Data_Sheet_2_Leaf Nutrient Resorption and Export Fluxes of Avicennia marina in the Central Red Sea Area.XLSX

<p>Red Sea mangroves occur in an oligotrophic sea without permanent freshwater inputs. Understanding the mechanisms to cope with nutrient limitation is, therefore, important to understand their distribution and nutrient dynamics in coastal ecosystems. We measured total number of meristems to estimate their leaves production and nutrients (N, P, and Fe) as a function of age in Avicennia marina leaves. Then estimated resorption rates; the recovery of nutrients from senescing leaves before they are shed in a total of 91 leaf from four different mangroves stands in the Central Red Sea. We found that the concentration of N and P but not Fe declined with age. Nutrient content also declined in the older leaves with high resorption capacity of 69 and 72% in N and P vs. low resorption of 42% in Fe. The role of Fe resorption is poorly studied in plants, nevertheless, this study could provide an insight into our knowledge of iron resorption in the mangroves, which has never been assessed before. The leaf nutrient export flux from senescing leaves in monospecific stand of Avicennia marina was 9, 0.4 and 1 g m⁻² year⁻¹ for N, P, and Fe respectively, suggesting mangrove litter-fall to be an important source of bioavailable iron in particular, due to its low resorption, to the adjacent oligotrophic ecosystem.</p

Fully-Automated Fluorimetric Determination of Aluminum in Seawater by In-Syringe Dispersive Liquid–Liquid Microextraction Using Lumogallion

A sensitive and selective automated in-syringe dispersive liquid–liquid microextraction (DLLME) method is presented. It was successfully applied to the determination of aluminum in coastal seawater samples. The complete analytical procedure including sampling, buffering, reaction of the analyte with fluorescence reagent lumogallion (LMG), extraction, phase separation, and quantification was completely automized and carried out within 4 min. DLLME was done using <i>n</i>-hexanol as an extracting solvent and ethanol as a dispersing solvent in a 1:8 v/v percent mixture. The Al–LMG complex was extracted by an organic solvent and separated from the aqueous phase within the syringe of an automated syringe pump. Two devices were specially developed for this work. These were (a) the fluorescence detector and accompanying flow cell for the organic phase enriched with the reaction product and (b) a heating device integrated into the holding coil to accelerate the slow reaction kinetics. The limits of detection (3σ) and quantification (10σ) were 8.0 ± 0.5 nmol L^–1 and 26.7 ± 1.6 nmol L^–1, respectively. The relative standard deviation for eight replicate determinations of 200 nmol L^–1 Al³⁺ was <1.5%. The calibration graph using the preconcentration system was linear up to 1000 nmol L^–1 with a correlation coefficient of 0.999. Ambient concentrations of samples were quantifiable with found concentrations ranging from 43 to 142 nmol L^–1. Standard additions gave analyte recoveries from 97% to 113% proving the general applicability and adequateness of the analyzer system to real sample analysis

Bacterial metabolism in experiments.

<p>Integrated bacterial production from changes in biomass (BP) and respiration (BR) in the two treatments (+ammonium; +krill excretion products) and controls, along the three experiments. BCD: Bacterial carbon demand (BP+BR). BGE: Bacterial growth efficiency [BP/(BP+BR)]. NGR: Net specific growth rate [ln (BB_T5/BB_T0)/T5, being BB bacterial biomass and T time in days].</p

Time series of oxygen and ammonium concentration.

<p>Time evolution of DO and NH₄⁺ in experimental units receiving krill excretion products, ammonium inputs and controls for the three experiments conducted.</p

Statistical ANOVAs analyses.

<p>Results of two-way repeated measures ANOVAs to determine the effects of treatment, time evolution, and the interaction between the two factors on bacterial production. The analyses indicate that there are significant differences (p<0.0001) between treatments, time evolution, and their interaction in the three experiments (see text for details). DF = Degree of freedom; F - ratio = Variance ratio.</p

Post hoc Bonferroni’s and Tukey’s mean comparisons tests.

<p>Pairwise numbers and letters between brackets indicate that the means of those values were significantly different at p<0.01. Values for “Treatment” are: A = ammonium, C = control, K = krill. Values for “Time” are 0 = T0, 1 = T1,… 5 = T5 (see text for details).</p

Comparative analysis of biological variables <i>in situ</i> and at the onset of experiments.

<p>Upper panel: Physical and biological parameters at 5 m depth, from the three sampling sites (<i>in situ</i>) where water was collected for experiments. Mean and standard deviation values (of 2–3 replicates, in parenthesis) of ammonium (NH₄⁺), dissolved organic carbon (DOC), iron (Fe), chlorophyll a (Chl a), bacterial abundance (BA) and bacterial production from Leucine uptake (BP-Leu). Lower panel: Mean and standard deviation values (of 2–3 replicates, in parenthesis) of NH₄⁺, DOC, BA and BP at the onset (T0) of the three experiments in the two treatments (ammonium, A; krill excretion products, K) and controls (C). Fe = Iron concentrations in the pre-filtered water used for experiments, before adding any treatment.</p

Map of stations.

<p>Location of the stations from where water was collected for experiments I, II and III.</p

Flow cytometric analysis.

<p>Cytograms of bacterial samples at the start of experiments in controls and end of experiments in krill treatments, giving a relative estimate of the distribution of cell groups in each sample. The red lines at the controls broadly separate two groups of bacterial assemblages: (i) HNA: cells with high green fluorescence and large size (side scatter) and (ii) LNA: cells with low green fluorescence and small size (side scatter). Notice that experiments II and III present HNA cells at T0 with higher fluorescence and side scatter than in experiment I (see text for explanation).</p

Maximum Likelihood tree from <i>C. racemosa</i> ITS calculated using the evolution Model TPM2+G with bootstraps calculated after 1000 replicates.

<p>Alignments of each cluster were BLAST against Genebank nucleotide database and got the highest hits with sequences from Verlaque et al. 2003 study [AY334305-Cluster A and AY173118-Cluster B] <i>C. prolifera</i> samples from Mallorca were used as outgroup. Genbank accession numbers are represented within brackets.</p