Publications
297 results found
Aquino R, Noriega C, Mascarenhas A, et al., 2022, Possible Amazonian contribution to Sargassum enhancement on the Amazon Continental Shelf., Sci Total Environ, Vol: 853
The Amazon Continental Shelf (ACS) has a coastline of ∼1000 km and is situated in a humid equatorial region with two distinct seasons, wet and dry, and two transitional climatic periods. A total of eight oceanographic cruises were conducted to investigate the dynamics of the inorganic nutrients dissolved in the surface layer of the water column of the ACS and their associations with Sargassum blooms. An excess of nitrogen-N* (NH4+ = 0.01-9.30 μmol l-1) was verified through the salinity gradient from the continent to the ACS, mainly during the period of maximum discharge of the Amazon and Tocantins-Pará rivers. The highest NH4+ concentrations coincided with the occurrence of macrophyte (Sargassum sp.) blooms in the mesohaline and oceanic regions. During this period the high values of NH4+ accompany the low values of Sea Surface Salinity (SSS), indicating the advection of the Amazonian plume towards the Caribbean Sea. In the Sargassum belts we observed a N:P ratio = 60:1 during wet period, while outside this region, the N:P ratio was 34:1. According to DIN vs. AOU ratio, we observed that heterotrophic processes prevail over productive processes, mainly in the mesohaline and low salinity regions. Nitrogen concentrations from runoff, mainly from hydrographic basins, showed significant increases in the last decade, mainly due to anthropogenic factors such as agriculture, deforestation, livestock, urban sewage (domestic and industrial), and demographic growth of the population in the Tocantins-Pará Basin. Additionally, associations of diatoms and cyanobacteria provide more nitrogen in the mesohaline and oceanic regions that nourishes Sargassum blooms. Seasonal comparisons (October and April) of Sargassum belts with other studies, indicated that currents play a fundamental role in the transport of these macrophytes from the east edge (Africa) to the west edge (Brazil and French Guiana) towards the Caribbean Sea in the tropical Atlantic.
Varona HL, Lira SMA, Araujo M, 2022, CalcPlotAnomaly: A set of functions in MATLAB for the computation and plotting of anomalies of oceanographic and meteorological parameters[Formula presented], Software Impacts, Vol: 14
CalcPlotAnomaly is a set of source code functions implemented in MATLAB and compatible with Octave, these functions are used for the computation of oceanographic (physical and biogeochemical), and meteorological parameter anomalies that are used by geoscientists and decision-makers. They use as input time-ordered data from observed data (in situ, satellite, or radar) and interannual model outputs (raw data, analysis, or reanalysis). These anomalies can be computed over the whole period, by months or seasons. Also included are functions for plotting anomalies in the form of time series.
Otsuka A, Noriega C, Feitosa F, et al., 2022, Characterization of microphytoplankton associations on the Amazon continental shelf and in the adjacent oceanic region, Journal of Sea Research, Vol: 189, ISSN: 1385-1101
This study aimed to characterize microphytoplankton functional associations on the Amazon continental shelf and in the nearby ocean environment, taking into account the influence of environmental changes caused by the plume of the Amazon River. Two cruises were conducted during the dry period, and 34 locations were sampled at two depths (surface and depth chlorophyll maximum - DCM) to identify the microphytoplankton present as well as to determine salinity, temperature and inorganic nutrients. A total of 144 taxa were identified in the region and were grouped into the phyla Bacillariophyta (75.70%), Cyanobacteria (19.42%), Miozoa (4.68%), Ochrophyta (0.19%) and Haptophyta (0.01%). The cell biovolume ranged from 3.27 to 2.3 × 105 mm−3 L−1 at the surface and from 1.43 to 1.0 × 103 mm−3 L−1 at the DCM, with the difference between depths being significant (U = 1052; p = 0.04). The microphytoplankton associations grouped based mainly on the availability of nutrients at the surface of the continental shelf were mainly characterized by the presence of functional associations of diatoms, where salinity was lower and more nutrients were available, and the oceanic region was characterized by groups of dinoflagellates and Trichodesmium spp., which prevailed in more saline, oligotrophic oceanic waters. The microphytoplankton associations at the DCM were mostly composed of groups of dinoflagellates. The environmental descriptors used in the present research revealed the important influence of the Amazon River plume and local currents (retroflection of the north current of Brazil-NBC) on various attributes of microphytoplankton distribution.
Cintra MM, Lentini CAD, Servain J, et al., 2022, Causes and processes of two opposite climatic years in the tropical Atlantic warm pools, DYNAMICS OF ATMOSPHERES AND OCEANS, Vol: 100, ISSN: 0377-0265
Mestre F, Rozenfeld A, Araujo MB, 2022, Human disturbances affect the topology of food webs, ECOLOGY LETTERS, Vol: 25, Pages: 2476-2488, ISSN: 1461-023X
Noriega C, Medeiros C, Varona HL, et al., 2022, Water Quality in a Tropical Estuarine Channel: Current Conditions, Trends, and Trophic Status (1990–2016), Water, Air, and Soil Pollution, Vol: 233, ISSN: 0049-6979
Long-term monitoring is required to assess the current state and trend of water quality in anthropogenic-influenced estuarine systems. In this study, we evaluated 1581 samples from a 27-year time series (1990–2016) of physicochemical parameters, microbiological, and heavy metals in the surface waters of the Santa Cruz estuarine channel, Brazil. The results showed that the salinity in the estuarine channel is classified as euhaline (salinity: 30.7) during the dry period and polyhaline (salinity: 26.5) during the rainy season. Statistical analysis showed a significant negative trend for dissolved oxygen (DO) (Mann–Kendall tau; p < 0.05; α: 0.05) with a decrease in DO of − 0.012 mg O2 l−1 year−1. Total phosphorus (TP) showed a significant positive trend in the period 2006–2016 (Kendall tau test; p = 0.0007; α = 0.05). In the last decade, TP showed an increased rate of + 0.007 mg P l−1 year−1. Additionally, the bacterial load (most probable number-MPN method) reached an average value of 55,000 MPN 100 ml, which is 22 times the allowable value for brackish water. Heavy metals (cadmium and manganese) showed a significant increase rate, induced by factors such as industrial growth in the adjacent region and changes in TP, pH, and oxygenation in the water, which changed the accumulation of Fe and Mn in the aquatic medium. The trophic state varied between unpolluted and eutrophic. Comparisons with other systems revealed high fluxes of TP (> 4 mol km−2 year−1). Demographic factors (28% average growth rate) and inadequate public sanitation policies (70% untreated sewage) appear to be the main causes of negative variations in some parameters, such as DO, TP, and pH.
Bonou F, Medeiros C, Noriega C, et al., 2022, A comparative study of total alkalinity and total inorganic carbon near tropical Atlantic coastal regions, Journal of Coastal Conservation, Vol: 26, ISSN: 1400-0350
This paper is based on a comparison of the carbon parameters at the western and eastern borders of the tropical Atlantic using data collected from 55 cruises. Oceanic and coastal data, mainly total alkalinity (TA), total dissolved inorganic carbon (CT), sea surface salinity (SSS) and sea surface temperature (SST), were compiled from different sources. These data were subdivided into three subsets: oceanic data, coastal data and adjacent to the Brazilian (western) and African coastal areas (eastern) data. Significant differences between the TA data (2099.4 ± 286.4 µmol kg−1) at the western and eastern edges (2198 ± 141.9 µmol kg−1) were observed. Differences in the CT values between the western edge (1779.6 ± 236.4 µmol kg−1) and eastern edge (1892.2 ± 94.2 µmol kg−1) were also noted. This pattern was due to the different variabilities in the carbon parameters between the eastern and western border coastal areas and to the biogeochemistry that drives these parameters. In the western coastal area, the physical features of the continental carbon and oceanic waters mixing with the freshwater that flows from the Amazon and Orinoco Rivers to the South American coast are different than the physical features of the water that flows from the Congo, Volta and Niger Rivers in the eastern region. Applying the TA empirical relationship to TA with values of SSS < 35 in the western and eastern regions leads to a higher root mean square error (rmse) in the eastern and western regions. Therefore, most of the existing TA empirical relationships are most useful at the regional scale due to the difference in the water properties of each region. The relationships of TA and CT determined in the western and eastern regions do not reproduce in situ data well, especially at the adjacent edges. This difference is explained by the difference between the African and Brazilian
Monteiro T, Batista M, Henley S, et al., 2022, Contrasting Sea-Air CO<inf>2</inf> Exchanges in the Western Tropical Atlantic Ocean, Global Biogeochemical Cycles, Vol: 36, ISSN: 0886-6236
The western Tropical Atlantic Ocean is a biogeochemically complex region due to the structure of the surface current system and the large freshwater input from the Amazon River coupled with the dynamics of precipitation. Such features make it difficult to understand the dynamics of the carbon cycle, leading to contrasting estimates in sea-air CO2 exchanges in this region. Here, we demonstrate that these contrasting estimates occur because the western Tropical Atlantic Ocean can be split into three distinct sub-regions in terms of the sea-air CO2 exchanges. The sub-region under the North Brazil Current domain acts as a weak annual CO2 source to the atmosphere, with low interannual variability. The sub-region under the North Equatorial Current influence acts as an annual CO2 sink, with great temporal variability. The third sub-region under the Amazon River plume influence shows greater interannual variability of CO2 exchanges, but it always acts as a net oceanic sink for CO2. Despite this large spatial variability, the entire region acts as a net annual CO2 sink of −1.6 ± 1.0 mmol m−2 day−1. Importantly, the Amazon River plume waters drive 87% of the CO2 uptake in the western Tropical Atlantic Ocean. In addition, we found a significant increasing trend in sea surface CO2 partial pressure in the North Brazil Current and North Equatorial Current waters. Such trends are more pronounced than the increase in atmospheric CO2 partial pressure, revealing the sensitivity of carbon dynamics in these sub-regions to global climate change.
Naimi B, Capinha C, Ribeiro J, et al., 2022, Potential for invasion of traded birds under climate and land-cover change, GLOBAL CHANGE BIOLOGY, Vol: 28, Pages: 5654-5666, ISSN: 1354-1013
Kouogang Tchuenkam FC, Mama AC, Gah-Muti SY, et al., 2022, Corrigendum: Variability of Sea Breezes Over the Cameroonian Coast and Their Interaction With the West African Monsoon (Front. Earth Sci., (2022), 10, 848684, 10.3389/feart.2022.848684), Frontiers in Earth Science, Vol: 10
In the published article, there was an error in the filter citations in the “Wind Reversal Criterion” and the “Sea Breeze Detection Algorithm” sections. A correction has been made to the Section Materials and Methods, Sub-section “Wind Reversal Criterion (Filter “b”)” which has now been corrected to “Wind Reversal Criterion (Filter “a”)”. A similar correction has been made to the Section Materials and Methods, Sub-section “Sea Breeze Detection Algorithm (Filter “a”)” which has now been corrected to “Sea Breeze Detection Algorithm (Filter “b”)”. The authors apologize for these errors and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.
Boavida-Portugal J, Araújo MB, Rosa R, 2022, Global Patterns of Small Pelagic Fishes’ Diversity: Present and Future, SIBIC 2022, Publisher: MDPI
Capuano TA, Varona HL, Araujo M, et al., 2022, High-resolution hydrodynamics and TS structure database of the Brazilian continental shelf and adjacent waters, Data in Brief, Vol: 42
This data set was obtained from two ROMS model simulations in the region of Brazil located at 60°W–15°W / 25°S - 15°N. One of the simulations takes into account the tide (obtained from the TPXO7 product) and the other one does not. The rest of the configuration was similar for both simulations, taking bathymetry from ETOPO2 and surface forcings from COADS climatology. Moreover, all boundaries were considered open and lateral conditions were taken from SODA, while initial conditions are derived from WOA09 and the river discharge climatology was obtained from Dai and Trenberth. In both experiments the KPP parameterization was used as vertical mixing scheme. The output files are in NetCDF format and are separated by months with a frequency of daily averages, containing 12 files for the simulation with tide and 12 for the simulation without tide, which are organized in two directories: Tide and noTide. This dataset is hosted at https://www.scidb.cn/en/detail?dataSetId=e1f188c4684048459823aaec4f168cc3.
Mestre F, Gravel D, García-Callejas D, et al., 2022, Disentangling food-web environment relationships: A review with guidelines, Basic and Applied Ecology, Vol: 61, Pages: 102-115, ISSN: 1439-1791
Food webs represent the energy fluxes and the nutrient cycling between interacting species that underpin several ecosystem functions. Whether and how interactions vary across environmental gradients is still largely unknown. We reviewed the literature searching for systematic relationships between structural food-web properties and environmental gradients. Temperature and biotic factors are amongst the most frequently addressed drivers of food-web structure. We also assessed the degree to which food-web ecology has accomplished a mechanistic understanding of ecosystem functioning. We found that most studies are one-off descriptions of local food webs making it difficult to achieve an understanding of the response to human or environmental gradients. The lack of a consistent theory predicting how food webs change across environmental gradients, the diversity of objectives in food-web studies, and the absence of a standardized methodology for analysing them severely limit progress in the field. Moving forward requires the establishment of a core set of testable predictions, agreed standards for data collection and analysis, and the development of geographically distributed experimental studies of food-web dynamics.
Kouogang Tchuenkam FC, Mama AC, Gah-Muti SY, et al., 2022, Variability of Sea Breezes Over the Cameroonian Coast and Their Interaction With the West African Monsoon, Frontiers in Earth Science, Vol: 10
The sea breeze characteristics of over two coastal areas of Cameroon were studied. The study used 3-hourly wind (speed and direction), rainfall, and atmospheric pressure data of 4 years (2006–2009) at Tiko and 5 years (2011–2015) at Ebodje to examine various characteristics of sea breezes. Statistics are presented that describe the occurrence, onset and cessation, and strength of the sea breezes. The frequency of occurrence clearly shows two regimes by two maxima (November and March) at Tiko and (January and July) at Ebodje. The results show that a sea breeze usually starts few hours (about 3–4 h) after the sunrise as a light onshore surface wind, has a mean duration of about 9 h at Tiko, and occurs during all seasons at both coastal areas. The sea breeze occurrence is found to be strongly influenced by the West African monsoon winds, and its onset and cessation times show a pronounced seasonal variation. The sea breeze strength is greater at Tiko than that at Ebodje during the West African monsoon season. Average daily hodographs for Tiko reveals that the sea breeze circulation is in both clockwise and anticlockwise rotation. There would be a significant seasonal effect of large-scale flows on sea breeze hodograph patterns. A wind roses analysis at Ebodje shows a high temporal variability of sea breeze frequencies at 09:00 (Local Standard Time: LST) in the south direction (36%), then at 15:00 LST in the west direction (26%), because of the preponderance of calm atmospheric situations conducive to its onset. Therefore, the circulation of the sea breeze is influenced by local factors (topography and vegetation). This phenomenon in the coastal regions of Cameroon can be the main factor controlling the transport of accidental near shore oil slicks and air pollutants.
Garcia CA, Savilaakso S, Verburg RW, et al., 2022, Strategy games to improve environmental policymaking, NATURE SUSTAINABILITY, Vol: 5, Pages: 464-471, ISSN: 2398-9629
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- Citations: 2
Mendoza M, Araujo MB, 2022, Biogeography of bird and mammal trophic structures, ECOGRAPHY, Vol: 2022, ISSN: 0906-7590
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- Citations: 1
Varona HL, Hernandez F, Bertrand A, et al., 2022, Monthly anomaly database of atmospheric and oceanic parameters in the tropical Atlantic ocean, DATA IN BRIEF, Vol: 41, ISSN: 2352-3409
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- Citations: 2
Varona HL, Araujo M, 2022, Hydro-thermodynamic dataset of the Amazon River Plume and North Brazil Current retroflection, Data in Brief, Vol: 40
This dataset was generated by the ROMS model, the output files constitute a monthly and weekly mean hydro-thermodynamics climatology of the region of Amazon and Para river mouths and the North Brazil Current retroflection (60.5°-24°W and 5°S-16°N, with 0.25° of horizontal resolution). This dataset includes the tri-dimensional grids of temperature, salinity and ocean currents at 32 depth levels, as well as the sea surface height. Sea surface temperature and sea surface salinity were validated using the SODA dataset, surface currents were validated with SCUD dataset and the vertical structure of temperature and salinity were compared with values recorded at 38°W,8°N and 38°W,12°N PIRATA buoys. The dataset is hosted on the website https://www.seanoe.org/data/00718/82958/. This dataset will help oceanographers and other researchers have information about the hydro-thermodynamics of this region.
Carreira RS, Zanardi-Lamardo E, Massone CG, et al., 2022, The mysterious oil spill in the northeastern coast of Brazil: tracking offshore seawater and the need for improved vessel facilities, Ocean and Coastal Research, Vol: 70
A scientific cruise between November 15 and December 18, 2019 aboard R/V Vital de Oliveira collected offshore seawater samples at 59 stations between the states of Ceará and Bahia. The objective was to identify hydrocarbon levels potentially associated with the mysterious oil spill that reached the northeastern coast of Brazil. Median concentrations of aliphatic hydrocarbons (AHs, 0.79 µg L-1) and polycyclic aromatic hydrocarbons (PAHs, 5.39 ng L-1) do not indicate contamination by crude oil and are comparable to baseline levels previously found in other areas of the Brazilian continental margin. The detailed composition of both groups of hydrocarbons revealed that some samples were contaminated during sampling and/or handling on-board. The data set presented herein highlights the diffculty in tracking small oil patches spread over a huge ocean area and, more importantly, the need for improving protocols of national research vessels used to collect seawater samples for trace organic analyses.
Silva K, Varona HL, Araujo M, et al., 2022, Characterization of dissolved inorganic carbon and dissolved oxygen in two impacted Amazonian lakes, Pan-American Journal of Aquatic Sciences, Vol: 17, Pages: 97-109
Six surface water campaigns were carried out in lakes Bolonha-LB and Água Preta-LAP (Brazil) during 2018 - 2019. Temporal and spatial variations of temperature, pH, electrical conductivity, dissolved oxygen (DO), total alkalinity (TA), turbidity, dissolved carbon dioxide (CO2aq), and partial pressure of CO2 (pCO2) were analyzed and estimated. High levels of CO2aq were observed during the study (104 - 998 μmol l-1), while CO2eq in equilibrium with the atmosphere ranged between 11.5 and 12.3 μmol l-1. The pCO2 values ranged from 3,400 to 23,600 μatm. DO ranged from 1.0 - 8.5 mg l-1 and showed significant spatial differences (p < 0.05) between the lakes studied. Apparent oxygen utilization (AOU) showed positive values in 98.5% of the samples collected, indicative of heterotrophic processes (respiration > production). The analysis of the relationships between AOU and excess CO2 indicated that about 65% of the carbon mineralization in the lakes is anaerobic, indicating the predominance of the respiration process in the systems studied. A comparative analysis with other 117 tropical lakes showed that LAP and LB are part of the 78% of lakes with CO2 supersaturation. This work showed that: the heterotrophic processes identified during this study are mainly a product of the inorganic contributions of organic matter from the adjacent urban region
Silva M, Araujo M, Geber F, et al., 2021, Ocean Dynamics and Topographic Upwelling Around the Aracati Seamount - North Brazilian Chain From in situ Observations and Modeling Results, Frontiers in Marine Science, Vol: 8
The hydrodynamics and the occurrence of topographic upwelling around the northern Brazilian seamount chain were investigated. Meteorological and physical oceanographic data collected under the REVIZEE-NE Program cruises around the Aracati Bank, the major and highly productive seamount in the area, were analyzed and used to force and validate simulations using the 3D Princeton Ocean Model (3D POM). The Tropical Water mass in the top 150-m layer and the South Atlantic Central Water (SACW) beneath it and down to a depth of 670 m was present. The thickness of the barrier layer varied seasonally, being thinner (2 m) during the austral spring (October–December) and thicker (20 m) during the austral autumn (April–June) when winds were stronger. The surface mixed and isothermal layers in the austral winter (July–September) were located at depths of 84 and 96 m, respectively. During the austral spring, those layers were located at depths of 6 and 8 m, respectively. The mean wind shear energy was 9.8 × 10–4 m2 s–2, and the energy of the surface gravity wave break was 10.8 × 10–2 m2 s–2, and both served to enhance vertical mixing in the area. A permanent thermocline between the 70- and 150-m depths was present throughout the year. The isohaline distribution followed an isotherm pattern of variation, but at times, the formation of low-salinity eddies was verified on the bank slope. The 3D POM model reproduced the thermohaline structure accurately. Temperature and salinity profiles indicated the existence of vertical water displacements over the bank and along the direction of the North Brazil Current, which is the strongest western boundary current crossing the equatorial Atlantic. The kinematic structure observed in the simulations indicated vertical velocities of O (10–3 m.s–1) in the upstream region of the bank during austral winter and summer seasons. During the summer, the most important vertical velocities
Noriega C, Medeiros C, Araujo M, et al., 2021, Long-term water quality conditions and trends in 12 tropical coastal rivers in Northeast Brazil., Environ Monit Assess, Vol: 193
The water quality and trends in 12 tropical rivers in northeastern Brazil over a 27-year period (1990-2016; N = 39,008 samples) were evaluated. The analyzed parameters included temperature, conductivity, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen (NH4+), total phosphorus (P), and fecal coliforms. Densely populated basins (> 1000 inhab km-2) presented lower DO values (average 3.4 mg l-1; 43% DO saturation), while those with low demographic density (< 100 inhab km-2) presented values that aligned well with the recommendations of environmental legislation (average 5.8 mg l-1; 75% DO saturation). The NH4+ and P compound concentrations were typical of water bodies affected by urban inputs. The average p values were above the allowable limit (< 0.1 mg l-1) at all stations. The NH4+ values were high at the stations showing low DO concentrations, which suggested that due to reducing conditions after NH4+ accumulation was favored in those aquatic systems. In densely populated basins, the average fecal coliform concentrations were > 40,000 MPN 100 ml-1, indicating the input of improperly treated domestic/industrial liquid wastes. For the period from 1990 to 2016, 45% of the stations (N = 19) showed a rate of DO reduction that ranged from 0.01 to 0.17 mg l-1.O2 year-1. An increase in NH4+ concentrations was observed in 33% of the stations (N = 14), with an estimated average increase rate from 0.013 to 1.8 mg l-1 NH4+ year-1. These results demonstrated that the rates of increase in anthropogenic factors were significant (p < 0.05), while the natural factors remained constant.
Costa da Silva A, Chaigneau A, Dossa AN, et al., 2021, Surface Circulation and Vertical Structure of Upper Ocean Variability Around Fernando de Noronha Archipelago and Rocas Atoll During Spring 2015 and Fall 2017, FRONTIERS IN MARINE SCIENCE, Vol: 8
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- Citations: 7
Taheri S, Naimi B, Rahbek C, et al., 2021, Improvements in reports of species redistribution under climate change are required, SCIENCE ADVANCES, Vol: 7, ISSN: 2375-2548
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- Citations: 24
Silva NBA, Flores-Montes M, Guennes M, et al., 2021, Phytoplankton cell size in an urban tropical estuarine system in Northeast Brazil, Regional Studies in Marine Science, Vol: 43
The variability of the phytoplankton community structure and cell size classes was quantitatively studied at an urban hypereutrophic tropical estuarine system to assess responses to inorganic nutrient levels. Samplings were carried out in three stations during the dry and wet seasons in 2015. Seasonal variability of temperature, salinity, phosphate, and ammonia levels was statistically significant, with higher values found in the dry season. Total chlorophyll a varied from 4.76 to 79.69 mg m−3 and the fractionated chlorophyll a (pico–nanophytoplankton) from 1.28 to 28.35 mg m−3. Cell density ranged from 172 x 10 3 to 8.1 × 10 6 cells L −1 with higher values during the dry season. The community structure was dominated by the nanophytoplankton (< 20μm fraction) with cyanobacteria being particularly abundant. Pico–nanophytoplankton contributed to 47% of the total biomass, representing 65% at point 1, 55% at point 3, and 38% at point 2. Thalassiosira sp 1, Melosira sp. and Chroococcus sp. were the dominant species in number of cells. The largest cell size variation occurred in the cyanobacteria and diatoms, which dominated the area and were favored by the increase of temperature, salinity, ammonia and phosphate during the dry season. The high values of nutrients demonstrated that the environment is hypereutrophic as a consequence of the release of domestic effluents from a highly urbanized area. Salinity and nutrients (nitrate and ammonia) were influential factors for the quantity and size of phytoplankton cells, leading to changes in community structure. The availability of ammonia in the study area favored the selection and dominance of species of the fraction < 20μm. However, the fraction > 20μm had a greater contribution to total chlorophyll a and biomass in the studied region.
Bennett JM, Sunday J, Calosi P, et al., 2021, The evolution of critical thermal limits of life on Earth, NATURE COMMUNICATIONS, Vol: 12
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- Citations: 70
Herrford J, Brandt P, Kanzow T, et al., 2021, Seasonal variability of the atlantic meridional overturning circulation at 11°&thinsp;s inferred from bottom pressure measurements, Ocean Science, Vol: 17, Pages: 265-284, ISSN: 1812-0784
Bottom pressure observations on both sides of the Atlantic basin, combined with satellite measurements of sea level anomalies and wind stress data, are utilized to estimate variations of the Atlantic Meridional Overturning Circulation (AMOC) at 11? S. Over the period 2013 2018, the AMOC and its components are dominated by seasonal variability, with peak-to-peak amplitudes of 12 Sv for the upper-ocean geostrophic transport, 7 Sv for the Ekman and 14 Sv for the AMOC transport. The characteristics of the observed seasonal cycles of the AMOC and its components are compared to results from an ocean general circulation model, which is known to reproduce the variability of the Western Boundary Current on longer timescales. The observed seasonal variability of zonally integrated geostrophic velocity in the upper 300 m is controlled by pressure variations at the eastern boundary, while at 500 m depth contributions from the western and eastern boundaries are similar. The model tends to underestimate the seasonal pressure variability at 300 and 500 m depth, especially at the western boundary, which translates into the estimate of the upper-ocean geostrophic transport. In the model, seasonal AMOC variability at 11? S is governed, besides the Ekman transport, by the geostrophic transport variability in the eastern basin. The geostrophic contribution of the western basin to the seasonal cycle of the AMOC is instead comparably weak, as transport variability in the western basin interior related to local wind curl forcing is mainly compensated by the Western Boundary Current. Our analyses indicate that while some of the uncertainties of our estimates result from the technical aspects of the observational strategy or processes not being properly represented in the model, uncertainties in the wind forcing are particularly relevant for the resulting uncertainties of AMOC estimates at 11<S.
Taheri S, Garcia-Callejas D, Araujo MB, 2021, Discriminating climate, land-cover and random effects on species range dynamics, GLOBAL CHANGE BIOLOGY, Vol: 27, Pages: 1309-1317, ISSN: 1354-1013
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- Citations: 10
Dossa AN, Silva AC, Chaigneau A, et al., 2021, Near-surface western boundary circulation off Northeast Brazil, PROGRESS IN OCEANOGRAPHY, Vol: 190, ISSN: 0079-6611
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- Citations: 19
de Santana CS, Lira SMDA, Varona HL, et al., 2020, Amazon river plume influence on planktonic decapods in the tropical Atlantic, Journal of Marine Systems, Vol: 212, ISSN: 0924-7963
The western tropical Atlantic is strongly influenced by the Amazon, receiving the full discharge from the largest river basin of the world. In order to ascertain the coastal-oceanic gradient in abundance and composition of planktonic decapod communities along the Amazon River Plume (ARP) and its retroflection, 33 plankton samples were obtained along three sampling transects: Coastal and oceanic area influenced by the ARP (Coastal IARP and Ocean IARP, respectively), and oceanic waters without ARP influence (Ocean). A total of 13,117 specimens, belonging to 33 taxa, were analyzed. The distribution of planktonic decapod communities was strongly influenced by the Amazon discharge, showing the following patterns: (1) The coastal-oceanic gradients in decapod abundance are similar to other shelf areas of eastern South America, with higher abundance in the area under ARP influence, (2) meroplanktonic decapods dominate in coastal and some oceanic areas due to the offshore transport of coastal organisms along the ARP retroflection, and (3) the ARP is clearly responsible for the observed differences in community structure between the three transects. Furthermore, this study highlights the importance of coastal and shelf environments as main sources of planktonic decapods for pelagic ecosystems in the tropical Atlantic during the period of strong North Brazil Current retroflection.
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