scholarly journals Diversity and abundance of isopod fauna associated with holdfasts of the brown alga Himantothallus grandifolius in Admiralty Bay, Antarctic

2015 ◽  
Vol 36 (4) ◽  
pp. 405-415 ◽  
Author(s):  
Karol Zemko ◽  
Krzysztof Pabis ◽  
Jacek Siciński ◽  
Magdalena Błażewicz-Paszkowycz
Keyword(s):  
Brown Alga ◽  
Austral Summer ◽  
The Other ◽  
Total Density ◽  
Depth Range ◽  
Soft Bottom ◽  
Admiralty Bay

Abstract Fifteen species of isopods, representing 10 families, were recorded on holdfasts of the brown alga Himantothallus grandifolius. Material was collected in the 15–75 m depth range during the austral summer of 1979/80. The isopod community was dominated by Caecognathia antarctica (mean density 12.4 ± 13.1 ind./100 ml) followed by Cymodocella tubicauda (mean density 0.7 ± 2.1 ind./100 ml). Mean total density of isopods reached the value of 16.1 ± 14.0 ind./100 ml. The comparison with the other studies showed that holdfasts are inhabited by a distinctive isopod community that differs from the isopod fauna associated with soft bottom of Admiralty Bay.

scholarly journals Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?

2012 ◽  
Vol 33 (2) ◽  
pp. 181-197 ◽  
Author(s):  
Krzysztof Pabis ◽  
Jacek Siciński
Keyword(s):  
Species Richness ◽  
Habitat Complexity ◽  
Feeding Guilds ◽  
Depth Range ◽  
Soft Bottom ◽  
Admiralty Bay ◽  
Sea Floor ◽  
Species Richness And Diversity ◽  
South Shetlands ◽  
High Species Richness

Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?Seventy-six species of Polychaeta were found in 19 quantitative samples collected in the deep sublittoral (200-500 m) of Admiralty Bay (South Shetlands). Three assemblages were distinguished by similarity analysis (clustering, nMDS). The soft bottom in depths from 200 to 300m was strongly dominated byMaldane sarsi antarcticaand had very low species richness and diversity. The second assemblage was distinguished in the areas of the sea floor in the same depth range but with aggregations of Ascidiacea and Bryozoa. It was again characterized by high abundance ofMaldane sarsi antarctica, but showed significantly higher species richness and diversity. Diversity of polychaete feeding guilds was also high in these areas. This pattern was probably associated with an increased habitat complexity due to the presence of dense aggregations of large suspension feeders. High species richness and diversity was also noted in the third assemblage, associated with the deepest sublittoral (400-500 m) of Admiralty Bay. This is the area characterized by very stable environmental conditions, where the assemblage was dominated byTharyx cincinnatus, Sternaspissp.,Maldane sarsi antarctica, andAsychis amphiglypta.

scholarly journals Soft bottom macrofauna of an All Taxa Biodiversity Site: Hornsund (77○N, Svalbard)

2010 ◽  
Vol 31 (4) ◽  
pp. 309-326 ◽  
Author(s):  
Monika Kędra ◽  
Sławomira Gromisz ◽  
Radomir Jaskuła ◽  
Joanna Legeżyńska ◽  
Barbara Maciejewska ◽  
...  
Keyword(s):  
Bottom Fauna ◽  
Sampling Effort ◽  
Biological Traits ◽  
Depth Range ◽  
Concerted Action ◽  
Soft Bottom ◽  
Species List ◽  
Biodiversity Inventory ◽  
Arctic Fjord ◽  
Large Material

Soft bottom macrofauna of an All Taxa Biodiversity Site: Hornsund (77○N, Svalbard) Hornsund, an Arctic fjord in the west coast of Spitsbergen (Svalbard), was selected as All Taxa Biodiversity Inventory (ATBI) site under EU 5th Framework Concerted Action BIOMARE (2000-2002), especially due to its pristine, undisturbed natural character. On the base of large material (89 stations located throughout the fjord and 129 Van Veen grab samples) collected during cruises of RV Oceania in July in 2002, 2003, 2005 and 2007 and literature search a comprehensive list of species recorded within Hornsund area, on the soft bottom with depth range of 30-250 m is provided. Over 220 species were identified including 93 species of Polychaeta, 62 species of Mollusca and 58 species of Crustacea. Species list is supported by information on the zoogeographical status, body length and biological traits of dominant species. Need for further research on Hornsund soft bottom fauna with more sampling effort is highlighted.

Quantitative analysis of a deep-water bryozoan collection from the Hebridean continental slope

2001 ◽  
Vol 81 (6) ◽  
pp. 987-993 ◽  
Author(s):  
David J. Hughes
Keyword(s):  
Quantitative Analysis ◽  
Continental Slope ◽  
Deep Water ◽  
The Other ◽  
Depth Range ◽  
Species Accumulation Curve ◽  
North West ◽  
Colony Density ◽  
Accumulation Curve ◽  
Total Fauna

Bryozoans were collected from nine stations between 569 and 1278 m depth on the Hebridean continental slope north-west of Lewis. The 21 species recorded from 1544 colonies included three species new to the British fauna. The bryozoan fauna, growing on pebbles, cobbles and small boulders, was dominated by species with encrusting, spot or ribbon-like colony morphologies. The few erect species were rare. Colony density on available rock substrata declined from 569 to 855 m, but was high at 1278 m, where the nodular species Turbicellepora boreale occurred on pebbles as small as 1 cm diameter. Cyclostomates made up >90% of the colonies in the shallowest sample and were present in lower numbers to 855 m. None were recorded at 1278 m. In the 569–855 m depth range, diversity and evenness were lowest at 569 m but relatively constant at the other stations. A species accumulation curve suggests that the 20 species recorded is a good estimate of the total fauna in this depth range.

A new species of the sessile crinoid Holopus d'Orbigny from the tropical western Atlantic, with comments on holopodid ecology (Echinodermata: Crinoidea: Holopodidae)

Zootaxa ◽  
2008 ◽  
Vol 1717 (1) ◽  
pp. 31 ◽  
Author(s):  
STEPHEN K. DONOVAN ◽  
DAVID L. PAWSON
Keyword(s):  
New Species ◽  
The Other ◽  
Depth Range ◽  
Center Line ◽  
Western Atlantic ◽  
A New Species

Holopus mikihe new species is only the sixth extant holopodid crinoid to be described. It differs from all other extant holopodids in having large and distinct raised tubercles in the center line of the aboral surface of proximal secundibrachials, giving it the appearance of a mailed fist. The holotype, from 758 m, also comes from outside the known depth range of the other tropical western Atlantic species, H. rangii d’Orbigny. Some comments are provided on the ecology of Caribbean holopodids, based upon data obtained during dives of the Johnson-Sea-Link manned submersibles.

Depth dependence of source parameters at Monticello, South Carolina

1983 ◽  
Vol 73 (6A) ◽  
pp. 1735-1751
Author(s):  
J. B. Fletcher ◽  
J. Boatwright ◽  
W. B. Joyner
Keyword(s):  
South Carolina ◽  
Stress Drop ◽  
Strong Dependence ◽  
Source Parameters ◽  
Failure Process ◽  
The Other ◽  
Depth Range ◽  
S Wave ◽  
S Waves ◽  
Stress Drops

Abstract Three estimates of stress differences, which include Brune stress drop, stress drop from rms of acceleration (arms), and the apparent stress, have been determined for 13 earthquakes at Monticello, South Carolina, a site of reservoir-induced seismicity. Data for nine of the events come from digitally recorded three-component seismograms at four or five stations that were deployed around the Monticello Reservoir in May and early June 1979. The data from the other four events come from a strong-motion accelerograph located on the dam abutment at the southwest end of the reservoir. Estimates of the seismic moment (Mo) range from 4.6 × 1017 to 3.4 × 1020 dyne-cm (S waves) and radiated energy from about 1011 to 3 × 1016 dyne-cm (S waves). Brune stress drops ranged from 0.5 bars to about 90 bars and show a strong dependence on depth (focal depths range from 0.07 to 1.4 km) and a moderate dependence on Mo. Arms stress drops from the direct S-wave span a similar range of values and also exhibit a strong dependence on depth. Apparent stresses are usually lower than the other estimates of stress differences by a factor of 2 to 4. Seismic stress differences are highest in the topmost 0.2 to 0.3 km, a depth range for which the in situ measurements of stress and pore pressure suggest that the rock is in a state of incipient failure. In this depth range, where the four largest events occurred, the stress drops are of the same order as the ambient shear stress. These data suggest that at Monticello, where pore fluids have a strong influence on the failure process, the largest stresses released seismically are in regions most conducive to failure and that the seismic efficiencies for events at Monticello are larger than have been reported for other tremors in different tectonic settings.

scholarly journals Bivalve mollusk assemblages on São Paulo's northern continental shelf, southeast Brazil

2005 ◽  
Vol 65 (4) ◽  
pp. 717-727 ◽  
Author(s):  
A. Soares-Gomes ◽  
A. M. S. Pires-Vanin
Keyword(s):  
Clustering Analysis ◽  
Biological Diversity ◽  
Permutation Test ◽  
Anthropogenic Activities ◽  
Austral Summer ◽  
Trophic Groups ◽  
Depth Gradient ◽  
Soft Bottom ◽  
Analysis Of Similarity ◽  
Mollusc Assemblages

Soft bottom bivalve mollusc assemblages were sampled along a depth gradient (10 to 100 m) on the northern São Paulo shelf during the austral summer and winter. A one-way analysis of similarity permutation test revealed there was no seasonal difference in the structure of the bivalve assemblages in the area. A clustering analysis indicated 3 groups of stations corresponding to the bathymetric gradient. Both K-dominance curves and Shannon and Pielou indexes showed higher biological diversity and higher evenness for the shallower area. Most of the bivalves found were classified as suspension-feeders, co-occurring with deposit-feeder species, suggesting an absence of negative interactions between these trophic groups. Differences in the frequency of disturbance along the depth gradient caused by wave storms - more common in winter - and also by predation and anthropogenic activities, such as dredging of fishing boats and input of gross sewage, likely explain the higher diversity found on the inner shelf of Ubatuba.

Detecting Ozone- and Greenhouse Gas–Driven Wind Trends with Observational Data

Science ◽  
2013 ◽  
Vol 339 (6119) ◽  
pp. 563-567 ◽  
Author(s):  
Sukyoung Lee ◽  
Steven B. Feldstein
Keyword(s):  
Greenhouse Gas ◽  
Observational Data ◽  
Ozone Depletion ◽  
Austral Summer ◽  
Tropical Convection ◽  
The Other ◽  
Frequency Of Occurrence ◽  
Westerly Jet ◽  
Poleward Shift ◽  
Antarctic Ozone

Modeling studies suggest that Antarctic ozone depletion and, to a lesser degree, greenhouse gas (GHG) increase have caused the observed poleward shift in the westerly jet during the austral summer. Similar studies have not been performed previously with observational data because of difficulties in separating the two contributions. By applying a cluster analysis to daily ERA-Interim data, we found two 7- to 11-day wind clusters, one resembling the models' responses to GHG forcing and the other resembling ozone depletion. The trends in the clusters' frequency of occurrence indicate that the ozone contributed about 50% more than GHG toward the jet shift, supporting the modeling results. Moreover, tropical convection apparently plays an important role for the GHG-driven trend.

The influence of landforms on sandalwood (Santalum spicatum (R.Br) A.Dc.) size structure and density in the north-eastern goldfields, Western Australia

2002 ◽  
Vol 24 (2) ◽  
pp. 219 ◽  
Author(s):  
J. E. Brand ◽  
P. J. Jones
Keyword(s):  
Western Australia ◽  
Land Surface ◽  
Size Structure ◽  
The Other ◽  
Total Density ◽  
Surface Type ◽  
The North ◽  
North Eastern ◽  
Land Systems ◽  
Santalum Spicatum

The density of Santalum spicatum was compared between 'land systems' and between 'land surface types' on four sheep stations in the north-eastern Goldfields: Yakabindie, Tarmoola, Glenorn and Minara. S.A spicatum density was recorded in 4–6A ha transect plots, with a total of 14,090 ha surveyed. Within each transect plot, the S. spicatum were divided into five groups based on stem diameter at 150A mm: < 25 mm, 25–74 mm, 75–124 mm, 125–174 mm and > 174 mm. The proportion of S. spicatum in each of the five size categories was similar between land surface types and between land systems, with the majority in two groups: 75–124 mm and 125–174 mm. S. spicatum recruitment was low, with less than 1.5 % seedlings (< 25 mm) and 7.9 % saplings (25–74 mm). Total density of S. spicatum on hills and ridges (0.65 stems/ha) was significantly higher than any other land surface type. The sandplains (0.05 stems/ha) supported the least. Within land systems, Laverton and Bevon (both hills and ridges) had the highest S. spicatum density. Yakabindie supported higher densities of S. spicatum than the other stations.

Stage-dependent sensitivity to ultraviolet radiation in zygotes of the brown alga Fucus serratus

Zygote ◽  
2003 ◽  
Vol 11 (2) ◽  
pp. 101-106 ◽  
Author(s):  
María Altamirano ◽  
Antonio Flores-Moya ◽  
Ralph Kuhlenkamp ◽  
Félix L. Figueroa
Keyword(s):  
Growth Rate ◽  
Uv Radiation ◽  
Growth Rates ◽  
Brown Alga ◽  
Radiation Condition ◽  
The Other ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Inhibition Of Growth ◽  
Fucus Serratus

Sensitivity to ultraviolet (UV) radiation (UV-A, λ = 315-400 nm; plus UV-B, λ = 280-315 nm) of zygotes of the brown alga Fucus serratus L. (Phaeophyta) has been assessed through effects on growth of developing germlings. Different stages of development were distinguished by considering 5 h periods of time after fertilisation. Both the stage of the zygote and the UV radiation condition significantly affected growth of developing germlings. The negative response of growth rate of early stages of the zygotes to UV radiation seemed to be caused by UV-B rather than UV-A radiation, as the lowest relative growth rates were always estimated for germlings developed from zygotes irradiated with UV-B radiation. As regards the stage of the zygote, those germlings that developed from zygotes irradiated at 5-10 h after fertilisation showed the strongest inhibition of growth compared with the other stages. These results point to polarisation as the most UV-sensitive process during the first 24 h of the development of the zygote. A non-linear relationship between the developmental stage of the zygote and the sensitivity to UV radiation is suggested.

Sign in / Sign up

Export Citation Format

Share Document