Maria Virgínia Alves Martins

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.

Environmental Quality Assessment of Bizerte Lagoon (Tunisia) Using Living Foraminifera Assemblages and a Multiproxy Approach

This study investigated the environmental quality of the Bizerte Lagoon (Tunisia) through an integrated approach that combined environmental, biogeochemical, and living benthic foraminiferal analyses. Specifically, we analyzed the physicochemical parameters of the water and sediment. The textural, mineralogical, and geochemical characteristics of the sediment, including total organic carbon, total nitrogen, simultaneously extracted metals (SEM), acid volatile sulfides (AVS), chlorophyll a, CaCO3, and changes in bacterial populations and carbon isotopes were measured. The SEM/AVS values indicated the presence of relatively high concentrations of toxic metals in only some areas. Foraminiferal assemblages were dominated by species such as A. parkinsoniana (20–91%), Bolivina striatula (<40%), Hopkinsina atlantica (<17%), and Bolivina ordinaria (<15%) that cannot be considered typical of impacted coastal lagoons both in Mediterranean and northeast Atlantic regions. The results of this work suggest that Bizerte Lagoon is a unique setting. This lagoon is populated by typical marine species that invaded this ecosystem, attracted not only by the prevailing favorable environmental conditions but also by the abundance and quality of food. The results indicate that the metal pollution found in some areas have a negative impact on the assemblages of foraminifera. At present, however, this negative impact is not highly alarming.

Foraminiferal biotopes and their distribution control in Ria de Aveiro (Portugal): a multiproxy approach

Ria de Aveiro, which is located in the centre of Portugal (40° 38′ N, 8° 45′ W), is a well-mixed and complex coastal lagoon that is separated from the sea by a sandy barrier and connects with the Atlantic through an artificial inlet. Tidal currents are the main factor controlling the lagoon’s hydrodynamics and, to a great extent, the sedimentary dynamic. The inner lagoonal zones receive input from several rivers and experience the pressure caused by the accumulation of organic matter and pollutants (namely, trace metals) from diverse anthropic activities. This paper is the first piece of work aiming to recognize, characterize and explain the main benthic foraminiferal biotopes in Ria de Aveiro. To provide a broad overview of this kind of setting, our results are compared to those of previous published studies conducted in similar transitional environments. The research is based on an investigation of 225 sites spread throughout this ecosystem. Utilizing a statistical approach, this study analyses the details of dead benthic foraminiferal assemblages composed of 260 taxa, the texture and composition (mineralogical and geochemical) of the sediment and physicochemical data. On the basis of the results of R-mode and Q-mode cluster analyses, several different biotopes can be defined as marsh biotope/near-marsh biotope; marginal urban/marginal urban mixing biotope; inner-outer lagoon biotope or enclosed lagoon; outer lagoon biotope, mixed sub-biotope; and outer lagoon, marine sub-biotope. These biotopes are related to foraminifera assemblages and substrate type and are influenced by local currents, water depth, chemical and physicochemical conditions, river or oceanic proximity, and anthropogenic impact, as evidenced by the mapping of the six factor loadings of the principal component analysis conducted herein. Based on a similar methodology of analysis as that applied in previous studies in the Lagoon of Venice, comparable biotypes were identified in Lagoon of Aveiro.

Organic matter quantity and quality, metals availability and foraminiferal assemblages as environmental proxy applied to the Bizerte Lagoon (Tunisia).

This study analyzes the benthic trophic state of Bizerte Lagoon (Tunisia) based on the total organic matter and the bioavailability of biopolymeric carbon including proteins (PTN), carbohydrates (CHO), lipids (LIP), chlorophyll a, as well as bacteria counts. The overall simultaneously extracted metals (SEM), and acid volatile sulfides (AVS) as well as the SEM/AVS ratio indicative of the toxicity of the sediments also were analyzed aiming to study their impact in the dimension, composition and structure of both dead and living benthic foraminiferal assemblages. In the studied sites TOC content is relatively high and the PTN/CHO values indicate that they can be considered as meso-eutrophic environments. The CHO/TOC and C/N values suggest that the OM which accumulated on the sediments surface has mainly natural origin despite the introduction of municipal and industrial effluents in the lagoon and the large bacterial pool. The living assemblages of benthic foraminifera of Bizerte Lagoon are quite different to other Mediterranean transitional systems studied until now. They are composed of typical lagoonal species but also include several marine and opportunistic species including significant numbers of bolivinids, buliminids, Nonionella/Nonionoides spp. and Cassidulina/Globocassidulina spp. These assemblages seem to benefitfrom the physicochemical parameters and the sediment stability. They may however face environmental stress in the lagoon related to the AVS production as a result of the organic matter degradation and toxicity in some areas due to the available concentrations of metals. Nonetheless statistical results evidence that the structure and dimension of assemblages are being controlled mostly by OM quantity and quality related mainly to the availability of PTN, CHO and chlorophyll a. Results of this work support the importance of considering OM quantity and quality in studies of environmental impact in coastal systems.

Biochemical Composition and Foraminiferal Content of Sediments for Determining Bottom Sector Environments in Guanabara Bay (Rio de Janeiro, Brazil)

ABSTRACT Clemente, I.M.M.M.; da Silva, F.S.; Laut, L.L.M.; Frontalini, F.; da Costa, V.L.; da Conceição Rodrigues, M.A.; Pereira, E.; Bergamaschi, S.; Filho, J.G.M., and Martins, M.V.A., 2015. Biochemical composition and foraminiferal content of sediments for determining bottom sector environments in Guanabara Bay (Rio de Janeiro, Brazil). Three cities in Brazil—Rio de Janeiro, Niterói, and São Gonçalo—with an estimated total population of 11 million people, are located in the surroundings of Guanabara Bay (RJ-Brazil), making it a highly contaminated coastal system. Because of its importance, Guanabara Bay has been one of the most studied coastal environments in Brazil. Despite that, this study represents the first investigation, to our knowledge, to couple benthic foraminifera with the quantity and quality of organic matter in the area. The spatial distribution of water salinity and the surface sediment reduction potential, grain size, total organic carbon, sulfur, bacterial organic carbon, biopolymers such as carbohydrates, proteins, lipids, bacterial enzyme esterase, and total foraminiferal assemblages were studied at 30 stations in Guanabara Bay. Based on these data, six bottom environments—industrial, marginal urban, marginal urban/industrial mixing, eutrophic, transitional, and outer— were identified and described.

Trace element accumulation and elutriate toxicity in surface sediment in northern Tunisia (Tunis Gulf, southern Mediterranean)

Metal concentrations in sediments were investigated in the Gulf of Tunis, Tunisia, in relation to anthropic activities along the Mejerda River and Ghar El Melh Lagoon, with effluents discharged into the gulf. Distribution of grain size showed that the silty fraction is dominant with 53%, while sand and clay averages are 34 and 12% respectively. Zn concentration increased in the vicinity of the Mejerda River while Pb was at its highest levels at the outlet of Ghar El Mehl Lagoon. Sediment elutriate toxicity, as measured by oyster embryo bioassays, ranged from 10 to 45% abnormalities after 24h, but no relation was found between metal concentration and sediment toxicity. The AVS fraction that represents monosulfide concentrations in the sediment was higher in the central part of the gulf than in the coastal zone. The results reveal the influence of AVS, TOC and grain size on metal speciation and sediment toxicity.

Environmental impact of the largest petroleum terminal in SE Brazil: A multiproxy analysis based on sediment geochemistry and living benthic foraminifera

The Dutos e Terminais do Centro Sul (DTCS) is one of the largest petroleum terminals of the South America located in the São Sebastião Channel (SSC) on the southeastern Brazilian coast. The aims of this study were to compare the sediment quality near the DTCS with that of several sites in the SSC region including the Araçá (AR) domestic sewage outfall and to assess the efficiency of the DTCS wastewater treatment plant. To achieve these goals, textural, geochemical, and living benthic foraminifera results were analyzed for the DTCS, AR, and SSC regions. Sediments in the DTCS area were silty with high concentrations of total organic carbon (1.7–2.4%), total nitrogen (0.2–0.3%), total sulfur (0.4–0.6%), and total (0.12–0.18%) and inorganic phosphorous (0.07–0.11%). These values were higher than those in sediments collected in the SSC and Araçá regions. The sediments’ concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the SSC and AR regions were lower than their corresponding probable effect levels (PELs). However, sediments near the DTCS were enriched with As, Cu, and Ni, whose concentrations exceeded their corresponding threshold effect levels (TELs). Around the DTCS outfall diffusers, living foraminiferal densities and diversities were lower than those for the other areas studied. In the DTCS area, it was necessary to search 50 to 190 cm3 of sediment to find 100 live specimens. In the SSC and Araçá areas, a maximum of 40 cm3 of sediment was enough to locate 100 live specimens. The lower density and diversity of living foraminifera around the DTCS than around the other areas illustrates the impact of the environmental stress caused by the presence of pollutants. These results indicate that the wastewater treatment plant efficiency is low and its discharge of pollutants from petrochemical waste liquids affects the benthic fauna around the DTCS in a potentially harmful manner.

Influence of dominant wind patterns in a distal region of the NW Iberian Margin during the last glaciation

This work combines planktonic foraminiferal assemblages, stable isotope, transfer function estimated sea surface paleotemperatures (SST) and export productivity (Pexp) with sedimentological records from the PC7 core to document paleoclimatic and paleoceanographic changes on a distal region of the NW Iberian Margin since the last glaciation (<≈68 ka). Neodymium and strontium isotope data are also used to identify the provenance of ice rafted debris (IRD) during Heinrich event 5 (H5). Our results are compared and combined with previously published records and evidence that melt water and icebergs from the Canada, Greenland, Iceland and Europe ice sheets arrived to the NW Iberian Margin causing a significant decrease of SST during the last six Heinrich Stadials (HS) and some Dansgaard–Oeschger (D-O) stadial events. εNd and 87Sr/86Sr indicate that the studied locality mostly received sediments from European Ice Sheets (EIS) during H5. During the HS and D–O stadial events, SSTs were in general higher than in other cores collected in inner areas of the NW Iberian Margin. The presence and intensification of Portugal Current probably induced heat transfer to this distal region of the Iberian Margin. Our results also suggest the occurrence of high variability in the intensity and wind patterns during the last glaciation. In some periods, the intensity of northerly winds could have been very strong and contributed to a significant stimulation of ocean productivity in this distal area through the intensification of upwelling. In general, oceanic productivity decreased during the HS and D–O as the presence of cold and less saline water prevented nutrient rich waters from deep levels reaching the surface. The high productivity events were bracketed by periods characterized by the highest influence of the Azores Current eastern branch during which northerly winds and the oceanic productivity should have been weakened. Supplementary material: Geochemical and foraminiferal data analysed in this work as well as Pearson Correlations between the analysed data are available at https://doi.org/10.6084/m9.figshare.c.3931813

The response of cultured meiofaunal and benthic foraminiferal communities to lead exposure: Results from mesocosm experiments

Lead (Pb) is regarded as a highly toxic element that poses a serious threat to biota. A mesocosm experiment was performed to assess the influence of Pb on meiofaunal (metazoans within 45-500 μm) and benthic foraminiferal (protozoan) communities. To this end, sediments bearing such communities were incubated in mesocosms, exposed to different levels of Pb in seawater, and monitored for up to 8 wk. Concentrations of Pb <1 ppm in water did not promote a significant increase of this metal in sediments. Relatively high concentrations of Pb seemed to affect meiofaunal and benthic foraminiferal communities by reducing their richness or diversity, and the abundance of the most sensitive taxa. The mesocosm approach can be considered an effective method to document the responses of meiofaunal and benthic foraminiferal communities to various kinds and concentrations of pollutants over time. This approach allows the evaluation of dose-response relationships, validates the outcomes of field studies, and possibly confirms the sediment quality guidelines and thresholds. Environ Toxicol Chem 2018;37:2439-2447.

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

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.