Cyanobacteria are major sources of oxygen, nitrogen, and carbon in nature. In addition to the importance of their primary metabolism, some cyanobacteria are prolific producers of unique and bioactive secondary metabolites. Chemical investigations of the cyanobacterial genus Moorea have resulted in the isolation of over 190 compounds in the last two decades. However, preliminary genomic analysis has suggested that genome-guided approaches can enable the discovery of novel compounds from even well-studied Moorea strains, highlighting the importance of obtaining complete genomes. We report a complete genome of a filamentous tropical marine cyanobacterium, Moorea producens PAL, which reveals that about one-fifth of its genome is devoted to production of secondary metabolites, an impressive four times the cyanobacterial average. Moreover, possession of the complete PAL genome has allowed improvement to the assembly of three other Moorea draft genomes. Comparative genomics revealed that they are remarkably similar to one another, despite their differences in geography, morphology, and secondary metabolite profiles. Gene cluster networking highlights that this genus is distinctive among cyanobacteria, not only in the number of secondary metabolite pathways but also in the content of many pathways, which are potentially distinct from all other bacterial gene clusters to date. These findings portend that future genome-guided secondary metabolite discovery and isolation efforts should be highly productive.

By collocating 10 years (1999–2009) of remotely sensed surface turbulent heat fluxes with satellite altimetry data, we investigate the impact of oceanic mesoscale eddies on the latent and sensible heat fluxes in the South Atlantic Ocean. In strongly energetic regions, such as the Brazil–Malvinas confluence and the Agulhas Current Retroflection, eddies explain up to 20% of the total variance in the surface turbulent heat fluxes with averaged anomalies of ± (10–20) W/m2. Cyclonic (anticyclonic, respectively) eddies are associated with negative (positive) heat flux anomalies that tend to cool (warm) the marine atmospheric boundary layer. A composite analysis of the turbulent heat flux anomalies inside the eddies reveals a direct relationship between eddy amplitude and the intensity of such anomalies. In addition, these anomalies are stronger near the eddy center, decaying radially to reach minimum values outside the eddies.

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[1] In the western tropical Atlantic, the North Brazil Current retroflection periodically sheds large anticyclonic rings, which then propagate northwestward. Between 1998 and 2000, the North Brazil Current Rings Experiment sampled a large number of these rings by shipboard and moored acoustic Doppler current profiler. Ten of the sampled rings are analyzed in this study, focusing on their sea surface dynamic properties. The rings exhibit a radial structure consisting of two regimes, an "inner" core region in near solid body rotation and an "outer" ring regime with an approximately exponentially decaying structure. The observations show a sharp change in vorticity at the regime transition and the presence of a strong opposite vorticity shield bounding the inner solid body core. We show that Gaussian models, commonly used to represent the surface expression of these and other rings, are adequate for determining the sea surface height anomaly but tend to poorly estimate other properties such as the maximum swirl velocity. Therefore, we propose a new two-part model as a better approximation of the rings' radial structure. According to the cyclogeostrophic balance approximation, the sea surface height distribution across the inner ring has a parabolic shape, while the outer ring has an exponential structure similar to the velocity field. Interestingly, many of the observed rings have an intensity very close to the theoretical limit for anticyclones at these latitudes, which is believed to be due to inertial instability.Citation: Castelão, G. P., and W. E. Johns (2011), Sea surface structure of North Brazil Current rings derived from shipboard and moored acoustic Doppler current profiler observations,

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Sampling errors are inevitable when measuring the ocean; thus, to achieve a trustable set of observations requires a quality control (QC) procedure capable to detect spurious data. While manual QC by human experts minimizes errors, it is inefficient to handle large datasets and vulnerable to inconsistencies between different experts. Although automatic QC circumvents those issues, the traditional methods results in high rates of false positives. Here, I propose a novel approach to automatically QC oceanographic data based on the anomaly detection technique. Multiple tests are combined into a single, multidimensional criterion that learns the behavior of the good measurements, and identifies bad samples as outliers. When applied to 13 years of hydrographic profiles, the anomaly detection resulted in the best classification performance, reducing the error by at least 50%. An open source Python package, CoTeDe, was developed to provide state of the art tools to quality control oceanographic data.

The estuarine system of Laguna (Santa Catarina, Brazil), composed by lagoons of Santo Antonio, Imaruí and Mirim, situated to 130 km south of Florianópolis was evaluated through the association of foraminifera and thecamoebians as biological indicator organisms. The study reveals different population density patterns reflecting the environmental conditions. It is observed the formation of 4 groups. The group representing the north of the lagoon of Imaruí and the south of the Mirim lagoon (stations 14-17) is related to low density of foraminifera and thecamoebians. In the north of the lagoon of Santo Antonio and in the south part of the lagoon of Imaruí (7-13), Ammotium salsum, Ammobaculites exigus and Gaudryina exillis dominate. The group lagoon inlet (1, 2, 4-6) is composed by the stations more influenced by saline waters, presenting the highest diversities, where Elphidium poeyanum and Saccamina sphaera dominate. The group formed by stations collected in the river D'Una, Tubarão, and Mirim lagoon (3, 18-25) presents M. fusca and species of thecamoebians as indicator of large fresh water influence. Despite high fresh water input, it was observed low efficiency in water renewal especially in the north part of the estuarine system.

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