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Wyświetlanie 1-5 z 5
Tytuł:
Testing the performance of empirical remote sensing algorithms in the Baltic Sea waters with modelled and in situ reflectance data
Autorzy:
Ligi, M.
Kutser, T.
Kallio, K.
Attila, J.
Koponen, S.
Paavel, B.
Soomets, T.
Reinart, A.
Powiązania:
https://bibliotekanauki.pl/articles/48045.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
remote sensing
algorithm
Baltic Sea
coastal water
chlorophyll a
optical property
phytoplankton assemblage
water reflectance
Opis:
Remote sensing studies published up to now show that the performance of empirical (band-ratio type) algorithms in different parts of the Baltic Sea is highly variable. Best performing algorithms are different in the different regions of the Baltic Sea. Moreover, there is indication that the algorithms have to be seasonal as the optical properties of phytoplankton assemblages dominating in spring and summer are different. We modelled 15,600 reflectance spectra using HydroLight radiative transfer model to test 58 previously published empirical algorithms. 7200 of the spectra were modelled using specific inherent optical properties (SIOPs) of the open parts of the Baltic Sea in summer and 8400 with SIOPs of spring season. Concentration range of chlorophyll-a, coloured dissolved organic matter (CDOM) and suspended matter used in the model simulations were based on the actually measured values available in literature. For each optically active constituent we added one concentration below actually measured minimum and one concentration above the actually measured maximum value in order to test the performance of the algorithms in wider range. 77 in situ reflectance spectra from rocky (Sweden) and sandy (Estonia, Latvia) coastal areas were used to evaluate the performance of the algorithms also in coastal waters. Seasonal differences in the algorithm performance were confirmed but we found also algorithms that can be used in both spring and summer conditions. The algorithms that use bands available on OLCI, launched in February 2016, are highlighted as this sensor will be available for Baltic Sea monitoring for coming decades.
Źródło:
Oceanologia; 2017, 59, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Do seasonal dynamics influence traits and composition of macrobenthic assemblages of Sundarbans Estuarine System, India?
Autorzy:
Bhowmik, M.
Mandal, S.
Powiązania:
https://bibliotekanauki.pl/articles/2079001.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
seasonal dynamics
macrobenthic assemblage
macroinvertebrate
climate change
taxonomic analysis
ecosystem functioning
biological trait
estuarine system
India
Opis:
The present study investigates the influence of seasonal dynamics on macrobenthic assemblages in four seasons of 2017—2018 from the central sector of Indian Sundarbans which is under the constant threat of climate change. Besides taxonomic analysis, a traitbased approach has also been applied to assess the change in their ecosystem functioning. The maximum species density (11675 ± 11883.31 ind. m−2) was observed during the spring season which declines considerably in the monsoon season (5875 ± 6224.08 ind. m−2). A total of 95 macrobenthic taxa were recorded from Sundarbans and they were dominated by families like Capitellidae, Donacidae, Magelonidae, Nereididae, Paraonidae and Spionidae. Overall, polychaetes have shown higher taxonomic and functional variation than other groups. Opportunistic polychaete species have shown a prominent compositional shift during post-monsoon seasons. Both the univariate and multivariate analyses have shown a significant relation between macrobenthic composition and environmental parameters. SIMPER has depicted that environmental parameters made the station 4 unique for several types of molluscs like Acteocina estriata, Stenothyra deltae and Meretrix meretrix during spring. Trait percentages also showed a seasonal succession pattern and among the trait categories, burrowers and deposit feeders dominated the estuary. A gradual increase in suspension feeders in spring has been noticed. RLQ approach with fourth-corner analysis was used to unravel the relationship between traits and environmental parameters. Hence, the present study provided a comprehensive idea about the species composition along with their trait categories from such a dynamic habitat. That could be the first stepping stone for a long term monitoring of macrobenthic assemblages from this largest delta on earth.
Źródło:
Oceanologia; 2021, 63, 1; 80-98
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery of macrobenthic assemblages following experimental sand burial
Autorzy:
Yanez, B.
Carballo, J.L.
Olabarria, C.
Barron, J.J.
Powiązania:
https://bibliotekanauki.pl/articles/48383.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sand
macrobenthic recovery
sand burial
wave exposure
disturbance
macrobenthic assemblage
periodic inundation
rocky coast
rocky shore
Opis:
Periodic inundation by sand is a very common feature of rocky coasts throughout the world. Even so, there have been few direct observations or experiments to investigate the role of sediments on intertidal rocky shores. We designed a field experiment in Mazatl´an Bay, Mexico, to test the initial impact and subsequent recovery of intertidal macrobenthic assemblages exposed to sand burial at two sites of varying wave exposure. Both sites supported different natural assemblages. Treatment plots for the addition of sediment and control plots (50×50 cm), separated by at least 1.5 m, were randomly placed across the mid-water tidal level. The initial response of the resident macrobenthos and the subsequent recolonization was monitored over a period of 95 days. The main effect of sediment deposition at both sites was mortality and removal of biota due to smothering. The recovery process was rapid and may in part have been the result of the mechanism by which the small, disturbed patches were recolonized. Most of the invertebrates colonized the patches as adults; several seaweeds exhibited vegetative growth as the major mechanism of colonization (e.g., Ulva lactuca Linnaeus, 1753, Amphiroa valonioides Yendo, 1902 and Chaetomorpha antennina (Borgensen) Kutzing, 1849). The rate of recovery varied between the sites, however. Recovery of species numbers proceeded quickly at the sheltered site (day 7), but took 95 days at the exposed site. In contrast, biomass reached control levels by day 45 at the sheltered site, but already by day 15 at the exposed site. By day 95, the assemblages recovered to 83.5% and 81% similarity with the controls at the sheltered and exposed sites respectively. Although differences in wave exposure could be very important in determining the different patterns of recovery at both sites, other biological processes may also play an important part.
Źródło:
Oceanologia; 2008, 50, 3; 391-420
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of shelf-transformed waters (STW) on foraminiferal assemblages in the outwash and glacial fjords of Adventfjorden and Hornsund, Svalbard
Autorzy:
Szymanska, N.
Pawlowska, J.
Kucharska, M.
Kujawa, A.
Lacka, M.
Zajaczkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/48678.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Atlantic water
foraminiferal assemblage
glacial fjord
outwash fjord
Adventfjorden
Hornsund
Svalbard
inflow water
salinity
water temperature
environment change
Opis:
A new dataset of benthic foraminiferal assemblages from Adventfjorden (tributary fjord of Isfjorden, West Spitsbergen) was compared with the results of a study conducted by Zajączkowski et al. (2010) in Hornsund (West Spitsbergen). According to Nilsen et al. (2016), Atlantic water inflow to the Isfjorden Trough occurs more readily than to anywhere else along the shelf of Spitsbergen; thus, we compared the foraminiferal assemblages of the outwash Adventfjorden fjord, located in the Isfjorden system, with glacial Hornsund, located in southwest Spitsbergen. Despite the juxtaposition of Adventfjorden and Hornsund the data revealed varying impacts of shelf-transformed water (STW) on the benthic foraminiferal assemblages. Outer and central Adventfjorden was dominated by Adercotryma glomerata, Recurvoides turbinata and Spiroplectammina sp., reflecting the presence of STW, while abundant Melonis barleeanus in the central area of the fjord indicated a large flux of unaltered organic matter. Only the head of the fjord was dominated by the glaciomarine taxa Cassidulina reniforme and Elphidium clavatum. Foraminiferal fauna characteristic of STW-influenced environments (i.e., Nonionellina labradorica and R. turbinata) were also observed in outer Hornsund. However, the glacier-proximal taxa E. clavatum and C. reniforme were dominant throughout the fjord, demonstrating the impacts of meltwater and high sedimentation. Therefore, it is likely that in Hornsund, glacial impact is a major environmental factor, which is stronger than the influence of STW.
Źródło:
Oceanologia; 2017, 59, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Holocene evolution of the Pomeranian Bay environment, Southern Baltic Sea
Autorzy:
Kostecki, R.
Janczak-Kostecka, B.
Powiązania:
https://bibliotekanauki.pl/articles/48852.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
aerobic condition
anaerobic condition
Ancylus Lake
Baltic Sea
diatom assemblage
ecological group
geochemistry
Holocene
lacustrine sediment
marine diatom
marine environment
paleogeographic development
Pomeranian Bay
sediment core
shallow lake
Opis:
This article focuses on the diatom assemblages and geochemical composition of sediment cores retrieved from the Pomeranian Bay. We also discuss similarities and differences in the diatom assemblages and the palaeogeographic development of nearby regions. Our main objective was to determine the characteristics and rate of the Littorina transgression in the Pomeranian Bay area. Sediments were divided into units based on differences in the distribution of diatom ecological groups and in geochemical ratios, such as Mg/Ca, Na/K and Fe/Mn. This study identified lacustrine sediments deposited during the time of the Ancylus Lake. This lacustrine-period sedimentation took place in a shallow lake under aerobic conditions. The record of the onset of marine environment dates to 8900–8300 cal BP and corresponds to the Littorina transgression. After about 8300 cal BP, sedimentation took place in a deeper marine environment with higher biogenic production and anaerobic conditions. The abrupt appearance of marine diatom species and increased geochemical salinity indicators reflect the large impact of the Littorina transgression on the Pomeranian Bay environment.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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