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The number of global Carboniferous series and stages should be consistent with those of the neighbouring Devonian and Permian systems. Therefore, two series and seven to nine stages are preferred instead of two subsystems, seven to nine series, and 21 to 35 stages.
Diatoms are one of the main constituents of marine phytoplankton in the Arctic, and thanks to their siliceous skeletons, diatom fossils are relatively well preserved in sediments. Due to their species-specific sensitivity to different ocean conditions, their abundance and assemblages in sediments are routinely used by paleoceanographers to reconstruct the state of the surface ocean in the past (Koç 2007). By using statistical methods, we can obtain valuable knowledge about their ecological preferences (Oksman et al. 2019) and generate quantitative reconstructions of various parameters, such as sea-surface temperature and sea-ice concentration through time (Krawczyk et al. 2021; Sha et al. 2014). The Marine Arctic Diatoms (MARDI) working group (WG) ( pastglobalchanges.org/mardi ) aims to advance knowledge on marine-diatom ecology and diatom-based reconstructions by compiling and harmonizing data from surface-sediment samples across the Arctic.
Within the Gulf of Alaska, in the North Pacific Ocean, three major events - both natural and human-caused – resulted in large-scale ecosystem changes during the last 50 years.
The status of submerged aquatic vegetation along the northern Gulf of Mexico is of concern because of its role in the ecology and economy of the coast. Recent studies by U.S. Geological Survey scientists help assess the factors that contribute to SAV distribution and health.
A bridled white-eye ( Zosterops conspicillata ) was captured in a mist net on the island of Saipan and transported to the island of Guam for an experimental study. Beginning on day three, it was immunosuppressed by intramuscular injections of dexamethasone. It was unexpectedly found dead on day 20, at which time it had lost 0.9 g (12.9% of initial body weight). Gross Pathology: Despite the weight loss, the white-eye was in good flesh, with abundant subcutaneous and visceral fat. The spleen was 3 x 11 mm, about 5 times normal size. The striatum of the forebrain was congested. There were no other lesions. Histopathology: There were microscopic abnormalities in skeletal muscle, brain, and gizzard (Figs. 1 and 2; Figure 2 is from a different white-eye which had virtually identical gizzard lesions).
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