Abstract The Cananéia-Iguape Estuarine-Lagoon Complex (CIELC) is an area of low anthropogenic impact; however, it is not completely isolated from human pressure, particularly in the northern sector. Considering this scenario, this study aims to identify the health of two catfish species Cathorops spixii and Genidens Genidens taking into account the hepatic pathological analysis and the accumulation of iron in the form of hemosiderin considering a temporal approach. Biometric measurements were taken, and the condition factor was obtained. The main liver alterations found in the two catfish species were necrosis, inflammation, hemorrhage, cytoplasmatic vacuolization, and pyknosis nuclei. Necrosis (2014: 57%; 2017: 71 %; and 2018: 20%) and pyknosis nuclei (2014: 86%; 2017: 43%; and 2018: 40%) was the most frequent alteration. However, cytoplasmatic vacuolization was the only change that was statistically significant over time. Regarding hemosiderin, catfish livers mostly presented a minimum degree of accumulation, which represents healthy results. Finally, histopathological observations in C. spixii and G. genidens catfish tissues are confirmed to be an efficient tool to evaluate the health of these fish and the changes induced by environmental conditions over the years. However, the absence of significant differences on the histopathological changes over time can suggest a physiological equilibrium of these fish in the CIELC. CananéiaIguape Cananéia Iguape EstuarineLagoon Estuarine Lagoon CIELC (CIELC impact however pressure sector scenario approach taken obtained necrosis inflammation hemorrhage 2014 (2014 57% 57 2017 7 % 2018 20% 20 86% 86 43% 43 40% 40 alteration However results Finally C G years 201 (201 5 2 8 4 (20 (2 (

ABSTRACT The emissions of CH4 and CO2, the primary greenhouse gases, have a significant impact on radiative forcing. This study investigated these gases along the Cananéia-Iguape estuarine system on the southern coast of the State of São Paulo, Brazil, which is a mangrove region characterized by low anthropogenic impact and a sparse population. As such, this area provides an ideal location for identifying natural emissions and background concentrations. The data for this study were collected using a portable gas analyzer (LGR-ICOSTM GLA131), known for its high sensitivity and precision in detecting gases, mounted on a research boat. The results obtained were promising for both gases. A small variability in CH4 concentrations was observed along the route, ranging from 1.84 ppm to 1.95 ppm, while CO2, showed greater variation in values obtained during routes, ranging from approximately 411 ppm to 575 ppm. This study underscores the importance of investigating areas with minimal environmental impact. Together with future analyses, this research should help improve Greenhouse Gas (GHG) inventories in Brazil by providing valuable baseline data for comparisons with more impacted areas. CH CO2 CO forcing CananéiaIguape Cananéia Iguape Paulo population such LGRICOSTM LGR ICOSTM GLA131, GLA131 GLA , GLA131) boat route 184 1 84 1.8 195 95 1.9 routes 41 57 analyses GHG (GHG GLA13 18 8 1. 19 9 4 5 GLA1

Abstract Some fish species can be used as target species and bioindicators of environmental disturbances. In this context, biological indicators such as the length, weight, and height of lapillus otoliths of the ariid species Cathorops spixii and Genidens genidens were considered bioindicators of contamination of the Cananéia-Iguape estuarinelagoon complex (CIELC) in this study. The CIELC is an estuary with spatial and temporal differences regarding its hydrobiochemical properties and this characteristic has been related to changes in biological predictors such as the otolith morphometrics of estuarine fish. Therefore, this study aimed to verify the responses of otolith dimensions to sexual and temporal changes, throughout the CIELC. In total, 163 wild catfish C. spixii and 55 G. genidens were collected during the winter period of 2009, 2017, and 2018 in the CIELC. In general, the weight and length of lapillus otoliths of C. spixii and G. genidens were good metrics adjusted to fish growth. Females of C. spixii were significantly larger than males and subadults and there were no significant differences regarding the sexual approach of G. genidens. The temporal approach showed significant differences between the years for both catfish. C. spixii sampled in 2009 and 2018 showed greater total length (TL) and total weight (TW) when compared with fish from 2014 and 2017 (p < 0.05). G. genidens collected in 2018 had greater TL and TW than the specimens sampled in the other years (p < 0.05). Otolith dimensions seem to have followed this same pattern, since females of C. spixii had higher values for otolith weight, height, and length than males and subadults (p < 0.05). The data obtained in this study can be a potential tool for application combined with other ecological analyses and conservation studies in the CIELC. disturbances context CananéiaIguape Cananéia Iguape (CIELC Therefore 16 C 5 G 201 general growth 200 (TL (TW p 0.05. 005 0.05 . 0 05 0.05) pattern 1 20 00 0.0 2 0.

Abstract The assessment of water quality using multiple abiotic and biological indicators is very important for understanding anthropogenic impacts and the health of the ecosystem. The Olaria is a short river system that flows into the Cananeia estuary. This aquatic system crosses the urban center of the city of Cananeia, where it eventually receives untreated domestic wastewater. This study aims to apply multi-indicators of environmental pollution to understand the influence of the Olaria system on the Cananeia estuary. For this purpose, indicators of water quality and genotoxic and pathological responses in fish were used. Data on salinity, pH, and silicates in surface water indicate a more accentuated continental influence in the inner part of the Olaria river system. Moreover, the data recorded on the inner area of the Olaria system, which presents lower hydrodynamic characteristics and the largest urban population, indicated the presence of dissolved oxygen and nutrients (phosphate [P-PO4 -3], nitrite [N-NO2-], and ammonium [N-NH4+]) at levels that exceed the established limits for water quality by the Brazilian environmental legislation (Conselho Nacional do Meio Ambiente - CONAMA). The presence of Escherichia coli in all analyzed water samples indicates a local or point source of domestic wastewater contamination near the Olaria system. Fish species such as Centropomus undecimalis (Robalo Flexa) and Sphoeroides testudineus (Baiacu Pintado) showed toxicogenetic damage, indicating clastogenic and/or aneugenic exposure in the aquatic environment. Hepatic pathologies such as pyknosis nuclei, inflammation, hepatocyte swelling, and necrosis were found in all specimens evaluated, and C. undecimallis exhibited all these pathological changes. These results highlight the importance of biomonitoring the effects of anthropogenic disturbance on the aquatic biota that frequent the Olaria system and are dependent on the water quality. ecosystem estuary multiindicators multi purpose used salinity pH Moreover population phosphate PPO4 PPO P PO4 PO [P-PO 3, 3 , -3] NNO2, NNO2 NNO N NO2 NO [N-NO2-] NNH4+ NNH4 NNH NH4+ NH4 NH [N-NH4+] Conselho CONAMA. CONAMA . CONAMA) Robalo Flexa Baiacu Pintado damage andor environment nuclei inflammation swelling evaluated C changes -3 [N-NO2- [N-NH4+ [N-NO2 [N-NH4 [N-NO [N-NH

Abstract The Cananéia-Iguape estuarine-lagoon complex (CIELC), located in the State of São Paulo, Brazil, is considered an area of the Biosphere Reserve. However, an artificial channel built in the northern sector of the system (Iguape) has promoted an unnatural input of fresh water into the system, leading to enhanced drainage of terrestrial material into the estuary and influencing silicon biogeochemistry within the complex. This study used the distribution of different fractions of silicon along the system as a proxy for the freshwater input. The samples were collected during August, 2012 (winter) and February 2013 (summer) and analyzed for dissolved silicate, biogenic silica, and lithogenic silica. Dissolved silicate reached values above 200 µmol L -1 in the two seasonal periods, indicating the constant supply of terrestrial material in the northern sector of the system associated with fresh water. Southward, where the system is more preserved (Cananéia-Ararapira), the concentration decreased dramatically. Lithogenic silica (LSi) reached extremely high values of ~700 µmol L -1. Biogenic silica (BSi) showed concentrations up to 120 µmol L -1 with distribution more dependent on assimilation processes and the nature of the biological communities than on the source of fresh water. The availability of different forms of Si revealed remineralization, deposition, adsorption, and uptake mechanisms with different dynamics in the northern and southern sectors of the system, evidencing the environmental impact by the Valo Grande Channel. CananéiaIguape Cananéia Iguape estuarinelagoon estuarine lagoon CIELC, CIELC , (CIELC) Paulo Brazil Reserve However (Iguape August 201 winter (winter summer (summer 20 1 - periods Southward CananéiaArarapira, CananéiaArarapira Ararapira (Cananéia-Ararapira) dramatically LSi (LSi 700 ~70 1. BSi (BSi 12 remineralization deposition adsorption Channel (CIELC 2 (Cananéia-Ararapira 70 ~7 7 ~

Abstract Estuaries are important features for global biogeochemical understanding, due to their highly coupled interaction between sediment and water. In those places, the land-sea transect sometimes has a gradient of physical and chemical characteristics, influencing the availability of nutrients and consequently primary production. This study aimed to observe the benthic aerobic respiration and sediment-water nutrient fluxes in a freshwater to marine transect in the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC) on the southeastern Brazilian Coast. This area contains the most pristine mangrove at the limit between tropical and subtropical zones, providing an ideal observatory for ecological research programs. Intact sediment cores were incubated in laboratory to determine fluxes of O2, TCO2, and dissolved nutrients. Three different sites with different salinities were sampled during the four seasons of the year. Sediment characteristics of the sites were compared, showing higher organic matter in the lowest saline (LS) site and higher phytopigments in the highest saline (HS) site, as expected. Benthic aerobic respiration, O2 and CO2 fluxes, ranged from −0.4 to −3.2 mmol m−2h−1 and 0.1 to 1.5 mmol m−2h−1, respectively, and exhibited statistically significant variations between seasons and in a salinity gradient. Dissolved inorganic nitrogen and silicate, ranging from −228.7 to 544.8 μmol m−2h−1 and −205.8 to 4,173.5 μmol m−2h−1, respectively, were generally released from the sediment, whereas phosphate ranged from −25.2 to 29.6 μmol m−2h−1 with more variation in time and space. The LS site was characterized as a nitrogen sink and a silicate and phosphate releaser, and the HS site was characterized as a nitrogen producer and a phosphorus consumer. However, seasonal and spatial variations were observed, and the interaction between space and time factors was always highly significant, indicating that the metabolic behavior of the benthic compartment depends on both trophic and physicochemical conditions. understanding water places landsea land sea production sedimentwater CananéiaIguape Cananéia Iguape EstuarineLagoon Estuarine Lagoon CIELC (CIELC Coast zones programs O TCO2 TCO year compared (LS (HS expected CO 04 0 4 −0. 32 3 2 −3. m2h1 mh m 2h 1 h m−2h− 01 0. 15 5 1. respectively 2287 228 7 −228. 5448 544 8 544. 2058 205 −205. 41735 173 4,173. 252 25 −25. 296 29 6 29. releaser consumer However observed conditions −0 −3 m2h m−2h 22 −228 54 20 −205 4173 17 4,173 −25 − −22 −20 417 4,17 −2 41 4,1 4,

Abstract The Cananéia-Iguape Estuarine-Lagoon Complex (CIELC) is an extremely productive coastal ecosystem. It encloses the Valo Grande channel, built 160 years ago, which introduces water from the Ribeira River directly into the estuarine system, contributing to important biogeochemical changes in the region. Many nutrients arrive at the estuary through this channel, as well as metals and other slightly soluble elements that become part of the sediments. This study aims to evaluate the processes that govern the distribution of rare earth elements (REE) in the sediments of the complex by using fractionation patterns, anomalies, and the geochemical signature of minerals to evaluate sources, natural levels, and the possible anthropogenic forcing to which CIELC is subjected. ∑REE* ranged from 14.2 to 285 mg kg -1 and showed a distribution related to depositional/textural characteristics influenced by the regional and local lithological setting and a possible contamination. The REE/Al ratio indicated enrichment in the sea adjacent to the estuary and at stations in the Ribeira River and Valo Grande. While the Hf/Al ratio indicated natural enrichment related to the presence of heavy minerals in most of these stations, this ratio fails to justify enrichment at some stations in the northern part of the estuary and the Ribeira River. Fractionation patterns and anomalies allowed us to identify the main heavy minerals related to REE enrichment at CIELC. Cerium (Ce) anomalies showed a possible relation with biologically mediated Ce +3 to Ce +4 oxidation processes in the most productive areas of the estuary. Europium (Eu) anomalies were strongly associated with different mineral assemblies in several CIELC sectors. Abundance, fractionation patterns, and REE anomalies corroborate the categorization of CIELC sediments as part of a pristine system in its southern region and as subject to anthropogenic influences in its northern area. CananéiaIguape Cananéia Iguape EstuarineLagoon Estuarine Lagoon (CIELC ecosystem channel 16 ago (REE sources levels subjected ∑REE 142 14 2 14. 28 1 - depositionaltextural depositional textural contamination REEAl Al HfAl Hf (Ce 3 + 4 Eu (Eu sectors Abundance area

Abstract The construction of a data bank concerning metal and metalloid content of bioindicator fish from coastal areas is very important as it can help environmental managers in decision making. In natural conditions, the concentration of elements can be influenced by abiotic parameters such as water salinity. In this study, catfish Cathorops spixii were evaluated concerning the total arsenic (As) concentration in the muscle tissues of individuals subjected to different abiotic conditions in the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC), which was recently included on the Ramsar list of wetlands of international importance. Seventy-four catfish were seasonally caught in the northern and southern regions of the CIELC and their hydrochemical parameters were obtained. C. spixii from the southern, best preserved, area showed arsenic concentrations around ten times higher than the maximum limit established for fish intended for human consumption. However, these high concentrations of arsenic could be associated with the abiotic parameters of the water, such as salinity variations, in this area. making study As (As CananéiaIguape Cananéia Iguape EstuarineLagoon Estuarine Lagoon CIELC, , (CIELC) importance Seventyfour Seventy four obtained C preserved consumption However variations (CIELC

THE ESTUARINE ENVIRONMENT AND pH VARIATION: NATURAL LIMTS AND EXPERIMENTAL OBSERVATION OF THE ACIDIFICATION EFFECT ON PHOSPHORUS BIOAVAILABILITY. This study shows the variation of pH in the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC). Data from 3 years (2019, 2021, 2022) were obtained in 17 points presenting the following ranges: temperature (14.88-27.05 ºC), pH (7.16-8.40) and DIP (0.20-11.28 µmol L-1) along a saline gradient (0.05-32.09) under different hydrodynamics, biogeochemical processes and anthropogenic influence. The pH buffering capacity due to the presence of weak acid salts in saline water (S ≥ 30) was associated to the lowest DIP, decreasing with low salinity values, confirming the direct correlation among salinity and pH. The highest temperatures in the winter of 2021, corroborated with the abnormal climate event in that year. An in vitro experiment showed results of the interaction of PID and sediments with different textures, with and without the presence of the benthic microbiota under a considerable decreasing of the pH (acidification) in relation to the natural condition of this environment. The P sediment flux characterized Iguape sector as a P sink with or without biota, Ararapira sector as a P source with biota and Cananéia, as P source without biota. The salt water buffered the pH and sediment buffered DIP both associated to the biogeochemical and hydrodynamic processes contribute to the homeostasis in the system. VARIATION BIOAVAILABILITY CananéiaIguape Cananéia EstuarineLagoon Estuarine Lagoon CIELC. CIELC . (CIELC) 2019, 2019 (2019 2021 2022 1 ranges 14.8827.05 14882705 14.88 27.05 14 88 27 05 (14.88-27.0 ºC, ºC , ºC) 7.168.40 716840 7.16 8.40 7 16 8 40 (7.16-8.40 0.2011.28 0201128 0.20 11.28 0 20 11 28 (0.20-11.2 L1 L L-1 0.0532.09 0053209 0.05 32.09 32 09 (0.05-32.09 hydrodynamics influence S 30 values year textures acidification (acidification environment system (CIELC 201 (201 202 8827 14.8827.0 1488270 1488 14.8 2705 27.0 2 (14.88-27. 168 7.168.4 71684 716 7.1 840 8.4 4 (7.16-8.4 2011 0.2011.2 020112 020 0.2 1128 11.2 (0.20-11. L- 0532 0.0532.0 005320 005 0.0 3209 32.0 (0.05-32.0 (20 882 14.8827. 148827 148 14. 270 27. (14.88-27 7.168. 7168 71 7. 84 8. (7.16-8. 0.2011. 02011 02 0. 112 11. (0.20-11 053 0.0532. 00532 00 320 32. (0.05-32. (2 14.8827 14882 (14.88-2 7.168 (7.16-8 0.2011 0201 (0.20-1 0.0532 0053 (0.05-32 ( 14.882 (14.88- (7.16- 0.201 (0.20- 0.053 (0.05-3 (14.88 (7.16 (0.20 (0.05- (14.8 (7.1 (0.2 (0.05 (14. (7. (0. (0.0 (14 (7 (0 (1

Abstract Over the last decades, regional climate changes, erosion, and heightened agricultural runoffs have increased nutrient and particle input in rivers, unbalancing the biogeochemical cycle of this suspended material along estuaries. In this context, particle fluxes in the euphotic zone, a very productive layer and important to maintain the food chain and estuarine preservation, require better understanding. This study aims to evaluate particle sedimentation fluxes in the photic zone of the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC), considering sectors under different salinities and trophic statuses. A cylindrical sediment trap was installed at the base of the photic layer to measure particle fluxes and photopigments. Meanwhile, water samples were taken to measure temperature, salinity, pH, dissolved oxygen, and nutrients. Valo Grande (a freshwater domain) showed high nutrient concentrations, in which high fluxes of phaeopigments and chlorophyll-b highlighted the contribution of vegetable detritus to particle sinking. In the Batatais mangrove creek, the high fluxes of organic particles (675.32 mg m-2 d-1) and chlorophyll-a (98.40 mg m-2 d-1) evinced a high contribution of microplankton to carbon sinking. During the winter of 2018, flocculation processes were evinced in the flood tide of the Cananéia Bay as an important driver of sedimentation rates, with considerable fluxes of inorganic particles (1161.20 mg m-2 d-1) and chlorophyll-a (83.27 mg m-2 d-1). In the summer of 2019, we observed a lower flux in total particles (451.24 mg m-2 d-1) in a period of haline stratification. In the Ararapira Channel, the lowest organic particle fluxes (<100 mg m-2 d-1) were associated with ultra-oligotrophic conditions, indicating a low influence of microplankton on sinking particles. These findings suggest that freshwater input, tidal variation, and trophic status are relevant controls of sinking particles in different CIELC sectors. decades changes erosion rivers estuaries context preservation understanding CananéiaIguape Iguape EstuarineLagoon Estuarine Lagoon CIELC, , (CIELC) statuses photopigments Meanwhile temperature salinity pH oxygen nutrients domain concentrations chlorophyllb chlorophyll b creek 675.32 67532 675 32 (675.3 m2 m 2 m- d1 d 1 d-1 chlorophylla 98.40 9840 98 40 (98.4 2018 rates 1161.20 116120 1161 20 (1161.2 83.27 8327 83 27 (83.2 d1. . 2019 451.24 45124 451 24 (451.2 stratification Channel <100 100 (<10 ultraoligotrophic ultra oligotrophic conditions variation (CIELC 675.3 6753 67 3 (675. d- 98.4 984 9 4 (98. 201 1161.2 11612 116 (1161. 83.2 832 8 (83. 451.2 4512 45 (451. <10 10 (<1 675. 6 (675 98. (98 1161. 11 (1161 83. (83 451. (451 <1 (< (67 (9 (116 (8 (45 < ( (6 (11 (4 (1

RESUMO O presente trabalho teve como objetivo monitorar a dispersão de plumas de efluentes provenientes dos emissários submarinos de Praia Grande e do Rio Itanhaém, por meio do processamento do modelo Delft3D (módulos hidrodinâmico e de qualidade da água) e do modelo Visual Plumes (módulo UM3). A modelagem de campo próximo indicou que as correntes geradas pelo vento foram mais eficientes do que as correntes de maré na diluição inicial das plumas dos emissários; e a modelagem de campo distante, validada qualitativamente, demonstrou que as concentrações dos potenciais poluentes de todas as plumas simuladas não ultrapassam os limites máximos estabelecidos pelo Conselho Nacional do Meio Ambiente quando essas plumas atingem as praias da região de estudo.

ABSTRACT This study’s goal was to monitor the dispersion of effluent plumes from the Praia Grande’s submarine outfalls and from the Itanhaém River by processing the Delft3D model (hydrodynamic and water quality modules) and the Visual Plumes model (UM3 module). The near field modeling indicated that wind-driven currents were more efficient than tidal currents in the initial dilution of the outfalls’ plumes; and the far field modeling, qualitatively validated, demonstrated that the potential pollutants’ concentrations in all the simulated plumes don’t exceed the maximum limits established by the National Environmental Council when these plumes reach the study region’s beaches.

Abstract: The human impact on estuarine regions results in an increasing concentration of trace elements in the environment, exposing aquatic organisms. In this study, Zn, Co, Cr, and As were determined in the muscle tissue of some fish species from Santos-São Vicente (SSV), a recognized polluted region, and in the Cananeia estuary (CAN). Genotoxicity was also determined for the evaluation of the chronic effect on ichthyofauna, to enlarge the bank of environmental data regarding the effects of pollution, and to suggest other fish bioindicator species that may contribute to monitoring programs. The obtained data showed a similar profile of an accumulation of Co and Zn in Micropogonias furnieri and Chaetodipterus faber, where: Santos Bay > CAN > inner area of SSV. A low frequency of micronucleus was observed. However, in general, fish from the inner area of the SSV estuary presented more nuclear abnormalities than fish from Santos Bay and CAN. In the inner area of SSV, Centropomus paralelus and Diapterus rhomneus showed more changes than other fish species. It was possible to consider that the habits of each species, contributed to a different profile of trace element accumulation, followed by the chemical components in the organism offering different vulnerability.

RESUMO O ensino de Ciências foi incorporado aos currículos escolares somente no século XIX. No Brasil-Império o ensino das Ciências Naturais era incipiente, embora ciências já fizessem parte do currículo do ensino secundário desde a criação do Colégio Pedro II, em 1837. Os primeiros cursos de nível superior em Geociências (Geologia, Geofísica, Meteorologia e Oceanografia) começaram a ser criados somente a partir da segunda metade do século passado. Atualmente, há cursos nessas modalidades em todo o país, que enfrentam, contudo, sérios obstáculos para que o ensino evolua de acordo com as necessidades atuais do mercado de trabalho, e das tendências impostas pelo avanço tecnológico. Neste trabalho analisamos entraves e lacunas profissionais no Ensino Superior e destacamos algumas práticas educacionais capazes de melhorar o aprendizado, que poderiam ser universalizadas. É inadiável expandir a área de Geociências nos cursos de formação e capacitação de professores para a Educação Básica; o artigo reúne alguns fatores essenciais para atingir essa meta.

ABSTRACT The teaching of Science was incorporated into school curricula only in the nineteenth century. In Imperial Brazil, the teaching of the natural sciences was incipient, although, since the creation of the Colégio Pedro II in 1837, Science was already part of the curriculum of secondary education. But only in the second half of the last century the earliest courses in Geosciences (Geology, Geophysics, Meteorology, and Oceanography) began to be created. Currently, there are courses in these modalities across the country. However, there are serious obstacles for teaching to evolve in keeping with the current needs of the professional market and the trends imposed by technological advances. In this work, we analyze obstacles and professional gaps in Higher Education, and highlight some educational practices capable of improving learning and which could be universalized. It is no longer possible to put off the expansion of the area of Geosciences in teacher training and qualification courses for Basic Education. This article brings together some essential factors to achieve this goal.

Resumo As áreas urbanizadas marcam sua presença nos sistemas hidrológicos com alguns sinais biogeoquímicos, incluindo entradas de silício. A influência natural da lixiviação e erosão é feita por contribuição de silicato e, às vezes, o solo agrícola possui microfilóticos e contribui com sílica biogênica. Uma vez no sistema hidrológico, o silício pode integrar os ciclos biogeoquímicos mostrando um equilíbrio ou não entre formas inorgânicas e biológicas que revela uma tendência de processos que ocorrem em cada setor da interface estuarino-marinha. Este estudo tem como objetivo avaliar o impacto de um rio fortemente poluído/urbanizado, cujo aporte pode ser evidenciado por diferentes formas de silício que podem marcar o aporte terrestre, processo de erosão, a presença de espécies de fitoplâncton com estruturas silicosas, principalmente associada a diatomáceas e, também, estudar a pluma do rio espalhando-se na área costeira realizando perfis de silício na região adjacente à foz do rio. A região costeira do Recife está sob influência dos insumos fluviais dos rios Capibaribe e Beberibe verificados pela baixa salinidade observada (mínimo 33,93). A distribuição de formas de silício mostrou variação setorial e os valores máximos foram distintos. O silicato dissolvido atingiu 14,40 µmol L-1, silício litogênico (LSi) no máximo de 25,76 µmol L-1 e sílica biogênica (BSi) atingindo 7,39 µmol L-1 perto da foz do rio em direção ao mar, evidenciando a influência do rio vindo do oeste, alcançando a barreira portuária no final e se propagando no mar em direção ao nordeste. Devido à maior disponibilidade de nutrientes nas estações mais próximas da costa, a produção primária foi incentivada com a evidência de altos valores de clorofila-a associados ao silicato dissolvido (r=0.71) e ao SiB (r=0.44). Nas estações mais distantes da costa, as formas de silício apresentaram concentrações muito baixas e BSi/Clorofila-a mostrou correlação negativa associada a concentrações de clorofila-a, evidenciando a participação de atores não silicosos na produção primária em profundidade média em águas tropicais oligotróficas.

Abstract The urbanized areas mark its presence in the hydrological systems with some biogeochemical signs including silicon inputs. Natural influence of leaching and erosion is done by silicate contribution and sometimes, the agriculturally soil contains microphytoliths and contributes with biogenic silica. Once in the hydrological system, the silicon can integrate the biogeochemical cycles showing a balance or not between inorganic and biological forms that reveals a tendency of processes that occur in each sector of the estuarine-marine interface. This study aims to evaluate the impact of a heavily polluted/urbanized river, whose input can be evidenced by the contribution of different forms of silicon that can evidence the terrestrial contribution, erosion process, the presence of phytoplankton species with siliceous structures, mainly associated to diatoms and also, to study the river plume spreading on the coastal area by undertaking silicon profiles in the region adjacent to the river mouth. The coastal region of Recife is under influence of fluvial inputs from Capibaribe and Beberibe rivers verified by observed low salinity (min. 33.93). The distribution of silicon forms showed sectorial variation, and the maximum values were dissimilar. Dissolved silicate reached 14.40 µmol L-1, lithogenic silicon (LSi) maximum of 25.76 µmol L-1 and biogenic silica (BSi) reaching 7.39 µmol L-1 near the river mouth toward the sea, evidencing the river influence coming from the west, achieving the port barrier at the end and propagating in the sea toward northeast. Due to higher nutrient availability in the stations nearest to the coast, primary production was encouraged with evidencing by high values of chlorophyll-a associated to silicate (r=0.71) and to BSi (r=0.44). In the stations more distant to the coast, the forms of silicon showed very low concentrations and BSi/Chlorophyll-a showed negative correlation associated with chlorophyll-a concentrations evidencing the participation of non-silicon actors in the primary production in medium depth in oligotrophic tropical waters.

Resumo Os compostos orgânicos dissolvidos encontrados na água do mar oferecem uma indicação de processos biogeoquímicos e influência antropogênica à luz de suas concentrações e comportamentos associados a diferentes áreas oceânicas. Os aportes de rios contribuem com cargas orgânicas para a água do mar de acordo com o nível de influência natural e urbana. Uma diluição deste material é esperada no oceano. Em torno das ilhas oceânicas, a quantidade de matéria orgânica é influenciada pelo ciclo de vida dos organismos marinhos e pela ocupação humana. As proporções de carbono orgânico dissolvido (DOC), nitrogênio orgânico dissolvido (DON), fósforo orgânico dissolvido (DOP) e sua associação com oxigênio dissolvido podem ser utilizadas para avaliar as condições ambientais em termos de impactos naturais e antropogênicos. A informação disponível sobre os compostos orgânicos dissolvidos essenciais (C, N e P) na água do mar é rara. Este estudo busca incentivar o uso de compostos orgânicos dissolvidos na avaliação de impacto ambiental nas áreas costeiras do Brasil. A distribuição espacial de DOC, DON, DOP e ureia foi analisada em quatro regiões: Itamaracá (ITA), Plataforma Interna de Recife (RIS), Ilha Fernando de Noronha (FN) e Porto de Recife (RH), todos em Pernambuco - Brasil. No caso do DOC, os valores obtidos variaram de 51,60 µmol L-1 (0,62 mg L-1) a 358,47 µmol L-1 (4,30 mg L-1), os valores de DOP variaram de 0,01 a 2,16 µm L-1, ambos Apresentando seus valores mais altos em RH, a área mais intensamente urbanizada. Em relação ao DON, um valor extremamente alto de 92,89 µmol L-1, com ureia atingindo 12 µmol L-1, ambos em RH, refletem a descarga orgânica e de esgoto. Às vezes, a concentração de ureia esteve associada ao tratamento precário de esgoto combinado com a atividade turística, como no caso de FN. Nenhuma variação espacial significativa foi observada para DOP tendo em conta todas as estações e regiões, e os valores apresentaram maior variação de FN. Os índices DOC:DON foram superiores a 7 (2-4 vezes a relação Redfield) e revelaram a qualidade da matéria orgânica e a importância do processo local de remineralização, confirmando que a N-limitação aumentou o uso de formas orgânicas, principalmente em FN. As condições oligotróficas preservadas em RIS, Itamaracá e FN foram observadas em relação aos compostos orgânicos dissolvidos (C, N, P), mas no que diz respeito ao FN, são recomendáveis ações de monitoramento efetivas, pois é uma área remota preservada.

Abstract The dissolved organic compounds found in seawater offer an indication of biogeochemical processes and anthropogenic influence in the light of their concentrations and behavior associated with different oceanic areas. River inputs contribute with organic loads to seawater according to the level of natural and urban influence. A dilution of this material is expected toward ocean. Around oceanic islands, the quantity of organic matter results from the life cycle of marine organisms and from human occupation. The ratios of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved organic phosphorus (DOP) and the association with dissolved oxygen can be used to evaluate the environmental conditions in terms of natural and anthropogenic impacts. Available information about the essential dissolved organic compounds (C, N and P) in seawater is rare. This study seeks to encourage the use of dissolved organic compounds in environmental impact assessment in coastal areas of Brazil. The spatial distribution of DOC, DON, DOP and urea was analyzed in four regions: Itamaracá (ITA), Recife Inner Shelf (RIS), Fernando de Noronha Island (FN) and Recife Harbor (RH), all in Pernambuco State - Brazil. In the case of DOC, the values obtained varied from 51.60 µmol L-1 (0.62 mg L-1) to 358.47 µmol L-1 (4.30 mg L-1), DOP values varied from 0.01 to 2.16 µmol L-1, both presenting their highest values in RH, the most intensely urbanized area. In relation to DON, an extremely high value 92.89 µmol L-1, with urea reaching 12 µmol L-1, both in RH, reflects organic and sanitary discharge. Sometimes the urea concentration was associated with precarious sewage treatment combined with tourist activity, as in the case of FN. No significant spatial variation was observed for DOP taking into account all the stations and regions, and the values presented a greater range of variation in FN. The DOC:DON ratios were higher than 7 (2-4 times the Redfield ratio) and revealed the quality of the organic matter and the importance of the local process of remineralization, confirming that the N-limitation enhanced the use of organic forms, mainly on FN. The preserved oligotrophic conditions of the RIS, Itamaracá and FN were observed in relation to dissolved organic compounds (C, N, P), but, as regards FN, effective monitoring actions are advisable as it is a pristine area.