Great Cumbrae Island Research Articles

Native oyster (Ostrea edulis, L. 1758) on Great Cumbrae Island, Scotland

Native oyster (Ostrea edulis, L. 1758) on Great Cumbrae Island, Scotland

Wind Energy Potential Assessment of Great Cumbrae Island Using Weibull Distribution Function

Wind energy is among the fastest growing energy generation technology which is highly preferred alternative to conventional sources of energy. The major Scottish Government target is to deliver 30% of her energy demand by 2020 from renewable sources of energy as well as meeting the emission targets as set under the Scotland Climate Change Act 2009. In this paper, wind energy potential assessment of Great Cumbrae Island was investigated. For this, a ten year mean monthly wind speed at height 50 m obtained from the National Aeronautic Space Administration (NASA) were analysed using the Weibull probability distributions to assess the wind energy potential of Great Cumbrae Island as a clean, sustainable energy resource. Results from the wind-speed model showed that Great Cumbrae Island as high wind-speed site with a mean wind speed of 7.598 m/s and having power density . The annual energy captured by four selected horizontal wind turbine models was determined. The result shows that GE 2.0 platform can capture 4.5 GWh energy in a year which is an acceptable quantity for wind energy.

Aspects of the Life Histories of Perioculodes Longimanus, Pontocrates Arcticus and Synchelidium Maculatum (Crustacea: Amphipoda) at Millport, Scotland

Detailed catch and life history data for Perioculodes longimanus and Pontocrates arcticus, together with more limited comparable information on Synchelidium maculatum, are reported. Samples were taken year-round using a 0–5 mm mesh D-net towed over sand in the immediate sublittoral zone (-2 to -6 m Chart Datum) in Kames Bay, Great Cumbrae Island, Scotland. Estimated population densities of Perioculodes longimanus were highest in summer. The occurrence of Pontocrates arcticus was more erratic and S. maculatum occurred only in midsummer in very low numbers. The mean sizes of all population categories of Perioculodes longimanus were bigger in summer than in late autumn and winter. Female Perioculodes longimanus parasitized with the copepod Sphaeronella minuta were significantly smaller than the whole category ‘sexable females’. Adult female S. minuta (one per amphipod brood pouch infected) carried — 70–200 eggs per sac. In both Perioculodes longimanus and Pontocrates arcticus females were larger than males. In Synchelidium maculatum, by contrast, males and females were not different in size. Gravid females were present virtually year-round in Perioculodes longimanus and Pontocrates arcticus, with particularly high proportions of ovigerous females in midsummer and low proportions in midwinter. Both of these species had an annual life cycle with only one generation per year. Longevity was estimated at 15 months. The sex ratio nearly always showed substantial female dominance in all three species. Fecundity appeared to be related to body size but, due to egg losses during sample processing, data were too few for detailed analysis. The eggs of Perioculodes longimanus and Pontocrates arcticus were elliptical in shape, with winter eggs being smaller than summer eggs in Perioculodes longimanus, but larger in Pontocrates arcticus. The percentage of ovigerous females in the population was significantly correlated with a range of environmental factors tested, the highest correlation being with maximum weekly air temperature (for Perioculodes longimanus) and daylength (Pontocrates arcticus), although causative effects cannot be established since temperature/daylength factors were not independent variables

Seasonal variation in copper and zinc concentrations in three talitrid amphipods (Crustacea)

Cu and Zn concentrations were determined for three talitrid amphipods, Orchestia gammarellus (Pallas), O. mediterranea Costa and Talitrus saltator (Montagu), collected at two-monthly intervals in 1987 from sites on Great Cumbrae Island, Firth of Clyde, Scotland. To account for size effects, log transformed Cu and Zn concentrations were regressed against log dry weight for each bimonthly sample of each species, and compared by analysis of covariance. Copper concentrations in O. gammarellus were significantly raised in March 1987, and lowered in November 1987. Copper concentrations in O. mediterranea and T. saltator were significantly lowered in November 1987. Cu concentrations differed interspecifically in the order O. gammarellus > O. mediterranea > T. saltator. There was no significant intraspecific seasonal variation in zinc concentration in any of the three species. Zn concentrations differed interspecifically in the order T. saltator > O. gammarellus > O. mediterranea.

Seasonal cycles of abundance of the flora and fauna associated withCladophora albida(Huds.) Kütz in rockpools

Seasonal data for one year on the flora and fauna associated with Cladophora albida (Huds.) Kutz from four rockpools (3 high-shore, 1 mid-shore) on Great Cumbrae Island, Firth of Clyde, Scotland are presented. A total of 131 858 animals was censussed. The mid-shore pool had a significantly lower annual mean density than the high-shore pools. Only at the most exposed site was a distinct seasonal trend apparent (lowest faunal density in spring, highest in summer). Species number showed no marked seasonal fluctuations neither did equitability. The lowest diversity was found in the mid-shore pool. Epiphytic cyanobacteria were present throughout the year. Diatoms were absent in the summer; possibly because of intense grazing by meiofaunal herbivores. The reduction in overall faunal density in the mid-shore pool was caused by the absence of large numbers of nematodes at this site related to the reduced availability of detritus and sand grains, perhaps reflecting greater wave scouring at this level on the shore....

Seasonal and diel variations of some physico-chemical parameters of Boulder shore habitats

Abstract The variations in physico-chemical conditions on a boulder shore on Great Cumbrae Island, Firth of Clyde, were investigated. Two micro-habitat types – dry understone and wet understone environments — were sampled at two positions on the shore, above and below MTL. Temperature, oxygen tension (P02), salinity, pH, Eh and humidity were measured under these stones over two tidal cycles once monthly for a period of a year. Temperature, P02, Eh and salinity showed the greatest diurnal and seasonal variation. High temperatures in the summer, combined with the presence of a large mass of decaying algae on the upper shore, served to deplete the P02 of the incoming tide and resulted in almost continuous hypoxic conditions on the upper shore during both immersion and emersion. Humidity was usually greater than 70 % under the stones. The major difference between the upper and lower shores was the duration of emersion during low tide which generally led to larger variations in most physico-chemical conditions...

Seasonal ecology of littoral epiphytic diatoms on Great Cumbrae Island.

Summary 216 species of diatoms have been found epiphytic on common intertidal marine algae from Great Cumbrae Island, Firth of Clyde, Scotland. Green and red algae had larger epiphytic floras than brown algae. Cocconeis spp. (especially C. scutellum var. scutellum) were common and abundant, and the endophytic Navicula endophytica was found in large numbers in fucoid algae. Similar epiphytic floras were observed on Cladophora rupestris, Polysiphonia lanosa, Gigartina stellata, and Palmaria palmata, but that on Enteromorpha intestinalis was quite distinct.

The effect of oxygen tension on the physiology and distribution of Echinogammarus pirloti (Sexton & Spooner) and E. obtusatus (Dahl) (Crustacea:Amphipoda)

Echinogammarus pirloti (Sexton & Spooner) and E. obtusatus (Dahl) are two closely related gammarid amphipods that occupy vertically separated upper and lower zones, respectively, on boulder shores on Great Cumbrae Island (Firth of Clyde, Scotland). Measurement of the oxygen tension of small isolated pools under boulders showed that PO 2 was one of the most variable environmental factors to which amphipods were exposed, and that the major difference between upper and lower shore sites was in the duration of hypoxia or anoxia. When subjected to conditions of declining PO 2 in the laboratory, both species exhibited a high degree of respiratory independence and compensated for the low oxygen tension by increasing ventilatory effort. Critical PO 2 values were low (15–25 Torr) and showed an inverse relationship with the size of the animal. Under anoxic conditions both species accumulated lactate at similar rates (≈4 μmol · g wet wt −1 · h −1). On returning to normoxia, recovery time was longer for E. obtusatus than for E. pirloti. A model predicting the limits of distribution of the two species, based on the recovery times from varying periods of anoxia, appeared to agree with field data obtained between 1982 and 1983.

Growth of the Queen Scallop Chlamys Opercularis in Suspended Cages in the Firth of Clyde

INTRODUCTIONEstimations of the growth of bivalves have traditionally been determined from measurements of animals collected on a regular basis from natural populations. Generally size frequency distributions have been analysed or growth rates estimated from measurements of the distances separating the annual rings (Hughes, 1970; Seed & Brown, 1978; Taylor & Venn, 1978). While both methods provide valuable information on shell growth, a more direct approach is to investigate experimentally the growth of individual animals held in cages and to follow the seasonal changes in the dimensions of their shells.The queen scallop Chlamys opercularis (L.) is found in large numbers in areas around Great Cumbrae Island in the Firth of Clyde where they form the basis for a small local fishery. In 1979 the British Steel Corporation started operating a deep-water terminal at Hunterston unloading and loading iron ore and coal. It was envisaged that accidental spillage of material during transfer from the vessels to the shore might affect the queen scallop populations in the area.

Bronze Age Burial Cists at Fintry Bay, Great Cumbrae Island

Bronze Age Burial Cists at Fintry Bay, Great Cumbrae Island

Population trends of great Cumbrae Island

Abstract Great Cumbrae, a small island in the Firth of Clyde only seven minutes by ferry from the mainland, with a relatively high standard of housing and services and a longstanding and profitable tourist industry, has suffered a serious loss in population over the last twenty years. In addition to an accelerating natural decrease in population, deaths now exceeding births by two to one, emigrants now outnumber immigrants. Factors responsible for growth and development and for present decline are considered.

The Flora of Great Cumbrae Island (Firth of Clyde)

The Flora of Great Cumbrae Island (Firth of Clyde)