Questioning the role of phenology shifts and trophic mismatching in a planktonic food web

Atkinson, Angus; Harmer, Rachel A.; Widdicombe, Claire E.; McEvoy, Andrea J.; Smyth, Tim; Cummings, Denise; Somerfield, Paul J.; Maud, J L; McConville, Kristian

doi:10.1016/j.pocean.2015.04.023

Cited by 72 publications

(90 citation statements)

References 49 publications

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“…Mesozooplankton sampling at station L4 is undertaken on a near weekly basis by a pair of vertical hauls of a Working Package 2 (WP2) net (200 μ m) from a depth of ∼ 50 m to the surface at a speed of ∼ 20 cm s −1 . The formaldehyde‐preserved hauls are analyzed for the mesozooplankton as described in Atkinson et al (). Copepodite stage composition of Calanus helgolandicus was determined for weekly samples from March 2002 to March 2004, as previously published (Hirst et al ), and supplemented with new data that we collected over a ∼ 2 yr period, from January 2012 to December 2013.…”

Section: Methodsmentioning

confidence: 99%

Mortality of Calanus helgolandicus: Sources, differences between the sexes and consumptive and nonconsumptive processes

Maud

Hirst

Atkinson

et al. 2018

Limnology & Oceanography

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While losses from mortality are as important as gains from reproduction in zooplankton population dynamics, the former are more challenging to quantify. We used two approaches to provide complementary insights into the mortality of a biomass-dominant copepod, Calanus helgolandicus, at Station L4 in the English Channel. Using a neutral-red staining method, we found that dead carcasses represented a mean of 9% of the C. helgolandicus copepodites sampled. The resulting nonconsumptive mortality rates are the first that have been derived for C. helgolandicus; and estimates suggest a contribution of 0-54% (median of 4.4%) to the total mortality rate. Consumptive mortality (i.e., that due to removal by predation), dominated for most of the year and contributed a mean of 89% to total mortality. Nonconsumptive mortality increased during summer and winter, and was positively related to maximum wind speed during the preceding 72 h, indicating that extreme weather events may lead to increased mortality. Using the Vertical Life Table approach, mortality rates across the CV-adult male stage pair were on average 2.5 times greater than those of CV-adult females. Adult male consumptive mortality rates were 6 times greater than those for females; adult male nonconsumptive rates were twice those of females, suggesting that predation is of greater significance to male loss rates. Summer CV-adult mortality rates were positively correlated to temperature, and to the abundance of predatory chaetognaths and siphonophores, suggesting that the gelatinous predator assemblage is the dominant agent for population control of late stage copepodites of C. helgolandicus at L4.

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Section: Methodsmentioning

confidence: 99%

Mortality of Calanus helgolandicus: Sources, differences between the sexes and consumptive and nonconsumptive processes

Maud

Hirst

Atkinson

et al. 2018

Limnology & Oceanography

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“…For instance, in some years the motile taxa peak first and in other years diatoms bloom in autumn. Indeed, interannual timings of each of these groups typically vary from year to year by about 2 months and independently of each other (Atkinson et al ).…”

Section: Plankton Biomass and Seasonality At L4mentioning

confidence: 99%

“…Differential phenological temperature sensitivities between taxa has attracted much interest, because it could lead to changes in the relative match or mismatch between trophic levels in a warming climate (Edwards and Richardson ; Aberle et al ; Thackeray et al ). The taxonomic richness and weekly resolution of L4 is good for determining phenology (Mackas et al ), and indeed some major heterotrophs showed strong temperature sensitivity in their timings (earlier when warmer), for example the heterotrophic dinoflagellate Gyrodinium spp., and the copepod genera Pseudocalanus and Acartia (Atkinson et al ). By contrast diatom timing remained overall unrelated to temperature as found elsewhere (Wiltshire et al ), being possibly cued also by light (Ji et al ).…”

Section: A Suite Of Explanations For Plankton Seasonality At L4mentioning

confidence: 99%

“…6-17 C in summer, when surface layer macronutrients are depleted to limiting levels (Smyth et al 2015). Average surface chlorophyll a (Chl a) values range typically from~0.5 mg Chl a m −3 in winter to~2-3 mg Chl a m −3 during blooms that can occur throughout the spring to autumn period (Widdicombe et al 2010;Atkinson et al 2015).…”

Section: Plankton Biomass and Seasonality At L4mentioning

confidence: 99%

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Comment. What drives plankton seasonality in a stratifying shelf sea? Some competing and complementary theories

Atkinson

Polimene

Fileman

et al. 2018

Limnology & Oceanography

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The Plymouth L4 time plankton series in the Western English Channel is a textbook example of a shallow, stratifying shelf sea system. Over its 30 yr of weekly sampling, this site has provided a diverse and contrasting suite of numerical and conceptual models of plankton bloom formation, phenology, and seasonal succession. The most recent of these papers, Kenitz et al. (2017) has initiated this comment, partly because we feel that it has presented a slightly misleading picture of the plankton composition at this site, and of a robust, recurring seasonal succession. We address this by illustrating the extent of inter‐annual variability in phenology that occurs at the site, and which needs to be captured better within models. However our main aim is to foster a much better integration of the variety of top‐down and bottom‐up processes that have all been suggested to be key in driving seasonal succession. Some of these, particularly the multiple grazing and growth controls contributing to the so‐called “loophole hypothesis” may be complementary, but others, such as the role of copepod feeding traits in driving species succession (Kenitz et al. 2017) offer testable competing hypotheses. The basic assumptions and outputs of all these models need to be validated more critically, both against time series data and process studies that include the finding of unselective feeding. We suggest that the variability in plankton phenology (and not just mean timing and amplitude) could be used to diagnose the performance of alternative models of plankton succession.

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“…For example, phenological shifts have been reported for plankton (Calbet et al 2014;Villarino et al 2015), benthos (Philippart et al 2003(Philippart et al , 2014Moore et al 2011;Richards 2012), and fish (Perry et al 2005;Neidetcher et al 2014;Asch 2015). These have in turn raised concerns about the synchrony of interactions and possible mismatches between different trophic levels (Beaugrand et al 2003;Donnelly et al 2011;Atkinson et al 2015).…”

Section: Introductionmentioning

confidence: 99%

A phenological shift in the time of recruitment of the shipworm, Teredo navalis L., mirrors marine climate change

Appelqvist

Havenhand

2016

Ecology and Evolution

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For many species, seasonal changes in key environmental variables such as food availability, light, and temperature drive the timing (“phenology”) of major life‐history events. Extensive evidence from terrestrial, freshwater, and marine habitats shows that global warming is changing the timings of many biological events; however, few of these studies have investigated the effects of climate change on the phenology of larval recruitment in marine invertebrates. Here, we studied temperature‐related phenological shifts in the breeding season of the shipworm Teredo navalis (Mollusca, Bivalvia). We compared data for the recruitment period of T. navalis along the Swedish west coast during 2004–2006 with similar data from 1971–1973, and related differences in recruitment timing to changes in sea surface temperature over the same period. We found no significant shift in the timing of onset of recruitment over this ~30‐year time span, but the end of recruitment was an average of 26 days later in recent years, leading to significantly longer recruitment periods. These changes correlated strongly with increased sea surface temperatures and coincided with published thermal tolerances for reproduction in T. navalis. Our findings are broadly comparable with other reports of phenological shifts in marine species, and suggest that warmer sea surface temperatures are increasing the likelihood of successful subannual reproduction and intensifying recruitment of T. navalis in this region.

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Questioning the role of phenology shifts and trophic mismatching in a planktonic food web

Cited by 72 publications

References 49 publications

Mortality of Calanus helgolandicus: Sources, differences between the sexes and consumptive and nonconsumptive processes

Mortality of Calanus helgolandicus: Sources, differences between the sexes and consumptive and nonconsumptive processes

Comment. What drives plankton seasonality in a stratifying shelf sea? Some competing and complementary theories

A phenological shift in the time of recruitment of the shipworm, Teredo navalis L., mirrors marine climate change

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