Morphological abnormalities in Acartia lilljeborgii Giesbrecht (1889) (Copepoda, Calanoida) in a tropical estuary under industrial development.

Morphological abnormalities in crustaceans have been registered and several are attributed to pollution and others anthropogenic activities. This study reports for the first time a temporal record of the amount and variety of morphological abnormalities in Acartia lilljeborgii, in an impacted neotropical estuary. The specimens were obtained from Suape port area, Northeast Brazil, between May 2009 and September 2010 using a 300 µm plankton net. Seven types of abnormalities were observed in one of the terminal spines of the prosome, but no temporal variation of abnormalities was found in our study. The deformities were registered in 85.7% of samples and they were found in up to 10% of the individuals (3.2 ± 2.9%). The proportion of females with abnormalities was greater than for males, in opposite to most previous reports. Due to its high distribution and abundance in part of the neotropical Atlantic coastal area, A. lilljeborgii has the potential to be used as a bioindicator of environmental conditions, although the reasons of the abnormality occurrences should be accurately investigated.

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

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly [Formula: see text] and [Formula: see text], were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m-3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 µmol kg-1) and dissolved inorganic carbon (1,303 < DIC < 2,062 µmol kg-1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with salinities >35 and higher-intensity winds, the CO2 flux is reversed. Lower fCO2sw values were observed in the NECC area. The ΔfCO2 in this region was less than 5 µatm (-0.3 mmol m-2 d-1), while the ΔfCO2 in the coastal region was approximately 50 µatm (+3.7 mmol m-2 d-1). During the cruise, heterotrophic and autotrophic processes were observed and are indicative of the influences of terrestrial material and biological activity, respectively.