scholarly journals Cell carbon content and biomass assessments of dinoflagellates and diatoms in the oceanic ecosystem of the Southern Gulf of Mexico

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247071
Author(s):  
Lorena Linacre ◽  
Citlalli Sánchez-Robles ◽  
Uriel Mirabal-Gómez ◽  
J. Rubén Lara-Lara ◽  
Carmen Bazán-Guzmán
Keyword(s):  
Gulf Of Mexico ◽  
Carbon Content ◽  
Size Structure ◽  
Late Summer ◽  
Euphotic Zone ◽  
Low Carbon ◽  
Centric Diatoms ◽  
Southern Gulf Of Mexico ◽  
Oceanic Ecosystem ◽  
Cell Carbon

This study assessed the cell carbon content and biomass for genera of dinoflagellates and diatoms in the oceanic ecosystem of the Southern Gulf of Mexico. Carbon content estimates were based on biovolume calculations derived from linear dimension measurements of individual cells and the approximate geometric body shape of each genus. Then, biomass assessments were performed for both groups in two gulf regions (Perdido and Coatzacoalcos) using these carbon content factors and cell abundances. After four seasonal cruises, 11,817 cells of dinoflagellates and 3,412 cells of diatoms were analyzed. Diverse body shapes and cell sizes were observed among 46 dinoflagellate genera and 37 diatom genera. Nano-cells of dinoflagellates (68% <20 μm) and micro-cells of diatoms (77% 20–200 μm, mostly 50–75 μm) were predominant. According to this cell-size structure, on average, diatoms contained 40% more carbon per cell than dinoflagellates. Contrasting carbon content estimates were observed within the genera of both microalgae. Large carbon averages (>10,000 pg C cell-1) were attributed to Gonyaulacal and some occasional genera of dinoflagellates (e.g., Pyrocystis and Noctiluca) and centric diatoms. In contrast, values up to 3 orders of magnitude lower were found for Peridinial and Gymnodinial dinoflagellates and pennate diatoms. Based on these carbon content estimates, which can be considered representative for most of this oceanic ecosystem, seasonal and regional differences were found in the biomass assessments conducted for these functional groups. Overall, dinoflagellates (mostly low-carbon Gymnodinales) had larger depth-integrated biomass than diatoms (mainly rich-carbon centric forms) within the euphotic zone. An exception to it was the late-summer cruise at the Coatzacoalcos region when a surface bloom of centric diatoms was observed in stations influenced by river runoff. This work contributes useful reference information for future ecological studies and models for understanding the biogeochemical functioning of this open-ocean ecosystem.

EASTERN STAINLESS TYPE 316L

Alloy Digest ◽  
1984 ◽  
Vol 33 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Carbon Content ◽  
Heat Treating ◽  
Low Carbon ◽  
Steel Company ◽  
Aisi Type ◽  
Type 316L ◽  
Molybdenum Steel

Abstract EASTERN STAINLESS Type 316L is a chromium-nickel-molybdenum steel with a very low carbon content (0.03 max.) Its general resistance to corrosion is similar to AISI Type 316 but, because of its low carbon content, it has superior resistance to the formation of harmful carbides that contribute to intergranular corrosion. Type 316L is used widely in many industries such as chemical, food, paper, textile, nuclear and oil. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-439. Producer or source: Eastern Stainless Steel Company.

EASTERN STAINLESS TYPE 304L

Alloy Digest ◽  
1983 ◽  
Vol 32 (6) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Carbon Content ◽  
Heat Treating ◽  
Low Carbon ◽  
Steel Company ◽  
Aisi Type ◽  
Type 304

Abstract EASTERN STAINLESS TYPE 304L is the basic 18-8 chromium-nickel austenitic stainless steel with a very low carbon content (0.03% max.). Its general resistance to corrosion is similar to AISI Type 304 but, because of its low carbon content, it has superior resistance to the formation of harmful carbides that indirectly contribute to intergranular corrosion. It is recommended for most articles of welded construction. Postweld annealing is not necessary. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-427. Producer or source: Eastern Stainless Steel Company.

scholarly journals Low-carbon cast microalloyed steel intercritically heat-treated at different temperatures: microstructure and mechanical properties

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Hadi Torkamani ◽  
Shahram Raygan ◽  
Carlos Garcia Mateo ◽  
Yahya Palizdar ◽  
Jafar Rassizadehghani ◽  
...  
Keyword(s):  
Carbon Content ◽  
Volume Fraction ◽  
Block Size ◽  
Tensile Tests ◽  
Total Elongation ◽  
Martensite Phase ◽  
Low Carbon ◽  
Steel Increase ◽  
Different Temperatures ◽  
The Impact

AbstractIn this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.

scholarly journals Critical In-Water Habitats for Post-Nesting Sea Turtles from the Southern Gulf of Mexico

2021 ◽  
Vol 9 (8) ◽  
pp. 793
Author(s):  
Abigail Uribe-Martínez ◽  
María de los Angeles Liceaga-Correa ◽  
Eduardo Cuevas
Keyword(s):  
Gulf Of Mexico ◽  
Marine Ecosystem ◽  
Satellite Telemetry ◽  
Marine Turtle ◽  
Home Ranges ◽  
The Bahamas ◽  
Turtle Species ◽  
Southern Gulf Of Mexico ◽  
Large Marine Ecosystem ◽  
Physical Features

Marine turtles are globally endangered species that spend more than 95% of their life cycle in in-water habitats. Nevertheless, most of the conservation, recovery and research efforts have targeted the on-land habitats, due to their easier access, where adult females lay their eggs. Targeting the large knowledge gaps on the in-water critical habitats of turtles, particularly in the Large Marine Ecosystem Gulf of Mexico, is crucial for their conservation and recovery in the long term. We used satellite telemetry to track 85 nesting females from their beaches after they nested to identify their feeding and residency habitats, their migratory corridors and to describe the context for those areas. We delimited major migratory corridors in the southern Gulf of Mexico and West Caribbean and described physical features of internesting and feeding home ranges located mainly around the Yucatan Peninsula and Veracruz, Mexico. We also contributed by describing general aggregation and movement patterns for the four marine turtle species in the Atlantic, expanding the knowledge of the studied species. Several tracked individuals emigrated from the Gulf of Mexico to as far as Nicaragua, Honduras, and the Bahamas. This information is critical for identifying gaps in marine protection and for deciphering the spatial connectivity in large ocean basins, and it provides an opportunity to assess potential impacts on marine turtle populations and their habitats.

Morphological variations of Phrosina semilunata Risso, 1822 juveniles (Crustacea: Amphipoda: Hyperiidea), new evidence from the Gulf of Mexico

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA
Keyword(s):  
Gulf Of Mexico ◽  
Monotypic Genus ◽  
Stages Of Development ◽  
Morphological Variations ◽  
Stages Of Growth ◽  
Early Stages ◽  
Southern Gulf Of Mexico ◽  
New Evidence ◽  
Lack Of Knowledge

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  

Distribution of pathogenic vibrios and Vibrio spp. in the water column and sediment samples from the southern Gulf of Mexico

2021 ◽  
Vol 173 ◽  
pp. 113116
Author(s):  
Johanna Bernáldez-Sarabia ◽  
Marcial L. Lizárraga-Partida ◽  
Edna L. Hernández-López ◽  
Jahaziel Gasperin-Bulbarela ◽  
Alexei F. Licea-Navarro ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Water Column ◽  
Sediment Samples ◽  
Southern Gulf Of Mexico ◽  
Pathogenic Vibrios ◽  
Vibrio Spp

40 Years of Weathering of Coastal Oil Residues in the Southern Gulf of Mexico

2019 ◽  
pp. 328-340
Author(s):  
Jagoš R. Radović ◽  
Isabel C. Romero ◽  
Thomas B. P. Oldenburg ◽  
Stephen R. Larter ◽  
John W. Tunnell
Keyword(s):  
Gulf Of Mexico ◽  
Southern Gulf Of Mexico
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