Global patterns in phytoplankton community size structure—evidence for a direct temperature effect

Mousing, Erik Askov; Ellegaard, Marianne; Richardson, Katherine

doi:10.3354/meps10583

Cited by 74 publications

(63 citation statements)

References 41 publications

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“…However, even if spatiotemporal influences could be fully accounted for, we would still not expect that DIN, P, and Si availability alone would be able to explain all the variation in the global distribution of phytoplankton community size structure. Other potentially important factors include the availability of other resources such as light and various micronutrients (Mitchell et al ; Coale et al ; Saito et al ), top‐down processes such as grazing by zooplankton or viral lysis (Kiørboe ; Fuhrman ), as well as physical constraints such as turbulence and temperature (Kiørboe ; Marañón et al ; Mousing et al ). We fully acknowledge that all of these factors play critical roles in regulating phytoplankton community structure and we cannot rule out that they may influence the patterns here interpreted as nutrient limitation effects.…”

Section: Discussionmentioning

confidence: 99%

Global patterns in phytoplankton biomass and community size structure in relation to macronutrients in the open ocean

Mousing

Richardson

Ellegaard

2018

Limnology & Oceanography

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Owing to the dynamic nature of nutrient‐phytoplankton interactions, ambient macronutrient concentrations reveal little about the impact of nutrient availability on phytoplankton biomass and community composition at any given point in time or space. Here, however, we examine a global dataset (n = 262) where phytoplankton community structure and biomass are related to ambient concentrations of dissolved inorganic nitrogen (DIN), phosphate (P), and silicate. The macroecological patterns emerging from the analysis suggests plausible causal relationships between nutrient availability and global phytoplankton community responses: When DIN and P are below ca. 5 μM and 0.5 μM, respectively, increases in the concentration of either nutrient correlate with increases in both biomass and the contribution of large cells to the total phytoplankton biomass. At higher concentrations, increasing DIN or P concentrations do not correlate with increases in biomass. However, the fraction of large phytoplankton continues to increase with increasing concentrations suggesting DIN and P availability to be important factors in controlling phytoplankton community composition over the entire spectrum of potential macronutrient availability in the open ocean. Ambient silicate concentrations were not strongly associated with phytoplankton community structure or biomass. Nor did the DIN/P ratio correlate with community structure indicating that this ratio is a poor descriptor of phytoplankton limitation at the community scale. No empirical evidence was found for commonly referred threshold values for nutrient limitation (i.e., 2 μM, 0.2 μM, and 2 μM for DIN, P, and silicate, respectively) suggesting that these threshold values may not contain any practical information.

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Section: Discussionmentioning

confidence: 99%

Global patterns in phytoplankton biomass and community size structure in relation to macronutrients in the open ocean

Mousing

Richardson

Ellegaard

2018

Limnology & Oceanography

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“…Bloom start date would likely result in different species assemblages that constitute the spring bloom each year (Dakos et al, 2009;Irigoien et al, 2000). The timing may also influence the size spectra and species composition of the bloom due to the effects of thermal conditions when the bloom develops (Barnes et al, 2011;Mousing et al, 2014) or due to the light regime affecting early versus late blooms (Polimene et al, 2014). We can suggest a number of mechanistic hypotheses of how bloom start might have affected the nutritional value of the spring phytoplankton available to zooplankton predators in western Gulf of Maine.…”

Section: Discussionmentioning

confidence: 99%

Spring bloom dynamics and zooplankton biomass response on the US Northeast Continental Shelf

Friedland

Leaf

Kane

et al. 2015

Continental Shelf Research

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a b s t r a c tThe spring phytoplankton bloom on the US Northeast Continental Shelf is a feature of the ecosystem production cycle that varies annually in timing, spatial extent, and magnitude. To quantify this variability, we analyzed remotely-sensed ocean color data at two spatial scales, one based on ecologically defined sub-units of the ecosystem (production units) and the other on a regular grid (0.5°). Five units were defined: Gulf of Maine East and West, Georges Bank, and Middle Atlantic Bight North and South. The units averaged 47 Â 10 3 km 2 in size. The initiation and termination of the spring bloom were determined using change-point analysis with constraints on what was identified as a bloom based on climatological bloom patterns. A discrete spring bloom was detected in most years over much of the western Gulf of Maine production unit. However, bloom frequency declined in the eastern Gulf of Maine and transitioned to frequencies as low as 50% along the southern flank of the Georges Bank production unit. Detectable spring blooms were episodic in the Middle Atlantic Bight production units. In the western Gulf of Maine, bloom duration was inversely related to bloom start day; thus, early blooms tended to be longer lasting and larger magnitude blooms. We view this as a phenological mismatch between bloom timing and the "top-down" grazing pressure that terminates a bloom. Estimates of secondary production were available from plankton surveys that provided spring indices of zooplankton biovolume. Winter chlorophyll biomass had little effect on spring zooplankton biovolume, whereas spring chlorophyll biomass had mixed effects on biovolume. There was evidence of a "bottom up" response seen on Georges Bank where spring zooplankton biovolume was positively correlated with the concentration of chlorophyll. However, in the western Gulf of Maine, biovolume was uncorrelated with chlorophyll concentration, but was positively correlated with bloom start and negatively correlated with magnitude. This observation is consistent with both a "top-down" mechanism of control of the bloom and a "bottom-up" effect of bloom timing on zooplankton grazing. Our inability to form a consistent model of these relationships across adjacent systems underscores the need for further research.Published by Elsevier Ltd.

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“…Also a direct effect of temperature on the phytoplankton community size structure was found in the global ocean (Mousing et al, 2014;López-Urrutia and Morán, 2015). However, Marañón et al (2014) argue that the correlation between temperature and size structure is due to an indirect effect through nutrient supply as they did not find a direct effect of temperature when data from similar nutrient supply regimes were used.…”

Section: Introductionmentioning

confidence: 99%

The Physiological Response of Picophytoplankton to Temperature and Its Model Representation

2016

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Picophytoplankton account for most of the marine (sub-)tropical phytoplankton biomass and primary productivity. The contribution to biomass among plankton functional types (PFTs) could shift with climate warming, in part as a result of different physiological responses to temperature. To model these responses, Eppley's empirical relationships have been well established. However, they have not yet been statistically validated for individual PFTs. Here, we examine the physiological response of nine strains of picophytoplankton to temperature; three strains of picoprokaryotes and six strains of picoeukaryotes. We conduct laboratory experiments at 13 temperatures between -0.5 and 33 • C and measure the maximum growth rates and the chlorophyll a to carbon ratios. We then statistically validate two hypotheses formulated by Eppley in 1972: The response of maximum growth rates to temperature (1) of individual strains can be represented by an optimum function, and (2) of the whole phytoplankton group can be represented by an exponential function Eppley (1972). We also quantify the temperature-related parameters. We find that the temperature span at which growth is positive is more constrained for picoprokaryotes (13.7-27 • C), than for picoeukaryotes (2.8-32.4 • C). However, the modeled temperature tolerance range ( T) follows an unimodal function of cell size for the strains examined here. Thus, the temperature tolerance range may act in conjunction with the maximum growth rate to explain the picophytoplankton community size structure in correlation with ocean temperature. The maximum growth rates obtained by a 99th quantile regression for the group of picophytoplankton or picoprokaryotes are generally lower than the rates estimated by Eppley. However, we find temperature-dependencies (Q 10 ) of 2.3 and of 4.9 for the two groups, respectively. Both of these values are higher than the Q 10 of 1.88 estimated by Eppley and could have substantial influence on the biomass distribution in models, in particular if picoprokaryotes were considered an independent PFT. We also quantify the increase of the chlorophyll a to carbon ratios with increasing temperature due to acclimation. These parameters provide essential and validated physiological information to explore the response of marine ecosystems to a warming climate using ocean biogeochemistry models.

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Global patterns in phytoplankton community size structure—evidence for a direct temperature effect

Cited by 74 publications

References 41 publications

Global patterns in phytoplankton biomass and community size structure in relation to macronutrients in the open ocean

Global patterns in phytoplankton biomass and community size structure in relation to macronutrients in the open ocean

Spring bloom dynamics and zooplankton biomass response on the US Northeast Continental Shelf

The Physiological Response of Picophytoplankton to Temperature and Its Model Representation

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