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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Total phosphorus (TP) records reflect variations in input and burial of organic matter (OM) in coastal and shelf sediments . At Antarctic regions , TP levels are often derived from natural sources; however, with emergent human pressure at these regions, anthropogenic sources of TP may play an important role. At the Antarctic Peninsula , Admiralty Bay attracts great scientific and touristic interest, especially during austral summer months, thus being vulnerable to human activities. Currently, only scarce spatial distributions of TP are available for this key region, whereas no vertical distributions have been determined. To fill this gap, we investigated short ( sediment cores in ten areas along Admiralty Bay for TP contents. We produced the first TP vertical distributions and established site-specific background values (from 492 ± 13 to 932 ± 17 μg g −1 ), which are related to hydrodynamics, sedimentology , and natural inputs of P. We observed a gradual surface TP enrichment at all sites, mainly due to input of fresh OM. Benefiting from our background values, we employ the Phosphorus Pollution Index (PPI) to assess possible human impacts . Generally, the increase of PPI suggests natural inputs of P. However, PPI ≥ 1.3 found at the nearby Comandante Ferraz Research Station (Brazil) can be linked to recent (past 2–3 decades) treated sewage inputs in Martel Inlet. We suggest PPI as a proxy for preliminary assessments of anthropogenic impacts in coastal Antarctic regions experiencing increased human pressure.

The Paranaguá Estuarine Complex (PEC) includes the naturally oligotrophic (NO) Mel Island which is surrounded by sea grasses, a naturally eutrophic (NE) Benito Inlet adjacent to mangrove wetlands and the highly impacted eutrophic (IE) Paranaguá Bay, home of one of Brazil's largest ports. The results from this study indicate that reactive As and pyrite increase with sediment depth near Paranaguá port in the IE region. At the NE region, near a mangrove fringe, the reactive As, Fe, Mn and pyrite remained relatively high along the sediment column while near the sea grasses at NO the As contents were low. The degree of trace metal pyritization (DTMP) and the degree of pyritization (DOP) was highest at the IE site, slightly increasing with depth. These baseline results indicate that influence of trophic conditions and presence of marine vegetation may be directly related to As behavior in coastal systems.

Particulate and dissolved metal concentrations were determined after the largest flood in the last 30 years on the east-west axis of the Paranaguá Estuarine Complex (PEC) and compared to the those of the dry period at two stations. Results confirmed that the flood greatly affected riverine outflows and the behavior of metals in the PEC. In particular, a sharp decrease in salinity was followed by extremely high SPM concentrations leading to a decrease in DO concentrations at both stations. For the dissolved phase, ANOSIM analysis showed a significant dissimilarity at each station between the sampled periods, whereas for the particulate phase this dissimilarity was found only for the samplings taken at the Antonina Station. KD values suggested dissolved Cu behavior was related to the presence of organic complexes and dissolved Mn had sediment resuspension of redox sediments and or/pore water injection as sources. Metal concentrations were lower than in polluted estuaries, though high enrichment factors found after the flood pointed to the influence of anthropogenic sources. In conclusion, the flood's influence was more evident at the Antonina Station, due to its location in the upper estuary, whereas in Paranaguá a high SPM content with low metal concentration was found, following the common pattern generally found in other marine systems subject to heavy rainfall events. Resumo Com o objetivo de avaliar a influência do maior evento de enchente dos últimos 30 anos no Complexo Estuarino de Paranaguá (CEP), ocorrido em 2010, concentrações de metais na fase particulada e dissolvida foram medidas em duas estações amostrais, e comparadas ao período seco. Os resultados confirmaram a influência desse evento no aumento do fluxo dos rios e no comportamento dos metais no CEP. Uma acentuada diminuição na salinidade, concomitante ao aumento de material particulado em suspensão, gerou a diminuição das concentrações de oxigênio dissolvido nas duas estações amostradas. A análise de ANOSIM indicou ausência de similaridade entre ambas as estações e períodos amostrados, enquanto que para a fase particulada essa diferença foi evidente apenas para a estação de Antonina. Os valores do coeficiente de partição (KD) sugeriram um input de manganês dissolvido por meio de processos de oxi-redução. As concentrações de metais registradas foram menores do que as encontradas em estuários poluídos; no entanto, o aumento do Fator de Enriquecimento após o evento de inundação sugeriu a influência de fontes antrópicas. Como conclusão geral, a influência do evento de inundação foi mais evidente na estação de Antonina, principalmente devido a sua localização na parte superior do estuário, enquanto que em Paranaguá o aumento do SPM foi acompanhado de uma diminuição na concentração de metais, seguindo o comportamento de metais registrados em outros estuários após eventos de inundação.

This study addresses the distribution of total phosphorus (TP) and its inorganic (IP) and organic (OP) fractions, grain-size and organic matter of surface and recent sediments, coupled to the behavior of total and dissolved inorganic phosphorus (TP and DIP) of the water column, of the semi-pristine Guaratuba Bay estuary, SE Brazil. Surface sediment samples were taken at 43 sites spread along the estuarine gradient and recent sediments from 3 short (35 cm long) cores from the upper, central and lower portions of the estuary, respectively. Highest TP and IP concentrations of surface sediments were detected within the upper sector and the transition zone between the upper and central sectors, all characterized by fine sediments, low salinities and water depths. In contrast, the lower sector and its narrow and deep tidal channel, subject to more intense tidal forcing, exhibited a higher fraction of sandy sediments with lower TP, IP and OP contents. In spite of the spatial variability in sediment grain size, IP corresponded to the major fraction of TP in all estuarine sectors and both TP and IP correlated significantly with the fine sedimentary (silt + clay) grain-size fraction. The fine surface sediments acted as a trap for IP at the fresh water–low salinity interface, which also corresponded to the region of a DIP sink in surface waters. In general, the short sediment cores showed that TP and IP contents increased from 15 cm depths to the top layer. Published sedimentation rates from additional cores taken at the sites of the short cores of this study, implied that depositional alterations of TP and IP increased during the early 1970s, which corresponded to the onset of anthropogenic disturbances from crop plantations in the lowland plains of the river end-member and urbanization at the estuary’s mouth and along the adjacent coast.

Mangrove sediment cores sampled from Sepetiba Bay (SE Brazil) were covered with tidal water spiked with 75Se, 51Cr and 60Co to evaluate the removal efficiency of these radiotracers by underlying sediments. Variable time-evolution trends were observed along 115 h experiments, with significant differences between removal efficiencies of all radiotracers observed only after 70 h (51Cr > 60Co > 75Se). After an event of 60Co release back to overlying water, there was a general trend of lower 60Co removal than observed for other radiotracers during the period from 20 to 54 h. After this event, alternated periods of higher 60Co and higher 75Se removal trends were observed, attributed to behavioural differences expected for such anionic and cationic radiotracers. While 75Se and 51Cr showed uniform time-evolution curves, as typically found in the literature for most radiotracers, 60Co removal rates presented oscillations, probably due to sensitivity to changes in redox conditions within underlying sediments. Results evidenced the role of mangrove sediments as trace element sinks, which have implications for coastal water quality and for possible uses of such sediments in wastewater treatment systems.

Sediments from Guaratuba Bay (PR, Brazil), a marine protected area, were collected and evaluated for geochemistry and toxicity. High levels of P and acute toxicity were observed in some samples. Concentrations of Cu, Cd, Pb and Zn were relatively low; however, Cd levels eventually exceeded Threshold Effect Level. Toxicities were associated to nutrients and metals enrichment. Results suggest that impacts are incipient and occur only at specific sites, associated to multiple contamination sources. Despite sediments quality seems to range between good and fair, attention is required to land-use planning around Guaratuba Bay and controlling local pollution sources.

Potential influences of the whole benthic organisms' activity (i.e., coupled faunal and microbial effects) on 58Co, 51Cr and 65Zn diffusion into surface mangrove sediment layers (0–6 cm depth) were evaluated in 36 h experiments. Benthic activity indices (BAI) were proposed, calculated as the relative percent difference between untreated sediments and formaldehyde-treated sediments data in relation to untreated sediments data. Benthic activity was estimated as responsible for 32%–44% of total inventories within sediments, being the chromate anion spiked the less affected radiotracer, while 65Zn was the most sensitive. Benthic activity was quantitatively evidenced as a control on trace metal diffusion into the sediments, contributing to determine the sediment role as a metal sink. This influence can also affect metal potential bioavailability, considering that recently diffused metals can be more readily available to biological uptake.

This work investigates the (223)Ra, (224)Ra, (226)Ra and (228)Ra isotope distribution in river, estuarine waters and sediments of the Paranagua Estuarine Complex (PEC). The stratification of the Ra isotopes along water columns indicate differing natural sources. In sediments, the radium isotope activities was inversely proportional to the particle size. The highest concentrations of (223)Ra, (224)Ra, (226)Ra and (228)Ra in the water column were found in the bottom more saline waters and towards the inner of the estuary. These relatively high concentrations towards the bottom of the estuary may be attributed to the influence of tidally driven groundwater source and desorption from particles at the maximum turbidity zone. The apparent river water ages from the radium isotope ratios, (223)Ra/(224)Ra and (223)Ra/(228)Ra, indicate that the principal rivers that flow into the estuary have residence times from between 6 and 11days.

Temporal variability of physicochemical parameters and phytoplankton primary productivity, abundance and composition were investigated at Babitonga Bay, southern Brazil, using a hierarchical sampling design on the scales of months, weeks and days during spring 2012 and summer 2013. Only temperature, respiration rates and concentrations of dissolved oxygen and silicate exhibited significant differences in the greatest timescale (seasons: spring; summer). In contrast, most physicochemical parameters, such as salinity and the concentration of nitrogen compounds, varied mainly among weeks and days. This short-scale variability was similarly observed for the microphytoplankton abundance, ranging from 0.04 to 1.7.106 cells L–1 during a bloom of the diatom Skeletonema costatum. Two major phytoplankton assemblages were associated with high primary production rates: > 30 μm centric diatoms such as Cyclotella spp. and Cymatodiscus sp., in spring; and a summer assemblage dominated by smaller, bloom-forming diatoms (S. costatum and Eucampia cornuta). Primary production ranged from 10.5 to 1793 mg C m–2 d–1 and varied significantly between days and months, being associated with the photosynthetic active radiation level and weather conditions on the sampling day. Abundance of specific plankton taxa appeared controlled by trophic interactions, as revealed for the mixotrophic, toxic dinoflagellate Dinophysis acuminata complex and its prey, the ciliate Mesodinium rubrum. Se investigaron la variabilidad temporal de los parámetros físico-químicos y la producción primaria (PP), abundancia y composición del fitoplancton en la Bahía de Babitonga, sur de Brasil, utilizando un diseño de muestreo jerárquico en las escalas de meses, semanas y días, durante la primavera/2012 y verano/2013. Sólo la temperatura, las tasas de respiración y las concentraciones de oxígeno disuelto y silicato mostraron diferencias significativas en las escalas de tiempo mayores (estaciones: primavera; verano). En contraste, la mayoría de los parámetros fisicoquímicos, tales como la salinidad y la concentración de compuestos de nitrógeno, varió principalmente entre semana y días. Tal variabilidad de corta escala se observó de manera similar para la abundancia de microfitoplancton, oscilando desde 0,04 a 1.7.106 céls. L–1 durante una floración de la diatomea Skeletonema costatum. Se asociaron dos importantes grupos de fitoplancton con altas tasas de PP: diatomeas céntricas > 30 μm como Cyclotella spp. y Cymatodiscus sp., en primavera; y un grupo de verano dominado por pequeñas diatomeas formadoras de floraciones (S. costatum y Eucampia cornuta). La PP varió de 10.5 a 1793 mg C m–2 d–1 y varió significativamente entre días y meses, siendo asociada con el nivel de radiación fotosintética activa y las condiciones meteorológicas en el día de muestreo. La abundancia de taxa específicos de plancton parece controlada por interacciones tróficas, como las revelada para el dinoflagelado tóxico mixotrófico, complejo Dinophysis acuminata y su presa, el ciliado Mesodinium rubrum.

The present study focuses on the nutrient sources and gradients in Paranagua Bay (Southern Brazil), where nutrient inputs are related to losses from fertilizer loading in Paranagua harbour and the discharge of untreated waste water. The input of dissolved inorganic nutrients to the bay from the harbour and city, as well as from river and atmospheric deposition, amounted to 642 t year−1 DIN-N and 92 t year−1 PO4-P. Harbour losses accounted for 6 % of total DIN-N and 39 % of total PO4-P loads to the bay, whereas sewage inputs from the city were responsible for 21 % and 22 %, respectively. River inputs made up 68 % of DIN-N, mainly in the form of nitrate, and 35 % of PO4-P loads, while atmospheric wet deposition was estimated to be in the order of 5 % of DIN-N and 4 % of PO4-P loads. Local maxima in nutrient levels deriving from highly concentrated sewage discharge were observed in front of the harbour and city of Paranagua, but the plumes are diluted rapidly due to short residence times. DIN concentrations are negatively correlated with salinity, indicating the importance of freshwater input as a main factor controlling nitrogen distribution. Elevated phosphate levels in the stratified middle section of the bay may result both from harbour emissions and phosphate remobilization from sediments. Generally lower DIN and PO4 concentrations during the warmer rainy season are supposed to be due to intensified assimilation rates especially in the middle section of the bay where dense phytoplankton blooms are observed. The bay as a whole cannot be classified as being seriously eutrophic, albeit eutrophication symptoms prevail in some restricted locations in front of Paranagua harbour.

An environmental assessment of the estuarine waters of Guaratuba bay, Paraná State, Brazil, is provided through the analysis of physical-chemical, biological and hydrographic dynamics. Twelve stations with a bi-monthly frequency (from October/2002 until August/2003) were sampled during spring and neap tides for the determination of pH, Secchi depth, CO2 saturation, dissolved oxygen, chlorophyll, suspended particulate matter and dissolved inorganic nutrients (nitrate, nitrite, ammonium, phosphate and silicate). Based on the evaluation of six parameters (chlorophyll, Secchi depth, CO2 saturation, dissolved inorganic nitrogen and phosphorus and dissolved oxygen), Guaratuba Bay shows a low to medium trophic status, i.e. from meso- to oligotrophic, and a predominant heterotrophic metabolism, meaning that respiration overcomes primary production. Horizontal stratification was observed during the rainy season, while during the dry season the system showed more homogeneous conditions. Inorganic and/or organic matter in Guaratuba Bay seem to be controlled mainly by the seasonality of precipitation and/ also by ebb and flood tidal phase variations.A dinâmica das variáveis físico-químicas, biológicas e hidrográficas, em escalas temporal e espacial, sua variabilidade e tendências, permite avaliar a qualidade ambiental de estuários. Esse trabalho descreve as flutuações da qualidade de água da Baía de Guaratuba, sul do Estado do Paraná. Foram amostrados doze pontos em campanhas bimensais (outubro/2002 a agosto/2003), em situação de sizígia e de quadratura, para a análise das variáveis pH, transparência, saturação de CO2, oxigênio dissolvido, clorofila-a, material particulado em suspensão e nutrientes inorgânicos dissolvidos (nitrato, nitrito, amônio, fosfato e silicato). Considerando as seis variáveis descritoras da qualidade de água (clorofila-a, profundidade de Secchi, saturação de CO2, fósforo e nitrogênio inorgânicos dissolvidos e oxigênio dissolvido), observou-se que a Baía apresentou estado trófico médio para baixo, i.e. de meso para oligotrófico, e que o seu metabolismo é predominantemente heterotrófico, ou seja, os processos de respiração superam os de produção. Foi verificada uma maior estratificação horizontal durante o período chuvoso e características relativamente mais homogêneas durante a estação mais seca. A qualidade da água na baía de Guaratuba parece ser controlada mais pelos aportes de material inorgânico e/ou orgânico associados a pluviosidade e/ou por variações com as fases de maré vazante e enchente.

Seasonal and spatial dynamics of the microphytobenthic biomass on a subtropical intertidal sand flat (25°32'S; 48°24'W) was investigated monthly from September 1995 to July 1996. Chlorophyll-a and Phaeophytin-a contents, temperature, salinity, inorganic nitrogen and phosphate pore water concentrations and sediment characteristics were assessed in the upper (HW), middle (MW) and lower (LW) sections of the flat. Microphytobenthic biomass content showed a conspicuous seasonal and spatial gradient. Higher chlorophyll-a contents were registered in the HW section of the tidal flat (from 11.78 µg.gsed-1 to 38.18 µg.gsed-1) decreasing towards the LW section (from 6.23 µg.gsed-1 to 18.23 µg.gsed-1). Microphytobenthic seasonality was determined mainly by turbulence of the water column, which was influenced by atmospheric events. The sediment properties and nutrient concentrations had a significant effect on the spatial and seasonal distribution of pigments on the intertidal flat. A dinâmica sazonal e espacial da biomassa microfitobêntica em uma planície arenosa intermareal (25º32'S; 48º24'W) foi investigada mensalmente de setembro de 1995 a julho de 1996. A concentração de clorofila-a e feofitina-a, a temperatura, salinidade, concentração de nitrogênio inorgânico e fosfato na água intersticial, além das características do sedimento, foram inferidas na região superior (HW), mediana (MW) e inferior (LW) da planície. A biomassa microfitobêntica apresentou gradientes sazonal e espacial bem definidos. Maiores concentrações de clorofila-a foram registradas na região superior da planície entre marés (HW, de 11.78 µg.gsed-1 até 38.18 µg.gsed-1), decrescendo em direção a região inferior da planície (LW, de 6.23 µg.gsed-1 a 18.23 µg.gsed-1). A sazonalidade microfitobêntica foi determinada principalmente pela turbulência da coluna de água, influenciada pelos eventos atmosféricos. As propriedades do sedimento e as concentrações de nutrientes foram significantes para a distribuição espacial e sazonal dos pigmentos na planície entre marés.

The aim of this study was to investigate the dynamics of the fluorescent dissolved organic matter (FDOM) in Paranaguá Estuarine System (PES) as to infer about the contribution of allochthonous FDOM to the estuarine waters in relation to tidal condition and seasons. Fluorescence spectroscopy was used for such purpose and DOM characterization through fluorescence emission was performed using excitation wavelengths of λex 350 nm and λex 450 nm, the two main fluorescence groups known to be present in natural DOM. Relations between emission wavelength (λem) and environmental variables, and the relevance of these variables to the different tides and seasons were identified by principal component analysis. The results showed that the first class of fluorophores (λex 350 nm) changed from the river (freshwater) towards the estuary, whilst the second class (λex 450 nm) has a more conservative nature and does not change as significantly as the first. Allochthonous DOM contribution to the estuarine system is intensified during the rainy season, especially in spring tides, whereas in the dry season the ratio of autochthonous DOM to total DOM in PES waters increased. We concluded that the variation of maximum λem of the first class of fluorophores (λex 350 nm) is mainly related to allochthonous contribution, whilst the maximum of emission for the second class of fluorophores (λex 450 nm) is dependent on the contribution of the different sources of organic matter (freshwater and marine water DOM contribution).O objetivo deste estudo foi investigar a dinâmica da matéria orgânica fluorescente (FMOD) no Complexo Estuarino de Paranaguá (CEP) para inferir sobre a contribuição da FMOD alóctone nas águas estuarinas em relação à condição de maré e estações do ano (seca e chuvosa). Empregou-se a técnica de espectroscopia de fluorescência, através da utilização de dois comprimentos de onda de excitação, os quais correspondem a duas classes conhecidas de fluoróforos, λex 350 nm e λex 450 nm, para desta forma determinar o comprimento de onda de máxima emissão (λem) da fluorescência da MOD. Relações entre λem e variáveis ambientais e a relevância das relações nas diferentes condições de maré (sizígia e quadratura) e estações do ano (seca e chuvosa) foram identificadas com o uso de análise de componentes principais. Os resultados demonstraram que a primeira classe de fluoróforos (λex 350 nm) foi alterada durante a transição rio estuário, enquanto a segunda classe (λex 450 nm) apresentou um comportamento mais conservativo. A contribuição da MOD alóctone no estuário foi intensificada durante a estação chuvosa, especialmente durante as marés de sizígia, enquanto na estação seca a MOD autóctone é preponderante na composição da MOD total no CEP. Conclui-se que a variação nos λem da primeira classe de fluoróforos (λex 350 nm) é principalmente relacionada à contribuição alóctone, enquanto as diferenças nos λem da segunda classe (λex 450 nm) estão relacionadas com as flutuações nas contribuições das diferentes fontes de MOD no CEP.

In this work, the density of bacterioplankton, bacterial biomass and environmental variables were monitored in two seasons (summer and winter), two times each month (spring tide and neap tide sampling), over a 12 h period, comprising a tidal cycle (semidiurnal), from subsurface and bottom waters, in a fixed station in the Estuarine Turbidity Maximum Zone (ETMZ) of Paranaguá Bay, Brazil. The data were treated with multivariate analyses methods in order to indentify the key controlling factors of the bacterial community dynamics. The microbial community seemed to be structured by a close relationship with the nutrients concentration, mainly by total phosphorous and nitrate. Regardless of variations throughout the tidal cycles, free-living bacteria had a dominant role on the Paranaguá's Bay ETMZ.

Urban sewage is considered one of the most important sources of marine pollution in South America, because most coastal cities do not have proper facilities to treat and dispose of sewage. The Paranagua estuarine system is an important estuarine environment of the South American coast where fishing, urban and tourist activities, industries and the main Brazilian grain shipping port are potential sources of pollution in this area. The anthropogenic input of sedimentary organic matter, represented by sewage contribution, was evaluated by fecal steroid concentrations. The coprostanol levels were comparatively low ( −1 ), except at the sites close to Paranagua city, where the coprostanol concentration reached 2.22 μg g −1 showing strong sewage contamination. Fecal steroid levels were comparable to the lower to midrange concentrations reported for coastal sediments worldwide. The results of this work demonstrated that sewage pollution can be considered a problem for a small part of the Paranagua estuary.

Paranagua Bay, on the coast of Parana State in southeastern Brazil (48°25′W, 25°30′S), is part of a large interconnected subtropical estuarine system that includes the Iguape-Cananeia Bay system on the southern coast of Sao Paulo State. Rather than being an estuary, Paranagua Bay (612 km2) is best defined as an estuarine system comprised of two main water bodies, the Paranagua and Antonina bays (260 km2) and the Laranjeiras and Pinheiros bays (200 km2). The system connects to the open sea through three tidal channels, with the main entrance area around Mel Island (152 km2; Fig. 10.1). The structural properties of the bay are typical for a marine ingression environment. Forced regressions, following sea-level maxima at approx. 120,000 and 5,100 B.P., have formed an upper and a lower geomorphologic zone, represented by a drowned, narrow paleo-valley west of Paranagua City and by wide beach ridge plains east of Paranagua, respectively (Angulo 1992; Angulo and Lessa 1997). An extensive coastal plain surrounds Paranagua Bay and the upper reaches of the bay originate about 50km inland at the piedmont of the Serra do Mar mountain range. Mangrove swamps and marshes mainly fringe the interior of the system, while ocean-exposed areas adjacent to the mouth are composed of extensive sand beaches and some rocky shores (Angulo 1992).