2020 Vol. 39, No. 2
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2020, 39(2): .
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2020, 39(2): .
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Seasonal and spatial variations of dimethylsulfoxide (DMSO) in the East China Sea and the Yellow Sea
2020, 39(2): 1-11.
doi: 10.1007/s13131-020-1549-5
Abstract:
Seasonal and spatial distributions of dissolved and particulate dimethylsulfoxide (DMSOd, DMSOp) were measured in the East China Sea and the Yellow Sea during March–April 2011 and October–November 2011. The concentrations of DMSOd and DMSOp in the surface water were 20.6 (5.13–73.8) and 8.90 (3.75–29.6) nmol/L in spring, and 13.4 (4.17–42.7) and 8.18 (3.44–22.6) nmol/L in autumn, respectively. Both DMSOd and DMSOp concentrations revealed similar seasonal changes with higher values occurring in spring, mainly because of the higher phytoplankton biomass observed in spring. Moreover, the ratios of DMSOp/chlorophyll a also exhibited an apparent seasonal change with higher values in autumn (35.7 mmol/g) and lower values in spring (23.4 mmol/g), thereby corresponding with the seasonal variation in the proportion of DMSO producers in the phytoplankton community between spring and autumn. In addition, DMSOd and DMSOp concentrations in the surface seawater revealed obvious diurnal variations with the maxima appearing in the afternoon.
Seasonal and spatial distributions of dissolved and particulate dimethylsulfoxide (DMSOd, DMSOp) were measured in the East China Sea and the Yellow Sea during March–April 2011 and October–November 2011. The concentrations of DMSOd and DMSOp in the surface water were 20.6 (5.13–73.8) and 8.90 (3.75–29.6) nmol/L in spring, and 13.4 (4.17–42.7) and 8.18 (3.44–22.6) nmol/L in autumn, respectively. Both DMSOd and DMSOp concentrations revealed similar seasonal changes with higher values occurring in spring, mainly because of the higher phytoplankton biomass observed in spring. Moreover, the ratios of DMSOp/chlorophyll a also exhibited an apparent seasonal change with higher values in autumn (35.7 mmol/g) and lower values in spring (23.4 mmol/g), thereby corresponding with the seasonal variation in the proportion of DMSO producers in the phytoplankton community between spring and autumn. In addition, DMSOd and DMSOp concentrations in the surface seawater revealed obvious diurnal variations with the maxima appearing in the afternoon.
Distribution patterns of 210Po, 210Pb and the particle export in the Taiwan Strait during the winter
2020, 39(2): 12-21.
doi: 10.1007/s13131-020-1550-z
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210Po and 210Pb are increasingly used to constrain particle dynamics in the open oceans, however they are less used in coastal waters. Here, distributions and partitions of 210Po and 210Pb were examined in the Taiwan Strait, as well as their application to quantify particle sinking. Activity concentrations of dissolved 210Po and 210Pb (<0.6 μm) ranged from 1.21 to 7.63 dpm/(100 L) and from 1.07 to 6.33 dpm/(100 L), respectively. Activity concentrations of particulate 210Po and 210Pb varied from 1.96 to 36.74 dpm/(100 L) and from 3.11 to 38.06 dpm/(100 L). Overall, particulate 210Po and 210Pb accounted for the majority of the bulk 210Po and 210Pb. 210Po either in dissolved or particulate phases showed similar spatial patterns to 210Pb, indicating similar mechanisms for controlling the distributions of 210Po and 210Pb in the Taiwan Strait. The different fractionation coefficients indicated that particles in the Zhemin Coastal Current (ZCC) inclined to absorb 210Po prior to 210Pb while they showed an opposite effect in the Taiwan Warm Current (TWC). Based on the disequilibria between 210Po and 210Pb, the sinking fluxes of total particulate matter (TPM) were estimated to range from –0.22 to 3.84 g/(m2·d), showing an overall comparable spatial distribution to previous reported sediment accumulation rates. However, our sinking fluxes were lower than the sedimentation rates, indicating a sediment resuspension in winter and horizontal transport of particulate matter from the Taiwan Strait to the East China Sea.
210Po and 210Pb are increasingly used to constrain particle dynamics in the open oceans, however they are less used in coastal waters. Here, distributions and partitions of 210Po and 210Pb were examined in the Taiwan Strait, as well as their application to quantify particle sinking. Activity concentrations of dissolved 210Po and 210Pb (<0.6 μm) ranged from 1.21 to 7.63 dpm/(100 L) and from 1.07 to 6.33 dpm/(100 L), respectively. Activity concentrations of particulate 210Po and 210Pb varied from 1.96 to 36.74 dpm/(100 L) and from 3.11 to 38.06 dpm/(100 L). Overall, particulate 210Po and 210Pb accounted for the majority of the bulk 210Po and 210Pb. 210Po either in dissolved or particulate phases showed similar spatial patterns to 210Pb, indicating similar mechanisms for controlling the distributions of 210Po and 210Pb in the Taiwan Strait. The different fractionation coefficients indicated that particles in the Zhemin Coastal Current (ZCC) inclined to absorb 210Po prior to 210Pb while they showed an opposite effect in the Taiwan Warm Current (TWC). Based on the disequilibria between 210Po and 210Pb, the sinking fluxes of total particulate matter (TPM) were estimated to range from –0.22 to 3.84 g/(m2·d), showing an overall comparable spatial distribution to previous reported sediment accumulation rates. However, our sinking fluxes were lower than the sedimentation rates, indicating a sediment resuspension in winter and horizontal transport of particulate matter from the Taiwan Strait to the East China Sea.
2020, 39(2): 22-27.
doi: 10.1007/s13131-020-1551-y
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The objective of this study was to estimate genetic parameters of body width (BW) to body length (BL) ratio (BW/BL) and of body weight traits (BWT) in turbot, and to elucidate the genetic mechanism of the two traits during ontogeny by dynamic genetic analysis. From 3 to 27 months, BW, BL and BWT of each communally stocked fish were measured every 3 months. The BW/BL ratio was measured at different sampling ages. A two-trait animal model was used for genetic evaluation of traits. The results showed that the heritability values of BW/BL ratio ranged from 0.216 8 to 0.314 8, corresponding to moderate heritability. The BWT heritability values ranged from 0.270 2 to 0.347 9 corresponding to moderate heritability. The heritability of BW/BL ratio was lower than that of BWT, except at 3 months of age. Genetic correlation between BW/BL ratio and BWT decreased throughout the measurement period. Genetic correlations were higher than the phenotypic correlations. The current results for estimating genetic parameters demonstrate that the BW/BL ratio could be used as a phenotypic marker of fast-growing turbot, and the BW/BL ratio and BWT could be improved simultaneously through selective breeding.
The objective of this study was to estimate genetic parameters of body width (BW) to body length (BL) ratio (BW/BL) and of body weight traits (BWT) in turbot, and to elucidate the genetic mechanism of the two traits during ontogeny by dynamic genetic analysis. From 3 to 27 months, BW, BL and BWT of each communally stocked fish were measured every 3 months. The BW/BL ratio was measured at different sampling ages. A two-trait animal model was used for genetic evaluation of traits. The results showed that the heritability values of BW/BL ratio ranged from 0.216 8 to 0.314 8, corresponding to moderate heritability. The BWT heritability values ranged from 0.270 2 to 0.347 9 corresponding to moderate heritability. The heritability of BW/BL ratio was lower than that of BWT, except at 3 months of age. Genetic correlation between BW/BL ratio and BWT decreased throughout the measurement period. Genetic correlations were higher than the phenotypic correlations. The current results for estimating genetic parameters demonstrate that the BW/BL ratio could be used as a phenotypic marker of fast-growing turbot, and the BW/BL ratio and BWT could be improved simultaneously through selective breeding.
2020, 39(2): 28-37.
doi: 10.1007/s13131-020-1547-7
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The present investigation focuses on population genetic structure analysis of the endangered giant clam species Tridacna maxima across part of the Red Sea, with the main aim of assessing the influence of postulated potential barriers to gene flow (i.e., particular oceanographic features and marked environmental heterogeneity) on genetic connectivity among populations of this poorly dispersive bivalve species. For this purpose, a total of 44 specimens of T. maxima were collected from five sampling locations along the Saudi Arabian coast and examined for genetic variability at the considerably variable mitochondrial gene cytochrome c oxidase I (COI). Our results revealed lack of population subdivision and phylogeographic structure across the surveyed geographic spectrum, suggesting that neither the short pelagic larval dispersal nor the various postulated barriers to gene flow in the Red Sea can trigger the onset of marked genetic differentiation in T. maxima. Furthermore, the discerned shallow COI haplotype genealogy (exhibiting high haplotype diversity and low nucleotide diversity), associated with recent demographic and spatial expansion events, can be considered as residual effect of a recent evolutionary history of the species in the Red Sea.
The present investigation focuses on population genetic structure analysis of the endangered giant clam species Tridacna maxima across part of the Red Sea, with the main aim of assessing the influence of postulated potential barriers to gene flow (i.e., particular oceanographic features and marked environmental heterogeneity) on genetic connectivity among populations of this poorly dispersive bivalve species. For this purpose, a total of 44 specimens of T. maxima were collected from five sampling locations along the Saudi Arabian coast and examined for genetic variability at the considerably variable mitochondrial gene cytochrome c oxidase I (COI). Our results revealed lack of population subdivision and phylogeographic structure across the surveyed geographic spectrum, suggesting that neither the short pelagic larval dispersal nor the various postulated barriers to gene flow in the Red Sea can trigger the onset of marked genetic differentiation in T. maxima. Furthermore, the discerned shallow COI haplotype genealogy (exhibiting high haplotype diversity and low nucleotide diversity), associated with recent demographic and spatial expansion events, can be considered as residual effect of a recent evolutionary history of the species in the Red Sea.
2020, 39(2): 38-48.
doi: 10.1007/s13131-018-1280-7
Abstract:
To explore the spatial pattern of macrobenthic communities and their response to environmental factors in the Prydz Bay, samples were collected using a 0.25-m2 box corer at 10 stations from November 2012 to April 2013. A total of 50 species of macrobenthos belonging to 8 phyla and 33 families were identified, of which polychaetes (e.g., Maldane sarsi) and sponges (e.g., Halichondria sp. and Leucosolenia sp.) were the most prominent groups. The macrobenthos in study area were categorized into five functional groups based on the feeding type, and the detritivorous group represented by polychaetes showed the highest average abundance, while the planktophagous group represented by sponges showed the highest average biomass. Macrobenthos abundance (0–592 ind./m2) and biomass (0–1 155.5 g/m2) in the Prydz Bay were relatively lower than those of other Antarctic shelf soft-bottom waters, although the compositions of the dominant species and functional feeding groups were similar. The results of the Spearman rank correlation analysis indicated that the average biomass of the macrobenthos and the biomass of the planktophagous group in the study area were negatively correlated with the water depth, sediment grain size and silt percentage. However, these variables were clearly not strong determinants of macrobenthos assemblage structure. Many factors not measured in the study, e.g., sediment organic matter and iceberg interference, have probably influenced the spatial distribution of macrobenthic community structure in the Prydz Bay.
To explore the spatial pattern of macrobenthic communities and their response to environmental factors in the Prydz Bay, samples were collected using a 0.25-m2 box corer at 10 stations from November 2012 to April 2013. A total of 50 species of macrobenthos belonging to 8 phyla and 33 families were identified, of which polychaetes (e.g., Maldane sarsi) and sponges (e.g., Halichondria sp. and Leucosolenia sp.) were the most prominent groups. The macrobenthos in study area were categorized into five functional groups based on the feeding type, and the detritivorous group represented by polychaetes showed the highest average abundance, while the planktophagous group represented by sponges showed the highest average biomass. Macrobenthos abundance (0–592 ind./m2) and biomass (0–1 155.5 g/m2) in the Prydz Bay were relatively lower than those of other Antarctic shelf soft-bottom waters, although the compositions of the dominant species and functional feeding groups were similar. The results of the Spearman rank correlation analysis indicated that the average biomass of the macrobenthos and the biomass of the planktophagous group in the study area were negatively correlated with the water depth, sediment grain size and silt percentage. However, these variables were clearly not strong determinants of macrobenthos assemblage structure. Many factors not measured in the study, e.g., sediment organic matter and iceberg interference, have probably influenced the spatial distribution of macrobenthic community structure in the Prydz Bay.
2020, 39(2): 49-58.
doi: 10.1007/s13131-020-1552-x
Abstract:
As an important part of the Bohai economic rim, the Laizhou Bay has been stressed by serious eco-environmental problems in recent years. In this study, the Shannon-Wiener index (H′), AZTI’s marine biotic index (AMBI) and the multivariate AMBI (M-AMBI) were used to assess the ecological quality status (EQS) of the Laizhou Bay according to macrobenthos data collected annually in August 2011–2014. The results showed that the overall benthic habitat quality in the Laizhou Bay was assessed as “Good”. However, 25% of the samples were classified as “Moderate”, “Bad” or “Poor” status under degraded conditions. Ecological group III (EGIII) species which had a certain tolerance to environmental disturbances had a higher proportion in each station, and most of them had appeared the pollution indicator species Capitella capitata. This indicated that the benthic habitat in the Laizhou Bay had been disturbed and polluted to some extent. The comparison of the three indices evaluation result and the RDA analysis showed that the H′ and M-AMBI were more suitable when the relative abundance of the single species was high and the macrobenthic community was significantly imbalanced; when the relative abundance of opportunistic species (EGIV and EGV) was high, the AMBI and M-AMBI could reflected the EQS objectively; in an undisturbed and polluted environment, all the three indices could indicate the benthic habitats quality. In summary, the better correlation between the three indices and environmental factors showed that they were well responsive to the tendency of the benthic habitats quality in the Laizhou Bay.
As an important part of the Bohai economic rim, the Laizhou Bay has been stressed by serious eco-environmental problems in recent years. In this study, the Shannon-Wiener index (H′), AZTI’s marine biotic index (AMBI) and the multivariate AMBI (M-AMBI) were used to assess the ecological quality status (EQS) of the Laizhou Bay according to macrobenthos data collected annually in August 2011–2014. The results showed that the overall benthic habitat quality in the Laizhou Bay was assessed as “Good”. However, 25% of the samples were classified as “Moderate”, “Bad” or “Poor” status under degraded conditions. Ecological group III (EGIII) species which had a certain tolerance to environmental disturbances had a higher proportion in each station, and most of them had appeared the pollution indicator species Capitella capitata. This indicated that the benthic habitat in the Laizhou Bay had been disturbed and polluted to some extent. The comparison of the three indices evaluation result and the RDA analysis showed that the H′ and M-AMBI were more suitable when the relative abundance of the single species was high and the macrobenthic community was significantly imbalanced; when the relative abundance of opportunistic species (EGIV and EGV) was high, the AMBI and M-AMBI could reflected the EQS objectively; in an undisturbed and polluted environment, all the three indices could indicate the benthic habitats quality. In summary, the better correlation between the three indices and environmental factors showed that they were well responsive to the tendency of the benthic habitats quality in the Laizhou Bay.
2020, 39(2): 59-68.
doi: 10.1007/s13131-020-1553-9
Abstract:
Centropages tenuiremis is a species with a wide distribution range in disturbed coastal waters. However, due to a lack of dietary information, it remains unclear as to how they maintain such dominance in fluctuating conditions. In this study, C. tenuiremis was collected from the Daya Bay Nuclear Power Plant both in inlet and outfall regions at 06:00, 12:00 and 18:00 on April 27, 2011 and their in situ diet was analyzed using a PCR protocol targeting 18S ribosomal genes. Thirty-four species of prey organisms were identified totally, including Dinophyta, Baciliariophyta, Viridiplantae, Rhizaria, Apicomplexa, Chordata, Mollusca, Arthropoda and Fungi, indicating an obvious omnivorous feeding habit of C. tenuiremis. Centropages tenuiremis obviously exhibited spatial and temporal variations in diet composition. More plant prey (land plants and phytoplankton) were consumed in the morning (~50%), while more animal prey (metazoans and protozoans) were ingested at midday and night (60%–70%). Furthermore, a more diverse diet was detected in the outfall region (10–11 taxa), where the temperatures were relatively higher and more fluctuating, than in the control region (5–10 taxa). This finding indicated that C. tenuiremis could potentially expand its food spectrum under stressful condition. Specifically, C. tenuiremis exhibited phytoplankton preference (58.62%–67.64%) in the outfall region with a lower omnivory index (0.27–0.35) than in the control region (0.51–0.95). However, phytoplankton density was lower than that in the control region, suggesting a possible herbivorous tendency of C. tenuiremis under elevated temperatures to balance the energy acquirement and feeding effort. The flexible food choices of C. tenuiremis observed here could effectively buffer environmental fluctuations and might be an important survival strategy in coastal ecosystems.
Centropages tenuiremis is a species with a wide distribution range in disturbed coastal waters. However, due to a lack of dietary information, it remains unclear as to how they maintain such dominance in fluctuating conditions. In this study, C. tenuiremis was collected from the Daya Bay Nuclear Power Plant both in inlet and outfall regions at 06:00, 12:00 and 18:00 on April 27, 2011 and their in situ diet was analyzed using a PCR protocol targeting 18S ribosomal genes. Thirty-four species of prey organisms were identified totally, including Dinophyta, Baciliariophyta, Viridiplantae, Rhizaria, Apicomplexa, Chordata, Mollusca, Arthropoda and Fungi, indicating an obvious omnivorous feeding habit of C. tenuiremis. Centropages tenuiremis obviously exhibited spatial and temporal variations in diet composition. More plant prey (land plants and phytoplankton) were consumed in the morning (~50%), while more animal prey (metazoans and protozoans) were ingested at midday and night (60%–70%). Furthermore, a more diverse diet was detected in the outfall region (10–11 taxa), where the temperatures were relatively higher and more fluctuating, than in the control region (5–10 taxa). This finding indicated that C. tenuiremis could potentially expand its food spectrum under stressful condition. Specifically, C. tenuiremis exhibited phytoplankton preference (58.62%–67.64%) in the outfall region with a lower omnivory index (0.27–0.35) than in the control region (0.51–0.95). However, phytoplankton density was lower than that in the control region, suggesting a possible herbivorous tendency of C. tenuiremis under elevated temperatures to balance the energy acquirement and feeding effort. The flexible food choices of C. tenuiremis observed here could effectively buffer environmental fluctuations and might be an important survival strategy in coastal ecosystems.
2020, 39(2): 69-78.
doi: 10.1007/s13131-020-1554-8
Abstract:
This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea. Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea. The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury. The main phyla of bacteria recorded included Proteobacteria (52.92%), Bacteroidetes (11.76%), Planctomycetes (7.39%), Acidobacteria (6.53%) and Chloroflexi (4.97%). The genus with the highest relative abundance was Desulfobulbus (4.99%), which was the dominant genus at most sampling stations, followed by Lutimonas and Halioglobus. The main factors influencing bacterial community structure were total organic carbon, followed by depth and total phosphorus. The content of lead, cadmium, chromium, copper and zinc had a consistent effect on community structure. Arsenic showed a negative correlation with bacterial community structure in most samples, while the impact of mercury on community structure was not significant. The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes. The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.
This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea. Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea. The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury. The main phyla of bacteria recorded included Proteobacteria (52.92%), Bacteroidetes (11.76%), Planctomycetes (7.39%), Acidobacteria (6.53%) and Chloroflexi (4.97%). The genus with the highest relative abundance was Desulfobulbus (4.99%), which was the dominant genus at most sampling stations, followed by Lutimonas and Halioglobus. The main factors influencing bacterial community structure were total organic carbon, followed by depth and total phosphorus. The content of lead, cadmium, chromium, copper and zinc had a consistent effect on community structure. Arsenic showed a negative correlation with bacterial community structure in most samples, while the impact of mercury on community structure was not significant. The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes. The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.
2020, 39(2): 79-88.
doi: 10.1007/s13131-020-1555-7
Abstract:
Mangrove wetlands can reduce heavy metal pollution by trapping heavy metals. In this study, the concentration, transport and bioaccumulation of Cr, Cd, Cu, Zn and Pb in the sediments and different parts of Aegiceras corniculatum at four different sites in the Qinzhou Bay in southwestern China were investigated. The results showed that although the potential ecological risk of all five heavy metals was slight, the concentration of Cr was at a moderate pollution level due to the emissions of industries and aquaculture waste water. Core sediment records indicated that the concentrations of heavy metals at the depth of 0–20 cm were relatively high, showing an increasing trend of heavy metals over the past 20–30 years. Cr, Cu, Pb and Cd accumulated mainly in the roots of A. corniculatum, while Zn accumulated mainly in the stems. Aegiceras corniculatum showed the strongest transport capacity for Zn and Cu and the strongest bioaccumulation ability for Cd. Compared with other mangrove communities, A. corniculatum can be chosen as a restoration species in tropical and subtropical coastal zones polluted by Zn, Cu and Cd.
Mangrove wetlands can reduce heavy metal pollution by trapping heavy metals. In this study, the concentration, transport and bioaccumulation of Cr, Cd, Cu, Zn and Pb in the sediments and different parts of Aegiceras corniculatum at four different sites in the Qinzhou Bay in southwestern China were investigated. The results showed that although the potential ecological risk of all five heavy metals was slight, the concentration of Cr was at a moderate pollution level due to the emissions of industries and aquaculture waste water. Core sediment records indicated that the concentrations of heavy metals at the depth of 0–20 cm were relatively high, showing an increasing trend of heavy metals over the past 20–30 years. Cr, Cu, Pb and Cd accumulated mainly in the roots of A. corniculatum, while Zn accumulated mainly in the stems. Aegiceras corniculatum showed the strongest transport capacity for Zn and Cu and the strongest bioaccumulation ability for Cd. Compared with other mangrove communities, A. corniculatum can be chosen as a restoration species in tropical and subtropical coastal zones polluted by Zn, Cu and Cd.
2020, 39(2): 89-100.
doi: 10.1007/s13131-019-1471-3
Abstract:
The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of (20.082±2.482) mg/(g·d), (12.825±1.623) mg/(g·d) and (6.411±1.029) mg/(g·d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079%–0.110% d–1) was lower than that of H. cylindracea (0.652%–1.644% d–1) and H. opuntia (0.360%–1.527% d–1). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis.
The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of (20.082±2.482) mg/(g·d), (12.825±1.623) mg/(g·d) and (6.411±1.029) mg/(g·d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079%–0.110% d–1) was lower than that of H. cylindracea (0.652%–1.644% d–1) and H. opuntia (0.360%–1.527% d–1). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis.
2020, 39(2): 101-106.
doi: 10.1007/s13131-019-1452-0
Abstract:
Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007. The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal. Ulva prolifera and Blidingia (Italic) sp. are the main species observed on Pyropia aquaculture rafts in the Subei Shoal. We found that U. prolifera has strong buoyancy and a rapid growth rate, which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea. The growth rate of floating U. prolifera was about 20%–31% d–1, which was much higher than Blidingia (Italic) sp. There were about 1.7 × 104 t of attached algae on the Pyropia aquaculture rafts in May 2012. We found that 39% of attached algae could float when the tide rose in the Subei Shoal, and U. prolifera accounted for 63% of the floating algae. Our analysis estimated that about 4 000 t of attached U. prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts. These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U. prolifera biomass attached to Pyropia aquaculture rafts, further impacting the scale of the green tide.
Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007. The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal. Ulva prolifera and Blidingia (Italic) sp. are the main species observed on Pyropia aquaculture rafts in the Subei Shoal. We found that U. prolifera has strong buoyancy and a rapid growth rate, which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea. The growth rate of floating U. prolifera was about 20%–31% d–1, which was much higher than Blidingia (Italic) sp. There were about 1.7 × 104 t of attached algae on the Pyropia aquaculture rafts in May 2012. We found that 39% of attached algae could float when the tide rose in the Subei Shoal, and U. prolifera accounted for 63% of the floating algae. Our analysis estimated that about 4 000 t of attached U. prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts. These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U. prolifera biomass attached to Pyropia aquaculture rafts, further impacting the scale of the green tide.
2020, 39(2): 107-122.
doi: 10.1007/s13131-020-1545-9
Abstract:
The East Sea (Sea of Japan) is a marginal, semi-closed sea in the northwestern Pacific. The Ulleung Basin area, which is located near the subpolar front of the East Sea, is known to have high primary production and good fisheries in spring season. After episodic wind-driven events during the spring of 2017, horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area. In addition, growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass. Because of strong northwestern wind, phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season. The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations. In contrast, the nutrient and chlorophyll a (Chl a) concentrations and the phytoplankton biomass were quite low in all locations. Bacillariophyceae was dominated group (>75.1% for coastal, 40.0% for offshore and 43.6% for island stations). In the algal bioassays, the phytoplankton production was stimulated by N availability. The in vivo Chl a values in the +N and +NP treatments were significantly higher than the values in the control and the +P treatments. Based on the field survey, the higher nutrients in coastal waters affected the growth of diatom assemblages, however, little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments. The growth of phytoplankton depended on the initial cell density. All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers, and the low level of biomass supply from the coasts resulted in low primary production. Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea.
The East Sea (Sea of Japan) is a marginal, semi-closed sea in the northwestern Pacific. The Ulleung Basin area, which is located near the subpolar front of the East Sea, is known to have high primary production and good fisheries in spring season. After episodic wind-driven events during the spring of 2017, horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area. In addition, growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass. Because of strong northwestern wind, phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season. The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations. In contrast, the nutrient and chlorophyll a (Chl a) concentrations and the phytoplankton biomass were quite low in all locations. Bacillariophyceae was dominated group (>75.1% for coastal, 40.0% for offshore and 43.6% for island stations). In the algal bioassays, the phytoplankton production was stimulated by N availability. The in vivo Chl a values in the +N and +NP treatments were significantly higher than the values in the control and the +P treatments. Based on the field survey, the higher nutrients in coastal waters affected the growth of diatom assemblages, however, little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments. The growth of phytoplankton depended on the initial cell density. All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers, and the low level of biomass supply from the coasts resulted in low primary production. Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea.
2020, 39(2): 123-131.
doi: 10.1007/s13131-020-1556-6
Abstract:
Chlorophyll a (Chl a), particulate organic carbon (POC) and biogenic silica (BSi) were determined in coastal waters adjacent to the Zhujiang (Pearl) River Estuary (ZRE) during summer, in order to examine the C:Chl a ratio of phytoplankton and phytoplankton carbon in the plume-impacted coastal waters during summer, as well as to assess the relative contribution of diatoms to the phytoplankton biomass, by the regression between Chl a, POC and BSi. Our results showed that the C:Chl a ratio (g/g) of phytoplankton was high (up to 142), likely due to high light intensity and nutrient limitation. The river plume input stimulated phytoplankton growth, especially diatoms, resulting in higher relative contribution of phytoplankton carbon (55%) and diatoms (34%) to POC in the plume-impacted region than those (33% and 13%) in high salinity area, respectively. Phytoplankton carbon (up to 538 μg/L) in the plume-impacted region was much higher than that (<166 μg/L) in high salinity area. Our findings were helpful to improve the biogeochemical model in coastal waters adjacent to the ZRE.
Chlorophyll a (Chl a), particulate organic carbon (POC) and biogenic silica (BSi) were determined in coastal waters adjacent to the Zhujiang (Pearl) River Estuary (ZRE) during summer, in order to examine the C:Chl a ratio of phytoplankton and phytoplankton carbon in the plume-impacted coastal waters during summer, as well as to assess the relative contribution of diatoms to the phytoplankton biomass, by the regression between Chl a, POC and BSi. Our results showed that the C:Chl a ratio (g/g) of phytoplankton was high (up to 142), likely due to high light intensity and nutrient limitation. The river plume input stimulated phytoplankton growth, especially diatoms, resulting in higher relative contribution of phytoplankton carbon (55%) and diatoms (34%) to POC in the plume-impacted region than those (33% and 13%) in high salinity area, respectively. Phytoplankton carbon (up to 538 μg/L) in the plume-impacted region was much higher than that (<166 μg/L) in high salinity area. Our findings were helpful to improve the biogeochemical model in coastal waters adjacent to the ZRE.
2020, 39(2): 132-137.
doi: 10.1007/s13131-020-1548-6
Abstract:
Coralline algae (CA), a type of primary calcifying producer presented in coastal ecosystems, are considered one of the highly sensitive organisms to marine environmental change. However, experimental studies on coralline algae responses to elevated seawater temperature and reduced pH have documented either contradictory or opposite results. In this study, we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature (30.8°C) and reduced pH (7.8). The aim of this analysis was to observe the direct and combined effects, while elucidating the growth and photosynthesis in this response. It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5% and 14.9% respectively. High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature, while they were deceased when both temperature and pCO2 were elevated. CA is among the most sensitive organisms to ocean acidification (OA) because of their precipitate high Mg-calcite. We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification, but offset by the effect of elevated temperature. Accordingly, our results also support the conclusion that global warming (GW) is a stronger threat to algal performance than OA. Our findings are also proposed that coralline algae may be more resilient under OA than GW.
Coralline algae (CA), a type of primary calcifying producer presented in coastal ecosystems, are considered one of the highly sensitive organisms to marine environmental change. However, experimental studies on coralline algae responses to elevated seawater temperature and reduced pH have documented either contradictory or opposite results. In this study, we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature (30.8°C) and reduced pH (7.8). The aim of this analysis was to observe the direct and combined effects, while elucidating the growth and photosynthesis in this response. It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5% and 14.9% respectively. High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature, while they were deceased when both temperature and pCO2 were elevated. CA is among the most sensitive organisms to ocean acidification (OA) because of their precipitate high Mg-calcite. We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification, but offset by the effect of elevated temperature. Accordingly, our results also support the conclusion that global warming (GW) is a stronger threat to algal performance than OA. Our findings are also proposed that coralline algae may be more resilient under OA than GW.
