Response of Benthic Foraminifera to organic matter quantity and quality and bioavailable concentrations of metals in Aveiro Lagoon (Portugal)

This work analyses the distribution of living benthic foraminiferal assemblages of surface sediments in different intertidal areas of Ria de Aveiro (Portugal), a polihaline and anthropized coastal lagoon. The relationships among foraminiferal assemblages in association with environmental parameters (temperature, salinity, Eh and pH), grain size, the quantity and quality of organic matter (enrichment in carbohydrates, proteins and lipids), pollution caused by metals, and mineralogical data are studied in an attempt to identify indicators of adaptability to environmental stress. In particular, concentrations of selected metals in the surficial sediment are investigated to assess environmental pollution levels that are further synthetically parameterised by the Pollution Load Index (PLI). The PLI variations allowed the identification of five main polluted areas. Concentrations of metals were also analysed in three extracted phases to evaluate their possible mobility, bioavailability and toxicity in the surficial sediment. Polluted sediment in the form of both organic matter and metals can be found in the most confined zones. Whereas enrichment in organic matter and related biopolymers causes an increase in foraminifera density, pollution by metals leads to a decline in foraminiferal abundance and diversity in those zones. The first situation may be justified by the existence of opportunistic species (with high reproduction rate) that can live in low oxic conditions. The second is explained by the sensitivity of some species to pressure caused by metals. The quality of the organic matter found in these places and the option of a different food source should also explain the tolerance of several species to pollution caused by metals, despite their low reproductive rate in the most polluted areas. In this study, species that are sensitive and tolerant to organic matter and metal enrichment are identified, as is the differential sensitivity/tolerance of some species to metals enrichment.CNPq [401803/2010-4]; [PEst-OE/CTE/UI4035/2014]info:eu-repo/semantics/publishedVersio

Study area.

<p>The studied sites are labelled with numbers. Legend: OvCh—Ovar Channel, SJCH—São Jacinto Channel, MuCh—Murtosa Channel, EsCh—Espinheiro Channel, MiCh—Mira Channel.</p

Distribution maps of foraminiferal density (FD, n.°/g), Shannon Index (H’) values and percentage of the specie: <i>A</i>. <i>tepida</i>, <i>H</i>. <i>germanica</i>, <i>E</i>. <i>excavatum</i>, <i>T</i>. <i>inflata</i>, <i>P</i>. <i>mediterranensis</i>, <i>E</i>. <i>margaritaceum</i> and <i>Q</i>. <i>seminula</i>.

<p>Legend: OvCh—Ovar Channel, SJCH—São Jacinto Channel, MuCh—Murtosa Channel, EsCh—Espinheiro Channel, MiCh—Mira Channel.</p

Total available concentrations (μg kg^-1) in the studied sites of toxic metals considered in this work.

<p>Legend: OvCh—Ovar Channel, MuCh—Murtosa Channel, EsCh—Espinheiro Channel, AvC—Aveiro city canals, AvH—Aveiro Harbor</p

Available concentrations (μg kg^-1) in the studied sites of: a) Zn, b) Pb, c) As, d) Cu and e) Hg, in the three mobile phases (S1, S2 and S3).

<p>Legend: OvCh—Ovar Channel, MuCh—Murtosa Channel, EsCh—Espinheiro Channel, AvC—Aveiro city canals, AvH—Aveiro Harbor</p

Distribution maps of: Pollution Load Index (PLI) values, total organic carbon (TOC, %) content, total concentrations of biopolymers (TBP, mg/g) and concentrations of proteins (PTN, mg/g), carbohydrates (CHO, mg/g) and lipids (LIP, mg/g).

<p>Legend: OvCh—Ovar Channel, SJCH—São Jacinto Channel, MuCh—Murtosa Channel, EsCh—Espinheiro Channel, MiCh—Mira Channel.</p

DCA comparing the species distribution in each site with available concentrations of metals (μg.kg^-1), in three mobile phases, S1, S2 and S3 and total available concentrations (elements signed with 1, 2, 3 and T, respectively).

<p>Legend of the benthic foraminifera species: <i>A</i>. <i>tepida</i> (A.tepid), <i>A</i>. <i>balkwilli</i> (A.balkwi), <i>A</i>. <i>pseudospiralis</i> (A.pseudosp), <i>A</i>. <i>mexicana</i> (A.mexic), <i>B</i>. <i>ordinaria</i> (B.ordin), <i>B</i>. <i>pseudoplicata</i> (B.pseud), <i>B</i>. <i>elegantissima</i> (B.elegan), <i>C</i>. <i>ungerianus</i> (C.unger), <i>E</i>. <i>excavatum</i> (E.excav), <i>E</i>. <i>margaritaceum</i> (E. margar), <i>E</i>. <i>williamsoni</i> (E.william), <i>E</i>. <i>macrescens</i> (E.macres), <i>G</i>. <i>praegeri</i> (G.praeg), <i>H</i>. <i>manilaensis</i> (H.manil), <i>H</i>. <i>germanica</i> (H.german), <i>L</i>. <i>lobatula</i> (L.lobat), <i>M</i>. <i>fusca</i> (M.fusca), <i>P</i>. <i>mediterranensis</i> (P.mediter), <i>Q</i>. <i>seminula</i> (Q.semin), <i>S</i>. <i>lobata</i> (S.lobata), <i>T</i>. <i>comprimata</i> (T.compri), and <i>T</i>. <i>inflata</i> (T.inflata). The coefficients of variance for the axis 1 and for the axis 2 is indicated.</p

Assessment of the trophic state of a hypersaline-carbonatic environment: Vermelha Lagoon (Brazil)

<div><p>Vermelha Lagoon is a hypersaline shallow transitional ecosystem in the state of Rio de Janeiro (Brazil). This lagoon is located in the protected area of Massambaba, between the cities of Araruama and Saquarema (Brazil), and displays two quite uncommon particularities: it exhibits carbonate sedimentation and displays the development of Holocene stromatolites. Due to both particularities, the salt industry and property speculation have been, increasingly, generating anthropic pressures on this ecosystem. This study aims to apply a multiproxy approach to evaluate the trophic state of Vermelha Lagoon based on physicochemical parameters and geochemical data for the quantification and qualification of organic matter (OM), namely total organic carbon (TOC), total sulfur (TS), total phosphorus (TP) and biopolymeric carbon (BPC), including carbohydrates (CHO), lipids (LIP) and proteins (PTN). The CHO/TOC ratio values suggest that OM supplied to the sediment is of autochthonous origin and results, essentially, from microbial activity. The cluster analyses allowed the identification of four regions in Vermelha Lagoon. The Region I included stations located in shallow areas of the eastern sector of Vermelha lagoon affected by the impact of the artificial channel of connection with Araruama Lagoon. The Region II, under the influence of salt pans, is characterized by the highest values of BPC, namely CHO promoted by microbiological activity. The Region III include stations spread through the lagoon with high values of dissolved oxygen and lower values of TP. Stromatolites and microbial mattes growth was observed in some stations of this sector. Region IV, where the highest values of TOC and TS were found, represents depocenters of organic matter, located in general in depressed areas. Results of this work evidences that the Vermelha Lagoon is an eutrophic but alkaline and well oxygenated environment (at both water column and surface sediment) where the autotrophic activity is greater than heterotrophic one. These particular conditions make this a special and rare ecosystem.</p></div

Distribution maps of biopolymeric carbon (BPC; mg C g^-1), carbohydrate (CHO; mg C g^-1), lipid (LIP; mg C g^-1) and protein (PTN; mg C g^-1) concentrations, and PTN/CHO and CHO/TOC ratios values.

<p>Distribution maps of biopolymeric carbon (BPC; mg C g^-1), carbohydrate (CHO; mg C g^-1), lipid (LIP; mg C g^-1) and protein (PTN; mg C g^-1) concentrations, and PTN/CHO and CHO/TOC ratios values.</p

Distribution maps of salinity, dissolved oxygen (mg L^-1), temperature (°C), pH, total sulphur (%), total organic carbon (%), total phosphorus (μg g^-1) and TOC/S ratio values.

<p>Distribution maps of salinity, dissolved oxygen (mg L^-1), temperature (°C), pH, total sulphur (%), total organic carbon (%), total phosphorus (μg g^-1) and TOC/S ratio values.</p