72 research outputs found
Seawater carbonate chemistry and respiration, clearance and calcification rates of the common cockle Cerastoderma edule
No full textThe combined effect of ocean acidification and warming on the common cockle Cerastoderma edule was investigated in a fully crossed laboratory experiment. Survival of the examined adult organisms remained high and was not affected by elevated temperature (+3 °C) or lowered pH (-0.3 units). However, the morphometric condition index of the cockles incubated under high pCO2 conditions (i.e. combined warming and acidification) was significantly reduced after six weeks of incubation. Respiration rates increased significantly under low pH, with highest rates measured under combined warm and low pH conditions. Calcification decreased significantly under low pH while clearance rates increased significantly under warm conditions and were generally lower in low pH treatments. The observed physiological responses suggest that the reduced food intake under hypercapnia is insufficient to support the higher energy requirements to compensate for the higher costs for basal maintenance and growth in future high pCO2waters
Was it as bad as cockle hunting!
No full textSketch from the scrapbook of Sarah E.E. Mitchell of Lisdillon on the East Coast of Tasmania 1875.
Sketch 56 taken 1875, by Catherine Mitchell.
We boated to Little Swanport River Minnie Giblin, Kate, Amy & self, Hamilton Radcliffe, & Mark S.M.. They two went looking for cockles grubbing them with their fingers but the tide rose & it was muddy. They tossed a coin, which should carry the other, Hamilton R., started with Mark on his back & could hardly carry him, & tottered several times before landing him in the boat. Mark used to say, “was it as bad as cockle hunting!!”
The sketches by Catherine Penwarne (Kate), eldest daughter of John and Catherine Mitchell (of Cornwall, England, who settled at Lisdillon, East Coast Tasmania in 1852) were made between 1860 and 1876, and portray aspects of 19th Century social and domestic life. Catherine’s sketches were compiled by her sister Sarah. E.E.Mitchell. Derived from her own collection, from those of friends and relations, and from John Ball, Kate's husband, they were compiled sometime between 1928 and 1933. The sketches are mounted in an album, together with: locks of Kate's hair on red silk; a pressed fern arrangement; a coloured photograph of John and Catherine Ball; and coloured views of Buckland Churchyard in 1850, showing the grave of Paul Thomas Mitchell, aged 3 days, and in 1879 showing the grave of Catherine Penwarne Ball. The scrapbook was bequeathed to The Royal Society of Tasmania in 1946.
RS 32/
Does insect pollination limit seed production in white cockle (Silene latifolia Poir.)?
No full textSilene latifolia Poir. (white cockle or white campion) is an important weed in western Canadian agriculture. White cockle is an indeterminate flowering dioecious species having staminate and pistillate flowers on separate plants. New plants originate almost exclusively from seed. Therefore, both male and female plants are required in order for seed production to occur. Due to the dioecious nature of the species, seed production may be limited. Experiments were conducted in 2009 and 2010 at or around Saskatoon, Saskatchewan. Floral morphology and anatomy of both staminate flowers and pistillate flowers were examined. Specifically, anther and stigma development, floral nectaries, floral nectary stomata, and staminodes and pistillodes were observed and characterized in this species, using both scanning electron microscopy and light microscopy. Furthermore, field experiments were designed to evaluate whether S. latifolia relies solely on insect pollinators for seed production and if so, determine when pollination is occurring, and to establish if seed production in this species is limited due to pollination limitation. It was found that S. latifolia was predominantly insect-pollinated and pollination occurred both day and night; however, in 2010 pollination occurred mainly at night. Furthermore, female plants that were further than 4m from a compatible pollen source experienced reduced pollination levels and thereby seed production was reduced. Results of the pollination experiments suggested that seed production in S. latifolia may be limited by insect-pollination. Our results help to illustrate the role of pollination in the establishment of S. latifolia in Saskatchewan. There were clear pollination limitations for S. latifolia as a weed, however, the unique floral biology of this species, such as indeterminate flowering, quick pollen release, and potentially large seed yields, has allowed it to establish in western Canada and become an important weed on forage and minimum tillage farms
Calcein and manganese experiments for marking the shell of the common cockle (<i>Cerastoderma edule</i>): tidal rhythm validation of increments formation
No full textThis work focuses on investigating the potential of calcein and manganese as growth
markers of the common cockle (Cerastoderma edule) in the bay of Somme
(France). Recapture of shells, previously marked using a chemical marking and then bred in
natural conditions, was performed in order to determine the shell growth patterns. Calcein
marking has shown a fluorescent increment in shells after only 30 min immersion time at
150 mg L-1, but also for shells immersed 3 h at 50 mg L-1. Likewise,
manganese shell marking was revealed under cathodoluminescence for shells immersed 1 h at
120 mg L-1 as well as for shells which spent 4 h at 90 mg L-1. A
numerical analysis performed on each marked cockles has revealed 23 micro-increments
between the mark and the ventral edge of the valves, corresponding to the 23 tides that
occurred during the 12 days at liberty post marking. The periodicity of increment
formation is thus validated for a tidal frequency. The growth rates of C.
edule, ranged from 11.67 to 19.94 μm d-1, decreased
significantly with increasing shell length. This preliminary study gives a clue to the
understanding of cockle growth and could be used in shellfish production for cockle age
monitoring, but also for chemical analysis to learn more about biomineralization process
of this species
Vaccaria pyramidata (Cow Cockle) : Cow Cockle
No full textClass: Dicotyledoneae
Family: Caryophyllaceae
Genus: Vaccaria
Species: pyramidat
Saponaria/Silene vaccaria (Cow Cockle) : Cow Cockle
No full textClass: Dicotyledoneae
Family: Caryophyllaceae
Genus: Saponaria/Silene
Species: vaccari
Ecologisch profiel van de litorale kokkelbank
No full text(See below for an English summary. Although the main content of this rapport is in Dutch) De Kokkel is een tweekleppig schelpdier dat algemeen voorkomt in de ondiepe kustwateren en estuaria van Nederland. Het dier leeft ondiep ingegraven in de bodem en komt vooral voor op bij laagwater droog vallende platen. Zijn voedsel bestaat uit in het water zwevende partikeltjes (plankton, detritus). De Kokkel komt niet regelmatig verspreid voor, maar in, soms zeer dichte, concentraties: de zogenoemde kokkelbanken. De kokkelbank die voorkomt op de bij laagwater droogvallende platen (litorale kokkelbank) is in het project Watersysteemverkenningen (WSV) gekozen als een van de biologische doelvariabelen voor het toetsen van de milieukwaliteit van de Nederlandse zoute wateren. In het Ecoprofiel komt naar voren dat het kokkelbestand in onze kustwateren grote jaarlijkse verschillen vertoont. Strenge winters en ijsgang hebben een sterk negatieve invloed op het voorkomen van kokkelbanken. Daarnaast wordt het kokkelbestand in sterke mate afgeroomd door de kokkelvisserij, met name in kokkelarme jaren. In het kader van de Structuurnota Zee- en kustvisserij zijn thans delen van de Waddenzee en de Oosterschelde gesloten voor de kokkelvisserij, en is tevens een regeling getroffen om in kokkelarme jaren een deel van het kokkelbestand te reserveren voor de daarop fouragerende steltlopers (o.a. Scholekster). -English- The Edible Cockle (Cerastoderma edule) is a common bivalve mollusc in Dutch estuarine and coastal waters. It lives very shallow in the sediment, mainly at intertidal flats. The species is a suspension feeder utilising suspended particles such as phytoplankton and detritus from the water column. Cerastoderma edule is not evenly distributed, but occurs aggregated in beds. In the 'Aquatic Outlook' project littoral beds with a density of more than 50 individuals per m^2 have been chosen as a sentinel for environmental quality of coastal waters. The Cockle stock shows large year-to-year fluctuations. Littoral beds of cockles are strongly affected by low winter temperatures and ice scour. Furthermore, cockle beds are intensively exploited by cockle fishers. Recent Dutch policy regarding fishery in coastal and marine waters provides in certain areas of the Wadden Sea and Oosterschelde to be closed for cockle fishery. In lean cockle years, in the area open for fishery a certain amount of cockles is withdrawn from fishery to become available for wader birds, such as the Oystercatcher (haematopus ostralegus).Watersysteemverkenningen (WSV) 199
Lifetime productivity of tree cavities used by cavity‐nesting animals in temperate and subtropical forests
No full textTree cavities are a critical multi-annual resource that can limit populations and structure communities of cavity-nesting vertebrates. We examined the regional and local factors influencing lifetime productivity (number and richness of occupants) of individual tree cavities across two divergent forest ecosystems: temperate mixed forest in Canada and subtropical Atlantic Forest, Argentina. We predicted that (1) species would accumulate more rapidly within cavities in the species-rich system (Argentina: 76 species) than the poorer system (Canada: 31 species), (2) cavity characteristics associated with nest-site selection in short-term studies would predict lifetime cavity productivity, and (3) species would accumulate more rapidly across highly used cavities than across cavities used only once, and in Argentina than in Canada. We monitored and measured nesting cavities used by birds and mammals over 22 breeding seasons (1995–2016) in Canada and 12 breeding seasons (2006–2017) in Argentina. Cavities were used an average of 3.1 times by 1.7 species in Canada and 2.2 times by 1.4 species in Argentina. Species richness within cavities increased with number of nesting events at similar rates in Canada and Argentina, in both cases much slower than expected if within-cavity species assemblages were random, suggesting that lifetime richness of individual cavities is more strongly influenced by local ecological factors (nest site fidelity, nest niche) than by the regional species pool. The major determinant of lifetime cavity productivity was the cavity’s life span. We found only weak or inconsistent relationships with cavity characteristics selected by individuals in short-term nest-site selection studies. Turnover among (vs. within) cavities was the primary driver of diversity at the landscape scale. In Canada, as predicted, species accumulation was fastest when sampling across high-use cavities. In Argentina, the rates of species accumulation were similar across high- and low-use cavities, and fastest when both high- and low-use cavities were pooled. These findings imply that biodiversity of cavity nesters is maintained by a mix of long-lived (highly productive, legacy trees) and many high-turnover (singleuse, fast decaying) tree cavities. Conservation of both long-lasting and single-use cavities should be incorporated into decisions about stand-level forest management, regional land use policies, and reserve networks.Fil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. University of British Columbia; CanadáFil: Trzcinski, Mark Kurtis. University of British Columbia; CanadáFil: Wiebe, Karen L.. University of Saskatchewan; CanadáFil: Edworthy, Amanda B.. University of British Columbia; CanadáFil: Martin, Kathy. Environment and Climate Change Canadá. Science & Technology Branch; Canadá. University of British Columbia; Canad
ASSESSMENT ON DEFECTS OF WET-BLUE HIDE AND PICKLED SKIN AT MODJO TANNERY
No full textAcross-sectional study was conducted from February to June 2015 with the objectives of identifying the major types of hide and skin defects and determining their prevalence in pickled skins of sheep and wet blue goat skins and hides originated from two districts namely Hitosa and Dodota of East Arsi Zone at the Colba and Gelan tanneries in Modjo town. A total of 389 wet blue cattle hides, 385 wet blue goat skin and 399 pickled sheep skin were examined. The study finding showed that there exist various defects responsible for the decline in quality of skin and hide. The major defects at the wet blue hide were flay cut (59.1), gouge mark (42.2), and putrefaction (35.2). In sheep pickled skin higher percentage of cockle (36.9), gouge mark (28.3) and scratch (27.0) were observed. In wet blue goat skin, cockle (48.1), veininess (44.6) and crack (41.9) were the major defects observed. The prevalence of cockle, veininess, scar, corduroying, crack, gouge mark, poor pattern and brand mark were significantly higher (P<0.05) in goat skin at wet blue stage than pickled sheep skin while putrefaction and shoat pox were significantly higher (P<0.05) in sheep skin compared to goat wet blue skin. The major defects that leads to rejection of wet blue hide were flay cut while cockle in sheep and goat skin. In pickled sheep skin, grade of 1-3 accounts 14 and grade 4-7 accounts 86 of the total observation. This study showed large proportion of skin and hides were subjected to rejection because of poor quality and this implies that integrated efforts towards improved livestock husbandry and better health care are vital issues for production of better-quality hide and skin. Furthermore, effective extension system and programs that could raise public awareness on ectoparasites and skin diseases control as well as on methods of flaying, preservation and handling of skins should be implemented. © 2020, Online Journal of Animal and Feed Research. All Rights Reserve
Heterogeneous microgeographic genetic structure of the common cockle (Cerastoderma edule) in the Northeast Atlantic Ocean: biogeographic barriers and environmental factors
No full textThe rights granted to the Author with respect to the Accepted Manuscript are subject to the conditions that (i) the Accepted Manuscript is not enhanced or substantially reformatted by the Author or any third party, and (ii) the Author includes on the Accepted Manuscript an acknowledgement in the following form, together with a link to the published version on the publisher’s website: “This version of the article has been accepted for publication, after peer review (when applicable) but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1038/s41437-023-00646-1. Use of this Accepted Version is subject to the publisher’s Accepted Manuscript terms of use https://www.springernature.com/la/open-research/policies/accepted-manuscript-terms#. Under no circumstances may an Accepted Manuscript be shared or distributed under a Creative Commons or other form of open access licenceKnowledge of genetic structure at the finest level is essential for the conservation of genetic resources. Despite no visible barriers limiting gene flow, significant genetic structure has been shown in marine species. The common cockle (Cerastoderma edule) is a bivalve of great commercial and ecological value inhabiting the Northeast Atlantic Ocean. Previous population genomics studies demonstrated significant structure both across the Northeast Atlantic, but also within small geographic areas, highlighting the need to investigate fine-scale structuring. Here, we analysed two geographic areas that could represent opposite models of structure for the species: (1) the SW British Isles region, highly fragmented due to biogeographic barriers, and (2) Galicia (NW Spain), a putative homogeneous region. A total of 9250 SNPs genotyped by 2b-RAD on 599 individuals from 22 natural beds were used for the analysis. The entire SNP dataset mostly confirmed previous observations related to genetic diversity and differentiation; however, neutral and divergent SNP outlier datasets enabled disentangling physical barriers from abiotic environmental factors structuring both regions. While Galicia showed a homogeneous structure, the SW British Isles region was split into four reliable genetic regions related to oceanographic features and abiotic factors, such as sea surface salinity and temperature. The information gathered supports specific management policies of cockle resources in SW British and Galician regions also considering their particular socio-economic characteristics; further, these new data will be added to those recently reported in the Northeast Atlantic to define sustainable management actions across the whole distribution range of the speciesThis study has been supported by the COCKLES project (grant number: EAPA_458/2016) of the INTERREG EUROPEAN PROGRAMME and the NERC-SHEAR project (NE/W001217/1)2024-02-19S
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