scholarly journals Shifts in Diatom Dominance Associated with Seasonal Changes in an Estuarine-Mangrove Phytoplankton Community

2020 ◽  
Vol 8 (7) ◽  
pp. 528
Author(s):  
Fareha Hilaluddin ◽  
Fatimah Md. Yusoff ◽  
Tatsuki Toda
Keyword(s):  
Environmental Changes ◽  
Skeletonema Costatum ◽  
Sampling Period ◽  
Abundant Species ◽  
Dry Season ◽  
Northeast Monsoon ◽  
Diatom Species ◽  
Phytoplankton Abundance ◽  
Wet Season ◽  
Total Phytoplankton

A study on seasonal phytoplankton abundance and composition in a mangrove estuary, Matang Mangrove Forest Reserve (MMFR), Malaysia, was carried out to determine the phytoplankton structure in this ecosystem, and to identify potential indicators of environmental changes. Phytoplankton samples were collected bimonthly from June 2010 to April 2011, to cover both dry (June to October) and wet (November to April) seasons, at four selected sampling sites along the river. Diatoms showed the highest number of species (50 species) from a total of 85 phytoplankton species from 76 genera. Diatoms contributed more than 90% of the total phytoplankton abundance during the dry season (southwest monsoon) and less than 70% during the wet season (northeast monsoon) as dinoflagellates became more abundant during the rainy season. Two diatoms were recorded as dominant species throughout the sampling period; Cyclotella sp. and Skeletonema costatum. Cyclotella sp. formed the most abundant species (62% of total phytoplankton) during the dry period characterized by low nutrients and relatively low turbidity. Skeletonema costatum contributed 93% of the total phytoplankton in October, which marked the end of the dry season and the beginning of the wet season, characterized by strong winds and high waves leading to the upwelling of the water column. Massive blooms of Skeletonema costatum occurred during the upwelling when total nitrogen (TN) and total phosphorus (TP) concentrations were highest (p < 0.05) throughout the year. The abundance of diatom species during the wet season was more evenly distributed, with most diatom species contributing less than 12% of the total phytoplankton. Autotrophic producers such as diatoms were limited by high turbidity during the northeast monsoon when the rainfall was high. During the wet season, Cyclotella and Skeletonema costatum only contributed 9% and 5% of the total phytoplankton, respectively, as dinoflagellates had more competitive advantage in turbid waters. This study illustrates that some diatom species such as Cyclotella sp. and Skeletonema costatum could be used as indicators of the environmental changes in marine waters.

scholarly journals Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil

2011 ◽  
Vol 83 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Giulliari A. S. T. Lira ◽  
Elcida L. Araújo ◽  
Maria Do Carmo Bittencourt-Oliveira ◽  
Ariadne N. Moura
Keyword(s):  
Rainy Season ◽  
Phytoplankton Community ◽  
Dry Season ◽  
Cylindrospermopsis Raciborskii ◽  
Phytoplankton Abundance ◽  
Vertical Variation ◽  
Total Phytoplankton ◽  
Physical And Chemical Variables ◽  
Different Depths ◽  
Physical And Chemical

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

scholarly journals Environmental Impact of Heavy Metals from Poultry Waste Discharged into the Olosuru Stream, Ikire, Southwestern Nigeria

2019 ◽  
Vol 9 (22) ◽  
Author(s):  
Abayomi Tolulope Oyewale ◽  
Taiwo Adekanmi Adesakin ◽  
Adedeji Idowu Aduwo
Keyword(s):  
Heavy Metals ◽  
Environmental Impact ◽  
Anthropogenic Activities ◽  
Sampling Period ◽  
Dry Season ◽  
World Health ◽  
Poultry Waste ◽  
Wet Season ◽  
Southwestern Nigeria ◽  
Southwest Nigeria

Background. Water supplies can be contaminated by anthropogenic activities. The poultry industry uses a variety of heavy metals as additives in chicken feed, but excretion, runoff and dumping of heavy metals can threaten water bodies and have adverse effects on human health. Objectives. The aim of the present study was to determine the environmental impact of heavy metals from poultry waste discharged into the Olosuru stream, located in Ikire, southwest Nigeria. Methods. In order to study changes in heavy metal loads, samples were collected six times during the wet season (September, October 2014 and April 2015) and dry season (November 2014, January and February 2015). The inhabitants of Olosuru village use water for domestic and agriculture purposes from the Olosuru stream which is located only a few meters from a poultry farm discharge point. Three stations were sampled, upstream to downstream, with 500 meter distance between each point. Results. Selected heavy metals concentrations in the Olosuru stream were all above the World Health Organization (WHO) standard for drinking water. The highest mean concentrations of heavy metals were recorded at the downstream station, while arsenic, iron and lead showed significant spatial and seasonal differences. Seasonally, the highest iron concentrations were recorded in the dry season (0.104±0.401 mg/L), while the mean concentrations of other heavy metals recorded during the sampling period were higher during the wet season. Conclusions. Concentrations of heavy metals in the present study were above acceptable limits. Poultry waste discharged into the Olosuru stream, can have negative impacts on the stream and health implications for local residents. Competing Interests. The authors declare no competing financial interests.

Abundance, Zonation and Foraging Ecology of Birds in Mangroves of Darwin Harbour, Northern Territory.

1996 ◽  
Vol 23 (4) ◽  
pp. 443 ◽  
Author(s):  
RA Noske
Keyword(s):  
Foraging Ecology ◽  
Avicennia Marina ◽  
Abundant Species ◽  
Dry Season ◽  
Mangrove Forests ◽  
Resident Species ◽  
Wet Season ◽  
Mangrove Species ◽  
Significant Seasonal Variation ◽  
Melaleuca Cajuputi

The density, seasonality, habitat utilization and foraging ecology of birds in mangals (mangrove forests) at a site on the upper reaches of Darwin Harbour were investigated by transect censusing and colour-banding over three years. Despite having only 10 species of plants, the site supported 17 confirmed and five probable breeding resident species of birds, and was visited by 30 more. From variable-width transect censuses, the mean density of birds on a 4-ha plot was estimated to be 25 ha-1, fairly consistent with densities obtained from territory mapping of colour-banded birds. Nearly 70% of the individuals belonged to just 4 species: two mangal-dependent species, the red-headed honeyeater (Myzomela erythrocephala) and the yellow white-eye (Zosterops lutea) and two more generalised species, the large-billed gerygone (Gerygone magnirostris) and the brown honeyeater (Lichmera indistincta). Only the red-headed honeyeater showed significant seasonal variation in abundance, with highest numbers during the late dry season after breeding. This coincided with the period of greatest food (nectar) availability in the mangal, due to flowering Bruguiera exaristata. Lowest numbers of the red-headed honeyeater (and the brown honeyeater) occurred in the late wet season when nectar was scarce in the mangal but abundant in Melaleuca cajuputi fringing the mangal. Several resident species held permanent territories, while others apparently shifted landward during the wet season, possibly due to the wetter conditions created by freshwater runoff and high spring tides Many species showed strong associations with particular mangal zones. Large-billed gerygones, grey whistlers (Pachycephala simplex), shining flycatchers (Myiagra alecto) and mangrove fantails (Rhipidura phasiana) were associated with the Rhizophora zone at the wetter (more frequently inundated) end of the plot; mangrove robins (Eopsaltria pulverulenta) and mangrove gerygones (Gerygone laevigaster), were encountered most in the Ceriops zone; and green-backed gerygones (Gerygone chloronata) strongly favoured the dry landward edge. Four foraging guilds were evident among 13 of the most abundant species, the largest of which was the insectivorous foliage-foraging guild. Species in this group partitioned resources by differential selection of mangrove species, heights and foraging techniques. The tiny (6.4 g) mangrove gerygone was the most specialized species, spending 80% of its time on Avicennia marina. Contrary to the literature, breeding of mangal-dwelling birds peaked during the dry season. The ecology, evolution and biogeography of mangrove-endemic birds is reviewed in the light of this study and recent information from Western Australia.

scholarly journals Temporal variation in the phytoplankton community of Acapulco Bay, Mexico

2012 ◽  
Vol 3 (1) ◽  
pp. 4 ◽  
Author(s):  
Agustín A. Rojas-Herrera ◽  
Juan Violante Gonzalez ◽  
Sergio García-Ibáñez ◽  
Víctor M.G. Sevilla-Torres ◽  
Jaime S. Gil-Guerrero ◽  
...  
Keyword(s):  
Species Composition ◽  
Temporal Variation ◽  
Rainy Season ◽  
Phytoplankton Community ◽  
Species Abundance ◽  
Sampling Period ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Diatom Species ◽  
Oceanic Environments

<p>Species composition and abundance of the phytoplankton community in Acapulco Bay, Mexico, were studied from May to December 2009. Samples were collected at 5 stations (4 coastal and 1 oceanic) at 3 depths (1, 5 and 10 m). Eighty-seven species were identified: 54 dinoflagellates, 32 diatoms and 1 silicoflagellate. The community was structured mainly by adiaphoric species, that is, species adapted to both neritic and oceanic environments. Species abundance and composition varied significantly during the sampling period due to increased nutrient concentrations in the rainy season. Dinoflagellate species were more abundant during the dry season, and diatom species dominated numerically during the rainy season.</p>

scholarly journals Myxomycete diversity in a humid montane forest on the eastern slopes of the Peruvian Andes

2020 ◽  
Vol 153 (3) ◽  
pp. 390-398
Author(s):  
Italo F. Treviño-Zevallos ◽  
Carlos Lado
Keyword(s):  
Species Turnover ◽  
Species Abundance ◽  
Alpha Diversity ◽  
Abundant Species ◽  
Montane Forest ◽  
Dry Season ◽  
Wet Season ◽  
Montane Forests ◽  
Peruvian Andes ◽  
Species Richness And Abundance

Background – The humid montane forests on the eastern slopes of the Peruvian Andes are known for their high biodiversity and natural resources. While their incredibly rich plant and animal communities are still in the process of being discovered, the diversity of smaller organisms such as the Myxomycetes are even more scarcely known. In this work, we document the Myxomycete diversity in these montane forests and evaluate species abundance, occurrence by substrates, distribution, and seasonality, thus documenting population status and species ecology.Material and methods – The study was carried out at the Wayqecha Biological Station located in the Cusco region of Peru. Two sampling campaigns took place in late January (wet season) and early May (dry season) of 2018. We performed a species inventory and evaluated alpha diversity, assemblage similarity, and abundance of Myxomycetes within six 100 m2 plots. We documented variations of species richness and abundance between seasons as well as between substrates. Results – We recorded a total of 81 taxa of Myxomycetes. The order Physarales was the most diverse, and the most abundant species were Didymium squamulosum and Diderma deplanatum during the wet and dry season, respectively. The substrate with highest diversity overall was dead leaves. Diversity was similar in both seasons but with a notable species turnover. Conclusion – The humid montane forest on the eastern slopes of the Andes in Peru revealed an unexpected richness in Myxomycetes. Based on our results, we conclude that this type of forest harbours one of the greatest Myxomycetes diversities in the Peruvian territory, also due to the important seasonal species turnover.

scholarly journals ANALYSIS OF THE SEASONAL IMPACT ON ISOTOPIC BASELINES OF DISSOLVED INORGANIC CARBON (DIC) IN COASTAL WATERS SPERMONDE, SOUTH SULAWESI

2019 ◽  
Vol 11 (1) ◽  
pp. 141-149
Author(s):  
Wa Ode Rustiah ◽  
Alfian Noor ◽  
. Maming ◽  
Muhammad Lukman
Keyword(s):  
Stable Carbon Isotopes ◽  
Environmental Changes ◽  
Dissolved Inorganic Carbon ◽  
Co2 Storage ◽  
Dry Season ◽  
Inorganic Materials ◽  
Stable Carbon ◽  
Wet Season ◽  
Carbon Isotopic ◽  
South Sulawesi

Stable carbon isotopes have been commonly used as indicators for assessing environmental changes in aquatic ecosystems. They can be used to study the dynamics of organic matter as for understanding the overall functioning of the ecosystem, the connectivity of estuaries with terrestrial and marine coastal habitats. The objective of this study is determining the seasonal natural effects over isotopic (13C/12C) baselines in monitoring CO2 storage in dissolved inorganic materials in Spermonde waters on the west coast of South Sulawesi to some outermost island. The results show that the stable carbon isotopic of DIC (d13C-DIC) in the wet season varied between -5.36 ‰ and -7.74 ‰. These value are higher than on dry season (-4.34 ‰ to -6.82 ‰). Likewise, DIC concentration in the rainy season ranged between 9.5 mg C/L and 11.7 mg C/L, while in the dry season it varied from 8.5 mg C/L to 9.3 mg C/L. The d13C-DIC and DIC concentrations decreased towards offshore, up to some of the outer islands. Increasing in the d13C-DIC in Spermonde waters indicate that the DIC is most likely enriched by atmospheric CO2(g), which is outnumbered those of aquatic photosynthesis. This study shows that different levels and composition of d13C-DIC stretch along different rivers are attributable to the varying landscapes and quality of organic matters.

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

2020 ◽  
Vol 49 (2) ◽  
pp. 193-205
Author(s):  
Aisha A. Al-Amri ◽  
Huda A. Qari ◽  
Mohsen M. El-Sherbiny
Keyword(s):  
Red Sea ◽  
Coastal Waters ◽  
Phytoplankton Biomass ◽  
Anthropogenic Activities ◽  
Skeletonema Costatum ◽  
Seasonal Distribution ◽  
Inorganic Nutrients ◽  
Diatom Species ◽  
Total Phytoplankton ◽  
Nitrite Nitrate

AbstractSeasonal 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.

scholarly journals Short-term variability of copepod abundance in Jurumirim Reservoir, São Paulo, Brazil

2001 ◽  
Vol 61 (4) ◽  
pp. 577-598 ◽  
Author(s):  
E. A. PANARELLI ◽  
M. G. NOGUEIRA ◽  
R. HENRY
Keyword(s):  
Rainy Season ◽  
Sampling Period ◽  
Abundant Species ◽  
Sao Paulo ◽  
Dry Season ◽  
Dispersion Pattern ◽  
São Paulo ◽  
Short Term ◽  
Copepod Abundance ◽  
Short Term Variability

Short-term variability in composition and abundance of copepod populations were studied during the dry (winter) and rainy (summer) seasons, at the dam region of Jurumirim Reservoir, São Paulo, Brazil. An intensive sampling program was carried out during 30 days in each period of the year. Samples and measurements were taken every other day at 0, 5, 10, 15, 20 and 25 m depths. The relationship between variability of the populations and some environmental factors was analyzed. The main species were: Argyrodiaptomus furcatus (Sars), Notodiaptomus iheringi (Wright), Mesocyclops longisetus (Thiébaud), Thermocyclops decipiens (Fischer), and T. minutus (Lowndes). Thermocyclops minutus was the most abundant species in dry season and its abundance varied significantly between sampling days. A large increase in abundance of calanoids occurred during the rainy season. This increase was correlated with higher temperature values. At that time, Notodiaptomus iheringi was dominant. This species showed significant short-term variations in abundance in both dry and rainy seasons. Significant variation in density of populations within the same sampling period might result from either the dispersion pattern of the populations or continuous substitution of the water masses. Significant correlation was observed between copepod abundance and temperature, especially for species of calanoids and there was also some correlations between densities of particular species of copepods and some phytoplankton taxa, mainly during the dry season. As for vertical distribution, most organisms were found between the surface and 15 m deep. During the rainy season, there was some evidence of the occurrence of spatial segregation between species of cyclopoids and calanoids, with the cyclopoids in a deeper position within the water column.

scholarly journals Fish metacommunity structure in Caño Maraca, an important nursery habitat in the Western Llanos of Venezuela

2018 ◽  
Vol 16 (4) ◽  
Author(s):  
Kirk O. Winemiller ◽  
Donald C. Taphorn ◽  
Leslie C. Kelso-Winemiller ◽  
Edwin O. López-Delgado ◽  
Friedrich W. Keppeler ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Changes ◽  
Fish Assemblages ◽  
Species Interaction ◽  
Dry Season ◽  
Life History Strategies ◽  
Suitable Habitat ◽  
Downstream Site ◽  
Wet Season ◽  
Spatial And Seasonal Variation

ABSTRACT We investigated spatial and seasonal variation of fish assemblages of Caño Maraca, a creek in Venezuela’s Western Llanos, a region with strong wet-dry seasonality. Fishes were surveyed over a 19-year period at three sites along the longitudinal gradient: a headwater site with a narrow channel, a middle site with shallow channels traversing a seasonal wetland, and a lower site where the channel has higher banks. Assemblage composition and presence of species with juveniles and various life history strategies were compared during wet and dry seasons. Overall, fish species richness was lowest at the headwater site and highest at the downstream site. During the wet season, however, species richness is greatest at the middle site, a pattern associated with migration into the site for reproduction and use of the wetland as a nursery. During the dry season, species richness is greater at the downstream site where habitat quality is sufficient to provide suitable habitat for many species. Fish movements and population dynamics in Caño Maraca respond to seasonal environmental changes, and the fish metacommunity appears influenced by species sorting (habitat selection), mass effects (source-sink dynamics), patch dynamics (interspecific differences in colonization and species interaction) as well as random factors (dry-season strandings).

scholarly journals Feeding habits of five dominant fish species from Matang Mangrove Estuaries, Malaysia based on stomach contents and stable isotope analyses

2021 ◽  
Author(s):  
M. K. Mohd Azim ◽  
S. M. Nurul Amin ◽  
D. Mazumder ◽  
A. Arshad ◽  
F. M. Yusoff ◽  
...  
Keyword(s):  
Fish Species ◽  
Environmental Changes ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Dry Season ◽  
Fish Diet ◽  
Wet Season ◽  
Dominant Fish ◽  
Dry Seasons ◽  
Wet And Dry Seasons

Abstract The centres of mangrove biodiversity and productivity have been under-represented in studies of fish diet and habitat utilization, particularly in relation to environmental changes between wet and dry seasons. Feeding habits of five dominant fish species (Thryssa kammalensis, Ambassis gymnocephalus, Escualosa thoracata, Stolephorus baganensis and Johnius belangerii) were investigated from two sites in the Matang Mangrove ecosystem, Perak Malaysia, with sampling encompassing both wet and dry seasons. The stomach fullness of the fish was on average significantly higher in the wet season (48%) than in the dry season (32%) with isopods and copepods forming a more important component of the fish diet during the wet season than the dry season. The stomach contents of each species were, on average: T. kammalensis {(Animal based (A) = 50.11%, Plant based (P) = 38.24%)}, A. gymnocephalus (A = 50.35%, P = 37.99%), E. thoracata (A = 42.09%, P = 44.4%), S. baganensis (A = 38.17%, P = 46.55%) and J. belangerri (A = 25.35%, P = 58.86%). Therefore, all five fish species can be considered omnivorous. The similarity among diets varied from 60-80% during the wet and dry season. During the dry season, stable carbon and nitrogen isotope values of the samples had less variation, indicating narrow dietary sources compared to the wet season where the distribution of their isotopic values was larger. Seasons should be considered for planning mangrove management, as results of this study found contracted trophic breadth for commercially valuable fish in the dry season.

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