Scottish Association for Marine Science

In Sri Lanka, few numbers of fish species are cultured as food fish, mainly in seasonal reservoirs in the dry zone under culture based fisheries practices (CBF). Cadmium and its compounds which enter to the reservoirs through rain runoff are most common environmental toxicants with potential for bioaccumulation and persistence in the body, and produce versatile biotic changes in the aquatic ecosystem. Present study was designed to study the chronic exposure of ecologically relevant concentrations of cadmium (Cd) on the growth, bioaccumulation, and hematological parameters of genetically improved farmed tilapia (GIFT). Fish were exposed to two concentrations of Cadmium (50 µg/L and 100 µg/L) with control. The highest concentration of cadmium is based on the maximum tolerance limit for the discharge of industrial waste water in to inland surface waters (100.0 µg/L) which has been recommended by the Board of Investment (BOI) of Sri Lanka. Eight fish with initial mean weigh of 12.84±0.53 g were randomly assigned quadruplicated treatments and experiment was lasted for six weeks. Daily food consumption and survival of the experimental fish were recorded, and total length and weight measurements of fish were taken fortnightly. At the end of the experiment, growth performances and feed utilization efficiencies were assessed by using % specific growth rate (%SGR), % average daily gain (%ADG) and feed conversion ratio (FCR). At the end of the experiment, the pattern of Cd accumulation, its affinity to selected tissues (muscle, skin, liver and gills) and hematological parameters such as red blood count (RBC), white blood count (WBC), hematocrit (HCT) and packed cell volume (PCV) of the experimental fish were examined. Mean total length, body weight, %ADG, %SGR, HCT and PCV were not affected by the treatments. Significantly highest survival rate (100%) was observed in control followed by Cd50 (87.50%) and CD100 (78.13%). The rate of Cd accumulation in various tissues were in the order of liver > gills > muscle > skin in

The present study was designed to evaluate the chronic exposure of iron (Fe) on the growth, haematological and histological parameters of the Guppy (Poecilia reticulata). This experiment was conducted with four iron concentrations (3 ppm: Fe-3, 5 ppm: Fe-5, 10 ppm: Fe-10 and 20 ppm: Fe-20) and the control which does not contain added iron. The lowest concentration of iron is based on the maximum tolerance limit for the discharge of industrial wastewater into inland surface waters (3 ppm) which has been recommended by the Board of Investment (BOI) of Sri Lanka. Fifteen male fish with an initial mean weight of 0.20±0.04 g were randomly assigned in triplicated treatments and the experiment lasted for 45 days. Daily food consumption and survival of the experimental fish were recorded and weight measurements of fish were taken fortnightly. At the end of the experiment, growth performances and feed utilization efficiencies were assessed by using percentage specific growth rate (%SGR), percentage average daily gain (%ADG) and feed conversion ratio (FCR). Red blood cell count (RBC), blood smears and histological variations of gill tissues of the experimental fish were also examined at the end of the experiment. Mean body weight was not affected by the treatments. There were no structural alterations observed in blood smears of fish in different treatments. The lowest FCR (1.35±0.07) was observed in Fe-3 while the highest %ADG and %SGR both were observed in the control (4.30±1.21 and 2.37±0.44). Significantly (p<0.05) the highest survival rate (100%) was observed in control followed by Fe-3 (86.7±2.6%), Fe-5 (82.0±2.5%), Fe-10 (73.3±1.4%) and Fe-20 (10.0±0.7%). Among tested treatments, the highest RBC was reported in the control and Fe-3 (1.83±0.30 ×10 6 /mm 3 and 1.92±0.49 ×10 6 /mm 3 respectively) followed by Fe-5 (1.22±0.31 ×10 6 /mm 3), Fe-10 (0.99±0.21 ×10 6 /mm 3) and Fe-20 (0.61±0.13×10 6 /mm 3). Histological sections of the gill tissues showed that secondary lamellae were arranged without proper order and were visualized as broken or eroded, fused and misshaped filaments in the high Fe levels. However, these alterations were not observed in the Fe-3. The results of this study revealed that there is a significant effect of the chronic exposure of iron on the growth performance, red blood cell counts and histological status of the gills of the guppy at the concentrations greater than the BOI recommended level (3 ppm).

Organisms residing in seasonal environments schedule their activities to annual cycles in prey availability and predation risk. These cycles may be particularly pronounced in pelagic ecosystems of the high-Arctic, where the seasonality in irradiance, and thus primary production, is strong. Here we report on the seasonal ecology and life strategy of a predatory planktivore in a high-Arctic fjord (Billefjorden, Svalbard ~78°N). We studied the chaetognath Parasagitta elegans (var. arctica), an abundant zooplankter of high-latitude seas, focusing on its age structure, seasonal vertical distribution, growth and timing of reproduction. The body-length data (range: 2 to 44 mm) revealed the presence of 3 size cohorts (Cohorts 0, 1 and 2), suggesting a 3 yr life span. Spring and early summer (May/June) was the main spawning season, as revealed by inspection of gonads and the presence of well-developed seminal receptacles prior to high numbers of newborns. Both Cohorts 1 and 2 reproduced, with male gonads maturing first in this hermaphrodite. Growth rates for all cohorts were highest in spring and early summer, and at this time of the year, the youngest year class (Cohort 0) was distributed near the surface where their feeding opportunities may peak. In winter, however, all cohorts were in deeper waters, suggesting seasonal migrations, possibly to follow the distributions of overwintering copepods. Scheduling of growth, maturation and reproduction in Arctic zooplankton populations is important baseline information for predictions of zooplankton responses to environmental change, particularly those associated with timing and phenology, pinpointing the need for more high-resolution studies on zooplankton annual routines.

We deployed the Lightframe On-sight Keyspecies Investigation
(LOKI) system, a novel underwater imaging system providing
cutting-edge imaging quality, in the Canadian Arctic during fall
2013. A Random Forests machine learning model was built to
automatically identify zooplankton in LOKI images. The model
successfully distinguished between 114 different categories of
zooplankton and particles. The high resolution taxonomical tree included
many species, stages, as well as sub-groups based on animal
orientation or condition in images. Results from a machine learning
regression model of prosome length (R2 = 0.97) were used
as a key predictor in the automatic identification model. Model internal
validation of the automatic identification model on test data
demonstrated that the model performed with overall high accuracy
(86%) and specificity (86%). This was confirmed by confusion
matrices for external testing results, based on automatic identifications
for 2 complete stations. For station 101, from which images
had also been used for training, accuracy and specificity were 85%.
For station 126, from which images had not been used to train the
model, accuracy and specificity were 81%. Further comparisons between
model results and microscope identifications of zooplankton
in samples from the two test stations were in good agreement
for most taxa. LOKI’s image quality makes it possible to build accurate
automatic identification models of very high taxonomic detail,
which will play a critical role in future studies of zooplankton dynamics
and zooplankton coupling with other trophic levels.

A new chloroplast-containing species of the sand-dwelling benthic dinoflagellate Thecadinium was isolated and cultured from a single cell collected from shallow waters of the marine Loch Ewe in North West Scotland. The cultured cells are described by light and scanning electron microscopy and the genetic affinities examined by comparison of ribosomal RNA gene sequences. Thecadinium foveolatum Bolch sp. nov. is heavily armoured with thecal plates that are ornamented with evenly distributed pores and contains numerous globular, dark golden-brown chloroplasts. Cells are broadly ovoid and slightly laterally compressed, with a descending cingulum displaced approximately half of the cell width. The thick thecal plates, numerous pores and the strongly displaced cingulum clearly differentiate this species from the only other chloroplastcontaining species, T. kofoidii, and the remaining non-photosynthetic Thecadinium species described. Analysis of largesubunit rDNA sequences of Thecadinium foveolatum and other members of the Peridiniphycidae indicate that this new species is allied to the gonyaulacalean lineage rather than the peridinialean taxa included in the analyses.

The roles of Biological Resource Centres (BRCs), such as the Culture Collection of Algae and Protozoa (CCAP), have extended beyond their traditional maintenance and provision of curated microorganisms to the user community. A major driver for change has been the exponential increase in metagenomics and environmental sequencing data over the last few years. This has underlined a critical requirement for molecular information on reference biological materials, which would allow better taxonomic interpretation, greater biological understanding and additional exploitation of these data. This is especially relevant for the relatively poorly studied protists (algal/autotrophic as well as heterotrophic) and prokaryotic cyanobacteria, which despite their huge biodiversity, reflected in the genomic data that has been generated, are underrepresented in BRCs worldwide. Here we describe the functionalities of the Culture Collection of Algae and Protozoa (CCAP) KnowledgeBase (http://www.ccap.ac.uk), developed as a one-stop shop for quality-controlled biological material, hyperlinked to manually curated molecular, bibliographic and taxonomic information. This has been built around the CCAP live collection, which constitutes one of the most genotypically diverse collections in the world with representatives of all the major eukaryotic lineages and the cyanobacteria.

Micro-algae synthesize high levels of lipids, carbohydrates and proteins photoautotrophically, thus attracting considerable interest for the biotechnological production of fuels, environmental remediation, functional foods and nutraceuticals. Currently, only a few micro-algae species are grown commercially at large-scale, primarily for "health-foods" and pigments. For a range of potential products (fuel to pharma), high lipid productivity strains are required to mitigate the economic costs of mass culture. Here we present a screen concentrating on marine micro-algal strains, which if suitable for scale-up would minimise competition with agriculture for water. Mass-Spectrophotometric analysis (MS) of nitrogen (N) and carbon (C) was subsequently validated by measurement of total fatty acids (TFA) by Gas-Chromatography (GC). This identified a rapid and accurate screening strategy based on elemental analysis. The screen identified Nannochloropsis oceanica CCAP 849/10 and a marine isolate of Chlorella vulgaris CCAP 211/21A as the best lipid producers. Analysis of C, N, protein, carbohydrate and Fatty Acid (FA) composition identified a suite of strains for further biotechnological applications e.g. Dunaliella polymorpha CCAP 19/14, significantly the most productive for carbohydrates, and Cyclotella cryptica CCAP 1070/2, with utility for EPA production and N-assimilation.

The Vibrio cholerae N-acetyl glucosamine-binding protein A (GbpA) is a chitin-binding protein involved in V. cholerae attachment to environmental chitin surfaces and human intestinal cells. We previously investigated the distribution and genetic variations of gbpA in a large collection of V. cholerae strains and found that the gene is consistently present and highly conserved in this species. Primers and probe were designed from the gbpA sequence of V. cholerae and a new Taq-based qPCR protocol was developed for diagnostic detection and quantification of the bacterium in environmental and stool samples. In addition, the positions of primers targeting the gbpA gene region were selected to obtain a short amplified fragment of 206 bp and the protocol was optimized for the analysis of formalinfixed samples, such as historical Continuous Plankton Recorder (CPR) samples. Overall, the method is sensitive (50 gene copies), highly specific for V. cholerae and failed to amplify strains of the closely-related species Vibrio mimicus. The sensitivity of the assay applied to environmental and stool samples spiked with V. cholerae ATCC 39315 was comparable to that of pure cultures and was of 10 2 genomic units/l for drinking and seawater samples, 10 1 genomic units/g for sediment and 10 2 genomic units/g for bivalve and stool samples. The method also performs well when tested on artificially formalin-fixed and degraded genomic samples and was able to amplify V. cholerae DNA in historical CPR samples, the earliest of which date back to August 1966. The detection of V. cholerae in CPR samples collected in cholera endemic areas such as the Benguela Current Large Marine Ecosystem (BCLME) is of particular significance and represents a proof of concept for the possible use of the CPR technology and the developed qPCR assay in cholera studies.

Rates of phytoplankton production and nitrogen assimilation were measured at various stations along a transect in the northwestern Indian Ocean, from near the equator, northwards into the upwelling system off the Arabian peninsula, during September–October 1986. The ...

The bacterioneuston is defined as the community of bacteria present within the neuston or sea surface microlayer. Bacteria within this layer were sampled using a membrane filter technique and bacterial diversity was compared with that in the underlying pelagic coastal seawater using molecular ecological techniques. 16S rRNA gene libraries of ª ª ª ª 500 clones were constructed from both bacterioneuston and the pelagic water samples and representative clones from each library were sequenced for comparison of bacterial diversity. The bacterioneuston was found to have a significantly lower bacterial diversity than the pelagic seawater, with only nine clone types (ecotaxa) as opposed to 46 ecotaxa in the pelagic seawater library. Surprisingly, the bacterioneuston clone library was dominated by 16S rRNA gene sequences affiliated to two groups of organisms, Vibrio spp. which accounted for over 68% of clones and Pseudoalteromonas spp. accounting for 21% of the library. The dominance of these two 16S rRNA gene sequence types within the bacterioneuston clone library was confirmed in a subsequent gene probing experiment. 16S rRNA gene probes specific for these groups of bacteria were designed and used to probe new librar-ies of 1000 clones from both the bacterioneuston and pelagic seawater DNA samples. This revealed that 57% of clones from the bacterioneuston library hybridized to a Vibrio sp.-specific 16S rRNA gene probe and 32% hybridized to a Pseudoalteromonas sp.-specific 16S rRNA gene probe. In contrast, the pelagic seawater library resulted in only 13% and 8% of 16S rRNA gene clones hybridizing to the Vibrio sp. and Pseudoalteromonas sp. probes respectively. Results from this study suggest that the bacterioneuston contains a distinct population of bacteria and warrants further detailed study at the molecular level.