ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

The reproductive biology of Hymenaster membranaceus from the Rockall Trough, North-East Atlantic Ocean, with notes on H. gennaeus (1982)

Pain, S. L. ; Tyler, P. A. ; Gage, J. D.

Springer

Marine biology 70 (1982), S. 41-50

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Samples of the deep-sea spinulosan asteroid Hymenaster membranaceus Wyville Thomson were collected in a timeseries of 19 bottom trawls spanning the period April 1978 to October 1981 from a 2200 m-deep station in the northern Rockall Trough. The reproductive biology of this species was studied from histological sections of the gonad, and compared with that of H. gennaeus H. L. Clark which was collected in the same hauls. At first sexual development, oogonia develop in nests surrounded by small accessory cells. Previtellogenic oocytes remain in the periphery but, at maturity, oocytes ranging up to 1 100 μm fill the ovary. A variety of accessory cells pack the lumen and may be nutritive or degenerative. It appears that a small number of oocytes are spawned intermittently, but there is no evidence of overproduction and break-down of superfluous oocytes. A few large oocytes become senescent and undergo internal break-down, releasing periodic acid Schiff-positive material into the lumen. Size-frequencies of oocytes indicate that eggs may be spawned as a continuous slow release, and there is no evidence of reproductive synchrony between or within samples. On reaching maturity, males appear always to be ready to release spermatozoa. Spawning is probably stimulated by egg release during chance encounters with mature females. There is no evidence for brooding, and from the large size and yolky nature of the egg direct lecithotrophic development at or near the seabed is inferred. A limited histological study of H. gennaeus indicates that egg production is very similar, but the two species differ in the nature of the accessory cells and amorphous material filling the lumen.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00397295

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Is annual reproduction in deep-sea echinoderms a response to variability in their environment? (1982)

Tyler, P. A. ; Grant, A. ; Pain, S. L. ; [et al.]

[s.l.] : Nature Publishing Group

Nature 300 (1982), S. 747-750

add to mindlist on the mindlist

Details

ISSN: 1476-4687

Source: Nature Archives 1869 - 2009

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Notes: [Auszug] One of the aims of a long-term time series sampling programme initiated by the Scottish Biological Association in the Rockall Trough (north-east Atlantic)12'13 is to test the hypothesis that annual periodicities may occur in deep-sea invertebrates. In 1975 a permanent station was established at ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/300747a0

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

The reproductive biology of echinothuriid and cidarid sea urchins from the deep sea (Rockall Trough, North-East Atlantic Ocean) (1984)

Tyler, P. A. ; Gage, J. D.

Springer

Marine biology 80 (1984), S. 63-74

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The reproductive biology of 5 species of echinothuriid (Phormosoma placenta, Calveriosoma hystrix, Araeosoma fenestrum, Sperosoma grimaldii and Hygrosoma petersii) and 2 species of cidarid (Cidaris cidaris and Poriocidaris purpurata) sea urchins from the deep sea (Rockall Trough) has been examined from samples collected during 1973–1983. In all species the gonads lie within the interambulacrum attached to aboral gonopores and when fully developed occupy most of the test not occupied by the gut or Aristotle's lantern. In all the species, initial oocyte development takes place along the germinal epithelium embedded in nutritive tissue. In all the echinothuriids and in Poriocidaris purpurata, the oocyte grows to ca. 200 to 450 μm, at which stage vitellogenesis begins. Oocyte growth continues until a maximum egg size of 1 100 to 1 500 μm is attained. In the echinothuriids, two types of nutritive tissue are found. In the carly stages of gametogenesis the oocyte is surrounded by well-structured periodic acid Schiff (PAS)-positive tissue. As the oocyte grows this tissue becomes vacuolated, suggesting that there is a transfer of nutriment to the developing oocyte. In Phormosoma placenta, unspawned oocytes are phagocytosed. There is no evidence of seasonality in any of the echinothuriid species or in Poriocidaris purpurata. Extrapolation with shallow-water echinothuriids suggests that larval development is lecithotrophic, omitting any planktotrophic phase. Of the species examined, only Cidaris cidaris has a reproductive strategy which produces a known larva, although the limited samples did not permit any determination of seasonality in this deep-sea population.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00393129

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Observations on the reproduction and postlarval morphology of pourtalesiid sea urchins in the Rockall Trough area (N.E. Atlantic Ocean) (1984)

Harvey, R. ; Gage, J. D.

Springer

Marine biology 82 (1984), S. 181-190

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Gametogenesis was studied histologically in the deep-sea species Pourtalesia jeffreysi (Wyville Thomson), P. miranda (A. Agassiz) and Echinosigra phiale (Wyville Thomson) collected during 1973–1983 from various positions at depths of 1 040 to 2 921 m in the Rockall Trough. The gonads are small and no synchrony in terms of the stage of gametogenic development was evident in females of the latter two species collected at different times of the year, indicating nonseasonal breeding. Males appear to be ripe at all times of the year. Follicle cells were well developed around the developing oocytes. Both the size range of the yolky ripe eggs (173 to 357 μm diam) and potential fecundity within the range of 1 000 to ∼ 4 000 oocytes per individual, are indicative of an abbreviated, indirect, lecithotrophic mode of development occurring in all three species. Pourtalesiid postlarvae occurred also in fine-meshed trawl hauls, and their morphology is described. It was not possible to distinguish between P. miranda and E. phiale at sizes 〈3 mm in length.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00394101

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Non-viable seasonal settlement of larvae of the upper bathyal brittle star Ophiocten gracilis in the Rockall Trough abyssal (1981)

Gage, J. D. ; Tyler, P. A.

Springer

Marine biology 64 (1981), S. 153-161

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Re-examination of ine structure of postlarvae previously identified as the abyssal species Ophiura ljungmani (Lyman) in a time series of samples taken from 1975 to 1980 from a 2900 m deep permanent station in the southern Rockall Trough (Northeast Atlantic Ocean) has shown the majority of the large summertime peak of brittle-star postlarvae to belong to a second species. Most were incomplete and probably corpses when collected. The few intact specimens present were identical to postlarvae collected in benthic samples from the neighbouring continental slope, where a dense population of the bathyal species Ophiocten gracilis (G. O. Sars) is present from 600 to 1 200 m depth. Examination of population size-structures indicates synchronous reproduction in January/February and annual recruitment to the population. The presence both of “Ophiopluteus ramosus” and intact postlarvae of Ophiocten gracilis in midwater plankton samples from the vicinity of the permanent station in March/April are thought to derive either from the adjacent slope population or, less probably, from larvae transported in the North Atlantic Current from the Flemish Cap area off Newfoundland. In deep water, viability of these benthic postlarvae is low, none surviving longer than the following winter in the Rockall Trough. These observations suggest a large seasonal transfer from the slope of non-viable larvae and postlarvae as food to the abyssal benthic community.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00397104

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Re-appraisal of age composition, growth and survivorship of the deep-sea brittle star Ophiura ljungmani from size structure in a sample time series from the Rockall Trough (1981)

Gage, J. D. ; Tyler, P. A.

Springer

Marine biology 64 (1981), S. 163-172

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Samples were taken from a 2 900 m deep permanent station (centred on 54°40′N; 12°16′W) in the southern Rockall Trough, from November 1975 to September 1980, inclusive. Revision of juvenile size frequencies was necessary after removal of postlarvae of an annual non-viable settlement of Ophiocten gracilis (G. O. Sars) that were mistakenly included in a previous analysis. The present study of the revised data shows that settlement of Ophiura ljungmani (Lyman) occurs in summer when disk-size frequencies are dominated by the newly metamorphosed postlarvae. The likely age composition in larger sizes was suggested from the progression of modes along the size axis in juvenile size classes in consecutive were developed from Gaussian mixtures fitted by constrained computer search using, as starting values, component parameter values suggested from the frequency histograms. Choice between competing solutions was made on the basis both of goodness-of-fit and biological plausibility. However, identification of year-class structure amongst sizes 〉3 to 4 mm disk diameter remained conjectural owing to the low frequencies of adults in the samples. Comparison of the fitted component-means in the time series suggested a marked seasonal growth pattern, with maximal growth in spring. Probable age composition amongst adult sizes was extrapolated from von Bertalanffy growth parameters estimated from the means of juvenile year classes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00397105

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Diets of some deep-sea brittle stars in the Rockall Trough (1984)

Pearson, M. ; Gage, J. D.

Springer

Marine biology 82 (1984), S. 247-258

add to mindlist on the mindlist

Details

ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The stomachs of 1 165 individuals of the species Ophiacantha bidentata (Retzius), Ophiactis abyssicola (M. Sars), Ophiocten gracilis (O. Sars), Ophiura irrorata (Lyman), O. ljungmani (Lyman) and Ophiomusium lymani Wyville Thomson, collected from the general area of the Rockall Trough from 1973 to 1983, were examined; 47% contained material. This varied in nature and in volume between individuals, but overall, the diets of the 6 species showed quite high similarity. The few differences evident are interpreted as reflecting different lifestyles. Except for Ophiocten gracilis, the probably motile, epifaunal species (Ophiura irrorata, O. ljungmani and Ophiomusium lymani) showed the greatest variety in items, and the lowest similarity with the remaining species; they are probably unselective omnivores, eating whatever small prey or organic detritus they are able to find. Ophiacantha bidentata and Ophiactis abyssicola showed both the least dietary variety, and the highest similarity to each other. This probably reflects their more sedentary lifestyle, feeding on current-borne particles and small prey from “perches” on sessile fauna. The stomach contents of Ophiocten gracilis consisted mainly of amorphous organic material and mineral particles, indicating a microphagous feeding mechanism. With O. gracilis, the proportion of stomachs with food decreased markedly in summer, this coinciding with seasonal gonadal development when stomachs frequently appeared ruptured or compressed. The possible importance of seasonal sedimentation of fast-sinking particulates from the surface is discussed in relation to finds of flocculent organic material, often containing diatom frustules, in stomachs of all 6 species. Some doubts remain as to whether our results are biased by specimens egesting stomach contents on capture. As in shallow water, deep-sea ophiuroids seem to be trophic generalists lacking in dietary specialization. Brief notes on parasites encountered are also given.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00392406

Permalink