Data from: Direct contribution of invertebrate holobionts to methane release from coastal sediments

<p>In this study, we incubated 103&nbsp;animals specimens equivalent to 19 macrofaunal species&nbsp;to quantify holobiont-associated methane (CH₄) fluxes&nbsp;and metabolic processes [oxygen (O₂)&nbsp;- respiration and ammonium (NH₄⁺) - excretion rates].&nbsp;The specific goals&nbsp;were&nbsp;to quantify holobionts CH₄&nbsp;production/uptake and to establish correlations between CH₄ fluxes and environmental factors (e.g., salinity).</p> <p>Invertebrates were collected in 4 coastal systems and&nbsp;incubated in 22 mL glass microcosms filled with 0.22 &micro;m twice-filtered <em>in situ</em> water. Individual and Mass-standardized CH₄ Production Rates (IPR and MPR, respectively), O₂ Respiration Rates (IRR and MRR) and&nbsp;&nbsp;NH₄⁺Excretion Rates (IER and MER)&nbsp;were measured in 103 animals&rsquo; incubations.</p> <p>1. IRR were calculated from linear regression analysis of the solute (O₂) versus time equation:&nbsp;</p> <p>&nbsp; &nbsp; &nbsp; &nbsp;<span class="math-tex">\(IRR=(Reg.Slope × V)/N\)</span></p> <p><em>&nbsp; &nbsp; &nbsp; &nbsp;where IRR (&micro;mol O₂ ind.^&minus;1 day^&minus;1) is the respiration of the chemical species O₂; Reg.Slope is the slope of the regression (&micro;mol O₂ L^&minus;1 day^&minus;1); V (L) is the water volume in the glass microcosm; N is the number of incubated animals per microcosm.</em></p> <p>2. IER and IPR&nbsp;were calculated from the difference in concentrations (NH₄⁺ and CH₄) in the water using the equation:</p> <p>&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class="math-tex">\(IER and IPR = ((C_f-C_i )×V)/(N×t)\)</span></p> <p><em>&nbsp; &nbsp; &nbsp; &nbsp; where IER and IPR (&micro;mol ind.^&minus;1 day^&minus;1 and nmol ind.^&minus;1 day^&minus;1) are the excretion or production of the chemical species (NH₄⁺ or CH₄); C_f and C_i (&micro;mol or nmol L^&minus;1) are the final and initial concentrations of the chemical species; V (L) is the water volume in the glass microcosm; N is the number of incubated animals per microcosm; and t (days) is the incubation time. Positive values represent productions while negative values represent uptake.</em></p> <p>Same equations were used to calculated mass-standardized rates, but instead of <em>N</em> the total animal biomass (g_dw) was used. Animals&rsquo; biomass was determined as dry weight (DW) or as dry weight shell free (DWSF) for bivalves, after the desiccation at 70&deg;C until constant mass. Water temperature and salinity were measured in situ with a multiple probe (556 MPS, YSI).&nbsp;&nbsp;Rates are reported as average &plusmn; standard error.</p>