scholarly journals What colour is penguin guano?

2017 ◽  
Vol 29 (5) ◽  
pp. 417-425 ◽  
Author(s):  
W.G. Rees ◽  
J.A. Brown ◽  
P.T. Fretwell ◽  
P.N. Trathan
Keyword(s):  
Predominantly White ◽  
Absorption Feature ◽  
Orkney Islands ◽  
Signy Island ◽  
Atmospheric Propagation ◽  
Almost All ◽  
Absorption Features ◽  
Reflectance Data ◽  
Pink Coloration

AbstractThe identification and quantification of Antarctic Pygoscelis penguin colonies depends increasingly on recognition of the characteristic optical properties of guano deposits, but almost all knowledge of these properties until now has been compromised by resolution and atmospheric propagation effects. Here we present hyperspectral reflectance data in the range 350–2500 nm, collected in situ from fresh guano deposits in Pygoscelis penguin colonies on Signy Island, South Orkney Islands. The period of data collection included the transition from predominantly white guano to the pink coloration characteristic of a krill-rich diet. The main identifiable features in the spectra are a broad absorption feature centred around 550 nm, responsible for the pink coloration and identified with the pigment astaxanthin, as well as several water absorption features. Variations in these features are responsible for differentiation between spectra. From these results we propose two spectral indices suitable for use with satellite data, one of which responds to the presence of astaxanthin in the guano and the other to water. Our results do not allow us to differentiate between penguin species from their guano, but do suggest that the breeding phenology of Pygoscelis penguins could be determined from a time series of multispectral imagery.

scholarly journals In situ photosynthesis and estimated annual production of the red macroalga Myriogramme mangini in relation to underwater irradiance at Signy Island (Antarctica)

1996 ◽  
Vol 8 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Patty E.M. Brouwer
Keyword(s):  
Early Spring ◽  
Water Type ◽  
Production Rates ◽  
Orkney Islands ◽  
Red Macroalgae ◽  
Surface Irradiance ◽  
Signy Island ◽  
Underwater Irradiance ◽  
First Time

For the first time, photosynthesis of Myriogramme mangini (Gain) Skottsberg, one of the dominant red macroalgae in the sublittoral of Signy Island (South Orkney Islands), was studied in situ under natural irradiance levels in specially developed incubation chambers. M. mangini is adapted to low irradiance levels. Water transparency varied over the year. A maximum attenuation coefficient (kd) of 0.328 m−1 was reached in January, and the water was clearest in September with a kd value of 0.079 m−1. Classification of the water type on a Jerlov scale, gave water type 4 in January and II in May and June. The mean kd value over the year was 0.158 m−1 and the water was classified as Jerlov's water type 1. The euphotic depths (Zeu) for 1%, 0.1% and 0.01% surface irradiance levels were 29.1 m, 43.7 m and 58.3 m, respectively. Photosynthetic characteristics were determined, with the oxygen production rates and irradiance levels measured in situ, using P-I curves. The initial saturation irradiance (Ik) varied significantly from 18.0 ± 1.5 μmol m−2 s−1 in autumn to 10.5 ± 1.8 μmol m−2 s−1 in early spring. Mean photosynthetic capacity (Pg max) ranged from 57.2 ± 1.3 μmol O2 g−1DW h−1 to 63.1 ± 1.6 μmol O2 g−1DW h−1. The photosynthetic efficiency (α) was 3.2 ± 0.2 μmol O2 g−1DW h−1 (μmol m−2 s−1)−1 in autumn and 6.0 ± 1.0 μmol O2 g−1DW h−1 (μmol m−2 s−1)−1 in early spring. Compensation irradiance (Ic) was low and ranged from 2.5 to 2.8 μmol m−2 s−1. Estimates of annual net production rates were 128.1 and 0.6 mmol O2 g−1DW y−1 at 5 m depth and 20 m depth, respectively. A maximum depth of occurrence of M. mangini was predicted at 22.9 m (2.7% of the surface irradiance).

scholarly journals Diversity of Biodeteriorative Bacterial and Fungal Consortia in Winter and Summer on Historical Sandstone of the Northern Pergola, Museum of King John III’s Palace at Wilanow, Poland

2021 ◽  
Vol 11 (2) ◽  
pp. 620
Author(s):  
Magdalena Dyda ◽  
Agnieszka Laudy ◽  
Przemyslaw Decewicz ◽  
Krzysztof Romaniuk ◽  
Martyna Ciezkowska ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Microbial Community Composition ◽  
Fungal Communities ◽  
Bacterial Strains ◽  
Microbial Biodiversity ◽  
Acidophilic Bacteria ◽  
Almost All ◽  
Generation Sequencing ◽  
King John

The aim of the presented investigation was to describe seasonal changes of microbial community composition in situ in different biocenoses on historical sandstone of the Northern Pergola in the Museum of King John III’s Palace at Wilanow (Poland). The microbial biodiversity was analyzed by the application of Illumina-based next-generation sequencing methods. The metabarcoding analysis allowed for detecting lichenized fungi taxa with the clear domination of two genera: Lecania and Rhinocladiella. It was also observed that, during winter, the richness of fungal communities increased in the biocenoses dominated by lichens and mosses. The metabarcoding analysis showed 34 bacterial genera, with a clear domination of Sphingomonas spp. across almost all biocenoses. Acidophilic bacteria from Acidobacteriaceae and Acetobacteraceae families were also identified, and the results showed that a significant number of bacterial strains isolated during the summer displayed the ability to acidification in contrast to strains isolated in winter, when a large number of isolates displayed alkalizing activity. Other bacteria capable of nitrogen fixation and hydrocarbon utilization (including aromatic hydrocarbons) as well as halophilic microorganisms were also found. The diversity of organisms in the biofilm ensures its stability throughout the year despite the differences recorded between winter and summer.

scholarly journals Experimental determination of reflectance spectra of Antarctic krill (Euphausia superba) in the Scotia Sea

2021 ◽  
pp. 1-13
Author(s):  
Anna Belcher ◽  
Sophie Fielding ◽  
Andrew Gray ◽  
Lauren Biermann ◽  
Gabriele Stowasser ◽  
...  
Keyword(s):  
Antarctic Krill ◽  
Euphausia Superba ◽  
Reflectance Spectra ◽  
Spectral Signature ◽  
Absorption Feature ◽  
Scotia Sea ◽  
Surface Ocean ◽  
Measuring Surface ◽  
Ground Truthing

Abstract Antarctic krill are the dominant metazoan in the Southern Ocean in terms of biomass; however, their wide and patchy distribution means that estimates of their biomass are still uncertain. Most currently employed methods do not sample the upper surface layers, yet historical records indicate that large surface swarms can change the water colour. Ocean colour satellites are able to measure the surface ocean synoptically and should theoretically provide a means for detecting and measuring surface krill swarms. Before we can assess the feasibility of remote detection, more must be known about the reflectance spectra of krill. Here, we measure the reflectance spectral signature of Antarctic krill collected in situ from the Scotia Sea and compare it to that of in situ water. Using a spectroradiometer, we measure a strong absorption feature between 500 and 550 nm, which corresponds to the pigment astaxanthin, and high reflectance in the 600–700 nm range due to the krill's red colouration. We find that the spectra of seawater containing krill is significantly different from seawater only. We conclude that it is tractable to detect high-density swarms of krill remotely using platforms such as optical satellites and unmanned aerial vehicles, and further steps to carry out ground-truthing campaigns are now warranted.

scholarly journals Genotypic diversity of S. mutans in dental biofilm formed in situ under sugar stress exposure

2007 ◽  
Vol 18 (3) ◽  
pp. 185-191 ◽  
Author(s):  
Rodrigo Alex Arthur ◽  
Cínthia Pereira Machado Tabchoury ◽  
Renata de Oliveira Mattos-Graner ◽  
Altair A. Del Bel Cury ◽  
Adriana Franco Paes Leme ◽  
...  
Keyword(s):  
Genotypic Diversity ◽  
Negative Control ◽  
Stress Exposure ◽  
Chain Reaction ◽  
Dental Biofilm ◽  
Polymerase Chain ◽  
Fermentable Carbohydrates ◽  
Almost All ◽  
Frequent Exposure

In situ dental biofilm composition under sugar exposure is well known, but sugar effect on the genotypic diversity of S. mutans in dental biofilm has not been explored. This study evaluated S. mutans genotypic diversity in dental biofilm formed in situ under frequent exposure to sucrose and its monosaccharide constituents (glucose and fructose). Saliva of 7 volunteers was collected for isolation of S. mutans and the same volunteers wore intraoral palatal appliances, containing enamel slabs, which were submitted to the following treatments: distilled and deionized water (negative control), 10% glucose + 10% fructose (fermentable carbohydrates) solution or 20% sucrose (fermentable and EPS inductor) solution, 8x/day. After 3, 7 and 14 days, the biofilms were colleted and S. mutans colonies were isolated. Arbitrarily primed polymerase chain reaction (AP-PCR) of S. mutans showed that salivary genotypes were also detected in almost all biofilm samples, independently of the treatment, and seemed to reflect those genotypes present at higher proportion in biofilms. In addition to the salivary genotypes, others were found in biofilms but in lower proportions and were distinct among treatment. The data suggest that the in situ model seems to be useful to evaluate genotypic diversity of S. mutans, but, under the tested conditions, it was not possible to clearly show that specific genotypes were selected in the biofilm due to the stress induced by sucrose metabolism or simple fermentation of its monosaccharides.

scholarly journals Feasibility Study of Transparency Estimation in Lake Nakaumi by SGLI using in-situ Spectral Reflectance Data

2009 ◽  
Vol 65 (1) ◽  
pp. 1046-1050
Author(s):  
Yuji SAKUNO ◽  
Yasushi MIYAMOTO ◽  
Toshiaki KOZU ◽  
Toyoshi SHIMOMAI ◽  
Tsuneo MATSUNAGA ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Spectral Reflectance ◽  
Lake Nakaumi ◽  
Reflectance Data

scholarly journals Comparative molecular cytogenetics in Melipona Illiger species (Hymenoptera, Apidae)

Sociobiology ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 696 ◽  
Author(s):  
Vanderly Andrade-Souza ◽  
Olivia Maria Pereira Duarte ◽  
Cinthia Caroline Cardoso Martins ◽  
Igor Silva Santos ◽  
Márcio Gilberto Cardoso Costa ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Number ◽  
Fluorescent In Situ Hybridization ◽  
Molecular Cytogenetics ◽  
Fluorochrome Staining ◽  
Rdna Sites ◽  
Cytogenetic Studies ◽  
Melipona Species ◽  
Almost All

Cytogenetic studies in Melipona are scarce with only 24 species analyzed cytogenetically. Of these, six species had the rDNA sites physically mapped and characterized by Fluorescent in situ Hybridization (fish). The aim of this study was to perform karyotype analyzes on Melipona species from different regions of Brazil, with a greater sampling representative of the Amazonian fauna and using conventional, fluorochrome staining and FISH with heterologous rDNA probes. The predominant chromosome number was 2n = 18, however, the subspecies M. seminigra abunensis and M. s. pernigra showed 2n = 22 chromosomes. The karyotypes were symmetrical, however M. bicolor, M. quadrifasciata, M. flavolineata, M. fuscopilosa, M. nebulosa presented the first pair heteromorphic in length. CMA3+ blocks also exhibited heteromorphism of size and in almost all cases coincided with rDNA sites, except for M. crinita and M. nebulosa, which presented additional non-coincident CMA3+ blocks. The CMA/ rDNA sites were terminal and interstitial in species with high heterochromatic content, and pericentromeric in those species with low heterochromatic content. In addition to pointing out cytogenetic features of cytotaxonomic importance, the reorganization of the genome in Melipona is discussed.

scholarly journals A Photometric Study of Regolith Intimate Mixing with Ice-Like Impurity

2021 ◽  
Author(s):  
Dwaipayan Deb ◽  
Pavan Chakraborty
Keyword(s):  
Solar System ◽  
Linear Trend ◽  
Geological Processes ◽  
Solar System Objects ◽  
Shadowing Effect ◽  
Mixing Proportion ◽  
In Situ Observations ◽  
End Members ◽  
Reflectance Data

Abstract Surfaces of solid solar system objects are covered by layers of particulate materials called regolith originated from their surface bedrock. They preserve important information about surface geological processes. Often regolith is composed of more than one type of particle in terms of composition, maturity, size, etc. Experiments and theoretical works are being carried out to constrain the result of mixing and extract the abundance of compositional end-members from regolith spectra. In this work we have studied, photometric light scattering from simulated surfaces made of two different materials – one is highly bright quartz particles ≈ 80µm and the other moderately bright sandstone particles ≈ 250µm. The samples were mixed with varying proportions and investigated at normal illumination conditions to avoid the shadowing effect. Said combinations may resemble ice mixed regolith on various solar system objects and therefore important for in situ observations. We find that the combinations show a linear trend in the corresponding reflectance data in terms of their mixing proportion and some interesting facts come out when compared to previous studies.

Theudium Austroatlanticum (Verrucariaceae), A New Species from the South Orkney Islands

1993 ◽  
Vol 25 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Alan Orange
Keyword(s):  
New Species ◽  
The South ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
A New Species

AbstractThelidium austroatlanticum sp. nov. is described from Signy island; it is characterized by an epilithic thallus, more or less appressed involucrellum, and 1-septate spores 30–40 μm long. Thelidium incavatum is also reported for Signy Island.

Colonization of depopulated crinoids by symbionts: who comes from the bottom and who from the water column?

2015 ◽  
Vol 95 (8) ◽  
pp. 1607-1612 ◽  
Author(s):  
E.S. Mekhova ◽  
P.Y. Dgebuadze ◽  
V.N. Mikheev ◽  
T.A. Britayev
Keyword(s):  
Water Column ◽  
Field Experiments ◽  
Dispersal Ability ◽  
Long Distance ◽  
Sandy Substrate ◽  
Limited Dispersal ◽  
Set Up ◽  
Almost All ◽  
High Degree

Previous experiments with the comatulid Himerometra robustipinna (Carpenter, 1881) demonstrated intensive host-to-host migration processes for almost all symbiotic species both within host aggregations and among hosts separated by several metres. The aim of this study was to check the ability of symbionts to complete long-distance migrations, by means of two in situ experiments which depopulated the crinoid host. Two different sets of field experiments were set up: exposure of depopulated crinoids (set 1) on stony ‘islands’ isolated from native crinoid assemblages by sandy substrate, and (set 2) in cages suspended in the water column. Hosts from set 1 were exposed for 1, 2, 3 and 4 weeks to assess whether substrate has an influence on the symbionts' long-distance migrations. In set 2 cages were exposed for 10–11 days, aiming to check whether symbionts were able to disperse through the water column with currents. These experiments allow the conclusion that post-settled symbionts can actively migrate among their hosts. Symbionts are able to reach their hosts by employing two different ‘transport corridors’, by drifting or swimming in water column, and by moving on the bottom. Comparison of experimental results allows the division of symbionts into two conventional groups according to the dispersal ability of their post-settled stages: (1) species able to complete long-distance migrations, (2) species unable to migrate or having limited dispersal ability. The finding of the free-living shrimp Periclimenes diversipes Kemp, 1922 in set 2 raises the question about the factors that affect such a high degree of specialization of crinoid assemblages.

Sign in / Sign up

Export Citation Format

Share Document