The inland waters of the Outer Hebrides

1979 ◽  
Vol 77 ◽  
pp. 329-351 ◽  
Author(s):  
A. R. Waterston ◽  
A. V. Holden ◽  
R. N. Campbell ◽  
P. S. Maitland
Keyword(s):  
Aquatic Vegetation ◽  
Sea Water ◽  
Inland Waters ◽  
Freshwater Species ◽  
Wide Range ◽  
Outer Hebrides ◽  
Freshwater Habitats ◽  
The Rich ◽  
Aqueous Conditions ◽  
Standing Waters

SynopsisThe Outer Hebrides comprise approximately 1·3% of the land area but 15·8% of the area of standing waters of Great Britain. Streams there are generally small and only three are as large as fifth order. The majority of the lochs occur below 200 m altitude and are less than 25 ha in area. A total of 1375 stream systems enter the sea, and drain the land mass through 9240 stream segments. There are just over 6000 lochs, of which less than half are connected to these networks. Most of the water systems are on geologically base-poor rock or soil, and less than 3%, situated on machair, are base-rich and eutrophic. The islands, due to their situation, receive precipitation in the form of very dilute sea water (with some non-marine sulphate probably derived from fossil fuel combustion) and this leads to unusual concentrations of chloride in the inland waters. Metamorphic rocks are resistant to weathering, so there is usually little variation in the composition of fresh waters except in the machair areas, where calcareous sands affect calcium concentrations and alkalinities.The flora and fauna reflect the aqueous conditions and there are some unique successions of species from high to low salinities even in the same water body. The lochs provide a wide range of habitats for aquatic vegetation, ranging from the rich machair lochs to the oligotrophic peaty lochs (which show marked similarities with their counterparts on the mainland). Three broad categories can be delineated on the basis of their water quality and vegetation: brackish lochs with varying degrees of marine influence, calcareous machair lochs which may also be affected by sea connections, and the peaty lochans of low alkalinity. A few brackish water animals are sufficiently euryhaline to exist in the machair lochs, which are otherwise dominated by freshwater species. The occurrence of chloride in inland waters enables some crustaceans, e.g. Neomysis integer, Gammarus duebeni and Diaptomus wierzejskii to extend into what are poor freshwater habitats. The main constituents of the freshwater fauna are molluscs and arthropods, and a few species of euryhaline fishes, i.e. salmon, sea and brown trout, three-spined and ten-spined sticklebacks and eels. There are some populations of non-migratory charr. No amphibians are present.

The fishes of inland waters in the Outer Hebrides

1979 ◽  
Vol 77 ◽  
pp. 377-393 ◽  
Author(s):  
R. N. Campbell ◽  
R. B. Williamson
Keyword(s):  
Brown Trout ◽  
West Coast ◽  
Inland Waters ◽  
Freshwater Species ◽  
Sea Trout ◽  
Last Glaciation ◽  
Freshwater Eel ◽  
Special Scientific ◽  
Outer Hebrides ◽  
Scientific Value

SynopsisOnly euryhaline fishes were able to recolonize Outer Hebridean fresh waters after the last glaciation so that inland waters now contain only six indigenous, truly freshwater species; salmon, trout, charr, three- and ten-spined stickleback and the freshwater eel. Parts of some lochs are invaded by the sea at stages in the tidal cycle and some 20 species of marine fish may be found at times in inland waters.Both salmon and sea trout occur in all the larger freshwater systems and sea trout are also found in many of the minor ones.The original sea trout gave rise to sedentary brown trout populations similar to those of the mainland.Fluctuations in the Hebridean salmon catch suggest that the stock is affected by the same factors as those affecting Scottish west coast stocks generally: the vast-majority return to fresh water as grilse, while sea trout stocks have been declining over the last 25 years.Brown trout and eels are almost ubiquitous. Charr occur in Lewis and parts of North Uist but have not been reported from Harris or South Uist and are now only present as sedentary forms. The three-spined stickleback is more widely distributed than the ten-spined.Outer Hebridean lochs in general have special scientific value because, unlike many Scottish mainland lochs, they have not been affected by the introduction of alien species and some are still in an unexploited state.

Inland waters in the Inner Hebrides

1983 ◽  
Vol 83 ◽  
pp. 229-244
Author(s):  
P. S. Maitland ◽  
A. V. Holden
Keyword(s):  
Great Britain ◽  
Plant Communities ◽  
Small Proportion ◽  
Aquatic Plant ◽  
Inland Waters ◽  
Running Waters ◽  
Land Area ◽  
Outer Hebrides ◽  
Standing Waters ◽  
Total Resource

SynopsisThe Inner Hebrides make up only a small proportion of the land area but a relatively higher percentage of the area of standing waters of Great Britain. Analyses of the 1:63,360 maps have provided the total numbers of standing and running waters on the islands (1,542 and 1,615 respectively) and are the basis for estimating the total resource there. The majority of lochs are small and relatively low lying. Most of the streams too are small and rarely larger than 4th order. Chemically, the waters are variable and range from some very acid nutrient-poor lochs on Islay to the unique marl lochs of Lismore. The algae of these islands have only occasionally been sampled and relatively little is known either about the higher aquatic plant communities—the ones studied are similar to those on the mainland. Few studies of the invertebrates of the inland waters have been carried out, and none of the surveys has been comprehensive. A review of the published and new data has enabled a broad account of the invertebrate communities to be presented. Only 15 species of fish occur here and most of the waters are dominated by the indigenous salmonids (salmon, trout and charr), sticklebacks or eels. Comparisons of the inland waters of the Inner Hebrides with those of other island groups (the Outer Hebrides and Shetlands) and the mainland of Scotland (especially Tayside) show that they have greater afiinities with the latter.

Sodium Influx and Loss in Freshwater and Brackish-Water Populations of the Amphipod Gammarus Duebeni Lilljeborg

1971 ◽  
Vol 54 (1) ◽  
pp. 255-268
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Body Surface ◽  
Brackish Water ◽  
Sea Water ◽  
Sodium Concentration ◽  
The Body ◽  
Experimental Population ◽  
Sodium Ions ◽  
Sodium Influx ◽  
Wide Range ◽  
Freshwater Habitats

1. Sodium influx was examined in Gammarus duebeni from freshwater habitats on the Kintyre and Stranraer peninsulas in western Britain, and from a brackish-water habitat in Ireland. The affinity for sodium ions in the uptake mechanism at the body surface was similar in animals from the three localities. 2. Compared with the parent population from Kintyre, an experimental population established for 2 years in water with a lower sodium concentration showed an increased affinity for sodium. 3. Sodium losses in the urine of animals from the above localities were negligible at external salinities below about 2% sea water. In contrast, urinary sodium losses in animals from a brackish-water population in Britain were higher at salinities ranging from 40% sea water to well below 2% sea water. 4. The affinity for sodium ions in uptake mechanisms at the body surface and in the antennary glands of G. duebeni from a wide range of habitats shows a market correlation with the sodium concentration of the habitat. The permeability of the body surface to outward movement of sodium is similar in G. duebeni from brackishwater and freshwater habitats. 5. It is suggested that most of the observed physiological differences between populations of G. duebeni are phenotypic in origin. The status of the freshwater ‘race’ in Ireland is briefly discussed.

Distribution of silica-scaled Chrysophyceae (Paraphysomonadaceae and Mallomonadaceae) in Australian inland waters

1985 ◽  
Vol 36 (6) ◽  
pp. 839 ◽  
Author(s):  
RL Croome ◽  
PA Tyler
Keyword(s):  
Electron Microscopy ◽  
Inland Waters ◽  
Population Densities ◽  
Species Numbers ◽  
Wide Range ◽  
Freshwater Habitats ◽  
Dystrophic Lakes ◽  
Australian Freshwater ◽  
First Time ◽  
Eleven Species

Thirty-two species of silica-scaled Chrysophyceae of the genera Spiniferomonas, Chrysosphaerella and Paraphysomonas, belonging to the Paraphysomonadaceae Preisig & Hibberd, 1983, and Mallomonas, Mallomonopsis and Synura, belonging to the Mallomonadaceae (Diesing, 1866) Preisig & Hibberd, 1983, are recognized by electron microscopy from a wide range of Australian freshwater habitats, from tropical to temperate regions, and from a range of trophic types of lake. Eleven species are reported from Australia for the first time, and three from the Southern Hemisphere for the first time. Although most of the species are of worldwide occurrence, several are as yet known only from Australia. Several highly dystrophic lakes in Tasmania are particularly rich in species numbers and in population densities.

scholarly journals Have Niche, Will Travel. New Means of Linking Diet and Ecomorphology Reveals Niche Conservatism in Freshwater Cottoid Fishes

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
T J Buser ◽  
D L Finnegan ◽  
A P Summers ◽  
M A Kolmann
Keyword(s):  
Niche Conservatism ◽  
Freshwater Species ◽  
Evolutionary Transitions ◽  
Adaptive Diversification ◽  
Functional Aspects ◽  
Ecological Evolution ◽  
Jaw Apparatus ◽  
Cottoid Fishes ◽  
Freshwater Habitats ◽  
Dietary Niche

Synopsis Evolutionary transitions between habitats have been catalysts for some of the most stunning examples of adaptive diversification, with novel niches and new resources providing ecological opportunity for such radiations. In aquatic animals, transitions from saltwater to freshwater habitats are rare, but occur often enough that in the Neotropics for example, marine-derived fishes contribute noticeably to regional ichthyofaunal diversity. Here, we investigate how morphology has evolved in a group of temperate fishes that contain a marine to freshwater transition: the sculpins (Percomorpha; Cottoidea). We devised a novel method for classifying dietary niche and relating functional aspects of prey to their predators. Coupled with functional measurements of the jaw apparatus in cottoids, we explored whether freshwater sculpins have fundamentally changed their niche after invading freshwater (niche lability) or if they retain a niche similar to their marine cousins (niche conservatism). Freshwater sculpins exhibit both phylogeographical and ecological signals of phylogenetic niche conservatism, meaning that regardless of habitat, sculpins fill similar niche roles in either saltwater or freshwater. Rather than competition guiding niche conservatism in freshwater cottoids, we argue that strong intrinsic constraints on morphological and ecological evolution are at play, contra to other studies of diversification in marine-derived freshwater fishes. However, several intertidal and subtidal sculpins as well as several pelagic freshwater species from Lake Baikal show remarkable departures from the typical sculpin bauplan. Our method of prey categorization provides an explicit, quantitative means of classifying dietary niche for macroevolutionary studies, rather than relying on somewhat arbitrary means used in previous literature.

scholarly journals The Survival of Haloferax mediterranei under Stressful Conditions

2021 ◽  
Vol 9 (2) ◽  
pp. 336
Author(s):  
Laura Matarredona ◽  
Mónica Camacho ◽  
Basilio Zafrilla ◽  
Gloria Bravo-Barrales ◽  
Julia Esclapez ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Sea Water ◽  
Industrial Applications ◽  
Growth Responses ◽  
Haloferax Mediterranei ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Wide Range ◽  
High Metal ◽  
Plasma Mass Spectrometry

Haloarchaea can survive and thrive under exposure to a wide range of extreme environmental factors, which represents a potential interest to biotechnology. Growth responses to different stressful conditions were examined in the haloarchaeon Haloferax mediterranei R4. It has been demonstrated that this halophilic archaeon is able to grow between 10 and 32.5% (w/v) of sea water, at 32–52 °C, although it is expected to grow in temperatures lower than 32 °C, and between 5.75 and 8.75 of pH. Moreover, it can also grow under high metal concentrations (nickel, lithium, cobalt, arsenic), which are toxic to most living beings, making it a promising candidate for future biotechnological purposes and industrial applications. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis quantified the intracellular ion concentrations of these four metals in Hfx. mediterranei, concluding that this haloarchaeon can accumulate Li+, Co2+, As5+, and Ni2+ within the cell. This paper is the first report on Hfx. mediterranei in which multiple stress conditions have been studied to explore the mechanism of stress resistance. It constitutes the most detailed study in Haloarchaea, and, as a consequence, new biotechnological and industrial applications have emerged.

scholarly journals Immigration and economic mobility

2021 ◽  
Author(s):  
Maria F. Hoen ◽  
Simen Markussen ◽  
Knut Røed
Keyword(s):  
Labor Market ◽  
Low Income ◽  
Labor Market Outcomes ◽  
Lower Class ◽  
Low Income Countries ◽  
Market Outcomes ◽  
Wide Range ◽  
Class Background ◽  
The Rich ◽  
Relative Prime

AbstractWe examine how immigration affects natives’ relative prime-age labor market outcomes by economic class background, with class background established on the basis of parents’ earnings rank. Exploiting alternative sources of variation in immigration patterns across time and space, we find that immigration from low-income countries reduces intergenerational mobility and thus steepens the social gradient in natives’ labor market outcomes, whereas immigration from high-income countries levels it. These findings are robust with respect to a wide range of identifying assumptions. The analysis is based on high-quality population-wide administrative data from Norway, which is one of the rich-world countries with the most rapid rise in the immigrant population share over the past two decades. Our findings suggest that immigration can explain a considerable part of the observed relative decline in economic performance among natives with a lower-class background.

Sodium Regulation and Adaptation to Fresh Water in Gammarid Crustaceans

1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Body Weight ◽  
Fresh Water ◽  
Body Surface ◽  
Sea Water ◽  
Sodium Concentration ◽  
The Body ◽  
Outward Diffusion ◽  
Gammarus Zaddachi ◽  
Freshwater Habitats ◽  
Sodium Regulation

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.

Zinc Regulation in the Lobster Homarus Gammarus: Importance of Different Pathways of Absorption and Excretion

1986 ◽  
Vol 66 (1) ◽  
pp. 175-199 ◽  
Author(s):  
G. W. Bryan ◽  
L. G. Hummerstone ◽  
Eileen Ward
Keyword(s):  
Sea Water ◽  
Carcinus Maenas ◽  
The Body ◽  
Shore Crab ◽  
Freshwater Crayfish ◽  
Uptake Mechanism ◽  
Major Pathway ◽  
Homarus Gammarus ◽  
Wide Range ◽  
Body Concentration

Zinc is one of the most important of the essential trace metals and more than 90 zinc-containing enymes and proteins have been discovered: furthermore, zinc increases the activity of many other enzymes (Vallee, 1978). It is not surprising, therefore, that in some groups of animals the body concentration is regulated against fluctuations in intake. Decapod crustaceans comprise one such group, although the ways in which regulation is achieved vary from species to species. In the freshwater crayfish, Austropotamobius pallipes, excretion in the faeces is a major pathway for removing zinc (Bryan, 1967a) whereas in the shore crab Carcinus maenas losses over the body surface also assume considerable importance (Bryan, 1966). On the other hand, preliminary work on the lobster Homarus gammarus (formerly H. vulgaris) suggests that in this species urinary excretion plays a major role in regulation (Bryan, 1964). The present work continues the study of zinc regulation in lobsters and its main aims are: (1) to measure rates of absorption from sea water over a wide range of concentrations and study the uptake mechanism; (2) to examine absorption from the stomach under different conditions; (3) to determine the relative importance of different pathways for the removal of zinc in response to various levels of intake.

scholarly journals Extendable stapling of unprotected peptides by crosslinking two amines with o-phthalaldehyde

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Bo Li ◽  
Lan Wang ◽  
Xiangxiang Chen ◽  
Xin Chu ◽  
Hong Tang ◽  
...  
Keyword(s):  
Condensation Reaction ◽  
Cysteine Residue ◽  
Amino Groups ◽  
One Pot ◽  
Peptide Substrates ◽  
Peptide Chemistry ◽  
Peptide Modification ◽  
Wide Range ◽  
Sequential Addition ◽  
Aqueous Conditions

AbstractPeptide modification methods that do not rely on the cysteine residue are underdeveloped, and their development could greatly expand the current toolbox for peptide chemistry. During the course of preliminary investigations into the classical ortho-phthalaldehyde (OPA)-amine-thiol condensation reaction, we found that in the absence of thiol, OPA readily condenses with two primary alkyl amines to form a class of underexplored isoindolin-1-imine compounds under mild aqueous conditions. From the intramolecular version of this OPA-2amines reaction, an efficient and selective methodology using mild reaction conditions has been developed for stapling unprotected peptides via crosslinking of two amino groups in both an end-to-side and side-to-side fashion. The stapling method is superfast and broadly applicable for various peptide substrates with the reacting amino groups separated by a wide range of different amino acid units. The macrocyclization reactions of selected substrates are completed within 10 seconds at 5 mM concentration and within 2 minutes at 50 μM concentration. Importantly, the resulting cyclized peptides with an isoindolinimine linkage can be extended in a one-pot sequential addition manner with several different electron-deficient π electrophiles, thereby generating more complex structures.

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