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© 2018. This work is published under https://creativecommons.org/licenses/by/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

The co-variation of key variables with simulated phytoplankton biomass in the Baltic proper has been examined using wavelet analysis and results of a long-term simulation for 1850–2008 with a high-resolution coupled physical–biogeochemical circulation model for the Baltic Sea. By focusing on inter-annual variations, it is possible to track effects acting on decadal timescales such as temperature increase due to climate change as well as changes in nutrient input. The strongest inter-annual coherence indicates that variations in phytoplankton biomass are determined by changes in concentrations of the limiting nutrient. However, after 1950 high nutrient concentrations created a less-nutrient-limited regime, and the coherence was reduced. Furthermore, the inter-annual coherence of mixed-layer nitrate with riverine input of nitrate is much larger than the coherence between mixed-layer phosphate and phosphate loads. This indicates a greater relative importance of the vertical flux of phosphate from the deep layer into the mixed layer. In addition, shifts in nutrient patterns give rise to changes in phytoplankton nutrient limitation. The modelled pattern shifts from purely phosphate limited to a seasonally varying regime. The results further indicate some effect of inter-annual temperature increase on cyanobacteria and flagellates. Changes in mixed-layer depth affect mainly diatoms due to their high sinking velocity, while inter-annual coherence between irradiance and phytoplankton biomass is not found.

Details

Title
Causes of simulated long-term changes in phytoplankton biomass in the Baltic proper: a wavelet analysis
Author
Hieronymus, Jenny 1 ; Eilola, Kari 1 ; Hieronymus, Magnus 1 ; Markus Meier, H E 2 ; Saraiva, Sofia 3   VIAFID ORCID Logo  ; Karlson, Bengt 1   VIAFID ORCID Logo 

 Research and Development Department, Swedish Meteorological and Hydrological Institute, Norrköping, Sweden 
 Department of Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany; Research and Development Department, Swedish Meteorological and Hydrological Institute, Norrköping, Sweden 
 University of Lisbon, Instituto Superior Técnico, Environment and Energy Section, Lisbon, Portugal 
Pages
5113-5129
Publication year
2018
Publication date
2018
Publisher
Copernicus GmbH
ISSN
17264170
e-ISSN
17264189
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2093241156
Copyright
© 2018. This work is published under https://creativecommons.org/licenses/by/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.