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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1897-3191
Pierwsze wydanie
23 Feb 2007
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 49 (2020): Zeszyt 2 (June 2020)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1897-3191
Pierwsze wydanie
23 Feb 2007
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

9 Artykułów

Research Article

Otwarty dostęp

Diversity and ecological characteristic of algae and cyanobacteria of thermokarst lakes in Yakutia (northeastern Russia)

Data publikacji: 18 Jun 2020
Zakres stron: 99 - 122

Abstrakt

Abstract

A total of 437 species (453 with infraspecific taxa) of algae and Cyanobacteria were identified in 2034 samples collected during the first research on nine thermokarst lakes in Yakutia carried out in 1986–1994 and 2001–2015. The richest algal flora was determined in Lake Aalah, represented by 241 taxa. Bacillariophyta species dominated in four lakes, whereas Chlorophyta and Cyanobacteria dominated in the others. The algal bioindication demonstrated preferences for benthic and plankticbenthic life, temperate temperature, low alkalinity, waters with moderate oxygenation, low to medium enrichment with chloride, low organic pollution, and mesotrophic state. Comparative floristic, CANOCO and JASP statistical methods divided the species and environmental variables into groups of lakes related to landscape terraces. Local landscape positions and high summer water temperatures may play a major role in the formation of algal flora. The index of algae taxa per area stabilized at about 70 species per km2. The highest polymorphism of algae floras, defined by the Subspecies/Species Index, was determined for the lakes of the Tungulunskaya terrace: Lake Ynakh, Lake Nal Tungulu and Lake Tungulu (1.041–1.058), and the average total flora was 1.036. Our results can help in monitoring and protecting the ecosystems of thermokarst lakes in Yakutia in the harsh climate environment of Northeastern Eurasia.

Key words

  • freshwater algae
  • ecological preferences
  • bioindication
  • lakes
  • Yakutia
Otwarty dostęp

Use of rotifer trophic state indices to show the effect of hydrobionts and nutrients on water trophic status in mesocosms

Data publikacji: 18 Jun 2020
Zakres stron: 123 - 131

Abstrakt

Abstract

We have determined how Crustacea, zebra mussels (Dreissena polymorpha), fish and nutrients affect the trophic state in mesocosms filled with water collected from the pelagic zone of a eutrophic lake. We hypothesized that the pool of nutrients would increase both directly due to the input of phosphorus and nitrogen and/or indirectly due to the introduction of animal biomass. We used trophic state indices based on the abundance and species structure of rotifers to assess changes in the trophic state in mesocosms. The role of small detritophages in rotifer communities increased as a result of treatments. Our results clearly demonstrated that D. polymorpha was able to reduce the trophic status of mesocosm waters as indicated by reduced rotifer trophic state indices regardless of interactions with other treatment factors. Contrary to our expectations, neither the nutrients added at the beginning of the experiment nor the introduction of crustaceans or fish affected the rotifer trophic indices.

Key words

  • Rotifera
  • eutrophic lake
  • effects of Dreissena’s
  • fish
  • Crustacea
Otwarty dostęp

Navicula dermochelycola sp. nov., presumably an exclusively epizoic diatom on sea turtles Dermochelys coriacea and Lepidochelys olivacea from French Guiana

Data publikacji: 18 Jun 2020
Zakres stron: 132 - 139

Abstrakt

Abstract

Epizoic diatom communities were studied on four turtle species (Chelonia mydas L., Eretmochelys imbricata L., Lepidochelys olivacea Eschscholtz and Dermochelys coriacea Vandelli) from the Eastern Caribbean, the Equatorial West Atlantic and the South Pacific. In the present study, we focused on one taxon of Navicula Bory de Saint-Vincent, described here as a new taxon, which was found on seven individuals of Dermochelys coriacea and one individual of Lepidochelys olivacea in French Guiana. The new Navicula taxon was found neither on Chelonia mydas (83 specimens examined) nor Eretmochelys imbricata (13 specimens examined). Furthermore, the new taxon appears to have a restricted biogeography, as so far it has only been reported from French Guiana. A species of Navicula is reported for the first time as a supposedly exclusive epizoic taxon. Navicula dermochelycola sp. nov. is characterized in detail; its ultrastructure is described and compared with other members of Navicula.

Key words

  • Rotifera
  • eutrophic lake
  • effects of Dreissena’s
  • fish
  • Crustacea
Otwarty dostęp

Accumulation of heavy metals (Fe, Zn, Cu, Mn, Cd and Pb) in mullets Planiliza subviridis (Valenciennes, 1836) and Ellochelon vaigiensis(Quoy & Gaimard, 1825) from Damb Harbor, Balochistan, Pakistan

Data publikacji: 18 Jun 2020
Zakres stron: 140 - 146

Abstrakt

Abstract

In this study, muscle samples collected from Planiliza subviridis (Valenciennes, 1836) and Ellochelon vaigiensis (Quoy & Gaimard, 1825) caught on the Balochistan coast (Damb Harbor) between January and December 2015 (during the northeast monsoon, post-monsoon and pre-monsoon seasons, and the southwest monsoon) were analyzed to determine concentrations of heavy metals: iron, zinc, copper, manganese, cadmium and lead by an atomic absorption spectrophotometer, expressed per unit of dry weight of each sample. The average measured level of Fe, Zn, Cu, Mn, Cd and Pb for P. subviridis was 26.70 ± 11.49 μg g−1, 13.82 ± 4.56 μg g−1, 1.66 ± 0.84 μg g−1, 0.24 ± 0.10 μg g−1, 0.06 ± 0.07 μg g−1 and 0.17 ± 0.14 μg g−1, respectively. The average level of the same metals for E. vaigiensis was 29.26 ± 10.18 μg g−1, 18.85 ± 6.28 μg g−1, 2.18 ± 1.01 μg g−1, 0.32 ± 0.14 μg g−1, 0.25 ± 0.11 μg g−1 and 0.30 ± 0.12 μg g−1, respectively. The highest Pb accumulation (0.56 μg g−1 and 0.61 μg g−1) detected in P. subviridis and E. vaigiensis is above the limit value (0.50 μg g−1) reported by FAO, hence the accumulation of Pb in these two fish species should be monitored in the future.

Key words

  • heavy metals
  • fish
  • Balochistan Coast
  • Damb Harbor
Otwarty dostęp

Hexabromocyclododecane contamination of herring gulls in the coastal area of the southern Baltic Sea

Data publikacji: 18 Jun 2020
Zakres stron: 147 - 156

Abstrakt

Abstract

Muscles and livers of herring gulls (Larus argentatus) found in the coastal area of the southern Baltic Sea were tested for the presence of hexabromocyclododecane (HBCD) isomers. They were detected in the muscles (ΣHBCD = 42.82 ± 30.65 ng g−1 l.w.) and livers (ΣHBCD = 65.51±27.96 ng g−1 l.w.) of all examined gulls. The α-HBCD isomer dominates in all types of samples. Our study has shown that bodies of gulls are less contaminated with HBCD than bodies of aquatic birds from other regions of the world. There was no clear correlation between HBCD concentrations and sex and age of birds. Nevertheless, it was indicated that the highest concentrations of HBCD and the α-HBCD isomer were found in the livers of immature females (mean = 89.31 ± 21.63 ng g−1 l.w. and mean = 76.72±24.54 ng g−1 l.w., respectively). The highest liver sequestration rates of the α-HBCD isomer were found in both adult and immature males (mean = 7.7 ± 13.7 and mean = 6.2 ± 11.9, respectively).

Key words

  • HBCD isomers
  • muscles and liver
  • Baltic Sea
Otwarty dostęp

Plant replacement trend in soft-water lakes with isoetids

Data publikacji: 18 Jun 2020
Zakres stron: 157 - 167

Abstrakt

Abstract

A number of small, shallow inland lakes in the Northern Hemisphere are acidic, soft-water water bodies, mostly fed by precipitation. Some of these lakes are home to Lobelia dortmanna and other aquatic macrophytes from the isoetid group. The present study identifies a plant species replacement trend along the main environmental gradient in such lakes, i.e. pH of water.

In 70 lakes covered by the study and ordered along the gradient of increasing alkalinity, bryophytes gradually decline. Their decreasing frequency is 86.8% (pH 4.0), 32.5% (pH 6.5) and <10% (pH 6.6–9.5). At the same time, the frequency of vascular plants increases from 13.2% in strongly acidic lakes up to 92.8% in alkaline ones. The majority of isoetids usually occur at pH 5.5–6.7, but one of them (Littorella uniflora) often (frequency 40.5%) occurs also in eutrophic, alkaline lakes (pH 9.0–9.5), where it forms large populations. In lakes ranked according to the decreasing alkalinity gradient, bryophyte populations have been found to be smaller, while vascular plants become more abundant. The decreasing water acidity leads to partial or total elimination of bryophytes, which are replaced by eutrophilic vascular plants, frequently accompanied by some stonewort species.

Key words

  • soft-water lakes
  • alkalinization of lakes
  • macrophyte replacement
Otwarty dostęp

Long-term changes in phytoplankton and macrophyte communities in an eutrophic shallow reservoir and prospects for its restoration

Data publikacji: 18 Jun 2020
Zakres stron: 168 - 183

Abstrakt

Abstract

Long-term changes in hydrochemistry and community structure of phytoplankton and macrophytes were analyzed in the Sestroretskiy Razliv reservoir (northwestern Russia). The average content of total phosphorus (TP) in May–October increased from 73 μg P l−1 in 1980 to 163 μg P l−1 in 2000. A significant increase in average chlorophyll a content from 16.6 μg l−1 in 1980 to 84.7 μg l−1 in 2000 and a shift in phytoplankton composition to the dominance of cyanobacteria over diatoms indicated a change in the trophic status of the reservoir from meso-eutrophic to hypertrophic. In 2016 and 2018, average TP was 96 and 101 μg P l−1, respectively. The average content of chlorophyll a was 43.6 μg l−1 in 2016 and 66.6 μg l−1 in warmer 2018, indicating persistent eutrophic conditions. Diatoms dominated both in 2016 and 2018, especially in 2016 characterized by unfavorable weather conditions. Cyanobacteria were more abundant in 2018 with higher summer temperatures. The decline of the total area covered by aquatic vegetation from 157 ha in 1980 to 76 ha in 2016 likely resulted from an increase in phytoplankton biomass and water turbidity. Based on the results of our observations, in addition to further reduction in nutrient loading, biomanipulation by introducing predatory fish as a restoration measure was proposed to improve the ecological status of the reservoir.

Key words

  • phytoplankton
  • cyanobacteria
  • macrophytes
  • shallow lakes
  • alternative stable states
  • eutrophication
Otwarty dostęp

Spat efficiency in the pearl oyster Pinctada radiata (Leach, 1814) in the surface and bottom water at Karantina Island

Data publikacji: 18 Jun 2020
Zakres stron: 184 - 192

Abstrakt

Abstract

The present study was carried out to determine the spat efficiency in the pearl oyster (Pinctada radiata, Leach, 1814) in surface and bottom water at Karantina Island (Izmir/Turkey). Polyethylene mesh bags were used as collectors. An annual average of 175.16 ± 11.32 spat m−2 was obtained from PSC (placed surface collectors) and 82.65 ±3.89 spat m−2 was obtained from PBC (placed bottom collectors). The largest number of new spat attachments occurred in August, both on PSC and PBC: 44 ± 3.46 and 26 ± 2.88 spats were found respectively in the outer and inner mesh bags of PSC, and 33 ±5.77 and 48 ± 6.92 spats were found respectively in the outer and inner mesh bags of PBC. New spat attachments (≥ 10 mm) continued throughout the study period, except April and May. Adult pearl oysters (≥ 50 mm) were found in May. There was a significant difference between PSC and PBC in the total number of spat attachments, the monthly spat attachments and the first spat attachments (p < 0.05). The total number of new spat attachments was positively correlated with temperature and chlorophyll a for both depths (p<0.05).

Key words

  • pearl oyster
  • spat settlement
  • growth
  • depths
  • Aegean Sea
Otwarty dostęp

Distribution and community structure of microphytoplankton in relation to increasing anthropogenic impact along coastal waters of Jeddah, the central Red Sea

Data publikacji: 18 Jun 2020
Zakres stron: 193 - 205

Abstrakt

Abstract

Seasonal distribution and diversity of surface phytoplankton have been studied in relation to anthropogenic activities at seven locations along the coastal waters of Jeddah, Saudi Arabia in 2017. The concentration of nitrite, nitrate, ammonia, phosphate and silicate varied over wide ranges: 0.04–20.27, 0.05–29.3, 0.22–78.16, 0.02–25.90 and 43–24.50 μmol l−1, respectively. Inorganic nutrients, phytoplankton biomass and density were at eutrophic levels at two lagoon locations (4 and 5), while other coastal locations showed oligotrophic characteristics of the Red Sea. Phytoplankton biomass was positively correlated with all measured inorganic nutrients. The total phytoplankton density varied between 52.4 × 103 and 40800 × 103 cells m−3 (average 6249.9×103 ± 10797×103 cells m−3). A total of 174 species of phytoplankton (95 diatoms, 75 dinoflagellates, 3 cyanophytes and 1 silicoflagellates) were recorded in this study, with the dominance of diatoms (95.1%). Higher densities observed at lagoon locations were mainly due to the proliferation of the diatom species Skeletonema costatum and Chaetoceros decipiens. In terms of diversity, dinoflagellates were more numerous than diatoms in July, otherwise mostly diatoms dominated. On the other hand, cyanophytes were more abundant in November. Based on the present study, anthropogenic activities (especially sewage effluent) in Jeddah coastal waters had a significant impact on the phytoplankton densities and diversity.

Key words

  • nutrients
  • phytoplankton
  • coastal water
  • Jeddah
  • Red Sea
9 Artykułów

Research Article

Otwarty dostęp

Diversity and ecological characteristic of algae and cyanobacteria of thermokarst lakes in Yakutia (northeastern Russia)

Data publikacji: 18 Jun 2020
Zakres stron: 99 - 122

Abstrakt

Abstract

A total of 437 species (453 with infraspecific taxa) of algae and Cyanobacteria were identified in 2034 samples collected during the first research on nine thermokarst lakes in Yakutia carried out in 1986–1994 and 2001–2015. The richest algal flora was determined in Lake Aalah, represented by 241 taxa. Bacillariophyta species dominated in four lakes, whereas Chlorophyta and Cyanobacteria dominated in the others. The algal bioindication demonstrated preferences for benthic and plankticbenthic life, temperate temperature, low alkalinity, waters with moderate oxygenation, low to medium enrichment with chloride, low organic pollution, and mesotrophic state. Comparative floristic, CANOCO and JASP statistical methods divided the species and environmental variables into groups of lakes related to landscape terraces. Local landscape positions and high summer water temperatures may play a major role in the formation of algal flora. The index of algae taxa per area stabilized at about 70 species per km2. The highest polymorphism of algae floras, defined by the Subspecies/Species Index, was determined for the lakes of the Tungulunskaya terrace: Lake Ynakh, Lake Nal Tungulu and Lake Tungulu (1.041–1.058), and the average total flora was 1.036. Our results can help in monitoring and protecting the ecosystems of thermokarst lakes in Yakutia in the harsh climate environment of Northeastern Eurasia.

Key words

  • freshwater algae
  • ecological preferences
  • bioindication
  • lakes
  • Yakutia
Otwarty dostęp

Use of rotifer trophic state indices to show the effect of hydrobionts and nutrients on water trophic status in mesocosms

Data publikacji: 18 Jun 2020
Zakres stron: 123 - 131

Abstrakt

Abstract

We have determined how Crustacea, zebra mussels (Dreissena polymorpha), fish and nutrients affect the trophic state in mesocosms filled with water collected from the pelagic zone of a eutrophic lake. We hypothesized that the pool of nutrients would increase both directly due to the input of phosphorus and nitrogen and/or indirectly due to the introduction of animal biomass. We used trophic state indices based on the abundance and species structure of rotifers to assess changes in the trophic state in mesocosms. The role of small detritophages in rotifer communities increased as a result of treatments. Our results clearly demonstrated that D. polymorpha was able to reduce the trophic status of mesocosm waters as indicated by reduced rotifer trophic state indices regardless of interactions with other treatment factors. Contrary to our expectations, neither the nutrients added at the beginning of the experiment nor the introduction of crustaceans or fish affected the rotifer trophic indices.

Key words

  • Rotifera
  • eutrophic lake
  • effects of Dreissena’s
  • fish
  • Crustacea
Otwarty dostęp

Navicula dermochelycola sp. nov., presumably an exclusively epizoic diatom on sea turtles Dermochelys coriacea and Lepidochelys olivacea from French Guiana

Data publikacji: 18 Jun 2020
Zakres stron: 132 - 139

Abstrakt

Abstract

Epizoic diatom communities were studied on four turtle species (Chelonia mydas L., Eretmochelys imbricata L., Lepidochelys olivacea Eschscholtz and Dermochelys coriacea Vandelli) from the Eastern Caribbean, the Equatorial West Atlantic and the South Pacific. In the present study, we focused on one taxon of Navicula Bory de Saint-Vincent, described here as a new taxon, which was found on seven individuals of Dermochelys coriacea and one individual of Lepidochelys olivacea in French Guiana. The new Navicula taxon was found neither on Chelonia mydas (83 specimens examined) nor Eretmochelys imbricata (13 specimens examined). Furthermore, the new taxon appears to have a restricted biogeography, as so far it has only been reported from French Guiana. A species of Navicula is reported for the first time as a supposedly exclusive epizoic taxon. Navicula dermochelycola sp. nov. is characterized in detail; its ultrastructure is described and compared with other members of Navicula.

Key words

  • Rotifera
  • eutrophic lake
  • effects of Dreissena’s
  • fish
  • Crustacea
Otwarty dostęp

Accumulation of heavy metals (Fe, Zn, Cu, Mn, Cd and Pb) in mullets Planiliza subviridis (Valenciennes, 1836) and Ellochelon vaigiensis(Quoy & Gaimard, 1825) from Damb Harbor, Balochistan, Pakistan

Data publikacji: 18 Jun 2020
Zakres stron: 140 - 146

Abstrakt

Abstract

In this study, muscle samples collected from Planiliza subviridis (Valenciennes, 1836) and Ellochelon vaigiensis (Quoy & Gaimard, 1825) caught on the Balochistan coast (Damb Harbor) between January and December 2015 (during the northeast monsoon, post-monsoon and pre-monsoon seasons, and the southwest monsoon) were analyzed to determine concentrations of heavy metals: iron, zinc, copper, manganese, cadmium and lead by an atomic absorption spectrophotometer, expressed per unit of dry weight of each sample. The average measured level of Fe, Zn, Cu, Mn, Cd and Pb for P. subviridis was 26.70 ± 11.49 μg g−1, 13.82 ± 4.56 μg g−1, 1.66 ± 0.84 μg g−1, 0.24 ± 0.10 μg g−1, 0.06 ± 0.07 μg g−1 and 0.17 ± 0.14 μg g−1, respectively. The average level of the same metals for E. vaigiensis was 29.26 ± 10.18 μg g−1, 18.85 ± 6.28 μg g−1, 2.18 ± 1.01 μg g−1, 0.32 ± 0.14 μg g−1, 0.25 ± 0.11 μg g−1 and 0.30 ± 0.12 μg g−1, respectively. The highest Pb accumulation (0.56 μg g−1 and 0.61 μg g−1) detected in P. subviridis and E. vaigiensis is above the limit value (0.50 μg g−1) reported by FAO, hence the accumulation of Pb in these two fish species should be monitored in the future.

Key words

  • heavy metals
  • fish
  • Balochistan Coast
  • Damb Harbor
Otwarty dostęp

Hexabromocyclododecane contamination of herring gulls in the coastal area of the southern Baltic Sea

Data publikacji: 18 Jun 2020
Zakres stron: 147 - 156

Abstrakt

Abstract

Muscles and livers of herring gulls (Larus argentatus) found in the coastal area of the southern Baltic Sea were tested for the presence of hexabromocyclododecane (HBCD) isomers. They were detected in the muscles (ΣHBCD = 42.82 ± 30.65 ng g−1 l.w.) and livers (ΣHBCD = 65.51±27.96 ng g−1 l.w.) of all examined gulls. The α-HBCD isomer dominates in all types of samples. Our study has shown that bodies of gulls are less contaminated with HBCD than bodies of aquatic birds from other regions of the world. There was no clear correlation between HBCD concentrations and sex and age of birds. Nevertheless, it was indicated that the highest concentrations of HBCD and the α-HBCD isomer were found in the livers of immature females (mean = 89.31 ± 21.63 ng g−1 l.w. and mean = 76.72±24.54 ng g−1 l.w., respectively). The highest liver sequestration rates of the α-HBCD isomer were found in both adult and immature males (mean = 7.7 ± 13.7 and mean = 6.2 ± 11.9, respectively).

Key words

  • HBCD isomers
  • muscles and liver
  • Baltic Sea
Otwarty dostęp

Plant replacement trend in soft-water lakes with isoetids

Data publikacji: 18 Jun 2020
Zakres stron: 157 - 167

Abstrakt

Abstract

A number of small, shallow inland lakes in the Northern Hemisphere are acidic, soft-water water bodies, mostly fed by precipitation. Some of these lakes are home to Lobelia dortmanna and other aquatic macrophytes from the isoetid group. The present study identifies a plant species replacement trend along the main environmental gradient in such lakes, i.e. pH of water.

In 70 lakes covered by the study and ordered along the gradient of increasing alkalinity, bryophytes gradually decline. Their decreasing frequency is 86.8% (pH 4.0), 32.5% (pH 6.5) and <10% (pH 6.6–9.5). At the same time, the frequency of vascular plants increases from 13.2% in strongly acidic lakes up to 92.8% in alkaline ones. The majority of isoetids usually occur at pH 5.5–6.7, but one of them (Littorella uniflora) often (frequency 40.5%) occurs also in eutrophic, alkaline lakes (pH 9.0–9.5), where it forms large populations. In lakes ranked according to the decreasing alkalinity gradient, bryophyte populations have been found to be smaller, while vascular plants become more abundant. The decreasing water acidity leads to partial or total elimination of bryophytes, which are replaced by eutrophilic vascular plants, frequently accompanied by some stonewort species.

Key words

  • soft-water lakes
  • alkalinization of lakes
  • macrophyte replacement
Otwarty dostęp

Long-term changes in phytoplankton and macrophyte communities in an eutrophic shallow reservoir and prospects for its restoration

Data publikacji: 18 Jun 2020
Zakres stron: 168 - 183

Abstrakt

Abstract

Long-term changes in hydrochemistry and community structure of phytoplankton and macrophytes were analyzed in the Sestroretskiy Razliv reservoir (northwestern Russia). The average content of total phosphorus (TP) in May–October increased from 73 μg P l−1 in 1980 to 163 μg P l−1 in 2000. A significant increase in average chlorophyll a content from 16.6 μg l−1 in 1980 to 84.7 μg l−1 in 2000 and a shift in phytoplankton composition to the dominance of cyanobacteria over diatoms indicated a change in the trophic status of the reservoir from meso-eutrophic to hypertrophic. In 2016 and 2018, average TP was 96 and 101 μg P l−1, respectively. The average content of chlorophyll a was 43.6 μg l−1 in 2016 and 66.6 μg l−1 in warmer 2018, indicating persistent eutrophic conditions. Diatoms dominated both in 2016 and 2018, especially in 2016 characterized by unfavorable weather conditions. Cyanobacteria were more abundant in 2018 with higher summer temperatures. The decline of the total area covered by aquatic vegetation from 157 ha in 1980 to 76 ha in 2016 likely resulted from an increase in phytoplankton biomass and water turbidity. Based on the results of our observations, in addition to further reduction in nutrient loading, biomanipulation by introducing predatory fish as a restoration measure was proposed to improve the ecological status of the reservoir.

Key words

  • phytoplankton
  • cyanobacteria
  • macrophytes
  • shallow lakes
  • alternative stable states
  • eutrophication
Otwarty dostęp

Spat efficiency in the pearl oyster Pinctada radiata (Leach, 1814) in the surface and bottom water at Karantina Island

Data publikacji: 18 Jun 2020
Zakres stron: 184 - 192

Abstrakt

Abstract

The present study was carried out to determine the spat efficiency in the pearl oyster (Pinctada radiata, Leach, 1814) in surface and bottom water at Karantina Island (Izmir/Turkey). Polyethylene mesh bags were used as collectors. An annual average of 175.16 ± 11.32 spat m−2 was obtained from PSC (placed surface collectors) and 82.65 ±3.89 spat m−2 was obtained from PBC (placed bottom collectors). The largest number of new spat attachments occurred in August, both on PSC and PBC: 44 ± 3.46 and 26 ± 2.88 spats were found respectively in the outer and inner mesh bags of PSC, and 33 ±5.77 and 48 ± 6.92 spats were found respectively in the outer and inner mesh bags of PBC. New spat attachments (≥ 10 mm) continued throughout the study period, except April and May. Adult pearl oysters (≥ 50 mm) were found in May. There was a significant difference between PSC and PBC in the total number of spat attachments, the monthly spat attachments and the first spat attachments (p < 0.05). The total number of new spat attachments was positively correlated with temperature and chlorophyll a for both depths (p<0.05).

Key words

  • pearl oyster
  • spat settlement
  • growth
  • depths
  • Aegean Sea
Otwarty dostęp

Distribution and community structure of microphytoplankton in relation to increasing anthropogenic impact along coastal waters of Jeddah, the central Red Sea

Data publikacji: 18 Jun 2020
Zakres stron: 193 - 205

Abstrakt

Abstract

Seasonal distribution and diversity of surface phytoplankton have been studied in relation to anthropogenic activities at seven locations along the coastal waters of Jeddah, Saudi Arabia in 2017. The concentration of nitrite, nitrate, ammonia, phosphate and silicate varied over wide ranges: 0.04–20.27, 0.05–29.3, 0.22–78.16, 0.02–25.90 and 43–24.50 μmol l−1, respectively. Inorganic nutrients, phytoplankton biomass and density were at eutrophic levels at two lagoon locations (4 and 5), while other coastal locations showed oligotrophic characteristics of the Red Sea. Phytoplankton biomass was positively correlated with all measured inorganic nutrients. The total phytoplankton density varied between 52.4 × 103 and 40800 × 103 cells m−3 (average 6249.9×103 ± 10797×103 cells m−3). A total of 174 species of phytoplankton (95 diatoms, 75 dinoflagellates, 3 cyanophytes and 1 silicoflagellates) were recorded in this study, with the dominance of diatoms (95.1%). Higher densities observed at lagoon locations were mainly due to the proliferation of the diatom species Skeletonema costatum and Chaetoceros decipiens. In terms of diversity, dinoflagellates were more numerous than diatoms in July, otherwise mostly diatoms dominated. On the other hand, cyanophytes were more abundant in November. Based on the present study, anthropogenic activities (especially sewage effluent) in Jeddah coastal waters had a significant impact on the phytoplankton densities and diversity.

Key words

  • nutrients
  • phytoplankton
  • coastal water
  • Jeddah
  • Red Sea

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