In situ primary productivity measurements on rocky shores

<p>These pictures show the adaptations made to the chambers described in Migné et al 2002 and Golléty et al 2008 to perform in situ measurements of CO2 fluxes on rocky shores as a function of light. In addition to the benthic chamber, a frame holding various light filters allows for the control of the amount of light reaching the chamber.</p> <p>Results from this work contribute to the first carbon budget of a canopy-dominated shore basedon in situ metabolism measurements performed at low tide (work in prep).</p

Effects of canopy removal and mechanical disturbance on the coefficient of temporal variation of community respiration (<i>V_CR</i>) at Nordostwatt.

<p>D− and D+ indicate undisturbed or mechanically disturbed treatments, respectively. Values are mean (± SEM, n = 2). Asterisk denotes a significant difference between canopy treatments.</p

Effects of canopy removal and mechanical disturbance on the Net Primary Productivity (NNP, panel A) and biomass (B) at Nordostwatt.

<p>D− and D+ indicate undisturbed or mechanically disturbed treatments, respectively. NPP and biomass were obtained 6 and 18 months after the onset of the experiment, respectively. Values are mean (± SEM, n = 5). Asterisk denotes a significant difference between canopy treatments.</p

Effects of removal of <i>Fucus serratus</i> canopy and mechanical disturbance on synchrony in species abundances (<i>φ_x</i>) at Nordostwatt and Westwatt.

<p>Values of <i>φ_x</i> = 1 indicate perfect synchrony; <i>φ_x</i> = 0 indicates perfect asynchrony. D– and D+ indicate undisturbed and mechanically disturbed treatments, respectively. Values are given as means ± SEM (n = 5). Asterisks denote significant differences between canopy treatments.</p

Relative contribution (%) of species to Bray-Curtis dissimilarities between assemblages with and without <i>Fucus serratus</i> canopy. “<b>↑</b>”, “<b>↓</b>”, and “<b>-</b>” denote positive, negative, and no effect of the loss of canopy on species abundance, respectively.

<p>Highest contributions for each site and sample date are in bold.</p

CAP ordination plots of species composition (A) before and (B) 1–3 days after canopy removal and mechanical disturbance treatments, and (C) long-term mean cover of <i>Fucus serratus</i> canopy.

<p>In panels A and B, the first and second CAP axes explained 41% and 34% of total inertia, respectively, at Nordostwatt and 68 and 17, respectively, at Westwatt. D− and D+ are undisturbed or disturbed treatments, respectively; C+ and C− indicate presence and removal of canopy, respectively. In panel C asterisks indicate significant differences between canopy treatments, and values are given as means ± SEM (n = 5)</p

ANOVA of the effects of canopy removal and mechanical disturbance on synchrony in species abundances, temporal coefficient of variation of community respiration (<i>V_CR</i>), and understorey community respiration.

<p>The abundance of <i>F. serratus</i> was included in the analyses of synchrony (“Species synchrony”). The analysis was repeated after excluding <i>F. serratus</i> abundance in order to check for consistency of results (“Understorey species synchrony”). DF, SS, and MS stand for degrees of freedom, sum of squares, and mean squares, respectively. Significant P-values are in bold.</p>1<p>For species synchrony, terms used as denominator for F-ratio are listed in the column <i>MS_den.</i> Error terms with highly conservative P-values (>0.25) were removed from the model. Synchrony was measured at Nordostwatt and Westwatt (n = 40). ²For <i>V_CR</i> and understorey community respiration (n = 2 and 3, respectively), the distribution of the F-ratio was obtained after 999 Monte Carlo samples of raw data. <i>V_CR</i> and understorey community respiration were measured at Nordostwatt.</p

Effect of <i>p</i>CO₂ on morphological variables, abnormality indices and intensity of birefringence.

<p>Legend: Summary of the non-parametric Kruskal-Wallis tests testing the effect of <i>p</i>CO₂ on each morphological variable, abnormality index and birefringence intensity.</p

Morphological variables.

<p>All measurements were taken on larvae lying on their right side. A: maximum shell length (L) (in μm); B: maximum shell height (h) (in μm); C: projected surface area of the left side (in mm²); D: deformity index, a is the angle of the abnormality (in degrees) and d, the depth of the abnormality (in μm).</p

Seawater parameters.

<p>Legend: Mean parameters of carbonate chemistry in each <i>p</i>CO₂ treatment at each temperature level. The pH on the total scale (pH_T) was measured daily and total alkalinity (A_T) was measured every 4 weeks. Other parameters were calculated with the CO₂SYS software <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093021#pone.0093021-Lewis1" target="_blank">[65]</a>. <i>p</i>CO₂: CO₂ partial pressure; DIC: dissolved inorganic carbon; Ω _Ar: saturation state of aragonite.</p