The vegetation of North Fen at Esthwaite in 1967-9

1978 ◽  
Vol 200 (1140) ◽  
pp. 331-351 ◽  

The vegetation of part of the fen at the north end of Esthwaite Water (2° 59' W 54° 22' N) has been surveyed three times: in 1914-16, 1929 and 1967-9. The maps provide direct evidence of vegetational succession. The main associations have retained their identity throughout the period of half a century but the reed-swamp has advanced southward into open water and been replaced along its landward edge by fen dominated by Carex rostrata . Comparing the position of this boundary with that of the shore on the Ordnance Survey of 1848, the southward movement has been 47 m at the mouth of the inflow stream and 28 m in the middle of the basin. Comparing all the surveys it is clear that the rate of movement has varied from one period to another by an order of magnitude (0.2- 3.0 m/a). The most prominent change since 1929 has been the southward extension of woodland of Alnus glutinosa and Salix cinerea on the alluvial part of the fen, the recent spread of Betula pubescens and Farxinus excelsior and gradual extension of Alnus glutinosa into the sedge-fen. A few saplings of Quercus petraea are now established beneath dying trees of Betula pubescens in the oldest part of the carr. Analytical and experimental evidence suggest that the vegetation may also be changing in response to an increased input of phosphate and nitrate.

1932 ◽  
Vol 69 (5) ◽  
pp. 209-233 ◽  
Author(s):  
G. D. Osborne

THE Carlingford-Barnave district falls within the boundaries of Sheet 71 of the Ordnance Survey of Ireland, and forms part of a broad promontory lying between Carlingford Lough on the north-east and Dundalk Bay on the south-west. The greater part of this promontory is made up of an igneous complex of Tertiary age which has invaded the Silurian slates and quartzites and the Carboniferous Limestone Series. This complex has not yet been investigated in detail, but for the purposes of the present paper certain references to it are necessary, and these are made below. The prevalence of hybrid-relations and contamination-effects between the basic and acid igneous rocks of the region is a very marked feature, and because of this it has been difficult at times to decide which types have been responsible for the various stages of the metamorphism.


2000 ◽  
Vol 78 (12) ◽  
pp. 1531-1544 ◽  
Author(s):  
Eric Nicolini ◽  
Daniel Barthélémy ◽  
Patrick Heuret

The growth and branching patterns of the main axis of 6-year-old sessile oak, growing in a natural regeneration in the north of France, were analysed each year retrospectively according to three increasing canopy density conditions: large gap, small gap, and dense canopy. Increasing gap size is associated with an increase in the total height, basal diameter, branching probability, and global polycyclism rate of the trees. At the growth unit or annual shoot level, from dense canopy to large gaps these botanical entities also show an increase in their total length, number of nodes, polycyclism, and branching rate as well as mean number of branches and mean internode length. A discussion of our results revealed some endogenous features of growth and branching patterns in young sessile oak trees. It is also shown that increasing canopy density generally tends to reduce the expression of the endogenous architectural sequence of differentiation of young sessile oak trees. Young trees growing below dense canopy thus seem to be "delayed" in their sequence of differentiation and appear to be in a "waiting" status, whereas young trees growing in large gaps exhibit an architecture very similar to trees growing in nurseries under nonlimiting growth conditions.Key words: architecture, Quercus petraea, growth, morphology, canopy density.


1980 ◽  
Vol 25 (93) ◽  
pp. 425-438
Author(s):  
B. Dey

AbstractThe study reported here illustrates the unique value of NOAA thermal infrared (TIR) images for monitoring the North Water area in Smith Sound and northern Baffin Bay during the periods of polar darkness. Wintertime satellite images reveal that, during the months of December through February, open water and thin ice occur in a few leads and polynyas. However, in March, the areas of open water and thin ice decrease to a minimum with a consequent higher concentration of ice. Two ice dams, in northern Kennedy Channel and in northern Smith Sound, regulate the flow of ice into northern Baffin Bay and also determine the areal variations of open water and thin ice in Smith Sound.


2018 ◽  
Vol 30 (1) ◽  
pp. 89-105
Author(s):  
Jay C. Martin

Boxy and with ‘unseaworthy form’, the sailing scow was not the most aesthetically pleasing of watercraft. Yet the durable hull design based upon European predecessors found a new home in North America where it proliferated on the Atlantic, Gulf, Pacific and Great Lakes coasts because of its practicality for largely unimproved waterways. Scows were widely used on the Great Lakes in the nineteenth century, moving beyond shallow waters and gaining a reputation for reliability in long-distance trade. Late in the century, the technology arrived in New Zealand, where it prospered in a niche market that combined open water voyages and shallow river, port, or beach loading and unloading. The Great Lakes scows presented an alternative for entry into ship ownership on the North American frontier. The development of the New Zealand scow confirmed these findings comparatively in an international context during the late nineteenth and early twentieth centuries.


1995 ◽  
Vol 52 (2) ◽  
pp. 416-424 ◽  
Author(s):  
James W. LaBaugh

Algal chlorophyll a is commonly used as a surrogate for algal biomass. Data from three lakes in western Nebraska, five wetlands in north-central North Dakota, and two lakes in north-central Minnesota represented a range in algal biovolume of over four orders of magnitude and a range in chlorophyll a from less than 1 to 380 mg∙m−3. Analysis of these data revealed that there was a linear relation, log10 algal biovolume = 5.99 + 0.09 chlorophyll a (r2 = 0.72), for cases in which median values of chlorophyll a for open-water periods were less than 20 mg∙m−3. There was no linear relation in cases in which median chlorophyll a concentrations were larger than 20 mg∙m−3 for open-water periods, an occurrence found only in shallow prairies lakes and wetlands for years in which light penetration was the least.


2018 ◽  
Vol 15 (8) ◽  
pp. 2289-2307 ◽  
Author(s):  
Nolwenn Lemaitre ◽  
Hélène Planquette ◽  
Frédéric Planchon ◽  
Géraldine Sarthou ◽  
Stéphanie Jacquet ◽  
...  

Abstract. The remineralisation of sinking particles by prokaryotic heterotrophic activity is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100–1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure, and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L−1), which was attributed to an intense bloom averaging 6 mg chl a m−3 between January and June 2014 and by an intense 1500 m deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L−1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were of the same order of magnitude as other fluxes obtained using independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m−2 d−1, respectively) were equalling and occasionally even exceeding upper-ocean POC export fluxes, deduced using the 234Th method. These results highlight the important impact of the mesopelagic remineralisation on the biological carbon pump of the studied area with a near-zero, deep (> 1000 m) carbon sequestration efficiency in spring 2014.


Author(s):  
Jaroslav Urban

The paper deals with the occurrence, development and harmfulness of Deporaus betulae (L.). The majority of field studies was carried out at Training Forest Enterprise (TFE) Masaryk Forest in Křtiny (District Brno-venkov) in 2010 and 2011. In addition to this, the species was studied in detail also in a laboratory. It occurred mostly on Betula pendula and Carpinus betulus. Rarely, the species was found on Alnus glutinosa and Corylus avellana and only sporadically on Fagus sylvatica, Quercus petraea, Tilia cordata and T. platyphyllos. In the studied area, larvae and pupae hibernate. Beetles occur on trees from the end of April to the beginning of July, sporadically later. Females lay on average 2.5 (in the laboratory 4.4) eggs into rolls on B. pendula, on C. betulus 2.2 eggs. During two months, they damage on average 5.3 cm2 leaves creating 14 rolls and laying 35 eggs into the rolls. Larvae consume only 1.7 cm2 leaf blade. The development of the species takes three to four months from egg laying to the departure of larvae into soil. On leaves of B. pendula of an average area of 14.2 cm2, females roll up the same area (about 11.2 cm2) as on leaves of C. betulus of an area of 21.7 cm2. Into the rolls, they lay on average the same number of eggs. The average number of eggs in rolls increases with the increased area of B. pendula leaf blade. Trees partly compensate for the reduction of assimilatory area also by the growth of the area of neighbouring undamaged leaves (on average by 12.7 %).


Records of sea level for several North Sea ports for the winter of 1953-4 have been in vestigated. They were split into 14-day intervals, and each 14-day record was Fourieranalyzed to determine if any non-astronomical periods were present. There was evidence of some activity between 40 and 50 h period, and a determination of the phase angles at different ports showed that the activity could be due to a disturbance travelling southwards from the north of the North Sea. The disturbance was partly reflected somewhere near the line from Lowestoft to Flushing, so that one part returned past Flushing and Esbjerg towards Bergen while the other part travelled towards Dover, and there was evidence of its existence on the sea-current records taken near St Margaret's Bay. These results were confirmed by subtracting the predicted astronomical tidal levels from the observed values of sea level and cross-correlating the residuals so obtained for each port with those found at Lowestoft. The residuals at Lowestoft and Aberdeen were compared with the meteorological conditions, and it was found that, although they could be attributed to a large extent to conditions within the North Sea, there was an additional effect due to a travelling surge which was of the same order of magnitude at both Lowestoft and Aberdeen and which was closely related to the rate of change with time of the atmospheric pressure difference between Wick and Bergen.


2021 ◽  
pp. 112-122
Author(s):  
A.A. SIN'KEVICH ◽  
◽  
B. BOE ◽  
S. PAWAR ◽  
YU. P. MIKHAILOVSKII ◽  
...  

Characteristics of developing convective clouds (Cu) in Karnataka state (India) during the thunderstorm formation are analyzed using weather radar and lightning detection network data. It is noted that radar characteristics of Cu which produced lightning, exceed those where lightning does not form. The study has shown that the number of negative cloud-to-ground strokes exceeds the number of positive ones by an order of magnitude. The radar characteristics of clouds in India and the North Caucasus are compared. Significant differences in lightning flash rates over the mentioned regions are registered. A low correlation is found between the supercooled volume and the flash rate of negative lightning. The paper also presents the results of studying the dynamic characteristics of four Cu seeded with a glaciogenic reagent. The thunderstorm risk is estimated for the clouds. It is shown that the seeding increases a probability of lightning events.


1986 ◽  
Vol 32 (112) ◽  
pp. 383-390 ◽  
Author(s):  
Konrad Steffen

AbstractThe surface condition of the North Water was investigated during two winters (i.e. the three polynyas: Smith Sound polynya, Lady Ann Strait polynya, and Barrow Strait polynya). Since no detailed information was available on ice conditions and the extent of open water during winter, radiometric temperature measurements of the sea surface had to be taken along a flight line of 2650 km from an altitude of 300 m. From November to March 1978-79 and 1980-81, 14 remote-sensing flights were carried out. On the basis of the radiometric measurements, the following ice types were identified: ice-free, dark nilas, light nilas, grey ice, grey-white ice, and white ice. A comparison between the thermal and the visual ice classification (the latter being based on grey tones of the aerial images) showed a deviation of 3%. The analysis showed that in November, December, and January more than 50% of the Smith Sound polynya was covered by young ice, nilas, and ice-free, whereas in February and March white ice was dominant. Moreover, it was found that the two polynyas in Smith Sound and Lady Ann Strait were much smaller than previously believed. In Barrow Strait, a semi-permanent polynya was observed in the winter of 1980-81. The occurrence of polynyas in Barrow Strait seems to be connected with the location of the fast-ice edge. On the basis of the calculated ice-type distribution and heat-flux rates for different ice types, an energy loss of 178 W m-2was found on the surface of the Smith Sound polynya due to open water and thin ice for the winter months November to March. Compared with other ice-covered sea surfaces in the Arctic, the heat release by the sea-water in the Smith Sound polynya is about 100 W m-2larger.


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