Seasonal changes in plankton respiration and bacterial metabolism in a temperate shelf sea

García-Martín, Enma Elena; Daniels, Chris J.; Davidson, Keith; Davis, Clare E.; Mahaffey, Claire; Mayers, Kyle; McNeill, Sharon; Poulton, Alex J.; Purdie, Duncan A.; Tarran, Glen A.; Robinson, Carol

doi:10.1016/j.pocean.2017.12.002

Cited by 19 publications

(21 citation statements)

References 61 publications

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“…The importance of the rate of ocean warming occurring over a few weeks in spring has received little attention, especially compared with the focus on absolute temperatures; yet, the rate of spring warming is presumably a good index of the likely development and strength of spring stratification and the resulting levels of both near‐surface nutrients and light available for phytoplankton (Garcia‐Corral, Martinez‐Ayala, Duarte, & Agusti, ; García‐Martín et al, ; Smyth et al, ). Changes in environmental conditions are not impacting the timing of the diatom bloom but are causing the seasonal switch to dinoflagellates to occur earlier, which may be due to a more intense spring thermocline, hence limiting nutrient re‐supply to near‐surface waters as the spring and summer progress and so promote earlier removal of near‐surface nutrients by diatoms.…”

Section: Discussionmentioning

confidence: 99%

Phenological shuffling of major marine phytoplankton groups over the last six decades

Chivers

Edwards

Hays

2020

Diversity and Distributions

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Aim: Phytoplankton form the basis of the marine food web and are responsible for approximately 50% of the world's photosynthesis. Changes to their ecology are, therefore, important: here, we examined seasonal patterns in ocean phytoplankton abundance for 45 taxa over 59 years collected from circa 410,000 km of line-transect sampling at temperate latitudes. Location: The North Sea. Methods: For our analysis we used plankton abundance data from the Continuous Plankton Recorder (CPR) survey, sea surface temperature measurements from the Hadley Centre, UK Meteorological Office and wind speed data from the International Comprehensive Ocean-Atmosphere Data Set, NOAA. Results:We found large differences in changes in the timing of peak abundance between the major phytoplankton groups. Late-summer blooming dinoflagellates (n = 10 taxa) tended to show a large seasonal advancement, the timing of peak abundance for dinoflagellates as group advancing 39 days over these six decades. By contrast diatoms (n = 35) did not show any change as a group in their timing of peak abundance over the time series. Granger causality testing suggested a major driver of these phenological changes has been ocean warming in general but more specifically the rate of spring temperature rise as the most important factor. We also found differences in the timing of peak abundance of harmful algal bloom taxa, with some showing peak abundance earlier while others have moved later. Main conclusions:There has been a fundamental transformation of the classic seasonal progression from blooms of diatoms to dinoflagellates, which lies at the heart of temperate marine food chains, as the classic bimodal diatom and dinoflagellate seasonal peaks are eroded to a more continuous, single, longer-lasting phytoplankton peak. This phenological shuffling within and between major taxonomic groups is likely to have profound implications for the transfer of energy to higher trophic levels. K E Y W O R D S climate change, marine plankton, phytoplankton abundance, phytoplankton phenology, sea surface temperature, spring temperature rise | 537 CHIVERS Et al. B I OS K E TCH E S William Chivers is a quantitative ecologist researching the effects of climate change on ecological communities. Martin Edwards is a marine ecologist looking at environmental change impacts on marine ecosystems including biodiversity, biogeographical and phenological changes. Graeme Hays is a marine ecologist looking at patterns of animal movement and abundance and their responses to climate change. Additional supporting information may be found online in the Supporting Information section. How to cite this article: Chivers WJ, Edwards M, Hays GC. Phenological shuffling of major marine phytoplankton groups over the last six decades. Divers Distrib. 2020;26:536-548.

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Section: Discussionmentioning

confidence: 99%

Phenological shuffling of major marine phytoplankton groups over the last six decades

Chivers

Edwards

Hays

2020

Diversity and Distributions

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“…There is little information about primary productivity (Qurban, Wafar & Heinle, 2019) and planktonic metabolism (López-Sandoval et al, 2019) in the Red Sea to allow an assessment of the seasonality of its metabolic balance (i.e., the periods of net autotrophy vs. net heterotrophy, García-Martín et al, 2019a;García-Martín et al, 2019b). We can still compare the respective biomasses of autotrophs and heterotrophs within the smaller size fraction, which collectively support to a large extent the higher trophic levels in oligotrophic environments.…”

Section: Seasonal Variation Of Picoplanktonmentioning

confidence: 99%

Seasonal variability and vertical distribution of autotrophic and heterotrophic picoplankton in the Central Red Sea

Al-Otaibi

Huete‐Stauffer

Calleja

et al. 2020

PeerJ

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The Red Sea is characterized by higher temperatures and salinities than other oligotrophic tropical regions. Here, we investigated the vertical and seasonal variations in the abundance and biomass of autotrophic and heterotrophic picoplankton. Using flow cytometry, we consistently observed five groups of autotrophs (Prochlorococcus, two populations of Synechococcus separated by their relative phycoerythrin fluorescence, low (LF-Syn) and high (HF-Syn), and two differently-sized groups of picoeukaryotes, small (Speuk) and large (Lpeuk)) and two groups of heterotrophic prokaryotes of low and high nucleic acid content (LNA and HNA, respectively). Samples were collected in 15 surveys conducted from 2015 to 2017 at a 700-m depth station in the central Red Sea. Surface temperature ranged from 24.6 to 32.6 °C with a constant value of 21.7 °C below 200 m. Integrated (0–100 m) chlorophyll a concentrations were low, with maximum values in fall (24.0 ± 2.7 mg m−2) and minima in spring and summer (16.1 ± 1.9 and 1.1 mg m−2, respectively). Picoplankton abundance was generally lower than in other tropical environments. Vertical distributions differed for each group, with Synechococcus and LNA prokaryotes more abundant at the surface while Prochlorococcus, picoeukaryotes and HNA prokaryotes peaked at the deep chlorophyll maximum, located between 40 and 76 m. Surface to 100 m depth-weighted abundances exhibited clear seasonal patterns for Prochlorococcus, with maxima in summer (7.83 × 104 cells mL−1, July 2015) and minima in winter (1.39 × 104 cells mL−1, January 2015). LF-Syn (0.32 – 2.70 × 104 cells mL−1 ), HF-Syn (1.11 – 3.20 × 104 cells mL−1) and Speuk (0.99 – 4.81 × 102 cells mL−1) showed an inverse pattern to Prochlorococcus, while Lpeuk (0.16 – 7.05 × 104 cells mL−1) peaked in fall. Synechococcus unexpectedly outnumbered Prochlorococcus in winter and at the end of fall. The seasonality of heterotrophic prokaryotes (2.29 – 4.21×105 cells mL−1 ) was less noticeable than autotrophic picoplankton. The contribution of HNA cells was generally low in the upper layers, ranging from 36% in late spring and early summer to ca. 50% in winter and fall. Autotrophs dominated integrated picoplankton biomass in the upper 100 m, with 1.4-fold higher values in summer than in winter (mean 387 and 272 mg C m–2, respectively). However, when the whole water column was considered, the biomass of heterotrophic prokaryotes exceeded that of autotrophic picoplankton with an average of 411 mg C m–2. Despite being located in tropical waters, our results show that the picoplankton community seasonal differences in the central Red Sea are not fundamentally different from higher latitude regions.

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“…The Red Sea is a semi-enclosed highly oligotrophic basin (Acker et al, 2008;Raitsos et al, 2013). It is known as one of the warmest tropical seas, with maximum sea surface temperatures ranging from 33.0 to 33.9 • C during summer (Chaidez et al, 2017;Osman et al, 2018), and up to 34-35 • C in certain parts of the basin (Rasul et al, 2015;Garcias-Bonet and Duarte, 2017;Almahasheer et al, 2018). Due to the prevailing arid conditions, the Red Sea experiences large evaporation rates (nearly 2 cm yr −1 of freshwater from the surface layers) while the lack of river runoff and low precipitation rates make this system one of the saltiest seas on the planet (Sofianos, 2002;Sofianos and Johns, 2015;Zarokanellos et al, 2017).…”

Section: C López-sandoval Et Al: Rates and Drivers Of Red Sea Plmentioning

confidence: 99%

Rates and drivers of Red Sea plankton community metabolism

et al. 2019

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Abstract. Resolving the environmental drivers shaping planktonic communities is fundamental for understanding their variability, in the present and the future, across the ocean. More specifically, addressing the temperature-dependence response of planktonic communities is essential as temperature plays a key role in regulating metabolic rates and thus potentially defining the ecosystem functioning. Here we quantified plankton metabolic rates along the Red Sea, a uniquely oligotrophic and warm environment, and analysed the drivers that regulate gross primary production (GPP), community respiration (CR), and net community production (NCP). The study was conducted on six oceanographic surveys following a north–south transect along the Saudi Arabian coast. Our findings revealed that GPP and CR rates increased with increasing temperature (R2=0.41 and 0.19, respectively; p<0.001 in both cases), with a higher activation energy (Ea) for GPP (1.20±0.17 eV) than for CR (0.73±0.17 eV). The higher Ea for GPP than for CR resulted in a positive relationship between NCP and temperature. This unusual relationship is likely driven by the relatively higher nutrient availability found towards the warmer region (i.e. southern Red Sea), which favours GPP rates above the threshold that separates autotrophic from heterotrophic communities (1.7 mmol O2 m−3 d−1) in this region. Due to the arid nature, the basin lacks riverine and terrestrial inputs of organic carbon to subsidise a higher metabolic response of heterotrophic communities, thus constraining CR rates. Our study suggests that GPP increases steeply with increasing temperature in the warm ocean when relatively high nutrient inputs are present.

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Seasonal changes in plankton respiration and bacterial metabolism in a temperate shelf sea

Cited by 19 publications

References 61 publications

Phenological shuffling of major marine phytoplankton groups over the last six decades

Phenological shuffling of major marine phytoplankton groups over the last six decades

Seasonal variability and vertical distribution of autotrophic and heterotrophic picoplankton in the Central Red Sea

Rates and drivers of Red Sea plankton community metabolism

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