scholarly journals Clione limacina in Plymouth Waters

1931 ◽  
Vol 17 (3) ◽  
pp. 785-795 ◽  
Author(s):  
Marie V. Lebour
Keyword(s):  
North Sea ◽  
Bay Of Biscay ◽  
The West ◽  
Boreal Species ◽  
Southern North Sea ◽  
The North ◽  
South West ◽  
The North Sea ◽  
Clione Limacina ◽  
Eggs And Larvae

The pteropod Clione limacina (Phipps), now regarded as one of the tectibranchs, occurs at times in the neighbourhood of Plymouth. In 1930, however, it was extraordinarily abundant, especially in the summer, and was breeding freely. Although not specially recorded it has been seen singly or in small numbers in almost any month of the year, and for some years the eggs and larvæ (not recognised at the time as belonging to Clione) have been seen in summer. So far it is known from the British coasts in the North Sea and the west and extreme south-west of England. Its distribution, as known up to 1908, is given fully for the area of International Fisheries Investigations by Paulsen (1910). There it is shown that it is an Arctic-boreal species, spreading southwards nearly to the Bay of Biscay, which is about its southerly limit. It is known to occur in the northern and mid North Sea, but not in the southern North Sea, and at that time was only recorded from the Channel in the extreme west. It is also common in the Atlantic. Paulsen was led to infer that Clione limacina did not enter the North Sea from the Channel, but its prevalence sometimes at Plymouth shows that it can come a long way up the Channel and, as few samples are taken to the east and in the southern North Sea, this view should be carefully reconsidered.

Benthic regions within the North Sea

1983 ◽  
Vol 63 (3) ◽  
pp. 683-693 ◽  
Author(s):  
M. F. Dyer ◽  
W. G. Fry ◽  
P. D. Fry ◽  
G. J. Cranmer
Keyword(s):  
North Sea ◽  
Benthic Invertebrates ◽  
The West ◽  
Classification Analysis ◽  
Faunal Assemblages ◽  
Southern North Sea ◽  
The North ◽  
Factors Influencing ◽  
The North Sea ◽  
Northern North Sea

During five annual ground fish surveys of the North Sea, all the benthic invertebrates trawled at 48 primary stations were recorded. The data were subjected to classification analysis, which showed a basic division between northern and southern North Sea benthos. The southern North Sea was further divided into three benthic regions, and the northern North Sea into four benthic regions (including one to the west of Shetland). The factors influencing the faunal assemblages in the various regions were discussed.

scholarly journals XXIV. On the effect of westerly winds in raising the level of the British Channel

1809 ◽  
Vol 99 ◽  
pp. 400-403
Keyword(s):  
North Sea ◽  
Royal Society ◽  
The West ◽  
Actual Position ◽  
The North ◽  
South West ◽  
North Eastern ◽  
Westerly Winds ◽  
The North Sea ◽  
A Current

Dear Sir, In the “ Observations on a Current that often prevails to the “Westward of Scilly ,” which I had the honour to lay before the Royal Society many years ago, I slightly mentioned, as connected with the same subject, the effect of strong westerly winds, in raising the level of the British Channel; and the escape of the super-incumbent waters, through the Strait of Dover, into the then lower level of the North Sea. The recent loss of the Britannia East India ship, Captain Birch, on the Goodwin Sands, has impressed this fact more strongly on my mind; as I have no doubt that her loss was occasioned by a current, produced by the running off of the accumulated waters; a violent gale from the westward then prevailing. The circumstances under which she was lost, were generally these: In January last she sailed from her anchorage between Dover and the South Foreland (on her way to Portsmouth), and was soon after assailed by a violent gale between the west and south-west. The thick weather preventing a view of the lights , the pilot was left entirely to the reckoning and the lead; and when it was concluded that the ship was quite clear of the Goodwin, she struck on the north-eastern extremity of the southernmost of those sands. And this difference between the reckoning (after due allowance being made for the tides) and the actual position, I conclude was owing to the northerly stream of current, which caught the ship when she drifted to the back , or eastern side of the Goodwin.

scholarly journals On the Value of Certain Plankton Animals as Indicators of Water Movements in the English Channel and North Sea

1935 ◽  
Vol 20 (2) ◽  
pp. 309-332 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
North Sea ◽  
Atlantic Water ◽  
English Channel ◽  
The West ◽  
Southern North Sea ◽  
The North ◽  
Channel Water ◽  
The North Sea ◽  
Apparent Influence ◽  
Neritic Species

The possibility that certain plankton organisms retained by a stramin net may prove of value as indicators in elucidating the water movements at the mouth of the English Channel is shown.The water populated by Sagitta setosa is shown to be clearly demarked from that in which S. elegans lives, the latter living to the west of the Channel mouth south of Ireland. The water in which S. elegans lives has here been called “western” water.It is shown that the planktonic indicators for “western” water are Sagitta elegans, Sagitta serratodentata, Aglantha rosea, Stephanomia bijuga, Clione limacina, Meganyctiphanes norvegica, Thysanoessa inermis, and Cosmetira pilosella (in spring and summer only). Sagitta setosa is regarded as an indicator of “Channel” water. Muggiæa, Salps, Doliolids, Liriope exigua and Euchœa hebes are regarded as indicators of “south-western” water.The geographical distribution of S. setosa is discussed. It is shown that it is probably a neritic species mainly confined to the English Channel and North Sea.S. setosa predominates off Plymouth when the easterly element in the Dover Straits current is suppressed and the flow of Atlantic water into the North Sea from the north is strong (Carruthers' Theory). The two Sagitta populations swing to and fro off Plymouth so that, with a strong flow of Atlantic water into the North Sea from the north, the S. elegans population is pushed westward to the mouth of the Channel and S. setosa occurs off Plymouth.During the course of the five years, 1930 to 1934, an agreement has been found between the occurrence or absence of concentrations of the diatom Rhizosolenia styliformis in the southern North Sea and the variations in the composition of the Sagitta population off Plymouth In the years in which Ehizosolenia, an indicator of Atlantic water, was abundant in the southern North Sea S. setosa predominated off Plymouth; when Rhizosolenia was absent S. elegans predominated.These diatom concentrations have been shown by Savage and Hardy t o have an apparent influence on the movements of the Herring which is reflected in the landings at Yarmouth and Lowestoft.

Director's Report

1898 ◽  
Vol 5 (2) ◽  
pp. 232-233
Author(s):  
E. J. Allen
Keyword(s):  
North Sea ◽  
Detailed Examination ◽  
Pelagic Fishes ◽  
The North ◽  
South West ◽  
The North Sea ◽  
The Many ◽  
Working Out ◽  
Eggs And Larvae ◽  
Distribution Of Fish

The various researches detailed in my last Report, which are being conducted by the Association's Naturalists, have been continued during the winter. Mr. Garstang has been chiefly occupied in investigations relating to the migratory pelagic fishes, giving special attention to the characteristics of mackerel from different localities, some 1500 of these fish having been subjected to detailed examination in the course of this enquiry. The samples of mackerel have been obtained from the south-west of Ireland (through H.M. Inspectors of Irish Fisheries), from the North Sea and from America, in addition to those captured near Plymouth. As the results so far obtained refer only to the autumn fish, it has been thought better to defer their publication until after the coming spring fishery, when further samples from the same localities, as well as from the Mediterranean and from Norway, will be examined.Mr. Garstang has also given much time to working out the results of the drift-bottle experiments, a report of which for the year 1897 will be found at p. 199. These experiments have proved more interesting and successful than we had anticipated when they were undertaken, and we purpose continuing and extending them during the coming year.Mr. Holt's papers in the present number of the Journal represent but a portion of the many observations which he has been able to make during the year on the eggs and larvæ of fishes. He has also given much attention to the question of the distribution of fish at different ages in this neighbourhood.

scholarly journals The Size of Diatoms II. Further Observations on Rhizosolenia styliformis (Brightwell)

1946 ◽  
Vol 26 (3) ◽  
pp. 271-284 ◽  
Author(s):  
R. S. Wimpenny
Keyword(s):  
North Sea ◽  
Indicator Species ◽  
Separate Species ◽  
Southern North Sea ◽  
Auxospore Formation ◽  
The North ◽  
The North Sea ◽  
Set Up ◽  
The Antarctic

1. Diameter measurements of Rhizosolenia styliformis from the Antarctic, the subtropical Atlantic and Pacific Oceans and from the North Sea and neighbouring waters have made it appear necessary to set up two varieties, oceanica and semispina, in addition to the type of the species R. styliformis. The type as I describe it has been called var. longispina by Hustedt, but elsewhere it has often been figured as the var. oceanica of this paper. Var. semispina is synonymous with the form represented by Karsten as R. semispina Hensen. It differs from R. semispina as drawn by Hensen and its synonym R. hebetata forma semispina Gran, but is thought likely to be linked by intermediates. If this is so R. hebetata may have to be extended to include and suppress R. styliformis, as var. semispina is linked to the type by intermediates. Var. oceanica has no intermediate forms and, if R. hebetata is to be extended, this variety should be established as a separate species.2. Var. oceanica is absent from the southern North Sea and appears to be an indicator species related to oceanic inflow.3. Auxospore formation was observed for the type in the southern North Sea in 1935 and biometric observations suggest that a period of 3-4 years elapsed between the production of auxospore generations in that area. Outside the southern North Sea for the type, measurements give no indication of auxospore generations occurring at intervals exceeding a year. While auxospore formation has been seen in var. oceanica from the Shetlands area samples of June 1935 and July 1938, this phenomenon has not been observed for var. semispina.

scholarly journals The impact of sedimentary alkalinity release on the water column CO<sub>2</sub> system in the North Sea

2016 ◽  
Vol 13 (3) ◽  
pp. 841-863 ◽  
Author(s):  
H. Brenner ◽  
U. Braeckman ◽  
M. Le Guitton ◽  
F. J. R. Meysman
Keyword(s):  
Coastal Zone ◽  
North Sea ◽  
Dissolved Inorganic Carbon ◽  
Co2 Uptake ◽  
Overlying Water ◽  
Southern North Sea ◽  
The North ◽  
Alkalinity Generation ◽  
The North Sea ◽  
The Impact

Abstract. It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO2 of seawater and hence increasing the CO2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O2), alkalinity (AT) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high AT and DIC fluxes were recorded in near-shore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of AT and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO2 dynamics of shallow coastal systems.

Marine Growth on North Sea Fixed Steel Platforms: Insights From the Decommissioning Industry

2014 ◽  
Author(s):  
Chadi Mallat ◽  
Alistair Corbett ◽  
Glyn Harris ◽  
Marc Lefranc
Keyword(s):  
North Sea ◽  
Gas Industry ◽  
Southern North Sea ◽  
The North ◽  
The North Sea ◽  
Insight Into

It is reputed in the Oil & Gas industry that marine growth is overestimated in the North Sea. Can we quantify this overestimation to better tackle the challenges marine growth incurs? This paper provides insight into the intrinsic and diverse nature of marine growth. It documents the biofouling development and the factors that affect it globally. Focus is made on fixed steel platforms in the North Sea approaching the end of their economic lives. A methodology to quantify the weight of marine growth is proposed and illustrated. 28 years after its installation, the weight of marine growth accumulated on Valhall 2/4G jacket located in Southern North Sea is evaluated based on the proposed method. It is confirmed that the current regulations overestimate the weight of marine growth in the North Sea.

scholarly journals Investigations Upon the Water Movements in the English Channel. Summer, 1924

1927 ◽  
Vol 14 (3) ◽  
pp. 685-721 ◽  
Author(s):  
J. N. Carruthers
Keyword(s):  
North Sea ◽  
English Channel ◽  
Average Speed ◽  
Southern North Sea ◽  
The North ◽  
Westerly Winds ◽  
The North Sea

In July, 1924, 250 floating, and an equal number of bottom-trailing, bottles were put out at selected places in the western English Channel. Fifty of each type were put out at each of the two routine Stations E2 and E3, and the same number was “liberated” at each of three selected stretches along the steamship route from Southampton to St. Malo. Those surface bottles, which did not strand locally, travelled rapidly up Channel towards the North Sea and across it. Many bottles arrived in the Skager-Rack after performing their journey of some 700 miles at the rate of 6 miles a day and more. An adequate study of wind conditions, as recorded at several stations along the length of the Channel and at one station in the southern North Sea, revealed the fact that there was, for some 5½ months (counting from the time of liberation of the bottles), an almost uninterrupted predominance of south-westerly winds—as recorded at all stations considered. The whole area of the Channel was swept by south-westerly winds of average speed of some 9 miles a day for at least 5½ months subsequent to the time of putting out of the bottles. July, 1924, had (according to the Falmouth Observatory records) the largest proportion of westerly winds experienced for 54 years; 20 days of this month had winds with westerly components. The association of the unusually persistent westerly winds with the rapid travel of surface bottles towards and across the North Sea is interesting.

scholarly journals Warm-water decapods and the trophic amplification of climate in the North Sea

2010 ◽  
Vol 6 (6) ◽  
pp. 773-776 ◽  
Author(s):  
J. A. Lindley ◽  
G. Beaugrand ◽  
C. Luczak ◽  
J.-M. Dewarumez ◽  
R. R. Kirby
Keyword(s):  
North Sea ◽  
Warm Water ◽  
Climate Signal ◽  
Southern North Sea ◽  
The North ◽  
Ecosystem Shift ◽  
The North Sea ◽  
Induced Changes ◽  
Water Species

A long-term time series of plankton and benthic records in the North Sea indicates an increase in decapods and a decline in their prey species that include bivalves and flatfish recruits. Here, we show that in the southern North Sea the proportion of decapods to bivalves doubled following a temperature-driven, abrupt ecosystem shift during the 1980s. Analysis of decapod larvae in the plankton reveals a greater presence and spatial extent of warm-water species where the increase in decapods is greatest. These changes paralleled the arrival of new species such as the warm-water swimming crab Polybius henslowii now found in the southern North Sea. We suggest that climate-induced changes among North Sea decapods have played an important role in the trophic amplification of a climate signal and in the development of the new North Sea dynamic regime.

Shallow marine Lower and Middle Miocene deposits at the southern margin of the North Sea Basin (northern Belgium): dinoflagellate cyst biostratigraphy and depositional history

2000 ◽  
Vol 137 (4) ◽  
pp. 381-394 ◽  
Author(s):  
S. LOUWYE ◽  
J. DE CONINCK ◽  
J. VERNIERS
Keyword(s):  
North Sea ◽  
Depositional Environment ◽  
Middle Miocene ◽  
Depositional History ◽  
Shallow Marine ◽  
Dinoflagellate Cyst ◽  
Southern North Sea ◽  
The North ◽  
Southern Margin ◽  
The North Sea

Detailed dinoflagellate cyst analysis of the Lower–Middle Miocene Berchem Formation at the southernmost margin of the North Sea Basin (northern Belgium) allowed a precise biostratigraphical positioning and a reconstruction of the depositional history. The two lower members of the formation (Edegem Sands and decalcified Kiel Sands) are biostratigraphically regarded as one unit since no significant break within the dinocyst assemblages is observed. The base of this late (or latest) Aquitanian–Burdigalian unit coincides with sequence boundary Aq3/Bur1 as defined by Hardenbol and others, in work published in 1998. A hiatus at the Lower–Middle Miocene transition separates the upper member (the Antwerpen Sands) from the underlying member. The greater part of the Antwerpen Sands were deposited in a Langhian (latest Burdigalian?)–middle Serravallian interval. The base of this unit coincides with sequence boundary Bur5/Lan1. Biostratigraphical correlation points to a diachronous post-depositional decalcification within the formation since parts of the decalcified Kiel Sands can be correlated with parts of the calcareous fossil-bearing section, up to now interpreted as Antwerpen Sands. The dinoflagellate cyst assemblages are dominated by species with a inner neritic preference, although higher numbers of oceanic taxa in the upper part of the formation indicate incursions of oceanic watermasses into the confined depositional environment of the southern North Sea Basin.

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