Herbivorous copepods with emphasis on dynamic Paracalanus quasimodo in an upwelling region

Abstract

Coastal upwelling is known to transfer the nutrientrich water from the deep ocean to the surface, which benefits primary production and consequently increases local organic production. Cabo Frio is favored by the phenomenon and copepods are one of the groups most benefited. According to the results presented here, the higher abundances of Pacalanus quasimodo relative to other species are due to its rapid response to upwelling-dependent blooms. Therefore this study aims to assess the herbivory and dynamics of many copepod populations with emphasis on P. quasimodo. The results showed that temperature influences primary production, which in turn benefits the seston biomass (R2 = 0.65, p = 0.008). The dominance of P. quasimodo was due to its emphasis on herbivory (R2 = 0.83) and lead to a decrease in the planktonic diversity (R2 = 0.63, p = 0.002). Our results revealed that predation by carnivorous copepods, like Corycaeus spp. and Oncaea spp. is the main opposing factor affecting P. quasimodo dominance. (R2 = 0.70, p = 0.004; βpredators = 0.41, p = 0.04). A ressurgência transfere a água rica em nutrientes do fundo dos oceanos para a superfície, o que beneficia a produção primária e, consequentemente, aumenta a produção biológica local. Cabo Frio é favorecido pelo fenômeno e os copépodes são um dos grupos mais beneficiados. Os resultados mostraram que Pacalanus quasimodo foi a espécie mais abundante em relação às demais devido sua resposta rápida à floração. Assim, este estudo tem como objetivo avaliar a herbivoria e dinâmica das populações de copépodes, com ênfase em P. quasimodo. Os resultados mostraram que a temperatura influencia a produção primária, que, por sua vez, favorece a biomassa séston (R2 = 0,65, p = 0,008). A dominância de P. quasimodo deveu-se à disponibilidade de alimento (R2 = 0,83) e a elevada densidade da população leva a um decréscimo da diversidade (R2 = 0,63, p = 0,002). Nossos resultados revelaram que a predação por copépodes carnívoros, como Corycaeus spp. e Oncaea spp., é o principal fator que afeta a dominância de P. quasimodo (R2 = 0,70, p = 0,004; βcopépodes predador = 0,41, p = 0,04). AbstrAct

First record of Oithona attenuata Farran, 1913 (Crustacea: Copepoda) from Brazil

“…Oithona attenuata is recorded here for the first time off Brazil, even though several studies had previously been conducted in the same place (Valentin, 1984;Dias and Araujo, 2006;Dias et al, 2010;Rosa and Monteiro-Ribas, 2012;Rosa et al, 2016). Its absence in plankton samples over the last 30 years leads us to suggest that this species was brought to Brazilian waters as an exotic species.…”

“…The entire field and laboratory procedure was performed with the assistance of the Instituto de Estudos do Mar Almirante Moreira (IEAPM). More details of the copepod assemblage can be found in the work by Rosa et al (2016).…”

Tracking of spatial changes in the structure of the zooplankton community according to multiple abiotic factors along a hypersaline lagoon

“…A low number of taxa was found during the study (Copepod, Pteropods [Order Thecosomata], Cirripedia larvae, Decapoda, and Polychaeta), when compared to past data from regions near the Araruama lagoon (Arraial do Cabo) (Rosa et al, 2016b). A previous study also found only three copepod genera (Coutinho et al, 1999).…”

“…These peaks may be related to peaks in phytoplankton abundance because, as mentioned by Souza et al (2003), phytoplankton density is highest in the Araruama lagoon when the salinity is at its lowest. Studies with zooplankton have shown that when phytoplankton peaks are accentuated, the greater food availability consequently leads to an increase in the density of zooplankton (Fernandes et al, 2012;Highfield and Eloire, 2010;Rosa et al, 2016b).…”

“…Eutrophication influences the planktonic community (Costa et al, 2018), and globally, the zooplankton community of hypersaline environments is usually poor in diversity and abundance. Indeed, in a previous study at the Araruama lagoon the copepod assembly was represented by three taxa only (Coutinho et al, 1999), whereas the copepod assembly of the adjacent Cabo Frio region has 39 taxa (Rosa et al, 2016b). The present study aimed to evaluate whether abiotic factors influence the spatial and temporal variation of zooplankton in the Araruama lagoon, and to compare the zooplankton diversity with the assembly of copepods of Cabo Frio, to understand which species of the region can adapt to the extreme conditions of the lagoon.…”