Temporal changes in pelagic copepod assemblages off Ubatuba, Brazil

Abstract

The inner shelf waters off Southeastern Brazil are periodically enriched by bottom intrusions of the cold and nutrient-rich South Atlantic Central Water (SACW), which is transported offshore by the Brazil Current. This study examined the temporal contrasts in abundance and structure of pelagic copepod assemblages in a neritic station off Ubatuba, in relation to hydrography and phytoplankton biomass, to investigate the effects of SACW bottom intrusions on copepod population dynamics during three consecutive years. The watercolumn characteristics shifted from a well-mixed, more turbid and phytoplankton-poor scenario during subsidence conditions to a stratified, less turbid and high Chl-a concentration scenario during SACW bottom intrusions, leading to increased copepod diversity, abundance, and biomass. The rise in copepod diversity during SACW intrusions was related to the contribution of oceanic species in addition to coastal water species. The copepod community was numerically dominated by small-sized species, such as Oncaea waldemari, Oithona plumifera, and clausocalanid and paracalanid copepodids, regardless of seasonality and SACW intrusions. Some large calanoid species contributed considerably to the total copepod biomass during intrusions. In addition to confirming that SACW seasonal intrusions play a key role in pelagic processes off Southeast Brazil, this study showed that the multiannual variability of SACW seasonal intrusions is important in regulating the structure and dynamics of copepod communities in this subtropical area.

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

“…The predominance of copepods, in terms of richness, in this area was previously described by Calef and Grice (1967) that mentioned 150 species, while Melo (2006) registered 109 species, among which 97 species were common to the work of Calef and Grice (1967) . Most of these species were also previously seen in the Brazilian Northeast ( Neumann-Leitão et al, 1999 , 2008 , Gusmão, 2000 ) and Southeast ( Miyashita et al, 2009 , Melo et al, 2016 ). Other important holoplanktonic groups were appendicularians [mainly, Oikopleura (Vexillaria) dioica ], chaetognaths ( Flaccisagitta enflata and Serratosagitta serratodentata ), and decapods of the family Luciferidae ( Belzebub faxoni ).…”

“…Zooplanktonic communities are strongly affected by the dynamics of abiotic processes (e.g., physical, chemical, and climate processes) that influence water masses in the marine milieu ( Haury et al, 1990 ; Boltovskoy, 1999 ). The higher density and biomass of plankton found in physical structures such as estuarine plumes, biogenic reefs, eddies and frontal zones ( Roman et al, 2001 ; North and Houde, 2003 ; Goldthwait and Steinberg, 2008 ; Flint et al, 2010 ; Hernández-León et al, 2013 ; Melo et al, 2016 ), have major effects on biogeochemical cycling and sustain higher-order consumers in trophic webs ( Pauly and Christensen, 1995 ; Benoit-Bird and McManus, 2012 ). The Amazon River generates an offshore plume of up to 1.5 × 10 6 km 2 that extends to the western tropical North Atlantic ( Coles et al, 2013 ; Goes et al, 2014 ), generating a physical and chemical gradient supporting diverse plankton communities ( Carpenter et al, 1999 ; Foster et al, 2007 ; Goes et al, 2014 ).…”

Biased measurements by stationary turbidity‐fluorescence instruments due to phototactic zooplankton behavior

“…Samples were brought to the laboratory and processed within 30 min upon collection. Microscopic sorting of the collected zooplankton indicated typical taxonomic composition dominated by a calanoid copepod Acartia lilljeborgi during winter and marine cladocerans Pseudevadne tergestina and Penilia avirostris and the calanoid Temora turbinata during summer (Lopes ; Melo Júnior ). In a dark room, a RINKO‐Profiler was positioned on top of a 7.8‐L glass tank filled with GF/F‐filtered seawater from the sampling location, assuring that the optical path of the fluorescence‐turbidity sensor was entirely submerged (Fig.…”

Small-scale distribution of the mesozooplankton in a tropical insular system

“…However, high values of abundance have already been recorded for C. americana in nocturnal sampling (Melo et al, 2010;Pessoa et al, 2014). This subgroup also included the Paracalanidae (Acrocalanus longicornis, Calocalanus pavo and Paracalanus aculeatus), a family of great importance in terms of abundance, biomass and daily production, besides being highly adapted to the oligotrophic conditions and having the ability to exploit other forms of food besides the phytoplankton (Miyashita et al, 2009;Melo Júnior et al, 2016). However, in FNA its participation in terms of abudance was low, caused by the selectivity of the plankton net mesh size used (300µm).…”