GROUP 9 FALMOUTH 2017
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HABITAT MAPPING
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ESTUARY
LABS
Biological Analysis was performed on samples collected on the RV Callista on 06/07/17 throughout the day at various points offshore of Falmouth.
This involved interpreting CTD data produced as the CTD rosette descended, on the
return of the CTD Rosette to the surface we fired Niskin Bottles at points of interest.
Phytoplankton samples were treated with Lugols iodine to kill any organisms in the
sample to prevent grazing.
Chlorophyll samples were also produced from this Niskin collected water.
Plankton
nets were also deployed at each station, which were opened at a certain depth and
winched upward until another depth was reached where the net was closed. The rationale
behind this was to obtain a representative sample of all the zooplankton species
in a particular depth range.
Below includes brief information about the common phytoplankton genera collected from the net samples
LABORATORY PROCESSING
Rhizosolenia spp.
Cylindrical diatom with two silica frustules found in both marine and brackish waters,
certain species will form long chains that form thick mats during blooms. They are
one of the most abundant genera' found in the global ocean (Werner, 1977).
Potentially
significant in global silica production, with mats produced in the North Pacific
potentially contributing 3% of the stock of biogenic silica (Shipe et al., 1999).
Silica use is not thought to be tightly linked to nutricline migration and limited
the availability of silica.
Mesodinium
A motile mixotrophic cilliate that is surrounded by cilia. When present in large numbers it can form "red tides", named after red phytopigments accumulated by individual cells during the consumption of cryptomonids. (Crawford, 1989)
Cryptomonas spp.
Is common in global fresh and brackish waters with green or brownish pigmented cells
whose slow growth rate is limited by nutrients. (Sandgren, 1991; John, Whitton and
Brook, 2008). They are phytoplankton that are known to swim along spiral shaped
paths (John, Whitton and Brook, 2008). They will take in increased concentrations
of nutrients in cold water with plenty of available light. (Cloern, 1977)
Mesoporos spp.
Small solitary dinoflagellate with a pore in each valve (Tomas et al., 1998). And have been linked to appearing in deep chlorophyll maximums in the Mediterranean. (Estrada, 1985).
concentrations of nutrients in cold water with plenty of available light. (Cloern, 1977)
Protoperidinium
A large open water photosynthetic dinoflagellate that can multiply to high concentrations in estuarine waters. (Tomas et al., 1998)
Certium furca
A marine dinoflagellate with an extreme asymmetrical set of theca with spines of uneven length
Thalassiosira
A largely marine group of centric diatoms
Guinardia
A diatom composed of large curved cells that have rounded edges.
References
Cloern, J. (1977). EFFECTS OF LIGHT INTENSITY AND TEMPERATURE ON CRYPTOMONAS OVATA
(CRYPTOPHYCEAE) GROWTH AND NUTRIENT UPTAKE RATES. Journal of Phycology, 13(4), pp.389-
Crawford, D. (1989). Mesodinium rubrum: the phytoplankter that wasn't. Marine Ecology
Progress Series, 58, pp.161-
Estrada, M. (1985). Deep Phytoplankton and Chlorophyll Maxima in the Western Mediterranean. Mediterranean
Marine Ecosystems, pp.247-
John, D., Whitton, B. and Brook, A. (2008). The freshwater algal flora of the British Isles : An identification guide to freshwater and terrestrial algae. Cambridge: Cambridge University Press, p.180.
Sandgren, C. (1991). Growth and reproductive strategies of freshwater phytoplankton.
Cambridge: Cambridge University Press, pp.105-
Shipe, R., Brzezinski, M., Pilskaln, C. and Villareal, T. (1999). Rhizosolenia mats:
An overlooked source of silica production in the open sea. Limnology and Oceanography,
44(5), pp.1282-
Tomas, C., Hasle, G., Syvertsen, E., Steidinger, K. and Tangen, K. (1998). Identifying marine diatoms and dinoflagellates. San Diego, CA: Academic Press, pp.418, 388.
Werner, D. (1977). The Biology of Diatoms. University of California Press, p.394.
Materials and Methods
Chlorophyll: filter papers were stored in acetone, at low temperature before being loaded one by one into a fluorometer in the laboratory. Described in more detail by Parsons et al., (1984).
Dissolved Silicon & Phosphate: calibration standards were made up using the working standards (known concentrations) provided. Described in more detail by Parsons et al., (1984).
Silicon: The Ammonium Molybdate and Mixed Reducing reagents were added in sequence
and the samples were loaded into a spectrophotometer -
The process for Phosphate is similar, only without the Ammonium Molybdate addition. Described in more detail by Parsons et al., (1984).
Nitrate: Flow Injection Analysis (FIA) was used to measure the nitrate concentration. Reagents were injected into the flowing sample stream and once reacted, the sample stream was passed through the Unicam 8625 UV Spectrophotometer and a plot with various peaks corresponding to nitrate concentrations was produced. This was to be compared to the known nitrate standards to ascertain the sample concentrations. Described in more detail by Johnson and Petty (1983).
Dissolved Oxygen: A Manganese (II) solution, followed by a strong alkali were added to each sample after retrieval from the niskin bottles. The precipitated Mn hydroxide is then treated with iodide to produce iodine equivalent to the original dissolved oxygen content. Subsequent titration with standard thiosulphate solution reveals the sample oxygen content. Described in more detail by Grasshoff et al., (1999).
Phytoplankton observations
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