Seasonal variations of cold tolerance in intertidal mollusks and relation to environmental conditions in the St. Lawrence Estuary

1983 ◽  
Vol 61 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
Edwin Bourget
Keyword(s):  
Cold Tolerance ◽  
Seasonal Variations ◽  
Macoma Balthica ◽  
Mya Arenaria ◽  
Tidal Period ◽  
Lawrence Estuary ◽  
Cold Tolerant ◽  
St Lawrence Estuary ◽  
Large Adult ◽  
Selection Of

Seasonal variations of cold tolerance of Mytilus edulis, Mya arenaria, Macoma balthica, and Acmaea testudinalis were examined. The lower median lethal temperature (MLT) of all species was low throughout the year, with reduced seasonal variation. High MLT values, between −10 and −15 °C, were observed for Acmaea testudinalis and Mya arenaria, while low values, between −12.5 and −20 °C, were observed for Macoma and Mytilus. Seasonal variations of MLT are partly explained by the seasonal variations of water salinity. Small (juveniles) Mytilus, Mya, and Macoma showed less cold tolerance than large (adult) Mytilus, Mya, and Macoma (MLT between −8.0 and −12.5 °C). The possibility of genetic adaptation due to the selection of cold tolerant individuals is discussed. Cold tolerance determinations of animals subjected to cyclic emersions of various durations to a "sublethal" temperature of −8 °C every 12.4 h (one tidal period) showed a cumulative and significant effect of repeated mild cold stress. The ecological significance of the results is discussed in relation to the conditions prevailing along the shores of the St. Lawrence Estuary.

Anadromous Sturgeons: Habitats, Threats, and Management

2007 ◽  
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Atlantic Sturgeon ◽  
Lawrence Estuary ◽  
Early Juvenile ◽  
Salt Wedge ◽  
Sandy Substrate ◽  
Core Areas ◽  
St Lawrence Estuary ◽  
Selection Of

<em>Abstract</em>.—Space use and habitat selection of early juvenile Atlantic sturgeon <em>Acipenser oxyrinchus</em> have been little studied and remain largely unknown throughout the species’ range. In 2000–2002, survey trawling, ultrasonic telemetry, benthos sampling, and hydrodynamic modeling were used to determine the summer movement patterns, home range size, and habitat use and selection of early juvenile Atlantic sturgeon in the St. Lawrence estuary. Sonic-tagged Atlantic sturgeon, assumed to be age 2 based on their size, used a global area estimated at 76 km2 that included two main core areas. Individual summer home range sizes varied from 1 to 8 km2, but core areas were generally smaller than 1 km2. The mean daily distance traveled ranged from 0.4 to 13.5 km/d and was significantly related to sturgeon size. Fish were located mostly in freshwater relatively close to the salt wedge boundary and far from the shore, intertidal zones, and islands. They mostly used the 6–10-m depth range relatively close to a channel, in areas with low bottom current velocities, and over silt–clay substrates. Salinity and distance from the salt wedge were the two most important variables explaining their habitat selection. Age-0 Atlantic sturgeon used similar depth ranges, bottom salinities, and current velocities, but occupied mainly sandy substrate. Management implications of these results are discussed in relation to the impact of dredging and sediment disposal operations in the St. Lawrence estuary.

scholarly journals NILs of Cold Tolerant Japonica Cultivar Exhibited New QTLs for Mineral Elements in Rice

2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Kazim Ali ◽  
Zheng-Hai Sun ◽  
Xiao-Meng Yang ◽  
Xiao-Ying Pu ◽  
Cheng-Li Duan ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Cold Tolerance ◽  
Morphological Analysis ◽  
Chilling Stress ◽  
Mineral Elements ◽  
Leaf Length ◽  
P Element ◽  
Booting Stage ◽  
Cold Tolerant ◽  
Selection Of

Chilling stress at booting stage can cause floret deterioration and sterility by limiting the supply of food chain and the accumulation of essential mineral elements resulting in reduction of yield and grain quality attributes in rice. Genomic selection of chilling tolerant rice with reference to the accumulation of mineral elements will have great potential to cope with malnutrition and food security in times of climate change. Therefore, a study was conducted to explore the genomic determinants of cold tolerance and mineral elements content in near-isogenic lines (NILs) of japonica rice subjected to chilling stress at flowering stage. Detailed morphological analysis followed by quantitative analysis of 17 mineral elements revealed that the content of phosphorus (P, 3,253 mg/kg) and potassium (K, 2,485 mg/kg) were highest while strontium (Sr, 0.26 mg/kg) and boron (B, 0.34 mg/kg) were lowest among the mineral elements. The correlation analysis revealed extremely positive correlation of phosphorus (P) and copper (Cu) with most of the cold tolerance traits. Among all the effective ear and the second leaf length correlation was significant with half of the mineral elements. As a result of comparative analysis, some QTLs (qBRCC-1, qBRCIC-2, qBRZC-6, qBRCHC-6, qBRMC-6, qBRCIC-6a, qBRCIC-6b, qBRCHC-6, and qBRMC-6) identified for calcium (Ca), zinc (Zn), chromium (Cr) and magnesium (Mg) on chromosome number 1, 2, and 6 while, a novel QTL (qBCPC-1) was identified on chromosome number 1 for P element only. These findings provided bases for the identification of candidate genes involved in mineral accumulation and cold tolerance in rice at booting stage.

Relationships between intertidal clam population and health status of the soft-shell clam Mya arenaria in the St. Lawrence Estuary and Saguenay Fjord (Québec, Canada)

2008 ◽  
Vol 34 (1) ◽  
pp. 30-43 ◽  
Author(s):  
F. Gagné ◽  
C. Blaise ◽  
J. Pellerin ◽  
M. Fournier ◽  
M.J. Durand ◽  
...  
Keyword(s):  
Health Status ◽  
Mya Arenaria ◽  
Lawrence Estuary ◽  
Soft Shell Clam ◽  
Saguenay Fjord ◽  
Soft Shell ◽  
St Lawrence Estuary ◽  
Clam Population

PRELIMINARY STUDIES ON THE COLD TOLERANCE OF SOYBEAN SEEDLINGS

1976 ◽  
Vol 56 (2) ◽  
pp. 371-375 ◽  
Author(s):  
D. A. LITTLEJOHNS ◽  
J. W. TANNER
Keyword(s):  
Cold Tolerance ◽  
Growth Analysis ◽  
Fresh Weight ◽  
Soybean Seedlings ◽  
Close Relationship ◽  
Cold Tolerant ◽  
Glycine Max L ◽  
Loam Soil ◽  
Selection Of

Emergence experiments were conducted on 32 soybean (Glycine max (L.) Merrill) cultivars at a 2.5-cm depth in Guelph loam soil at 10, 20 and 30 C. Differences in emergence were found among cultivars at 10 C but not at 20 and 30 C. Results of the emergence experiment at 10 C permitted classification of cultivars into cold tolerant, intermediate and intolerant groupings. There was no close relationship between maturity group and degree of cold tolerance. Differences in speed of germination were found among cultivars at 10 C. A correlation coefficient (r = +0.616) between germination and emergence indicates that germination at 10 C would be effective in the selection of cold tolerant types. Growth analysis studies on seedlings up to the unifoliolate leaf stage showed that cold tolerant cultivars had a higher fresh weight at a specific age at 10 C. This was attributed to the faster emergence of the cold tolerant cultivars.

scholarly journals MaMAPK3-MaICE1-MaPOD P7 pathway, a positive regulator of cold tolerance in banana

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jie Gao ◽  
Tongxin Dou ◽  
Weidi He ◽  
Ou Sheng ◽  
Fangcheng Bi ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Cold Tolerance ◽  
Molecular Breeding ◽  
Cold Resistance ◽  
Oxidoreductase Activity ◽  
Tropical Fruit ◽  
Over Expression ◽  
Cavendish Banana ◽  
Cold Tolerant ◽  
Necrotic Symptoms

Abstract Background Banana is a tropical fruit with a high economic impact worldwide. Cold stress greatly affects the development and production of banana. Results In the present study, we investigated the functions of MaMAPK3 and MaICE1 involved in cold tolerance of banana. The effect of RNAi of MaMAPK3 on Dajiao (Musa spp. ‘Dajiao’; ABB Group) cold tolerance was evaluated. The leaves of the MaMAPK3 RNAi transgenic plants showed wilting and severe necrotic symptoms, while the wide-type (WT) plants remained normal after cold exposure. RNAi of MaMAPK3 significantly changed the expressions of the cold-responsive genes, and the oxidoreductase activity was significantly changed in WT plants, while no changes in transgenic plants were observed. MaICE1 interacted with MaMAPK3, and the expression level of MaICE1 was significantly decreased in MaMAPK3 RNAi transgenic plants. Over-expression of MaICE1 in Cavendish banana (Musa spp. AAA group) indicated that the cold resistance of transgenic plants was superior to that of the WT plants. The POD P7 gene was significantly up-regulated in MaICE1-overexpressing transgenic plants compared with WT plants, and the POD P7 was proved to interact with MaICE1. Conclusions Taken together, our work provided new and solid evidence that MaMAPK3-MaICE1-MaPOD P7 pathway positively improved the cold tolerance in monocotyledon banana, shedding light on molecular breeding for the cold-tolerant banana or other agricultural species.

scholarly journals Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
Author(s):  
M. Alkhatib ◽  
P. A. del Giorgio ◽  
Y. Gelinas ◽  
M. F. Lehmann
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bottom Water ◽  
Estuarine Sediments ◽  
Internal Source ◽  
Lawrence Estuary ◽  
Element Partitioning ◽  
Sediment Porewaters ◽  
St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Pre-exposure to Cu2+ and CuO NPs leads to infection of caged blue mussels, Mytilus edulis L., by pathogenic microalga: Pilot study in the Lower St. Lawrence Estuary (Québec, Canada)

2021 ◽  
Vol 166 ◽  
pp. 112180
Author(s):  
Michael Zuykov ◽  
Galina Kolyuchkina ◽  
Graeme Spiers ◽  
Michel Gosselin ◽  
Philippe Archambault ◽  
...  
Keyword(s):  
Pilot Study ◽  
Mytilus Edulis ◽  
Lawrence Estuary ◽  
Blue Mussels ◽  
Cuo Nps ◽  
St Lawrence Estuary
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