Hydrographic and biological controls in two subarctic fjords: An environmental case study of how climate change could impact phytoplankton communities

Quigg, A; Nunnally, CC; McInnes, AS; Gay, S; Rowe, GT; Dellapenna, TM; Davis, RW

Hydrographic and biological controls in two subarctic fjords: An environmental case study of how climate change could impact phytoplankton communities

Quigg, A Nunnally, CC McInnes, AS

Gay, S Rowe, GT Dellapenna, TM Davis, RW

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Publication Type:: Journal Article
Citation:: Marine Ecology Progress Series, 2013, 480 pp. 21 - 37
Issue Date:: 2013-04-22

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Field	Value	Language
dc.contributor.author	Quigg, A	en_US
dc.contributor.author	Nunnally, CC	en_US
dc.contributor.author	McInnes, AS https://orcid.org/0000-0002-8340-3133	en_US
dc.contributor.author	Gay, S	en_US
dc.contributor.author	Rowe, GT	en_US
dc.contributor.author	Dellapenna, TM	en_US
dc.contributor.author	Davis, RW	en_US
dc.date.issued	2013-04-22	en_US
dc.identifier.citation	Marine Ecology Progress Series, 2013, 480 pp. 21 - 37	en_US
dc.identifier.issn	0171-8630	en_US
dc.identifier.uri	http://hdl.handle.net/10453/116569
dc.description.abstract	Over the past 50 yr, Alaska has warmed at more than twice the rate of the rest of the United States so that climate change impacts are much more pronounced in this region. Simpson and Sheep Bays are pristine fjords in Prince William Sound which differ significantly in terms of size and bathymetry, watershed topography and presence of alpine glaciers. During summers in 2006 to 2008, we investigated the relationship between hydrography and phytoplankton ecology. We found phytoplankton standing stocks and productivity were higher in Simpson relative to Sheep Bay. Phytoplankton physiology (measured with a fluorescence induction and relaxation system) was not significantly different (p > 0.05) in the 2 fjords: FV/FM = 0.32 to 0.67, σPSII = 141 to 391 Å2 quanta-1, τQa = 125 to 1020 μs, and p = 0.06 to 0.39. Resource (also known as nutrient) limitation assays revealed a gradient of nutrient co-limitation (NSi to NP, respectively) from the delta to the mouth in Simpson Bay. Phytoplankton dynamics were found to be driven by wind mixing and nutrient upwelling which fueled productivity in the upper water column. A comparison of temperature/salinity profiles measured in the present study with those in 1996/1997 revealed a decadal change in hydrography. Both fjords exhibited deep vertical gradients indicative of moderate vertical mixing in 1996/1997, while those measured in 2007/2008 were shallow, with significant stratification. These changes in hydrography, associated with climate change at these high latitudes, will likely lower phytoplankton productivity due to decreased reintroduction of nutrients to surface waters. Consequences to higher trophic levels of reduced food supply require further investigation, including food web and modeling studies. © Inter-Research 2013.	en_US
dc.relation.ispartof	Marine Ecology Progress Series	en_US
dc.relation.isbasedon	10.3354/meps10225	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Hydrographic and biological controls in two subarctic fjords: An environmental case study of how climate change could impact phytoplankton communities	en_US
dc.type	Journal Article
utslib.citation.volume	480	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0608 Zoology	en_US
utslib.for	0405 Oceanography	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	open_access
pubs.publication-status	Published	en_US
pubs.volume	480	en_US

Abstract:

Over the past 50 yr, Alaska has warmed at more than twice the rate of the rest of the United States so that climate change impacts are much more pronounced in this region. Simpson and Sheep Bays are pristine fjords in Prince William Sound which differ significantly in terms of size and bathymetry, watershed topography and presence of alpine glaciers. During summers in 2006 to 2008, we investigated the relationship between hydrography and phytoplankton ecology. We found phytoplankton standing stocks and productivity were higher in Simpson relative to Sheep Bay. Phytoplankton physiology (measured with a fluorescence induction and relaxation system) was not significantly different (p > 0.05) in the 2 fjords: FV/FM = 0.32 to 0.67, σPSII = 141 to 391 Å2 quanta-1, τQa = 125 to 1020 μs, and p = 0.06 to 0.39. Resource (also known as nutrient) limitation assays revealed a gradient of nutrient co-limitation (NSi to NP, respectively) from the delta to the mouth in Simpson Bay. Phytoplankton dynamics were found to be driven by wind mixing and nutrient upwelling which fueled productivity in the upper water column. A comparison of temperature/salinity profiles measured in the present study with those in 1996/1997 revealed a decadal change in hydrography. Both fjords exhibited deep vertical gradients indicative of moderate vertical mixing in 1996/1997, while those measured in 2007/2008 were shallow, with significant stratification. These changes in hydrography, associated with climate change at these high latitudes, will likely lower phytoplankton productivity due to decreased reintroduction of nutrients to surface waters. Consequences to higher trophic levels of reduced food supply require further investigation, including food web and modeling studies. © Inter-Research 2013.

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