ombles-chevaliers adultes indigènes. Ceci appuie l'hypothèse de la sensibilité chez ces poissons.Mots clés: subarctique, limnologie, irradiance, lumière sous-marine, omble-chevalier, sensibilite spectrale, Islande |
format |
Article in Journal/Newspaper |
author |
Heinermann, P.H. Ali, M.A. |
author_facet |
Heinermann, P.H. Ali, M.A. |
author_sort |
Heinermann, P.H. |
title |
The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
title_short |
The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
title_full |
The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
title_fullStr |
The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
title_full_unstemmed |
The Underwater Photic Environment of Two Subarctic Icelandic Lakes |
title_sort |
underwater photic environment of two subarctic icelandic lakes |
publisher |
The Arctic Institute of North America |
publishDate |
1993 |
url |
https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372 |
long_lat |
ENVELOPE(-57.831,-57.831,51.500,51.500) |
geographic |
Arctic Chevalier |
geographic_facet |
Arctic Chevalier |
genre |
Arctic Arctic charr Arctic Iceland Islande Omble chevalier Phytoplankton Subarctic subarctique* |
genre_facet |
Arctic Arctic charr Arctic Iceland Islande Omble chevalier Phytoplankton Subarctic subarctique* |
op_source |
ARCTIC; Vol. 46 No. 1 (1993): March: 1–96; 17-26 1923-1245 0004-0843 |
op_relation |
https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372/48307 https://journalhosting.ucalgary.ca/index.php/arctic/article/view/64372 |
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ARCTIC |
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46 |
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1 |
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1766290772662943744 |