Atlantic Advection Driven Changes in Glacial Meltwater: Effects on Phytoplankton Chlorophyll-a and Taxonomic Composition in Kongsfjorden, Spitsbergen

Poll, Willem H. van de; Maat, Douwe S.; Fischer, Philipp; Rozema, Patrick D.; Daly, Oonagh B.; Koppelle, Sebastiaan; Visser, Ronald J. W.; Buma, Anita G. J.

doi:10.3389/fmars.2016.00200

Cited by 42 publications

(35 citation statements)

References 34 publications

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“…The C treatment contained in situ nutrient concentrations (no nutrients added) (Table ). To all other treatments, nutrients were added according to natural concentrations observed at Kongsfjorden during winter (Van de Poll et al ). Therefore, 11.0 μ M NO 3 was added to all treatments containing additional N (N, NP, NPSi), 0.7 μ M PO 4 was added to all treatments containing additional P (P, NP, NPSi), and 5.0 μ M Si was added to all treatments containing additional Si (Si, NPSi).…”

Section: Methodsmentioning

confidence: 99%

Photophysiology of nitrate limited phytoplankton communities in Kongsfjorden, Spitsbergen

Kulk

Poll

Buma

2018

Limnology & Oceanography

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In Arctic coastal regions, the phytoplankton bloom is often initiated by meltwater induced stratification in spring, while subsequent nutrient depletion is believed to drive phytoplankton succession in summer. The associated changes in photophysiology are difficult to identify, because these can be governed by acclimation to light and nutrient availability as well as variations in phytoplankton biomass and taxonomic composition. In the present study, the consequences of nutrient limitation for photophysiology and growth were assessed in natural phytoplankton communities from Kongsfjorden, Spitsbergen. A series of nutrient addition experiments demonstrated N-limitation from mid-June onwards and possible co-limitation with P later in summer. The onset of N-limitation was associated with a pronounced change in taxonomic composition from a dictyochophytes to a haptophytes dominated community. Fast Repetition Rate fluorometry measurements of photosystem II (PSII) photophysiology showed that the dictyochophytes dominated community was characterized by high PSII efficiency and electron transport rates which were efficiently used for growth. Marked changes in PSII photophysiology were observed later in summer, with decreasing efficiencies, lower connectivity between reaction centers, and slower turnover rates. Simultaneously, alternative electron requirements downstream of PSII became more important and energy was likely allocated to the uptake of nutrients rather than carbon fixation and growth. Relief of nutrient limitation during the nutrient addition experiments did not lead to pronounced changes in PSII photophysiology. It is, therefore, concluded that PSII photophysiology of the phytoplankton community in Kongsfjorden is associated with changes in species composition rather than a direct effect of nutrient availability or nutrient limitation.

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Section: Methodsmentioning

confidence: 99%

Photophysiology of nitrate limited phytoplankton communities in Kongsfjorden, Spitsbergen

Kulk

Poll

Buma

2018

Limnology & Oceanography

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“…The currents are dominated by the M2 lunar tidal component that enters the North Sea from the north and moves as a Kelvin wave cyclonically through the North Sea (Otto et al, 1990;Howarth, 2001). Strong tidal currents in the channels connecting the Wadden Sea with the German Bight drive an intense exchange and a net import of suspended particulate matter and nutrients into the Wadden Sea (Burchard et al, 2008;Staneva et al, 2009;van Beusekom et al, 2012) and sustain its muddy component and the high productivity of the intertidal mud flats (Postma, 1984;van Beusekom et al, 1999;van Beusekom and de Jonge, 2002;Colijn and de Jonge, 1984). The tides thus cause a complex pattern of mixing conditions just off the barrier islands and the mouths of the estuaries of the rivers Elbe, Weser, and Ems.…”

Section: The German Bightmentioning

confidence: 99%

“…23; Wirtz and Kerimoglu, 2017). Previous modelling attempts such as of van Leeuwen et al (2013) or Schrum et al (2006) do not capture the extreme vertical squeezing of chlorophyll a within thin layers, which may affect model-derived estimates of total primary production. Our new model results also reveal how reconstructed pelagic patterns decouple from benthic respiration patterns.…”

Section: Modelling and Data Assimilationmentioning

confidence: 99%

The Coastal Observing System for Northern and Arctic Seas (COSYNA)

et al. 2017

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Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change.The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables.

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“…At high latitude systems, the majority of picophytoplankton are eukaryotes and/or prokaryotic cyanobacteria belonging to the genus Synechococcus. The role of picophytoplankton in northern systems has received more attention in recent years van De Poll et al, 2016;Sherr et al, 2003;Tremblay et al, 2009), although traditionally the focus has been on larger, spring-blooming phytoplankton (Leblanc, 2005;Rees et al, 1999;Velasco et al, 2013). During bloom periods the relative abundance of picophytoplankton is low (Li et al 1993), but a bloom is a short-term feature and smaller phytoplankton and associated grazers dominate the rest of the year.…”

Section: Introductionmentioning

confidence: 99%

Heterotrophic nanoflagellate grazing facilitates subarctic Atlantic spring bloom development

Paulsen¹,

Riisgaard²,

John³

et al. 2017

Aquat. Microb. Ecol.

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My study underpins that picophytoplankton are important contributors to primary production, especially during the winter-spring transition (Paper I and III) and autumn (Paper V). They boosted the growth of heterotrophic microorganisms before the onset of the diatom spring bloom in the Subarctic Atlantic (Paper I) and dominated the phytoplankton biomass in the high turbid parts of a NE Greenland fjord influenced by glacial meltwater (Paper V). Picophytoplankton were better adapted to low light conditions and demonstrated higher growth rates, than larger phytoplankton (Paper I, II, III, V). In the Polar-influenced water near Greenland, Synechococcus were negligible, while in the Atlantic influenced waters picoeukaryotes and Synechococcus were often equally abundant and the latter dominated on several occasions during autumn and winter (Paper I and III). Unexpectedly, abundances of Synechococcus were as high at 65°N as at 79°N, and molecular analysis suggests the presence of new clades specially adapted to Arctic conditions. Bacteria were generally rather carbon-than nutrient limited, and their abundance increased rapidly in response to the pre-bloom picophytoplankton production of labile carbon in both the Arctic and Subarctic (Paper I and V). In NE Greenland the terrestrial DOM supplied from the Greenland ice sheet proved to be highly bioavailable compared to the 7 autochthonous fjord DOM (Paper IV). The in situ changes in DOM, which were examined via fluorescence signal of different DOM components (FDOM), surprisingly demonstrated that the highest net-growth of bacteria was not coupled to the labile glacial runoff in the surface, but rather to sub-surface the humic-DOM, commonly considered to be refractory. This may be explained by the presence of specific dominating taxa of bacteria that had the ability to degrade humic-DOM (Paper V).Across regions, HNF exerted strong control of picophytoplankton and bacteria (Paper I, II, III, V). HNF grew significantly faster than microzooplankton and were therefore less affected by mixing and relatively more important grazers than their micro-sized counterparts in well-mixed water columns (Paper I and II). HNF larger than 5µm controlled picophytoplankton particularly in the early productive season, while small HNF (3-5µm) mainly kept bacteria in check in autumn (Paper III, V). In conclusion, the studies underline that pico-sized plankton play a fundamental part in the carbon transfer in high latitude ecosystems both as primary producers and via the microbial loop. Picophytoplankton appeared better adapted than larger phytoplankton to low light conditions, and bacteria were capable of degrading terrestrial derived DOM, however, these abilities are highly community specific. The data suggest that a change in mixing patters will affect the microbial food structure and that shifts in coastal microbial community composition should be anticipated with increased runoff. 8 List of publicationsThe thesis is based on preliminary data and the following fived papers referred to in the t...

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Atlantic Advection Driven Changes in Glacial Meltwater: Effects on Phytoplankton Chlorophyll-a and Taxonomic Composition in Kongsfjorden, Spitsbergen

Cited by 42 publications

References 34 publications

Photophysiology of nitrate limited phytoplankton communities in Kongsfjorden, Spitsbergen

Photophysiology of nitrate limited phytoplankton communities in Kongsfjorden, Spitsbergen

The Coastal Observing System for Northern and Arctic Seas (COSYNA)

Heterotrophic nanoflagellate grazing facilitates subarctic Atlantic spring bloom development

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