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Chang-keun Kang - One of the best experts on this subject based on the ideXlab platform.

  • Seasonal Variations of Microphytobenthos in Sediments of the Estuarine Muddy Sandflat of Gwangyang Bay: HPLC Pigment Analysis
    2009
    Co-Authors: Yong-woo Lee, Eun Jung Choi, Young-sang Kim, Chang-keun Kang
    Abstract:

    Seasonal variations of microalgal biomass and community composition in both the sediment and the seawater were investigated by HPLC pigment analysis in an estuarine muddy sandflat of Gwangyang Bay from January to November 2002. Based on the photosynthetic pigments, fucoxanthin, diadinoxanthin, and diatoxanthin were the most dominant pigments all the year round, indicating that diatoms were the predominant algal groups of both the sediment and the seawater in Gwangyang Bay. The other algal pigments except the diatom-marker pigments showed relatively low concentrations. Microphytobenthic chlorophyll concentrations in the upper layer (0.5 cm) of sediments ranged from 3.44 (March at the middle site of the tidal flat) to 169 (July at the upper site) mg , with the annual mean concentrations of at the upper, middle, and lower tidal sites, respectively. Depth-integrated chlorophyll concentrations in the overlying water column ranged from 1.66 (November) to 11.7 (July) mg , with an annual mean of . Microphytobenthic biomasses were about 310 times higher than depth-integrated phytoplankton biomass in the overlying water column. The physical characteristics of this shallow estuarine tidal flat, similarity in taxonomic composition of the phytoplankton and Microphytobenthos, and similar seasonal patterns in their biomasses suggest that resuspended Microphytobenthos are an important component of phytoplankton biomass in Gwangyang Bay. Therefore, considering the importance of Microphytobenthos as possible food source for the estuarine benthic and pelagic consumers, a consistent monitoring work on the behavior of Microphytobenthos is needed in the tidal flat ecosystems.

  • Microphytobenthos seasonality determines growth and reproduction in intertidal bivalves
    Marine Ecology Progress Series, 2006
    Co-Authors: Chang-keun Kang, Yong-woo Lee, Eun Jung Choy, Jae-ki Shin, In-soo Seo, Jae-sang Hong
    Abstract:

    The annual cycles of phytoplanktonic and microphytobenthic biomasses as food sources for intertidal bivalves were investigated in a temperate estuarine muddy sandflat of Kwangyang Bay (Korea) from January to December 2002. Seasonal patterns in growth and reproductive activity of a suspension-feeder Laternula marilina and a deposit-feeder Moerella rutila were examined in order to assess their relationship with the annual cycles of pelagic and benthic microalgae, and were com- bined with analyses of δ 13 C and δ 15 N of bivalve tissues and their potential food resources. Biomasses of phytoplankton and Microphytobenthos peaked in late spring-summer, and demonstrated a uni- modal pattern of seasonal variation. Photosynthetic pigment composition showed a predominance of diatom marker pigment, fucoxanthin, in the water and the sediments throughout the year. Similar patterns of annual cycles in pelagic and benthic microalgal biomasses and similarities in taxonomic composition indicated that resuspended Microphytobenthos is an important contributor to the bay's phytoplankton component. This was supported by the δ 13 C values of suspended particulate organic matter (POM) and physical characteristics of the bay. Synchrony in growth and reproductive activity was observed for both bivalves: their shell and tissue growth and gonadal development were achieved together during late spring and summer when chlorophyll a (chl a) concentrations were highest. This temporal coupling of macrofaunal and microalgal processes indicated that the activities of intertidal bivalves might depend largely on Microphytobenthos seasonality. The isotopic signa- tures of the bivalve tissues demonstrated their dependence on organic matter of microphytobenthic source irrespective of season, despite a comparable contribution of phytoplankton to the diet of the suspension-feeding bivalve. These results highlight the importance of seasonal development of Microphytobenthos as an available food source during the critical period of gamete production and growth for both suspension- and deposit-feeding bivalves.

  • Stable isotope evidence of benthic microalgae-based growth and secondary production in the suspension feeder Cerastoderma edule (Mollusca, Bivalvia) in the Marennes-Oléron Bay
    Hydrobiologia, 2000
    Co-Authors: Pierre-guy Sauriau, Chang-keun Kang
    Abstract:

    The contribution of natural food sources to the growth and secondary production of the suspension feeding bivalve Cerastoderma edule (L.) was estimated under field conditions in the Marennes-Oléron Bay (Atlantic coast, France). Monthly estimates of abundance, biomass and cockle growth were combined with seasonal analyses of δ13C and δ15N ratios of juvenile and adult cockles, together with their potential food sources [i.e. suspended particulate organic matter (POM), Microphytobenthos, macroalgae and seagrass] sampled at mid-tide level in a muddy sandflat. Adult cockles grew mainly in spring, whereas juveniles grew in summer and autumn, following spat recruitment in early summer. Total annual production and elimination of cockles were estimated to be 32.5 and 34.7 g AFDW m−2 yr−1. Relative contributions of each year class to production were ca 40, 41, 11 and 6% for 0-group, 1-, 3- and 4-yr-old cockles in 1995, respectively. Quantitative assessment of proportions of food sources to the annual secondary production of cockles was obtained by using a simple carbon isotope-mixing model with Microphytobenthos (δ13C = −16.0±0.6‰) and POM (δ13C = −22.2±1.1‰) as end-members. On average, more than 70% of the total annual cockle production originated from Microphytobenthos, with a much higher contribution for the 0-group (88%) than for adult cockles (60%). The between-age difference was induced mainly by changes in the availability of food resources (benthic versus planktonic) during the non-synchronous growing seasons of juvenile and adult cockles.

  • stable isotope evidence of benthic microalgae based growth and secondary production in the suspension feeder cerastoderma edule mollusca bivalvia in the marennes oleron bay
    Hydrobiologia, 2000
    Co-Authors: Pierre-guy Sauriau, Chang-keun Kang
    Abstract:

    The contribution of natural food sources to the growth and secondary production of the suspension feeding bivalve Cerastoderma edule (L.) was estimated under field conditions in the Marennes-Oleron Bay (Atlantic coast, France). Monthly estimates of abundance, biomass and cockle growth were combined with seasonal analyses of δ13C and δ15N ratios of juvenile and adult cockles, together with their potential food sources [i.e. suspended particulate organic matter (POM), Microphytobenthos, macroalgae and seagrass] sampled at mid-tide level in a muddy sandflat. Adult cockles grew mainly in spring, whereas juveniles grew in summer and autumn, following spat recruitment in early summer. Total annual production and elimination of cockles were estimated to be 32.5 and 34.7 g AFDW m−2 yr−1. Relative contributions of each year class to production were ca 40, 41, 11 and 6% for 0-group, 1-, 3- and 4-yr-old cockles in 1995, respectively. Quantitative assessment of proportions of food sources to the annual secondary production of cockles was obtained by using a simple carbon isotope-mixing model with Microphytobenthos (δ13C = −16.0±0.6‰) and POM (δ13C = −22.2±1.1‰) as end-members. On average, more than 70% of the total annual cockle production originated from Microphytobenthos, with a much higher contribution for the 0-group (88%) than for adult cockles (60%). The between-age difference was induced mainly by changes in the availability of food resources (benthic versus planktonic) during the non-synchronous growing seasons of juvenile and adult cockles.

  • Food sources of an infaunal suspension-feeding bivalve Cerastoderma edule in a muddy sandflat of Marennes-Oléron Bay, as determined by analyses of carbon and nitrogen stable isotopes
    Marine Ecology Progress Series, 1999
    Co-Authors: Chang-keun Kang, Pierre-guy Sauriau, Pierre Richard, Gérard F. Blanchard
    Abstract:

    Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oléron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ13C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronce-les-Bains tidal flats had δ13C values distinct from that of the POM: Microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6‰), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ15N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for Microphytobenthos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ13C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ15N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: Microphytobenthos and POM. Seasonal variations in δ13C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to Microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.

Gérard F. Blanchard - One of the best experts on this subject based on the ideXlab platform.

  • Food sources of an infaunal suspension-feeding bivalve Cerastoderma edule in a muddy sandflat of Marennes-Oléron Bay, as determined by analyses of carbon and nitrogen stable isotopes
    Marine Ecology Progress Series, 1999
    Co-Authors: Chang-keun Kang, Pierre-guy Sauriau, Pierre Richard, Gérard F. Blanchard
    Abstract:

    Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oléron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ13C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronce-les-Bains tidal flats had δ13C values distinct from that of the POM: Microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6‰), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ15N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for Microphytobenthos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ13C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ15N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: Microphytobenthos and POM. Seasonal variations in δ13C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to Microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.

  • food sources of the infaunal suspension feeding bivalve cerastoderma edule in a muddy sandflat of marennes oleron bay as determined by analyses of carbon and nitrogen stable isotopes
    Marine Ecology Progress Series, 1999
    Co-Authors: Chang-keun Kang, Pierre-guy Sauriau, Pierre Richard, Gérard F. Blanchard
    Abstract:

    Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oleron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ 13 C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronce-les-Bains tidal flats had δ 13 C values distinct from that of the POM: Microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6‰), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ 15 N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for Microphytobenthos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ 13 C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ 15 N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: Microphytobenthos and POM. Seasonal variations in δ 13 C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to Microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.

  • Effect of production and biomass of intertidal Microphytobenthos on meiofaunal grazing rates
    Journal of Experimental Marine Biology and Ecology, 1995
    Co-Authors: Paul A Montagna, Gérard F. Blanchard, Alain Dinet
    Abstract:

    Abstract Microphytobenthos dominate primary production in unvegetated intertidal habitats. Meiofauna are likely to be important consumers of this productivity, yet little is known about meiofauna herbivory in these environments. We studied meiofaunal grazing on Microphytobenthos from an intertidal mudflat on the southwest coast of France. Meiofaunal grazing rates were measured in response to manipulations that varied Microphytobenthos production and biomass to determine if meiofauna have functional responses to changes in food quality and quantity. Harpacticoid and ostracod grazing rates did not change in response to changes of Microphytobenthos production, but nematode grazing rates did increase with increasing production. As Microphytobenthos biomass increased, meiofauna responded with greater grazing rates, removing more biomass per unit time, yet taking longer periods of time to deplete (or clear) the microbial population. Therefore, meiofauna taxa exhibited functional responses to Microphytobenthos as food, although different taxa had different responses. The impact of these responses in the laboratory could be seen in the field. For example, when chlorophyll a (Chl a) concentration in the top 1 cm of sediment increased from 31.7 mg · m−2 to 124 mg · m−2 2 wk later, the total community grazing rates increased from 32.9 ng Chl a · h−1 to 176 ng Chl a · h−1. Harpacticoid densities also increased 2.7 times, but nematode and ostracod densities remained the same. The results of this study support the idea that intertidal meiofauna, particularly harpacticoids, have a dependent relationship with their autotrophic food resources in intertidal habitats and can regulate their behavior to maximize intake of food.

  • Photo synthetic characteristics of Microphytobenthos in Marennes-Oléron Bay, France: Preliminary results
    Journal of Experimental Marine Biology and Ecology, 1994
    Co-Authors: Gérard F. Blanchard, Valerie Cariou-le Gall
    Abstract:

    Abstract The photosynthetic characteristics of Microphytobenthos inhabiting an intertidal mudflat in Marennes-Oleron Bay (France) have been studied on samples collected at the air-sediment interface during low tide. Photosynthesis-Irradiance (P-I) parameters were estimated at different times of low tide in March and in July. In summer, two different sediment depths were also compared. The results point out different kinds of changes in the photophysiological characteristics of Microphytobenthos, according to the time scale under consideration. At a seasonal scale, there was an increase of I k from March to July, thus indicating photoacclimation of Microphytobenthos. At an hourly scale there was no change in I k . In March, there was no change in P-I parameters, but there was a significant change of α B and P m B in July with the highest values at T 3 (middle of low tide) at the surface of the sediment. It is speculated that this change could be due to an endogenous photosynthetic rhythm. There was no difference in the photosynthetic characteristics of Microphytobenthos from the photic and the aphotic layers, suggesting sediment mixing by physical and/or biological processes (or microalgal migration) at a rate compatible with the persistence of the photosynthetic response in the aphotic layer. Although benthic microalgae did experience photoinhibition in experimental conditions, there was no indication of a photoinhibitory effect in situ. This suggests that microalgae were not exposed to strong illumination for extended periods of time during low tide in spite of the direct exposure of the mudflat to incident irradiance. We suggest that the strong attenuation of light within the sediment, selfshading within algal mats, the motility of microalgae, and bioturbation can explain this apparent paradox.

  • photosynthetic response of natural assemblages of marine benthic microalgae to short and long term variations of incident irradiance in baffin bay texas1
    Journal of Phycology, 1992
    Co-Authors: Gérard F. Blanchard, Paul A Montagna
    Abstract:

    This study was designed to understand the high variability characterizing primary production rates of Microphytobenthos. The photosynthetic efficiency (αB) and photosynthetic capacity (PBmax) of the Microphytobenthos were measured at different times of the day on two different dates (8 May and 7 July 1990). In July, unusually low light conditions were caused by the development of a brown tide (chrysophytes). Both light-limited and light-saturated photosynthesis changed at hourly and monthly scales. There was a linear relationship between αB and PBmax, suggesting a common response to environmental factors [αB= 0.0075(±0.00063)·PBmax+ 0.00097(±0.0071), R2= 0.94]. Incident irradiance at the sediment-water interface was the primary physical factor that explained variability of both αB (84%) and PBmax (92%). Temperature had a negative but minor effect that explained an extra 8% and 2% of the variance, respectively. There was no diel rhythm of αB and PBmax and incident irradiance was regulated by wind-induced currents. Therefore, Microphytobenthos photosynthesis seemed to be primarily controlled by wind events in Baffin Bay.

J E E Van Beusekom - One of the best experts on this subject based on the ideXlab platform.

Francis Orvain - One of the best experts on this subject based on the ideXlab platform.

  • Contrasted impact of two macrofaunal species (Hediste diversicolor and Scrobicularia plana) on Microphytobenthos spatial distribution and photosynthetic activity at microscale
    Marine Environmental Research, 2021
    Co-Authors: Jerome Morelle, Olivier Maire, Anais Richard, Alex Slimani, Francis Orvain
    Abstract:

    Microphytobenthos is most often the primary source of carbon for coastal soft-sediment communities, especially in intertidal and shallow subtidal environments. The influence of benthic macrofaunal organisms on microphytobenthic biomass, spatial distribution and photosynthetic capacities is not only resulting from their feeding intensity but also indirectly from their bioturbation activity, which regulates nutrient fluxes and sediment mixing. This study compares the impact of two species (Hediste diversicolor and Scrobicularia plana) that dominate macrofaunal communities in estuarine intertidal mudflats on microphytobenthic biomass and photosynthetic activity. Imaging-PAM fluorescence was used to non-invasively map the development of microphytobenthic biomass and to assess its spatial extent. Our results showed that, due to intense deposit feeding, Scrobicularia plana quickly limited Microphytobenthos growth and photosynthetic activity, even at low density (<250 ind m(-2)). In contrast, the negative impact of Hediste diversicolor on Microphytobenthos development due to direct consumption was very low. Thereby, the stimulation of nutrient fluxes at the sediment-water interface resulting from bioirrigation seems to enhance Microphytobenthos growth and photosynthesis.

  • Contrasted impact of two macrofaunal species (Hediste diversicolor and Scrobicularia plana) on Microphytobenthos spatial distribution and photosynthetic activity at microscale.
    Marine environmental research, 2020
    Co-Authors: Jerome Morelle, Olivier Maire, Anais Richard, Alex Slimani, Francis Orvain
    Abstract:

    Microphytobenthos is most often the primary source of carbon for coastal soft-sediment communities, especially in intertidal and shallow subtidal environments. The influence of benthic macrofaunal organisms on microphytobenthic biomass, spatial distribution and photosynthetic capacities is not only resulting from their feeding intensity but also indirectly from their bioturbation activity, which regulates nutrient fluxes and sediment mixing. This study compares the impact of two species (Hediste diversicolor and Scrobicularia plana) that dominate macrofaunal communities in estuarine intertidal mudflats on microphytobenthic biomass and photosynthetic activity. Imaging-PAM fluorescence was used to non-invasively map the development of microphytobenthic biomass and to assess its spatial extent. Our results showed that, due to intense deposit feeding, Scrobicularia plana quickly limited Microphytobenthos growth and photosynthetic activity, even at low density (

Pierre-guy Sauriau - One of the best experts on this subject based on the ideXlab platform.

  • Stable isotope evidence of benthic microalgae-based growth and secondary production in the suspension feeder Cerastoderma edule (Mollusca, Bivalvia) in the Marennes-Oléron Bay
    Hydrobiologia, 2000
    Co-Authors: Pierre-guy Sauriau, Chang-keun Kang
    Abstract:

    The contribution of natural food sources to the growth and secondary production of the suspension feeding bivalve Cerastoderma edule (L.) was estimated under field conditions in the Marennes-Oléron Bay (Atlantic coast, France). Monthly estimates of abundance, biomass and cockle growth were combined with seasonal analyses of δ13C and δ15N ratios of juvenile and adult cockles, together with their potential food sources [i.e. suspended particulate organic matter (POM), Microphytobenthos, macroalgae and seagrass] sampled at mid-tide level in a muddy sandflat. Adult cockles grew mainly in spring, whereas juveniles grew in summer and autumn, following spat recruitment in early summer. Total annual production and elimination of cockles were estimated to be 32.5 and 34.7 g AFDW m−2 yr−1. Relative contributions of each year class to production were ca 40, 41, 11 and 6% for 0-group, 1-, 3- and 4-yr-old cockles in 1995, respectively. Quantitative assessment of proportions of food sources to the annual secondary production of cockles was obtained by using a simple carbon isotope-mixing model with Microphytobenthos (δ13C = −16.0±0.6‰) and POM (δ13C = −22.2±1.1‰) as end-members. On average, more than 70% of the total annual cockle production originated from Microphytobenthos, with a much higher contribution for the 0-group (88%) than for adult cockles (60%). The between-age difference was induced mainly by changes in the availability of food resources (benthic versus planktonic) during the non-synchronous growing seasons of juvenile and adult cockles.

  • stable isotope evidence of benthic microalgae based growth and secondary production in the suspension feeder cerastoderma edule mollusca bivalvia in the marennes oleron bay
    Hydrobiologia, 2000
    Co-Authors: Pierre-guy Sauriau, Chang-keun Kang
    Abstract:

    The contribution of natural food sources to the growth and secondary production of the suspension feeding bivalve Cerastoderma edule (L.) was estimated under field conditions in the Marennes-Oleron Bay (Atlantic coast, France). Monthly estimates of abundance, biomass and cockle growth were combined with seasonal analyses of δ13C and δ15N ratios of juvenile and adult cockles, together with their potential food sources [i.e. suspended particulate organic matter (POM), Microphytobenthos, macroalgae and seagrass] sampled at mid-tide level in a muddy sandflat. Adult cockles grew mainly in spring, whereas juveniles grew in summer and autumn, following spat recruitment in early summer. Total annual production and elimination of cockles were estimated to be 32.5 and 34.7 g AFDW m−2 yr−1. Relative contributions of each year class to production were ca 40, 41, 11 and 6% for 0-group, 1-, 3- and 4-yr-old cockles in 1995, respectively. Quantitative assessment of proportions of food sources to the annual secondary production of cockles was obtained by using a simple carbon isotope-mixing model with Microphytobenthos (δ13C = −16.0±0.6‰) and POM (δ13C = −22.2±1.1‰) as end-members. On average, more than 70% of the total annual cockle production originated from Microphytobenthos, with a much higher contribution for the 0-group (88%) than for adult cockles (60%). The between-age difference was induced mainly by changes in the availability of food resources (benthic versus planktonic) during the non-synchronous growing seasons of juvenile and adult cockles.

  • Food sources of an infaunal suspension-feeding bivalve Cerastoderma edule in a muddy sandflat of Marennes-Oléron Bay, as determined by analyses of carbon and nitrogen stable isotopes
    Marine Ecology Progress Series, 1999
    Co-Authors: Chang-keun Kang, Pierre-guy Sauriau, Pierre Richard, Gérard F. Blanchard
    Abstract:

    Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oléron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ13C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronce-les-Bains tidal flats had δ13C values distinct from that of the POM: Microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6‰), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ15N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for Microphytobenthos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ13C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ15N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: Microphytobenthos and POM. Seasonal variations in δ13C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to Microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.

  • food sources of the infaunal suspension feeding bivalve cerastoderma edule in a muddy sandflat of marennes oleron bay as determined by analyses of carbon and nitrogen stable isotopes
    Marine Ecology Progress Series, 1999
    Co-Authors: Chang-keun Kang, Pierre-guy Sauriau, Pierre Richard, Gérard F. Blanchard
    Abstract:

    Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oleron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean δ 13 C value of -22.2 ± 1.1‰ (n = 19). Benthic primary producers on Ronce-les-Bains tidal flats had δ 13 C values distinct from that of the POM: Microphytobenthos (-16.0 ± 0.6‰), the macroalgae Enteromorpha compressa (-17.6 ± 2.8‰), Fucus serratus (-17.4 ± 2.6‰), Fucus vesiculosus (-18.5 ± 1.6‰), Phorphyra umbilicalis (-19.7 ± 0.5‰), Ulva rigida (-14.7 ± 2.0‰) and the seagrass Zostera noltii (-11.1 ± 1.0‰). Mean δ 15 N values of all macroalgae species ranged from 7.6 ± 1.3 to 8.9 ± 1.0‰, while those for Microphytobenthos, POM and seagrass were 5.3 ± 0.8, 5.0 ± 0.9 and 6.5 ± 1.3‰, respectively. The mean δ 13 C value of spat (-15.3 ± 0.8‰) and juvenile cockles (-15.7 ± 0.7‰) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 ± 1.2‰). The δ 15 N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 ± 0.9‰ for 0-group and 8.4 ± 1.1‰ for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: Microphytobenthos and POM. Seasonal variations in δ 13 C values reflect a higher dependence of adult cockles on POM variability while spat and juveniles are more closely linked to Microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.