ALBERT

Notes: Fry were reared in Windermere lakewater at pH 7.0 or acidified to pH 4.5–5.0. Oxygen uptake by 0.1–5.0 g fry was compared at pH 7.0 and 4.0, using artificial lakewater in the respirometer. No significant differences in oxygen uptake were found at these two pH levels. Measurements of oxygen uptake by sea trout fry (Salmo trutta L.) at pH 7.0 are included.

Notes: Female-specific markers of reproductive activity [plasma 17β-oestradiol (E2), vitellogenin (VTG) and alkali-labile phosphoprotein phosphorous (ALP)] were measured over 12 months in a captive population of brown trout Salmo trutta. During the early months of the reproductive season (February to May) and using the concentration of plasma E2 or plasma ALP as a marker for females the proportion of fish in which sex was misidentified was high (15–50%). The misidentification rate was considerably lower (1–8%) using plasma VTG. Preliminary evaluation of a commercial immunochromatographic VTG test system as a screen for the presence or absence of VTG in plasma from brown trout provided results that were consistent with those obtained from direct measurement of plasma VTG levels by enzyme-linked immunosorbent assay (ELISA). These preliminary conclusions were verified by sampling upstream-migrating anadromous brown trout, sea trout, and Atlantic salmon Salmo salar trapped over a 6 month period. Plasma E2 levels did not satisfactorily discriminate between male and female sea trout and Atlantic salmon. Plasma VTG levels in both species, however, were bimodally distributed and it was assumed that this divergence corresponded to male (plasma VTG levels 〈10 μg ml−1) and female (plasma VTG levels 〉800 μg ml−1) fishes. Plasma ALP provided a more accurate indication of sex in the wild Atlantic salmon and sea trout than was suggested by the pilot study on captive brown trout. The commercial immunochromatographic VTG test system provided results that were wholly consistent with the data obtained from the trapped fishes by direct measurement of plasma VTG.

Notes: Comparisons are made of pH and the concentrations of major ions in streamwater from Brownrigg Well (the source of Whelpside Ghyll) and from the River Duddon. pH in Brownrigg Well is usually 〉5.7, but the concentrations of sodium, potassium and possibly calcium are near to the minima required to support the amphipod Gammarus pulex. In contrast most insect taxa are not affected by low ionic concentrations. It is postulated that these had a wider distribution in mountain streams prior to the acidification of poorly buffered waters by acid rainfall resulting from large-scale combustion of fossil fuels.

Notes: SUMMARY. The number of flagellar segments on the antennules of Gammarus pulex was quantitatively related to body size in animals from natural populations and to moulting and instar number of isolated animals grown from birth in the laboratory. The number of segments was 5.0 at birth increasing to means of 19–20 in females and 21–22 in males at sexual maturity or c. 5 mg wet wt reached after nine or ten moults. Addition of segments to the paired flagellae of juveniles was not regular and the number of segments cannot be used to identify particular instars of individuals or to determine their age. The mean interval (days) between moults progressively increased in the later juvenile instars and was exponentially related to moult number, age and the number of flagellar segments; the moult interval is also exponentially related to these variables in adults.

Notes: SUMMARY. The composition of bulk (wet and dry) precipitation in 1975 and 1976 was similar to that found 22 years previously. In 1975, mean values for nine precipitation samplers at one site (Wraymires) ranged from pH 4.3 to 4.5; similar values were obtained in 1976. Samplers covered with fine-mesh plastic gauze caught substantially more Ca2+ and K+ than open samplers, but pH and SO2-4+ NO3- concentrations were similar in open and covered samplers. In precipitation, c. 50% of H+ was balanced by NO3- and c. 50% by SOi; 80% of the SO2-4 was balanced by Ca2+ and Mg2+.Conccntrations of major cations (H+, Na+, K+,Ca2+, Mg2+) and anions (CI-, NO3- SO2-4 and alkalinity [Alk—largely HCO3-]) in upland water- bodies were similar to those found in precipitation, but pH levels were generally higher and above 6.0 m some tarns. At lower altitudes, on base-rich roeks and soils, Ca2+ and Alk become dominant. Results of a survey of lakes and tarns in 1974–78 are compared with a survey in 1953–56 and published data (chiefly for pH and Alk) for 1947–50, 1932 and 1928. Comparisons are also made with other measurements of Alk in three productive lakes (Blelham Tarn, Esthwaite Water and Windermere) for 1936–39 and 1945–80. Winter levels of NO3-N, PO4-P and Si are given for these lakes; although the first two have increased during the late 1960s and the 1970s there has been no significant change in the last. NO3- and probably some SO2-4. In productive lakes a substantial (c. 50%) rise in mean Alk occurred during the late 1960s and the 1970s, possibly related to increased winter levels of NO3-N and PO4-P derived from sewage and fertilizers. In this period the maximum pH levels reached in summer were notably high, sometimes exceeding pH 10. The rise in Alk, conductivity and pH of surface waters is influenced by climatic factors (a decade of drier years), sewage input and biological productivity within the lakes.Considerable seasonal fluctuations in the concentrations of major ions, a characteristic feature of surface waters in the English Lake District, are illustrated and some implications for cation-anion balance briefly discussed. Mid-winter concentrations are usually high forNa+, K+, Cl-. NO3-and low for Ca2+, Mg2+, Alk. SO2-4.Alkalinity. pH and conductivity of Lake District tarns and lakes show no signs of acidification during the period 1928–80. On the contrary, productive lakes have become more alkaline and some unproductive low-alkalinity (〈 100 μ-equiv. 1-1) lakes also show signs of alkalization, with increased mean concentrations of Na+. Ca2+ and Mg2+, balanced by Alk.

Notes: SUMMARY. 1. The distribution of softwater and acid tarns and streams in central Cumbria is briefly summarized and compared for the periods 1983-85 and 1949-56.2. Fifty-three upland tarns (altitude 〉350m) and forty lowland tarns (altitude 〈320m) were sampled on Skiddaw Slates, the Borrowdale Volcanic Series, and igneous intrusions. On these bedrocks, tarns and streams would be highly sensitive to further acidification if acid deposition increases above current levels. Twenty-six upland and seven lowland tarns are permanently acid with zero or negative alkalinity values throughout the year; mean pH ranged from 5.3 to 4.2. The other sixty upland and lowland tarns had positive mean Alk in the summers of 1983-85, ranging from 7 to 1227μequiv. I−1 Alk and mean pH5.7 to 〉7.0. Thirty-one of the sixty tarns had mean Alk 〈 100μequiv. I−1 in summer (May-September); sixteen became temporarily acid (negative Alk) for varying periods in winter. Acid episodes also occurred in the tarns in 1949-56.3. Acid and very low alkalinity tarns and streams commonly occur on the high western, central and northern fells. Few occur on the high eastern felts, where there are veins of calcite in exposed rocks.4. Seventy-five lowland tarns were sampled on Silurian Slates in southern Lakeland. On these bedrocks, tarns and streams are not highly sensitive to further acidification. Only six tarns had summer mean Alk 〈100μequiv. 1−1. No permanently acid tarns or streams were found.5. Over a mean span of about 30 years. Eel Tarn appears to have become slightly more acid and Harrop Tarn slightly less acid. The remainder of all tarns surveyed in 1983-85 have altered little, although there is a heavy load of acidic deposition on to the catchments and some tarns contain very low concentrations of Alk. Rapid acidification in recent years has been prevented by the neutralizing capacity of volcanic and sedimentary rocks. These rocks produce relatively high concentrations of Alk, up to 650μequiv.l−1 in some spring-fed streams on the central fells and even more at lower altitudes. Absence of coniferous

Notes: SUMMARY. 1. The ranges of concentrations for pH, CV. Na+. K+Ca2+, Mg2+ are given for streams draining igneous rocks (Borrowdale Volcanics) and sedimentary muds, silts and shales (Silurian Slates) in the catchment of Windermere (230 km2). Impacts on the biota are briefly discussed. Relative contributions of inputs from various sources are examined: precipitation, rocks and soils, sewage, deicing salt used on highways./2. In bulk precipitation, ratios of Na+/CV (as μequiv. I−1) ranged from 0.41 to 1.83 over a 2-year period. The overall volume-weighted mean ratio was 0.86, as in seawater, hut 2′4%(1975) and 5.7% (1976) of Cl− was non-marine in origin, being balanced by H + (in winter), K and Ca2+ (in summer). In moorland headwater streams, CI− is largely derived from precipitation: there is a pronounced annual cycle of midwinter high and midsummer low concentrations unrelated to stream discharge. Na* and K+ display similar cycles but Na+, Ca2+ and Mg2+ (and pH) are discharge-related due to leaching from rocks and soils: 10–20% Na+, 15–17% Mg2+ and 65–75% Ca2+ are so-derived whereas K+ comes from precipitation. Na+/Cl+ ratios in streams on Borrowdale Volcanics alter seasonally, with midsummer values 〉1. Lower values occur in streams on Silurian Slates where some CI− is apparently derived from rocks.3. Seasonal changes in streamwater concentrations of Cl, Na4 andK+are exponentially related to time. Instantaneous rates of change i day-11) are compared in relation to position in the catchment and inputs from anthropogenic sources. Deicing salt has raised (10–100-fold) the concentrations of Na* and Cl− in streams on mountain passes; the effects persist throughout the year.

Notes: SUMMARY. 〈list xml:id="l1" style="custom"〉1Mean tarnwater concentrations of CI- and other ions (Na +, K+, Ca2+, Mg2+, SO42-+ NO3-) decrease with increasing distance from the sea and altitude but are also related to solid geology. Lowest concentrations occur on slow-weathering igneous rocks (Borrow-dale Volcanics); minima of c. 100 μequiv. CI-I-1 are similar to the volume-weighted mean for bulk precipitation. At least 10–20% of Na+ is leached from upland catchments, giving Na+/CI- ratios greater than the equivalent ratio (0.86) in seawater and precipitation. Evapotranspiration at 20–30% annual rainfall accounts for CI- concentrations in many tarns on igneous rocks but not all; some CI- may be leached from the rocks in upland catchments and come from groundwaters at low altitudes near the sea. Sea-spray has little influence on tarnwaters near the coast.2On sedimentary rocks overall mean CI- concentrations are 27–73% higher than equivalent means on Borrowdale Volcanics; concentrations of other ions are also higher. A 5-fold to 10-fold range of CI-concentrations is not simply due to increased evapotranspiration. Na+/CI- ratios are 〈 0.86, especially on Skiddaw Slates where tarnwaters contain 10% or more excess CI- balanced by Ca2+, apparently derived from groundwaters rich in CaCI2. On other sedimentary rocks (Silurian Slates and Carboniferous, Triassic and Permian series) tarn waters display a similar but less pronounced excess of CI- and Ca2-+ relative to Na+. Some extra CI- may be captured by dry deposition on vegetation but a portion, perhaps 15–30% of the total, apparently comes from the rocks or from groundwaters via deep aquifers in contact with seawater or connate water.3Anthropogenic sources on the catchments are also considered: deicing salt used on highways in winter accounts for a 27% increase of CI- in Windermere South Basin over a 20-year period.

Notes: Sodium and potassium in streamwater were measured over a period of 2 years, and concentrations of other major ions were occasionally monitored. The supply of sodium, potassium and calcium in rainfall was measured over a period of 1 year. A tentative budget is given for annual income and output of sodium, potassium and calcium in the Duddon catchment. Sodium and potassium concentrations in streamwater were independent of stream discharge; both ions displayed an annual cycle of high concentrations in winter and low concentrations in summer. The input of sodium was dependent on rainfall, wind direction and wind speed; 40% of the annual supply in rain was precipitated in the autumn. Sodium income in rainfall during the remaining 9 months of the year was insufficient to balance the output in streamwater. Annual income of potassium in rainfall was equal to annual output in streamwater. But potassium was retained on the catchment during spring and summer and was slowly released to the streams in autumn and winter. Only about 10% of the annual calcium output was derived from atmospheric sources.