An Investigation into changes in the phytoplankton community in Loch Creran, a Scottish sea loch.

Whyte, Callum T (2012) An Investigation into changes in the phytoplankton community in Loch Creran, a Scottish sea loch. PhD thesis, Edinburgh Napier University.

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    Short term and irregular sampling in Loch Creran over recent decades suggested
    that changes may be occurring in the phytoplankton community in the loch. This
    study sought to confirm this suggestion. After instigating a regular sampling regime
    during 2008 and 2009 it became clear that significant changes had occurred, relative
    to information from the 1970s, in both the numbers of phytoplankton in the loch and
    in their biomass, particularly during the time of the spring bloom. Utilising a tool to
    assess change in the phytoplankton community, it also became clear that significant
    changes had occurred in the composition of the phytoplankton in Loch Creran.
    Work was undertaken to explore possible explanations behind these changes.
    The e�ect that toxic, anti-fouling compounds, arising from an increase in leisure
    boating in Loch Creran, were having on the productivity of phytoplankton in the
    loch was considered by adapting an existing assimilative capacity model for phytoplankton
    growth. It was found, that at present levels of boating activity, the concentration
    of anti-fouling products present in the loch, would not be great enough
    to significantly impact on phytoplankton growth.
    Nutrient samples collected during 2009 showed no significant changes in the concentration
    of silicate or nitrate in the loch, but phosphate levels were found to be
    significantly lower. A review of the e�ects of grazing on phytoplankton by farmed
    mussels in Loch Creran indicated that, at current levels, this would not account for
    the decrease in phytoplankton numbers observed in the loch.
    Significant changes were observed in the water temperature in the loch and in the
    intensity and pattern of local rainfall. Increased levels of rainfall in the first three months of the year were found to be high enough to influence the rate of flushing and the rate of phytoplankton washout from the loch. A correlation was found
    between the availability of light in the surface layers of the loch and the concentration
    of phytoplankton present in these layers. This correlation was found to
    exist, throughout the year and not only, as previously thought, during the winter
    In conclusion, the observed decline in phytoplankton numbers in Loch Creran, was
    attributed to changes in local weather patterns, that had an impact on the physical
    structure of the water column, washout rates, the pattern and intensity of heterotrophic
    grazing and the availability of light.

    Item Type: Thesis (PhD)
    Uncontrolled Keywords: phytoplankton; weather patterns; environment; Loch Creran;
    University Divisions/Research Centres: Faculty of Health, Life & Social Sciences > School of Life, Sport and Social Sciences
    Dewey Decimal Subjects: 500 Science > 570 Life sciences; biology > 577 Ecology > 577.7 Marine ecology
    Library of Congress Subjects: Q Science > QH Natural history > QH301 Biology
    Item ID: 5696
    Depositing User: Mrs Lyn Gibson
    Date Deposited: 24 Oct 2012 10:22
    Last Modified: 24 Oct 2012 10:22

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