Yearly variation of bacterial production in the Arraial do Cabo protection area (Cabo Frio upwelling region): an evidence of anthropogenic pressure

Abstract

Arraial do Cabo is where upwelling occurs more intensively on the Brazilian coast. Although it is a protection area it suffers anthropogenic pressure such as harbor activities and sporadic sewage emissions. Short-time studies showed a high variability of bacterial production (BP) in this region but none of them evaluated BP during long periods in a large spatial scale including stations under different natural (upwelling and cold fronts) and anthropogenic pressures. During 2006, we sampled surface waters 10 times (5 in upwelling and 5 in subsidence periods) in 8 stations and we measured BP, temperature as well as the concentrations of inorganic nutrients, pigments and particulate organic matter (POM). BP was up to 400 times higher when sewage emissions were observed visually and it had a positive correlation with ammonia concentrations. Therefore, in 2007, we did two samples (each during upwelling and subsidence periods) during sewage emissions in five stations under different anthropogenic pressure and we also measured particles abundance by flow cytometry. The 12 samples in the most impacted area confirmed that BP was highest when ammonia was higher than 2 μM, also reporting the highest concentrations of chlorophyll a and suspended particles. However, considering all measured variables, upwelling was the main disturbing factor but the pressure of fronts should not be neglected since it had consequences in the auto-heterotrophic coupling, increasing the concentrations of non fluorescent particles and POM. Stations clustered in function of natural and anthropogenic pressures degrees and both determined the temporal-spatial variability.

Picoplankton Bloom in Global South? A High Fraction of Aerobic Anoxygenic Phototrophic Bacteria in Metagenomes from a Coastal Bay (Arraial do Cabo—Brazil)

“…The Arrial do Cabo (Rio de Janeiro state, Brazil) region is affected by upwelling, a phenomena where the up-flow of cold and nutrient-rich waters disturbs ecosystem dynamics, increasing biomass and primary production. This phenomenon can lead to a picoplankton bloom, when the primary producers (including Aerobic anoxygenic phototrophic bacteria) exploit these nutrients coming up from deep cold waters (Alonso-Gutiérrez et al, 2009 ; Coelho-Souza et al, 2013 ; Wemheuer et al, 2014 ).…”

Bacterial and Archaeal Communities Variability Associated with Upwelling and Anthropogenic Pressures in the Protection Area of Arraial do Cabo (Cabo Frio region - RJ)

“…We found a positive correlation between both nutrients and Carlsson et al (2012) observed that additions of C, N and P (alone or in combination) stimulated microbial growth and activity in both inshore and offshore stations in the Arraial do Cabo coast. In this nutrient input, there was highest heterotrophic production as well as during sewage discards (Coelho-Souza et al 2013a). Heterotrophic bacteria are important to P cycle as dissolved inorganic P consumers (Duhamel and Moutin 2009) and phosphorous spurs bacterial growth (Yuan et al 2011).…”

The Effect of Light on Bacterial Activity in a Seaweed Holobiont

“…Physico-chemical water variables (nutrients, chlorophyll, temperature and salinity) were available over the period of study through the weekly monitoring of the Brazilian navy (Instituto de Estudos do Mar Almirante Paulo Moreira -IEAPM) and methods used are described elsewhere [6]. Solar light radiation was measured every 5 minutes during all experimental periods using a LICOR LI-1.000 Datalogger/Li-193 SA spherical quantum sensor.…”