The daily and seasonal patterns of colony attendance for the parakeet auklet were examined on Buldir and St. Paul islands, where fieldwork was conducted in 2001, 2002, and 2004, respectively. The ...timing of breeding events for the parakeet auklet was measured by monitoring the productivity plots on Buldir Island, and the timing of chick hatching was determined by observing birds that carried food to chicks on St. Paul Island. On Buldir Island, direct observations of birds on water were used to collect data on parakeet auklet attendance as it was impossible to count the birds directly on land because of lush vegetation covering the slope of the colony. The birds were counted on a designated plot on water below the colony. On St. Paul Island, observations of birds on both the water and the cliffs were used to collect data on parakeet auklet attendance patterns. On each count day, the birds present at the plot were counted every 15 min. Parakeet auklets have two peaks in their attendance pattern on the water near the colony on Buldir Island. As the breeding season progressed, the peak timing of birds moved slightly toward the afternoon. On St. Paul Island, prior to egg-laying, the numbers of parakeet auklets attending the breeding colony peaked in the morning. As the breeding season progressed, the peak of bird attendance at the colony broadened and shifted toward the evening. During the chick-rearing period, birds arrived at the land plot throughout the day, but there was a peak in the numbers attending in the evening. The observations showed that the weather conditions strongly influenced the numbers of birds present at the plot. Strong winds decreased the number of parakeet auklets in the nearshore area. On windy days, the birds left the plot earlier than usual.
—Observations were conducted from the R/V
Akademik Mstislav Keldysh
in the Drake Passage, the vicinities of the Antarctic Peninsula, the Scotia Sea, and the northern Weddell Sea during two cruises in ...January–early March 2020 (cruise 79) and during a single cruise in January–February 2022 (cruise 87). The data make it possible to assess the number of the most abundant sea mammals in the area near the South Shetland Islands, Scotia Sea, and Powell Basin. The 2022 observation area in the Antarctic was located about 150 km east of the 2020 area. The survey area, which was a bit larger than 343 000 km
2
in January–February 2020, hosted approximately 1200 humpback whales (
Megaptera novaeangliae
) and 2800 fin whales (
Balaenoptera physalus
). In 2022, this area hosted approximately 2500 fin whales and again more than 1200 humpback whales. The numbers of the Antarctic fur seals in each season here were assessed at approximately 2000–3000 animals. The type of distribution of these two whale species along the track of the vessel indicated the absence of intra- or interspecies food competition during the austral summers of 2020 and 2022. It was possible to evaluate the total numbers of Antarctic fur seal (
Arctocephalus gazella
); however, this assessment appeared less precise than the same ones for humpback and fin whales.
A survey of the expedition on the R/V
Akademik Mstislav Keldysh
in the waters south of the southernmost tip of Argentina, in the Drake Passage, as well as in the vicinities of the Antarctic ...Peninsula, the Scotia Sea, and the northern part of the Weddell Sea, was undertaken during two trips: January 16–February 6 (hereafter, January) and February 8–March 3 (hereafter, February), 2020. We propose a new method for analyzing the results of ecological studies and, based on this method, present new information on the ecology and spatial distribution of marine mammals and seabirds of the Antarctic. A number of marine mammal and seabird species showed similar ecological fingerprints, indicating their similar spatial distributions and the same relations to the environmental conditions regardless of their systematic position. The fin whale, the humpback whale, the snow petrel, the Adélie penguin, the Antarctic petrel, and the southern fulmar showed similar specific patterns of ecological fingerprints in January, showing the association of these species to the sea areas with icebergs and/or cut ice. In February, the allocation of the whale species to icy areas weakened what was mirrored in their ecological fingerprints, while all the above-mentioned bird species still preserved this association. The ecological fingerprints clearly circumscribe the broadness of the abiotic ecological niche occupied by individual species or species clusters. Ecological fingerprints are capable of showing changes in species distribution areas in certain periods (the southern royal albatross), in the strategy of the area usage patterns (the Antarctic fur seal), as well as in other ecological features, including those not yet considered.
It is difficult to survey crevice-nesting seabirds because nest-sites are hard to identify and count, and the number of adult birds attending a colony can be extremely variable within and between ...days. There is no standardized method for surveying crevice-nesting horned puffins (Fratercula corniculata), and consequently little is known about abundance or changes in their numbers. We examined the variability in colony attendance of horned puffins at 5 breeding colonies in the North Pacific to assess whether variation in count data can be reduced to a level that would allow us to detect changes in the number of birds attending a colony. We used within-year measures of variation in attendance to examine the power to detect a change in numbers between 2 years, and we used measures of among-year variation to examine the power to detect trends over multiple years. Diurnal patterns of attendance differed among colonies, and among-day variation in attendance was generally lowest from mid- to late-incubation to early chick rearing. Within-year variation in water counts was lower than in land counts, and variation was lower using a daily index based on 5 counts per day than it was using 1 count per day. Measures of among-year variation in attendance also were higher for land-based than water-based counts, and they were higher when we used a 10-day survey period than when we used a 30-day period. The use of either 1 or 5 counts a day during the colony-specific diurnal peak of attendance had little influence on levels of among-year variation. Overall, our study suggests that variation in count data may be reduced to a level that allows detection of trends in numbers. However, more studies of interannual variability in horned puffin attendance are needed. Further, the relationship between count data and breeding population size needs more study before the number of birds present at the colony can be used with confidence as an index of population trend.
Microbial volatiles have a significant impact on the physiological functions of prokaryotic and eukaryotic organisms. Various ketones are present in volatile mixtures produced by plants, bacteria, ...and fungi. Our earlier results demonstrated the inhibitory effects of soil bacteria volatiles, including ketones, on cyanobacteria. In this work, we thoroughly examined the natural ketones, 2‐nonanone and 2‐undecanone to determine their influence on the photosynthetic activity in Synechococcus sp. PCC 7942. We observed for the first time that the ketones strongly inhibit electron transport through PSII in cyanobacteria cells in vivo. The addition of ketones decreases the quantum yield of primary PSII photoreactions and changes the PSII chlorophyll fluorescence induction curves. There are clear indications that the ketones inhibit electron transfer from QA to QB, electron transport at the donor side of PSII. The ketones can also modify the process of energy transfer from the antenna complex to the PSII reaction center and, by this means, increase both chlorophyll fluorescence quantum yield and the chlorophyll excited state lifetime. At the highest tested concentration (5 mM) 2‐nonanone also induced chlorophyll release from Synechococcus cells that strongly indicates the possible role of the ketones as detergents.
First the data were obtained for the enthalpy and heat capacity of liquid gadolinium with temperature measurement, ranging from 2000 K up to 4000 K. The heat capacity of gadolinium obtained under ...pulse current heating (5 μs), is consistent with the experimental data of stationary measurements near 2000 K (the magnitude of the heat capacity of liquid gadolinium equals ≈0.3 J/g-K for both cases). Above 3000 K, the heat capacity increases slightly, reaching values of 0.5 J/g-K for temperatures of 4000-4500 K (under a slightly elevated pressure).
The spatial distribution pattern of phytoplankton primary production (PP) and chlorophyll was studied by the data of three cruises in August–September 2015, 2017, and 2018. The integral primary ...production (IPP) in water columns along the transect from the Lena River mouth to the continental slope was 2.8 times higher than that along the transect from the Khatanga River mouth, which was explained by the illumination and mineral nutrition. The rise in the chlorophyll content in the layer of photosynthesis (Chl
pl
) along the transects across the continental slope was related to the formation of deep-water maxima. The increase in IPP and Chl
pl
was allocated to the continental slope. The mean IPP < 100 mg C/m
2
per day in August–September is the evidence of oligotrophy of the Laptev Sea late in summer and early in autumn.
The breeding biology of the Pigeon Guillemot (Cepphus columba) was studied at Cape Ulyakhpen, the Chukotka Peninsula, Russia, in 1988-1990. In 1989 the bulk of Pigeon Guillemot population arrived in ...the vicinity of the colonies on the south coast of the peninsula in late April. In 1989 and 1990, the median dates of laying, hatching and fledging were 23 and 20 June; 20 and 17 July; 25 and 19 August, respectively. The average clutch size was 1.77 ± 0.42 eggs, with the average egg dimensions, 61.2 ± 2.1 mm and 41.1 ± 1.3 mm. Replacement clutches were initiated on average 12.3 ± 0.8 days after losing the first clutch. During incubation eggs lost on average 15.2 ± 0.4 per cent of their initial mass. Chicks averaged 39.2 ± 3.7g at hatching and 402.4 ± 40.9 g. at fledgling (87.2% of adult mass). Chicks left their nests at the age of 36.3 ± 2.8 days. Chick mass at fledging showed no significant intra- and interannual variation.
Pyroxene glass-ceramic enamels based on combinations of blast furnace slag and some additives were produced and investigated. The batch compositions and technological regimes of enameling were ...developed to produce high temperature protective coatings for carbon steel (ASTM 1010/1008). The composition of raw materials was selected to match the values of the thermal expansion coefficients of the glass-ceramic coating (~11∙10−6 K−1) and metal substrate (~12∙10−6 K−1) taking into account the temperatures of fluidization (Tf ~ 800°) and crystallization (Tc = 850−1020 °C) of the corresponding glasses. The covered and thermally treated samples of carbon steel were produced using single-layer enameling technology and investigated to specify structure, phase composition and properties of the coating and coating-steel interface. The obtained coatings were characterized with excellent adhesion to the steel (impact energy ~3 J) and protective properties. The closed porous structure of the coatings promoted low thermal conductivity (~1 W/(m·K)) and high (up to 1000 °C) thermal resistance, whereas the pyroxene-like crystalline phases supported high wear and chemical resistance as well as micro-hardness (~480 MPa) and thermal shock resistance (>30 cycles of 23–700 °C). The obtained cheap coatings and effective protective coatings could be used at the temperatures up to 1100 °C in the corrosive atmosphere and under the action of abrasive particles.
We conducted seabird surveys along the entire coast of the Chukotka Peninsula (northwestern Siberia, Russia) from 1983 to 1991. We present the first comprehensive descriptions of the distribution and ...size of Chukotkan seabird colonies. Thirteen species of seabirds were recorded breeding on the peninsula, with an additional 13 migrant or vagrant species. Our estimate that at least 3 300000 seabirds breed on the Chukotka Peninsula demonstrates the importance of this region to arctic seabird populations. Colony size and species composition may be determined by availability of adequate breeding sites, access to foraging areas, and variable ice conditions. /// Исследования, связанные с ИЗУЧСllием распредслсния и видового состава колониii морских птиц, провоДЛиСh на побережье Чукотского полуострова в 1983-91 гг. В 1985 г был обследован участок побeрeжья от мыса Сердце-Камснь на ссвсрс до мыса БСРlIнга - на юге, в 1987 г. - от пос. CнPCIllIКн до о. Ратманова. ПраКТllчеСКIl все работы ВЫПОЛНЯЛIIСЬ с воды, что позволило достаточно IJOЛlIO провести учеты птиц на ПТIIЧЬИХ базарах. Исследования показали, что на побережье полуострова гнсздится трllllадцать видов MOPCКlIX птиц И еще тр"надцать ВIIДОВ отмечены как МИгрllрующие или залетные. Общая численноС'гь морских ППЩ, гнездящихся в колопнях, ОЦСlIивается, как минимум, в 3,3 млн. особей, однако она явно заНllжена IIЗ-за трудностей учета скрытогнсздящихся ВIIДОВ ЧИС'ПIКОIIЫХ (TYIIIIKOB, конюг, чистиков И пр.). Численность, видовой состав и распределеllие КОJlОlшii морских птиц по побсрсжыо полуострова зависит от ряда причин: ледовой обстановки, наличия и С'груктуры бсрсговых обрывов, ха- . рактсрn ТСЧСНIlЙ, ОllРСДСЛЯЮЩIlХ ДОСТУПIIОСТЬ кормов И расстояния от мест ГНСЗДОВUIШЯ до МСС'Г кормеЖКlI. Нсмuщ)важную роль в формировании авифауны южного lIобсрсжья IlгpaCT СIlРСlIlIковская стаЦlIонарная береговая полыHbli, поддеРЖlIвающая самую северную в ПаЦllфllКС ПОПУЛЯЦIIЮ глупыша и являющаяся местом ЗИМОВКII ряда BIIДOB морских IIТИЦ. /// De 1983 à 1991, on a effectué des relevés d'oiseaux marins tout le long du rivage de la péninsule de Tchoukotka (nord-ouest de la Sibérie, en Russie). On présente les premières descriptions exhaustives de la distribution et de la taille des colonies d'oiseaux marins de la Tchoukotka. On a relevé 13 espèces d'oiseaux marins nichant sur la péninsule, et, en plus, 13 espèces d'oiseaux en migration ou errants. Notre estimation d'une population nicheuse d'au moins 3 300000 oiseaux marins dans la péninsule de Tchoukotka illustre l'importance de la région pour les populations d'oiseaux marins de l'Arctique. La taille des colonies et la composition des espèces pourraient être déterminées par la disponibilité de sites adéquats pour les nids, l'accès à des zones d'alimentation, et la variabilité des conditions de la glace.
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