Effective Diahaline Diffusivities in Estuaries

<p>The present study aims to estimate effective diahaline turbulent salinity fluxes and diffusivities in numerical model simulations of estuarine scenarios. The underlying method is based on a quantification of salinity mixing per salinity class, which is shown to be twice the turbulent salinity transport across the respective isohaline. Using this relation, the recently derived universal law of estuarine mixing, predicting that average mixing per salinity class is twice the respective salinity times the river run‐off, can be directly derived. The turbulent salinity transport is accurately decomposed into physical (due to the turbulence closure) and numerical (due to truncation errors of the salinity advection scheme) contributions. The effective diahaline diffusivity representative for a salinity class and an estuarine region results as the ratio of the diahaline turbulent salinity transport and the respective (negative) salinity gradient, both integrated over the isohaline area in that region and averaged over a specified period. With this approach, the physical (or numerical) diffusivities are calculated as half of the product of physical (or numerical) mixing and the isohaline volume, divided by the square of the isohaline area. The method for accurately calculating physical and numerical diahaline diffusivities is tested and demonstrated for a three‐dimensional idealized exponential estuary. As a major product of this study, maps of the spatial distribution of the effective diahaline diffusivities are shown for the model estuary.</p>

First record of Salacia tetracythara Lamouroux, 1816 (Hydrozoa, Sertulariidae) as an alien hydroid for the Atlantic Ocean

We present here the first record of Salacia tetracythara as an alien species for the Atlantic Ocean, specifically the coast of the state of Sergipe, northeast Brazil. The species was found attached to an artificial experimental plate installed in the rainy period (July-October 2017), in an estuarine region of the Sergipe River near the Sergipe Harbour. Salacia tetracythara is characterized by a small triangular space below each hydrotheca and two types of microbasic mastigophore nematocysts that differ in shape, size, and location. The species was described from Australia and has been recorded only for tropical to temperate regions of the Indo-Pacific. Salacia tetracythara seems to be a recent introduction into the Atlantic Ocean and, its introduction probably derived from ship transport between the Sergipe Harbour and regions of Oceania and/or Asia. Further investigation should be conducted to determine whether the species is established in the region and how far inside the estuary it has gone.

Evaluation of 210Pb levels in the estuarine region of an industrial complex

Currently, the increase in the environmental radioactivity levels was due to anthropic activities, such as the oil industries that produce around 2.5x104 to 2.25x105 tons of contaminated materials per year. Thus, the study aimed to determine the 210Pb concentrations in the estuarine region of the SUAPE industrial complex in the state of Pernambuco. The 210Pb concentrations were determined in soil, sediment, fish, and leaf samples, using ion exchange and gamma spectrometry methods. 210Pb concentrations in soils, sediments, fish, and mangrove leaves ranged from less than LD (Detection Limit) to 992.35 Bq.kg-1. The results showed that the area related to the preoperational situation found values above those estimated for regions considered natural, presenting anthropogenic interference.

Nutritional vulnerability of early zoeal stages of the invasive shrimp Lysmata vittata (Decapoda: Caridea) in the Atlantic Ocean

Lysmata vittata is considered an invasive shrimp in the Atlantic Ocean and some characteristics might have contributed to its invasive success, such as its larval nutritional vulnerability during the early stages of development. The objective of this study was to evaluate the early larval stages of the shrimp L. vittata. Ovigerous specimens were captured in an estuarine region of north-eastern Brazil. Zoeae were assigned to two experiments: (1) the point of no return (PNR), consisting of treatments with an increasing number of days of starvation and subsequent days of feeding; and (2) the point of reserve saturation (PRS), consisting of treatments with an increasing number of days of feeding and subsequent days of starvation. Two control groups were considered: continuous starvation (CS) and continuous feeding (CF). Nutritional vulnerability was estimated by the time when 50% of the initially starved larvae (PNR50) lost the ability to moult to the next stage, when 50% of the initially fed larvae (PRS50) were capable of moulting to the next stage. In the CF, the mean development time (±SD) of the larvae that reached stage III was 4.36 ± 0.74 days with a mortality of 70%, and the mean carapace length (±SD) was 0.61 ± 0.04 mm CL. The PNR50 and PRS50 were 2.42 ± 0.14 and 1.32 ± 0.83 days, respectively. The nutritional vulnerability index (PRS50/PNR50 = 0.54) indicates that L. vittata presents intermediate dependence on exogenous food during the early larval stages, which might help our understanding of the invasive potential of this species in the Atlantic Ocean.

Novos dados sobre a Pré-história Antiga no concelho de Palmela. A intervenção arqueológica no sítio do Poceirão I.

Presentation of the results of the archaeological intervention at Poceirão I (Palmela) in 2009. The work consisted of conducting systematic prospecting using a grid and a survey to diagnose the archaeological potential, recording a combustion structure and stratigraphic reading. The results obtained, allowed to individualize two Locus, a considerable dispersion of chipped stone artifacts in flint, quartz and quartzite, but without pottery. However, the strong destruction of the site, the absence of preserved anthropic contexts and a stratigraphy with reduced potential was confirmed in the excavated area. Based on the observed surface data and the materials exhumed, on Poceirão I settlement seems to have been occupied, during the Mesolithic, by groups of hunter-gatherers from the Tejo-Sado inter-estuarine region.

JENIS-JENIS UDANG DI KAWASAN ESTUARIA DESA BATANJUNG SEBAGAI MODUL PENDAMPING MATERI BIOLOGI SMA KELAS X

The species of shrimps in the estuarine areain Batanjung Village have great potential for the academic field, and have not been used as a supplementary module for Biologyon animalia concept, phylum Artrophoda in crustaceas class, for the tenth grade ofsenior high school. This research aims to produce avalid module for Biology on the shrimp species in the estuarine region of Batanjung Village for the tenth grade of SMAN 1 Basarang. Theresearch type used is Research and development (R & D). There are 9 steps in this activity.The result of the field research shows that there are 11 species of shrimps, namely Harpiosquilla raphideae. Peneaus monodon, Peneaus merguensis, Peneaus indicus, Peneaus Vanamae, Metapeneaus monoceros, Palaemon adpersus, Palaemon concinnus, Macrobrachium nipponse, Macrobrachium equidens, Macrobrachium rosenbergii. Furthermore, the species of shrimp were designed to be a supplementary module for Biology for the tenth grade of SMA. The teaching materialswere validated by three experts, and the legibility test were done by the tenth-grade students of SMAN-1 Basarang. The results of validity and legibility test shows that the created teaching materials can be used as the supplementary materials for Biology of the tenth grade of SMA.