A statistical examination of the catches, numbers, and biomass taken by three commonly used plankton nets

1965 ◽  
Vol 16 (3) ◽  
pp. 293 ◽  
Author(s):  
H Barnes ◽  
DJ Tranter
Keyword(s):  
Standard Deviation ◽  
Indian Ocean ◽  
Chemical Analysis ◽  
The Other ◽  
Single Observation ◽  
Large Bulk ◽  
The Indian Ocean ◽  
Percentage Standard Deviation

A comparison has been made between the Indian Ocean standard net (IOSN), the tropical Juday net (TJN), and the Clarke-Bumpus sampler (CBS). Various components of the zooplankton have been counted and the results submitted to analyses of variance. The variability of the catches is greatest with the TJN, the percentage standard deviation of a single observation rangingfrom 73 to 135 %; the valuesfor the IOSN and the CBS are similar toeach other: 42-51 %. The greater variability of the TJNis ascribed to its smaller mesh with consequent clogging, and arises from variability in the volume filtered and from the difficulty of washing down such a large and fine net efficiently. There is no evidence that the larger zooplankton avoid the smaller CBS any more successfully than they avoid the two large nets; as expected, the smaller zooplankton organisms escape more readily through the IOSN with its coarser meshes than through the other two nets. The catches for the IOSN and the CBS agree very well when expressed per volume of water filtered. The main advantage of the larger nets--as regards the organisms considered here-is in the greater volume of water filtered; this would be of importance if a large bulk of material were required for, say, chemical analysis or if a search were being made for rare organisms.

Detrital and authigenic minerals in sediments from the western part of the Indian Ocean

1986 ◽  
Vol 50 (355) ◽  
pp. 69-74 ◽  
Author(s):  
A. E. Tsirambides
Keyword(s):  
Indian Ocean ◽  
Oxygen Isotope ◽  
Western Indian Ocean ◽  
The Other ◽  
Authigenic Minerals ◽  
Volcanic Material ◽  
Two Samples ◽  
The Indian Ocean ◽  
Isotope Analyses ◽  
Mn Oxides

AbstractMineralogical and oxygen isotope analyses have been performed on nine western Indian Ocean core samples in order to distinguish the detrital from authigenic minerals in the sediments. Following the removal of carbonates, organic constituents and Fe and Mn oxides, the residue was separated into five size fractions, the principal minerals present being feldspar, quartz, clinoptilolite, and clay minerals.Oxygen isotope compositions for two samples reflect an authigenic origin for clinoptilolite by the submarine alteration of volcanic material. Oxygen isotope compositions of two separates (free from feldspar and clays) suggest a detrital origin for the quartz in this area. The same mode of origin is apparent for the other components too, except possibly for some smectite which may have formed authigenically.

Genetic variation and relationships among Afrotropical species of Myotis (Chiroptera: Vespertilionidae)

2019 ◽  
Vol 100 (4) ◽  
pp. 1130-1143 ◽  
Author(s):  
Bruce D Patterson ◽  
Paul W Webala ◽  
Julian C Kerbis Peterhans ◽  
Steven M Goodman ◽  
Michael Bartonjo ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Maximum Likelihood ◽  
Indian Ocean ◽  
Nuclear Data ◽  
The Other ◽  
Data Sets ◽  
Species Trees ◽  
Nuclear Introns ◽  
Geographic Structure ◽  
The Indian Ocean

Abstract The genus Myotis is nearly cosmopolitan and the second-most speciose genus of mammals, but its Afrotropical members are few and poorly known. We analyzed phylogenetic and phylogeographic relationships of six of the eight known Afrotropical species using Cytb and sequences from four nuclear introns. Using Bayesian and maximum-likelihood approaches to generate single-locus, concatenated, and species trees, we confirmed prior evidence that the clade containing Afrotropical Myotis also contains both Palearctic and Indomalayan members. Additionally, we demonstrate that M. bocagii is sister to the Indian Ocean species M. anjouanensis, that this group is sister to M. tricolor and the Palearctic M. emarginatus, and find evidence suggesting that M. welwitschii is the earliest-diverging Afrotropical species and sister to the remainder. Although M. tricolor and M. welwitschii are both currently regarded as monotypic, both mitochondrial and nuclear data sets document significant, largely concordant geographic structure in each. Evidence for the distinction of two lineages within M. tricolor is particularly strong. On the other hand, geographic structure is lacking in M. bocagii, despite the current recognition of two subspecies in that species. Additional geographic sampling (especially at or near type localities), finer-scale sampling (especially in zones of sympatry), and integrative taxonomic assessments will be needed to better document this radiation and refine its nomenclature.

Belts and roads every- and nowhere: Conceptualizing infrastructural corridorization in the Indian Ocean

2020 ◽  
Vol 38 (5) ◽  
pp. 815-819
Author(s):  
Henryk Alff
Keyword(s):  
Indian Ocean ◽  
Silk Road ◽  
The Other ◽  
Assemblage Theory ◽  
Static State ◽  
Maritime Silk Road ◽  
The Indian Ocean ◽  
The One ◽  
Human Actors

This article scrutinizes the Maritime Silk Road Initiative by framing it not as a static, state-centric device to channel Chinese developmental ambitions, but by emphasizing the flexible character of its production and the provisional configuration of its materialization. It draws on assemblage theory as a conceptual angle to, on the one hand, focus on the agentive character of human and non-human ‘actors’ such as ‘traveling’ discourses of development or infrastructures to explore Maritime Silk Road Initiative’s materialization ‘on the ground’ in its emergent rather than resultant way, on the other.

scholarly journals Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 3190-3209 ◽  
Author(s):  
Lisan Yu ◽  
Xiangze Jin ◽  
Robert A. Weller
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Seasonal Cycle ◽  
Arabian Sea ◽  
Heat Fluxes ◽  
The Other ◽  
Net Heat Flux ◽  
The Indian Ocean ◽  
The Mean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

DAMAGE AND RECONSTRUCTION OF LIFELINES IN PHANG NGA PROVINCE, THAILAND AFTER THE 2004 INDIAN OCEAN EARTHQUAKE AND TSUNAMI

2010 ◽  
Vol 04 (02) ◽  
pp. 83-93 ◽  
Author(s):  
SHIRO TAKADA ◽  
YASUKO KUWATA ◽  
ARUN PINTA
Keyword(s):  
Indian Ocean ◽  
Basic Concept ◽  
City Planning ◽  
The Other ◽  
Other Hand ◽  
The Indian Ocean ◽  
The Difference ◽  
Okushiri Island

The Indian Ocean earthquake and tsunami occurred in December 2004 caused destructive damage to Phang Nga Province, Thailand. We carried out two times of interview surveys about 1 and 3 years after the event to administrative bodies and lifeline companies for getting the information on lifeline damage, restoration and reconstruction situation, and summarized the basic concept of reconstruction plan of tsunami suffered towns considering lifeline restoration. On the other hand, as for the comparison of reconstruction problems, the lifelines recovery is reviewed at Aonae district in Okushiri Island after the 1993 Hokkaido-Nansei-oki earthquake. As the result, the difference of the process of reconstruction of town and lifelines has been revealed and the importance of preparing of the reconstruction plan before the event under the consideration of a long-term city planning is pointed out.

scholarly journals Evolution of two troughs in the tropical Indian Ocean and their characteristic features

MAUSAM ◽  
2021 ◽  
Vol 43 (4) ◽  
pp. 395-398
Author(s):  
M.S. SINGH ◽  
B. Lakshmanaswamy
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
South Asian ◽  
Tropical Indian Ocean ◽  
The Other ◽  
The South ◽  
The Indian Ocean ◽  
Characteristic Features

Evolution and characteristic features of double trough systems in the tropical Indian Ocean have been studied with the help of Climatological Atlas (Part I andIl) ~f the Tropical Indian Oc.ean (Hastenrath and Lamb 1979). It is confirmed that there are two troughs (Northern Hemisphere EquatorIal Trough and Southern Hemisphere Equatorial Trough) in this region (including south Asian landmass) all the year round, one in northern hemisphere and the other in southern. Both are migratory in nature and, perhaps, thermal in origin.  In the convergent zones of the two troughs, there is extensive cloudiness. The migration of these trough systems during their respective summer seasons appear to be related to the extensive heating of the south Asian/ African land masses surrounding the Indian Ocean in north and west.  

scholarly journals Tsunami risk reduction in the new normal era based on community building in Watulimo, Indonesia

2021 ◽  
Vol 916 (1) ◽  
pp. 012033
Author(s):  
F Shoimah ◽  
F Usman ◽  
S Hariyani
Keyword(s):  
Social Capital ◽  
Indian Ocean ◽  
Natural Capital ◽  
Disaster Risk ◽  
The Other ◽  
New Normal ◽  
Tsunami Disaster ◽  
Geological Processes ◽  
Other Hand ◽  
The Indian Ocean

Abstract The coastal area of Watulimo District is included as a tsunami-prone area that is directly adjacent to the Indian Ocean. The Indian Ocean is the subduction zone of the Indo-Australian Plate and the Eurasian Plate, which results in geological processes and high-intensity seismic activities that can trigger tsunamis. On the other hand, in the new normal era, the coast of Watulimo District includes a high-level COVID-19 zone with 74 cumulative cases, comprising 6 active cases, 54 recovered cases, and 14 deaths. The study aimed to examine the level of capacity of coastal communities in Watulimo District, Trenggalek Regency, based on five livelihood capitals (natural capital, financial, physical, human, and social capital) to reduce tsunami disaster risk in the new normal era. The analytical method used in this research consisted of scoring analysis and pentagon assets analysis. The capacity of the coastal community in Watulimo District shows that the sub-villages with high capacity are Gading, Prigi, and Ketawang Sub-villages. On the other hand, the sub-villages with medium capacity are Gandu, Tirto, Gendingan, Sumber, and Gares Sub-villages. Meanwhile, the sub-village with low capacity is Karanggongso Sub-village, due to the low human capital and social capital. Therefore, in efforts to reduce disaster risk, the area that needs to be prioritized for handling is Karanggongso Sub-village through improvements in social conditions, one of which is by prioritizing education levels, such as training related to the threat of the tsunami disaster and the COVID-19 outbreak.

Portuguese discovery and conquest.

2021 ◽  
pp. 206-221
Author(s):  
James F. Hancock
Keyword(s):  
Indian Ocean ◽  
Fifteenth Century ◽  
Atlantic Coast ◽  
Terms Of Trade ◽  
The Other ◽  
Sea Power ◽  
The Indian Ocean ◽  
Spice Trade

Abstract Opens on a summary about the Medieval European knowledge of the Spice Trade, the chapter also show how Portugal dominated Europe in terms of trade and invasion in the fifteenth century. It goes on with the summary of Portuguese invasion of Africa through the Treaty of Tordesillas and the navigation of Vasco de Gama in the Atlantic coast. After de Gama's navigation, the Portuguese conquest of India began which led to the Portuguese-Mamluk Naval war and established Portuguese sea power in the Indian Ocean. Lastly, the chapter gives a brief summary of the other Portuguese navigations.

Apseudomorph Tanaidacea from the continental shelf of Angola and Namibia with descriptions of three new species

Zootaxa ◽  
2012 ◽  
Vol 3583 (1) ◽  
pp. 31 ◽  
Author(s):  
RALF BOCHERT
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
West Africa ◽  
Continental Shelf ◽  
Morphological Features ◽  
The Other ◽  
Investigation Area ◽  
The Indian Ocean ◽  
Three New Species ◽  
Southwest Africa

Four apseudomorph tanaidaceans are recorded from benthos of the shelf off Angola and off northern Namibia (SouthWest Africa). Of these, three are new to science, one each in the genera Hemikalliapseudes, Calozodion andApseudopsis. The genus Hemikalliapseudes now contains four species, all described from West Africa (Angola andMauretania). The new species Hemikalliapseudes sebastiani sp. nov. is separated from other species of this genus byfeatures of several appendages, and the shape of the cephalothorax, pereonites and telson. The genus Calozodion ismainly distributed in the Atlantic and also in the Indian Ocean. Calozodion dominiki sp. nov. is the tenth representativeof the genus and is readily distinguished from all others in that the cheliped propodus of the male has only smallprocesses proximo-ventrally. The new species was widely distributed in the investigation area. Apseudopsis cuanzanussp. nov. is a new member of this species-rich and widely-distributed genus. It differs from the other species of this genusby a combination of several morphological features, including the absence of a dorsodistal spine on the pereopod 1merus, the lack of anterolateral spines on the pereonites, the shape of rostrum and by the absence of plumose setae on pereopod six basis.

Migrant waders at Aldabra, September 1967—March 1968

1971 ◽  
Vol 260 (836) ◽  
pp. 549-559 ◽  
Keyword(s):  
Seasonal Variation ◽  
Indian Ocean ◽  
Royal Society ◽  
Safety Net ◽  
The Other ◽  
Check List ◽  
Firm Conclusion ◽  
Dromas Ardeola ◽  
The Indian Ocean ◽  
Wintering Ground

Observations of palaearctic waders during the first three phases of the Royal Society Expedition to Aldabra, between 1 September 1967 and 14 March 1968 are listed and compared with those from other places in the area. Seventeen species are included in the check list, of which four are considered vagrants, and the rest more or less regular migrants. Counts made during the expedition with the intention of finding the seasonal variation in numbers of the birds have proved statistically invalid, and only a few tentative conclusions may be drawn from them. The Turnstone, Arenaria i. inter pres , may be a winter resident in fair numbers, as may the Whimbrel, Numenius p. phaeopns . Although no firm conclusion can be drawn, it is suggested that most of the other birds are passage migrants, with few staying at Aldabra for the winter. Thus the island is not an important wintering ground for any species, though it probably has some value as a resting place for the birds during their migratory flights. For the Crab Plover, Dromas ardeola , however, it may be one of the few wintering grounds where the species occurs in any numbers, and as such important. The suggestion is made that the other islands in the Indian Ocean, east of the axis of Madagascar, may function not as a destination but as a ‘safety net’ for vagrant birds or flocks.

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