Manuel Flores-Montes

Eutrophication effects on phytoplankton size-fractioned biomass and production at a tropical estuary.

Size-fractioned phytoplankton (pico, nano and microplankton) biomass and production were estimated throughout a year at Recife harbor (NE Brazil), a shallow well mixed tropical hypereutrophic estuary with short residence times but restricted water renewal. Intense loads of P-PO4 (maximum 14 μM) resulted in low N:P ratios (around 2:1), high phytoplankton biomass (B=7.1-72 μg chl-a L(-1)), production (PP=10-2657 μg C L(-1) h(-1)) and photosynthetic efficiency (P(B)=0.5-45 μg C μg chl-a(-1)), but no oxygen depletion (average O2 saturation: 109.6%). Nanoplankton dominated phytoplankton biomass (66%) but micro- and nanoplankton performed equivalent primary production rates (47% each). Production-biomass models indicate an export of the exceeding microplankton biomass during most of the year, possibly through grazing. The intense and constant nutrient and organic matter loading at Recife harbor is thus supporting the high microplankton productivity that is not accumulating on the system nor contributing to oxygen depletion, but supporting the whole systems trophic web.

Eutrophication and water quality in a tropical Brazilian estuary

ABSTRACT Nascimento-Filho, G.A.; Montes, M. de J.F.; Gaspar, F.L.; Paulo, J.G.; Feitosa, F.A. Eutrophication and water quality in a tropical estuary. The use of indexes and trophic state models are gaining importance in evaluating the degree of anthropogenic influence on estuarine eutrophication and the impact on coastal and adjacent areas. A TRIX index and an ASSETS model were used to evaluate the level of eutrophication in the estuary of Suape Industrial Port Complex. The values for the TRIX trophic state multivariate index revealed the increase towards the upper estuary, going from 2.26 at high tide at station 1 (low estuary), demonstrating a medium trophic state and good water quality, to 6.43 at low tide at station 3 (upper estuary), showing an elevated trophic state and poor water quality, where continental drainage is accelerating the eutrophication process in the environment. In the evaluation generated by the ASSETS eutrophication model, the estuary eutrophication level was considered to be moderate, with Overall Human Influence considered Low, General Eutrophication Conditions also considered Low. Finally, the Determination of Future Outlook showed an unchanged expression and perspectives for slow degradation. The comparison between the index and model showed some similarities, in general, TRIX quantified the Massangana river estuary at a level medium of eutrophication and ASSETS qualified it as moderate.

Series temporales de variables hidrobiológicas en un estuario tropical (Brasil)

Este trabajo muestra los resultados de series temporales en el estuario de Barra de Jangadas en el Noreste de Brasil. El estudio fue realizado durante siete dias consecutivos desde una marea de sicigia a una de cuadratura, en una estacion fija durante el periodo seco (enero) y lluvioso (julio), en 2001. Se analizaron parametros meteorologicos (precipitacion pluviometrica, evaporacion, intensidad de los vientos), hidrologicos (temperatura, salinidad, pH, oxigeno disuelto-OD y tasa de saturacion, DBO5, nutrientes (NH3 +NH4, NO2 -, NO3 -, PO4 -3, SiO2)), batimetria, intensidad de las corrientes y clorofila-a. El analisis de componentes principales (ACP), explico el 80% de la varianza total, mostrando una relacion inversa entre nutrientes y OD, salinidad y pH. Este analisis mostro una correlacion positiva entre la bajamar y los nutrientes, indicativo de polucion de origen antropogenica. La temperatura del agua vario poco estacionalmente, similar a la clorofila-a que caracterizo un ambiente eutrofico con valores superiores a 20 mg m-3. Mayores concentraciones de sal ocurrieron en el mes estival y sin mostrar estratificacion vertical. El oxigeno disuelto vario significativamente entre ambos periodos. Los valores totales de nitrogeno y fosforo inorganico disuelto en julio fueron en promedio 2 y 5 veces superiores a los de enero, respectivamente. Las medias de N:P variaron de 35:1 en enero a 8:1 en julio, siendo ambos, el fosfato y el nitrogeno limitantes para el crecimiento del fitoplancton. Diferencias dia/noche evidenciaron que, en enero, el amonio decrecio en mayor proporcion que el resto de los compuestos nitrogenados, indicativo de la asimilacion por los organismos autotroficos durante el dia.

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

The Amazon generates the worlds largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with salinities >35 and higher-intensity winds, the CO2 flux is reversed. Lower fCO2sw values were observed in the NECC area. The ΔfCO2 in this region was less than 5 μatm (−0.3 mmol m−2 d−1), while the ΔfCO2 in the coastal region was approximately 50 μatm (+3.7 mmol m−2 d−1). During the cruise, heterotrophic and autotrophic processes were observed and are indicative of the influences of terrestrial material and biological activity, respectively.

Dynamics of Chlorophyll a and Oceanographic Parameters in the Coastal Zone: Barra das Jangadas-Pernambuco, Brazil

ABSTRACT Otsuka, A.Y.; Feitosa, F.A.N.; Flores-Montes, M.J., and Silva, A., 2016. Dynamics of chlorophyll a and oceanographic parameters in the coastal zone: Barra das Jangadas-Pernambuco, Brazil. The Pernambuco shelf, inserted into the NE-E continental margin of Brazil, is about 187 km long and is characterized by reduced width, shallow depth, gentle slope, relatively warm water, and high salinity. It is influenced to some extent by translittoral rivers, the Jaboatão River being among these. This study aimed to analyze the dynamics of chlorophyll a and hydrological parameters on the Pernambuco inner continental shelf under the influence of the Jaboatão River plume. Bimonthly samplings were carried out during the rainy and dry seasons at one point in the estuarine area and four points along the adjacent inner continental shelf. The parameters evaluated were chlorophyll a, temperature, salinity, transparency, dissolved oxygen, suspended particulate matter, pH, depth, and inorganic nutrients. Most parameters had significant seasonal variation. In the dry period, chlorophyll-a ranged from 2.89 to 34.71 mg m−3 in the estuary and varied from 0.21 to 9.67 mg m−3 on the shelf. In the rainy period, it varied from 0.79 to 12.46 mg m−3 in the estuary and from 0.26 to 4.59 mg m−3 on the shelf. According to a principal components analysis, chlorophyll a showed a direct relationship with oxygen saturation rate and temperature and an inverse relationship with pH, salinity, and water transparency. Two points on the shelf (points 3 and 4) were most influenced by river outflow. The limiting factor for phytoplankton biomass was water turbidity due to the higher values reached in the dry period. The estuarine zone was in a stage of high eutrophication, thus sometimes affecting the waters of the inner shelf. RESUMO A plataforma de Pernambuco está inserida na margem continental nordeste-leste do Brasil, possui cerca de 187 Km de extensão e se caracteriza por ter uma reduzida largura, pouca profundidade, declive suave, águas relativamente quentes, elevada salinidade. Recebe influência de alguns rios translitorâneos, dentre eles, o rio Jaboatão. O presente trabalho apresentou como objetivo analisar a dinâmica da clorofila a e parâmetros hidrológicos na plataforma continental de Pernambuco sob o efeito da pluma do rio Jaboatão. Foram realizadas coletas bimestrais, no período chuvoso e estiagem, em um ponto na zona estuarina e quatro ao longo plataforma continental adjacente. Os parâmetros avaliados foram: clorofila a, salinidade, oxigênio dissolvido, material particulado em suspensão e nutrientes inorgânicos dissolvidos. A maioria dos parâmetros apresentou variação sazonal significativa. A clorofila a no estuário variou de 2,89 à 34,71 mg.m−3 e na plataforma continental de 0,21 à 9,67 mg.m−3 no período de estiagem e, no período chuvoso, apresentou uma variação no estuário de 0,79 à 12,46 mg.m−3 e na plataforma de 0,26 à 4,59 mg.m−3. De acordo com ACP, a clorofila a apresentou uma relação direta com a temperatura e taxa de saturação do oxigênio e inversa com pH, salinidade e transparência da água. Os pontos da plataforma que mais sofreram influência do deságüe fluvial foram os pontos centrais P3 e P4. O fator limitante para a biomassa fitoplanctônica foi a turbidez da água e os maiores teores foram observados no período de estiagem. A zona estuarina encontra-se em um elevado processo de eutrofização antrópica e, desta forma, vem interferindo na qualidade das águas da plataforma continental.

Depositional evolution in a estuarine lagoonal system under a port influence in Northeastern Brazil

ABSTRACT Martins, S. E. M; Barcellos, R. L; Flores-Montes, M. J. and França, E. J. 2016. Depositional evolution in a lagoonal estuarine system under a port influence in Northeastern Brazil. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 83–87. Coconut Creek (Florida), ISSN 0749-0208. The Holocene evolution reconstruction corroborates to understand sediment dynamics and, recent anthropogenic environmental changes; in addition, may subsidize the future prospects of its development. The aim of this work is to elaborate a historical comparative analysis of the total organic matter content (TOM), calcium carbonate (CaCO3) and grain size variation in a estuarine environment and adjacent inner shelf area under influence of Recife Port (8°03′S/34°53″W), Northeastern Brazil. Two sediment cores were collected (Jun/2013), one (1.26m long) in the inlet of the estuarine system (T2E); and another (1.30m long) in a sheltered area of a breakwater adjacent to the estuary mouth (T3E). The sedimentation rate, measured based on breakwater building (1909), was 1.18 cm.year−1 in T3E and 0.81 cm.year−1 in T2E. The cores presented preservation of structures indicative of waves and currents processes, such as erosive surfaces, linsen bedding, flaser bedding, and wavy bedding, environment features of shallow platform. Both cores presented variations in sediment composition with an essential carbonate sandy base ranging upward to a terrigenous mud on their tops. The change in sediment composition indicates environmental changes such as the increase in the sediment suspension concentrations, directly influenced by changes in coastal engineering in the Recife Port. The results indicate how important local rivers sediments input and estuarine processes are to deposition features in the estuarine lagoonal system, like the mud trapping and preservation in the inner shelf shallow areas adjacent to the Recife Port.

Short and Medium Term Variation in the Dynamics of the Mesozooplankton Community of an Amazonian Estuary

ABSTRACT Leite, N.R.; Magalhães. A.; Silva, L.M.; Andrade, T. P.; Matos, J. B.; Costa, A. K.;Pereira, L.C.C.; Flores-Montes, M.J., and Costa, R.M.da., 2016. Short and Medium Term Variation in the Dynamics of the Mesozooplankton Community of an Amazonian Estuary. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 218–222. Coconut Creek (Florida), ISSN 0749-0208. The aim of this study was to investigate the short- and medium-term variation in the dynamics of the zooplankton community, in a macrotidal estuary (the Taperaçu) of the Amazon Coast of northern Brazil. This estuary has a characteristic funnel shape, with extensive sandbars running down the middle and current patterns typical of a shallow estuary, in addition to substantial seasonal variation. Fluctuations in zooplankton densities were analyzed in the context of the influence of the tidal cycle, temperature, salinity, turbidity, pH, dissolved oxygen concentration and chlorophyll-a concentrations. Data were collected in months of June, September and December 2012 and March, June, and September/2013. Samples were taken at three fixed stations, S1, S2, and S3 at 3-hour intervals over a nychthemeral cycle during the neap tide. The data were analyzed using a two-way ANOVA (to test the significance of the variation among stations, months, tides, and the circadian cycle) and PCA. Five principal species were identified–A. tonsa, A. lilljerborgii, P. marshi, P. quasimodo, O. oswaldocruzi and O.dioica. The results indicate that the patterns of variation (temporal, tidal, and spatial) in the zooplankton of the Taperaçu estuary were determined primarily by precipitation, salinity, turbidity, and chlorophyll-a concentrations, due to the strong local hydrodynamics and the unique morphodynamic characteristics of the estuary that provoke the constant mixing of its waters.

Spatiotemporal variation in salinity during drought years in an Amazonian estuary (Taperaçu)

ABSTRACT Costa, A.K.R.; Pereira, L.C.C.; Costa, S.F.S.; Leite, N.R; Flores-Montes, M.J., and Costa, R.M., 2016. Spatiotemporal variation in salinity during drought years in an Amazonian estuary (Taperaçu), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 48–52. Coconut Creek (Florida), ISSN 0749-0208. This study investigated the spatial and temporal variation in salinity in an Amazonian estuary (Taperaçu). Data were collected in the field every three months between April 2012 and March 2015. During each field campaign, CTDs were used to collect data over a 25-hour period at three fixed stations, in the upper, middle and lower estuary. Precipitation data were obtained from INMET (Brazilian Institute of Meteorology). March to May were the months of highest precipitation (around 1000–1400 mm), although 2012 and 2013 were considered to be drought years in eastern Amazonia (annual precipitation < 1800 mm). While the Taperaçu does not have any direct fluvial input, it is connected to the Caeté Estuary through the Taici creek and is connected to adjacent wetlands. Salinity varied considerably between seasons, peaking in the dry season (in particular, in December) in the lower sector of the estuary (40). During the rainy season, salinity reached values of less than 10 in the upper estuary. The drought years (2012–2013) were characterized by higher salinity in comparison with more typical years (2014–2015). These results indicate that the minor estuaries of the Amazon coast, such as the Taperaçu, may contribute to the understanding of the influence of atypical climatic periods on hydrological variables (such as salinity), and their implications for the local biological communities.

Modern sedimentary processes and seasonal variations of organic matter in an urban tropical estuary, Jaboatão River (PE), Brazil

ABSTRACT Barcellos, R.L., Flores-Montes, M.J., Alves, T.M.F. and Camargo, P.B. 2016. Modern sedimentary processes and seasonal variatios of organic matter in a urban tropical estuary, Jaboatão River (PE) Brazil. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 38–42. Coconut Creek (Florida), ISSN 0749-0208. The aim of this research is to evaluate the environmental conditions in the Jaboatao River estuarine system (8°14′S/34°55′W), by studying sedimentary organic matter, which may provide information about anthropogenic influence in this tropical mesotidal estuary. The catchment area is 442 km2 with a population estimated at 500,000 inhabitants, and is characterized as an urban coastal plain estuarine system. Thirty surface sediment samples were collected in November-2010 (dry season) and May-2011 (rainy season). Results indicated that the adjacent sediments from continental shelf are sandy, moderately sorted and bioclastic (74.8%CaCO3), differing from estuarine sediments, which although sandy (silty-sand) are lithoclastic (17.4%CaCO3) and poorly sorted. The predominance of sand observed in both seasons is due to the small length of the river (75km) and to the low supply of mud sediments, since its drainage basin is located mostly on sandy coastal plain. Carbon and nitrogen contents indicates a sensitive seasonal variation with large ranges, varying from 0.03–8.51% and from 0.00–0.54%, respectively, with higher contents prevailing in the inner portions of the estuary and gradually decreasing towards the shelf. The organic matter origin, according to the C/N ratios and δ13C values reflected the occurrence of marine organic matter in shelf samples (C/N<7.0/δ13C>-20.0‰PDB). However, the estuary terrigenous organic matter proportion increases upward (C/N>15.0). The δ13C values are typical of C4 higher plants (−27.0‰PDB) and domestic sewage mix (−26.7‰PDB), ranging from −28.0 to −25.9‰PDB and indicating evidences of urban pollution in Jaboatão estuarine sediments.