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

Araújo, Moacyr; Noriega, Carlos; Hounsou-Gbo, Gbèkpo Aubains; Veleda, Dóris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando Antônio do Nascimento; Flores‐Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro Augusto Mendes de Castro; Otsuka, Amanda Yumi; Travassos, Keyla; Schwamborn, Ralf; Neumann‐Leitão, Sigrid

doi:10.3389/fmicb.2017.01358

Cited by 32 publications

(28 citation statements)

References 68 publications

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“…In our study, the general pattern of chlorophyll-a and sestonic biomass was of high values under the influence of the Amazon plume at coastal stations, including those under the reef area, while lower values were observed at oceanic stations. Araujo et al (2017) highlight the productive characteristic in the Amazon plume in comparison to oceanic adjacent area. Similar observations were made by Subramaniam et al (2008) that affirm the river plume contribution as a nutrient provider to enhance primary production.…”

Section: Discussionmentioning

confidence: 90%

Zooplankton From a Reef System Under the Influence of the Amazon River Plume

et al. 2018

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At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km2) that includes mainly large sponges but also rhodolith beds. The mesozooplankton associated with the pelagic realm over the reef formation was characterized, considering the estuarine plume and oceanic influence. Vertical hauls were carried out using a standard plankton net with 200 μm mesh size during September 2014. An indicator index was applied to express species importance as ecological indicators in community. Information on functional traits was gathered for the most abundant copepod species. Overall, 179 zooplankton taxa were recorded. Copepods were the richest (92 species), most diverse and most abundant group, whereas meroplankton were rare and less abundant. Species diversity (>3.0 bits.ind-1) and evenness (>0.6) were high, indicating a complex community. Small holoplanktonic species dominated the zooplankton, and the total density varied from 107.98 ind. m-3 over the reef area to 2,609.24 ind. m-3 in the estuarine plume, with a significant difference between coastal and oceanic areas. The most abundant copepods were the coastal species ithona plumifera and Clausocalanus furcatus and early stages copepodites of Paracalanidae. The holoplanktonic Oikopleura, an important producer of mucous houses, was very abundant on the reefs. The indicator species index revealed three groups: (1) indicative of coastal waters under the influence of the estuarine plume [Euterpina acutifrons, Parvocalanus crassirostris, Oikopleura (Vexillaria) dioica and Hydromedusae]; (2) characterized coastal and oceanic conditions (Clausocalanus); (3) characterized the reef system (O. plumifera). Two major copepods functional groups were identified and sorted according to their trophic strategy and coastal-oceanic distribution. The species that dominated the coastal area and the area over the rhodolith beds are indicators of the estuarine plume and are mixed with species of the North Brazil Current. These species practically disappear offshore, where occur oceanic species commonly found in other oligotrophic tropical areas. This ecosystem shows a mixture of estuarine, coastal and oceanic communities coexisting in the waters over the Amazon reefs, with no significant differences among these areas. However, the MDS clearly separated the communities along the salinity gradient in the plume.

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Section: Discussionmentioning

confidence: 90%

Zooplankton From a Reef System Under the Influence of the Amazon River Plume

et al. 2018

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“…However, during boreal summer the NBC may retroflect, carrying the Amazon River plume far into the western Atlantic (e.g., Lefèvre et al, 1998;Coles et al, 2013). In fact, every late summer/autumn, the Amazon River outflow covers around 2 × 10 6 km 2 of the western North Atlantic, and the river delivers approximately half of all freshwater input into the tropical Atlantic (see Araujo et al, 2017, and references therein). ) and the Mozambique Channel.…”

Section: Tropical North Atlanticmentioning

confidence: 99%

Long-chain diols in settling particles in tropical oceans: insights into sources, seasonality and proxies

Bar

Ullgren

Thunnell³

et al. 2019

Biogeosciences

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Abstract. In this study we analyzed sediment trap time series from five tropical sites to assess seasonal variations in concentrations and fluxes of long-chain diols (LCDs) and associated proxies with emphasis on the long-chain diol index (LDI) temperature proxy. For the tropical Atlantic, we observe that generally less than 2 % of LCDs settling from the water column are preserved in the sediment. The Atlantic and Mozambique Channel traps reveal minimal seasonal variations in the LDI, similar to the two other lipid-based temperature proxies TEX86 and U37K′. In addition, annual mean LDI-derived temperatures are in good agreement with the annual mean satellite-derived sea surface temperatures (SSTs). In contrast, the LDI in the Cariaco Basin shows larger seasonal variation, as do the TEX86 and U37K′. Here, the LDI underestimates SST during the warmest months, which is possibly due to summer stratification and the habitat depth of the diol producers deepening to around 20–30 m. Surface sediment LDI temperatures in the Atlantic and Mozambique Channel compare well with the average LDI-derived temperatures from the overlying sediment traps, as well as with decadal annual mean SST. Lastly, we observed large seasonal variations in the diol index, as an indicator of upwelling conditions, at three sites: in the eastern Atlantic, potentially linked to Guinea Dome upwelling; in the Cariaco Basin, likely caused by seasonal upwelling; and in the Mozambique Channel, where diol index variations may be driven by upwelling from favorable winds and/or eddy migration.

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“…Specimens from two Eirenidae species were found in a scientific expedition along the Amazonian coast of northern Brazil (Araujo et al 2017, Tosetto et al 2019. Species of the family are typically coastal and/ or estuarine, often occurring in high abundance (Canché-Canché and Castellanos-Osorio 2005, Morales-Ramírez and Nowaczyk 2006, Mediseh et al 2017.…”

Section: Absent 2x Umbrella Diametermentioning

confidence: 99%

New species of Eirenidae (Hydrozoa: Leptothecata) from the Amazonian coast (northern Brazil)

Tosetto

Neumann‐Leitão

Júnior³

2020

scimar

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Two new Eirenidae medusae species were collected on the Amazonian coast, Eutima marajoara n. sp. and Helgicirrha angelicae n. sp. The former differs from other species of the genus by the gonads extending along almost the entire length of the subumbrellar portion of the radial canals but not connected to the ring canal, up to 40 marginal tentacles with conical bulbs and 48 marginal warts, lateral cirri and adaxial papillae on some marginal warts and tentacular bulbs. Helgicirrha angelicae n. sp. differs from other species of the genus by the gonads on the middle portion of the radial canals with medusa buds, the short gastric peduncle, up to 20 marginal tentacles, some with adaxial papillae, up to three marginal warts and two statocysts between successive tentacles, and lateral cirri both on tentacle bulbs and marginal warts.

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

Cited by 32 publications

References 68 publications

Zooplankton From a Reef System Under the Influence of the Amazon River Plume

Zooplankton From a Reef System Under the Influence of the Amazon River Plume

Long-chain diols in settling particles in tropical oceans: insights into sources, seasonality and proxies

New species of Eirenidae (Hydrozoa: Leptothecata) from the Amazonian coast (northern Brazil)

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