Primary production and plankton stocks in the Pacific Ocean and their seasonal variation according to remote sensing and field observations

Data collected from 20 years of observations by the P. P. Shirshov Institute of Oceanology (about 250 comprehensive ecosystem stations) are summarized to evaluate the primary production and biomass of the principal groups of plankton in the Pacific Ocean. The stations were classified into geographical regions according to satellite determined criteria. The areas of these regions were evaluated according to CZCS data from 1978 to 1986. The total value of primary production was evaluated as 26·9 Gt C year⁻¹. Taking the “bottle effect” correction into account, this value may be as high as 45.6 Gt C year⁻¹. Total biomass values of phytoplankton (134 Mt C), bacteria (86 Mt C), protozoa (26 Mt C) and mesoplankton (184 Mt C) were also calculated. Seasonal variabilities of all these values were remarkably insignificant.     

Phytoplankton production characteristics in the Eastern Atlantic and Atlantic sector of the Southern Ocean in October–November 2004

Production parameters of surface phytoplankton were measured along three transects: La Manche-Cape Town (I); Cape Town-54°S (II); 0°-49°W (along 54°S) (III). The Canary upwelling waters were most productive along transect I, where the surface chlorophyll a (Chl ₀) and the surface primary production (PP ₀) were as high as 4.3 mg/m³ and 173 mg C/m³ per day, respectively. Mosaic patterns in the distribution of these parameters were recorded in the northeastern regions of the South Subtropical Anticyclonic Gyre (Chl ₀ = 0.03–0.35 mg/m³; PP ₀ = 1.6–12.6 mg C/m³ per day). Along transect II, the average twofold southward increase in Chl ₀ (from 0.2 to 0.4 mg/m³) and the concurrent decline of the phytoplankton assimilation activity ( AN ₀) resulted in deviations from typical latitudinal changes inPP ₀. At most sites, PP ₀ values varied between 6 and 15 mg C/m³ per day. Negligible changes in Chl ₀ (0.36–0.85 mg/m³), PP ₀ (8–19 mg C/m³ per day), and AN ₀ (0.7–1.6 mg C/mg chl a per hour) were registered for the oceanic waters along transect III. Along all the transects, PP ₀ depended on Chl ₀ to a greater extent than AN ₀. The values of the latter parameter were largely determined by the water temperature and showed a slight correlation with the insolation. Along transect II, the integrated primary production (PP _int) and the layer-integrated chlorophyll a in the upper 200 m (Chl _0–200) generally varied from 180 to 360 mg C/m² per day and from 30 to 70 mg/m², respectively. In the Polar Front region, an increase in Chl _0–200, PP _int, Chl ₀, and PP ₀ up to respective values of 190 mg/m², 520 mg C/m² per day, 1.2 mg/m³, and 32 mg C/m³ per day was observed. A comparison of the water column (0–100 m) stability with the vertical distribution of the primary production and chlorophyll content along transect II implies that the thick (>100 m) upper mixed layer (UML) formed in response to the strong water cooling and wind forcing was largely responsible for the limited primary production in the Subantarctic and Antarctic regions. The large UML thickness resulted in an intense removal of plant cells from the photosynthetic layer and light starvation of a significant (up to 60%) part of the phytoplankton community.     

Anthropogenic influence on the planktonic community in the basin of Mamala Bay (Oahu Island,Hawaii) based on field and satellite data

The anthropogenic impact on the biomass of coastal plankton communities caused by submerged disposal of urban sewage waters (dumping) was studied. The observations were carried out in August–September of 2002–2004 in Mamala Bay (Oahu Island, Hawaii) using satellite and sea truth methods. An analysis of the variability of the integral indicators of the water column determined on the basis of shipborne measurements allowed us to divide them into two groups: the elements most sensitive to the pollution (heterotrophic bacteria (H-Bact), the phototrophic cyanobacteria Synechococcus spp. (SYN), and chlorophyll a (CHLa)) and the elements that manifested episodic positive dependence on the inflow of the polluted waters (heterotrophic unicellular eukaryotes, small unicellular algae, the phototrophic green bacteria Prochlorococcus spp., as well as the total biomass of microplankton). It was shown that the submerged wastewater disposal in the region of the diffuser of the dumping device led to an insignificant (1.2–1.4 times, on the average) local increase in the integral biomass of H-Bact, SYN, and in the content of CHLa. A similar but sharper (1.5–2.1, on the average) increase in these parameters was found in the water layers with maximal biomasses. The possible pathways of disposed waters (under the pycnocline, at its upper boundary, and in the entire mixed layer) were analyzed on the basis of studying the vertical displacement of the biomasses of H-Bact, SYN, and prochlorophytes. The possibility of using the optical anomalies distinguished from satellite data as markers of anthropogenic eutrophication caused by dumping was confirmed. Application of such markers depends on the water transparency and on the shapes of the curves of the vertical distribution of autotrophic organisms.     

The first U–Pb SIMS age datings of zircons from upper Permian deposits of the Northeastern Russia: Significance for interregional correlations

The Regional Stratigraphic Scale (RSS) of the Permian deposits in northeastern Russia represents the only complete stratigraphic succession of Permian marine deposits distinguished in Russia, which serves as a standard at the correlation of Permian deposits of all regions of the eastern part of the Boreal Biogeographic Superrealm. However, a high level of faunistic endemism makes it extremely difficult to correlate directly stratons of the RSS with stages of the International Stratigraphic Scale (ISS) of the Permian deposits. The first U–Pb SIMS age datings of zircons from felsic tuffs of the Omchak Formation of the Ayan-Yuryakh Anticlinorium (the lower part of the Permian Khivachian Horizon of the RSS of northeastern Russia) allowed us to obtain the important reference level for the Upper Permian subdivision of the Permian RSS. The zircon age of 257.1 ± 3.0 Ma is in good agreement with the stratigraphic position of the studied sample, which makes it possible to correlate the surrounding deposits with the Wuchiapingian Stage of the Permian deposits in the International Stratigraphic Scale.     

The first detailed δ13Соrg record in Permo-Triassic boundary deposits in the Kolyma–Omolon region (Northeast Asia)

Doklady Earth Sciences - We have obtained the first detailed δ13Сorg record in Permian-Triassic boundary sediments in deepwater facies in Northeast Asia (Kolyma–Omolon region,...     

Spatiotemporal variability of chlorophyll <Emphasis Type="Italic">a</Emphasis> in the Altantic and Indian sectors of the Southern Ocean during February–April of 2000 according to satellite and expeditionary data

In February and April 2000, in the Southern Ocean between Africa and Antarctica, the concentration of chlorophyll (C _chs) in the surface layer was not high (0.1–0.3 mg/m³). The zones of increased C _chs values (0.6–2.0 and over 2.0 mg/m³) were located between the Southern Subtropical and Subantarctic fronts, near the Polar front, and to the south of the Antarctic Divergence. From February to April, in the open areas of the Southern Ocean, a general C _chs decrease was observed. A similar trend was also noted in the near-shore seas of the East Antarctic. At the shelf of the Sea of Cosmonauts, within the upper mixed layer, the content of chlorophyll amounted to 0.34–0.37 mg/m³. In the area of the continental slope, we registered the formation of a subsurface chlorophyll maximum (0.52–0.56 mg/m³) at a 20-m depth, which deepened to 70 m when passing to the deep-water area. The positive correlation with a high coefficient (r = 0.939) between the field and satellite data (C _chs and C _sat, respectively) allows one to conclude about the applicability of the SeaWiFS algorithm for the estimation of the chlorophyll content within the surface layer in the Antarctic areas studied. In the course of the ice formation in Prydz Bay, during five days, the content of chlorophyll in different phases of the new ice increased by a factor of 2.9, whereas the values of this parameter in the surrounding waters remained quite invariable. The C _sat values were 6.3 times as high as those obtained experimentally for the sludge ice. Because of the large areas occupied by floating ice, the sole usage of satellite data may cause great errors in the productivity estimation of the East Antarctic seas.     

The First Data on the N Isotopic Composition of the Permian and Triassic of Northeastern Russia and Their Significance for Paleotemperature Reconstructions

Doklady Earth Sciences - It is proposed that unstable temperature conditions in the Late Wuchiapingian and Early Changhsingian (Late Permian) changed in the Boreal Superrealm to less contrasting...