Plankton Community as a Bio-indicator of Water Quality in Situ Ciburuy Padalarang, West Bandung Regency, West Java

This research was conducted to determine the water quality of Situ Ciburuy based on the plankton community as water quality bio-indicator. This research used the survey method and the observation result data were analyzed descriptively. The abundance of phytoplankton is about 340 – 8913 ind/L indicates that the abundance of phytoplankton is moderate and the abundance of zooplankton is about 7 – 30 ind/L indicates that the abundance of zooplankton is low. The Simpson diversity index for the phytoplankton group ranged from 0.29 – 0.33 and the Simpson Diversity Index for the zooplankton group ranged from 0.42 – 0.56 while the Simpson Dominance Index for the phytoplankton group ranged from 0.67 – 0.71 and the Simpson Dominance Index for zooplankton ranged from between 0.44 – 0.58 which indicates Situ Ciburuy is in an unstable condition. Based on the value of the Saprobic Index ranged between (-0.2) to (0). Situ Ciburuy belongs to α / β – mesosaprobic phase and categorized in the moderately polluted category.

A modelling approach to simulate Chlorophyta and Cyanobacteria biomasses based on historical data of a Brazilian urban reservoir

A process-based model was used to simulate a hindcast based on the worst historical water quality condition of a tropical urban reservoir. Paranoá Lake is located in Brasília-DF, Brazil, and went through intense eutrophication in the 70s and 90s, with an important cyanobacterial bloom event in 1978. The parameters of phytoplankton were calibrated, focusing on the group of Chlorophyta (green algae) and Cyanobacteria (blue-green algae) at four depths (1, 10, 15 and 20m). The results indicated that the model was able to reproduce the Cyanobacteria biomass in comparison with the observations (RMSE=22-29.10-3 mgC L-1). On the other hand, the simulated Chlorophyta biomass showed good agreement with the observed data only in the bottom layer (RMSE=29. 10-3 mgC L-1 at 20m). In the hindcast simulation, the model was able to predict a significant increase in cyanobacterial biomass facing a water quality deterioration. In the meantime, the simulated Chlorophyta biomass decreased, which may indicate the phytoplankton group succession in response to the environmental conditions.

Water Quality Improvement Shifts the Dominant Phytoplankton Group From Cryptophytes to Diatoms in a Coastal Ecosystem

We investigated long-term variations in the dominant phytoplankton groups with improvements in water quality over 11 years in the Yeongil Bay on the southeastern coast of Korea. River discharge declined during the study period but TN from river discharge remained stable, indicating the input of enriched nutrients to the bay was fairly consistent. NH4+ levels decreased with a decrease in TN from the POSCO industrial complex. While the study region was characterized by the P-limited and deficient environment, cryptophytes dominated with the intensified P-limitations. The relative abundance of cryptophytes declined from 70% in 2010 to 10% in 2016, but that of diatoms increased from 70% in 2009 to 90% in 2016. Correlation analysis showed a positive correlation of cryptophytes with NH4+ and a negative correlation with photic depth. Generalized additive models also exhibited an increase in diatom dominance and a decrease in cryptophyte dominance with an increase in water quality, indicating that a decrease in NH4+ and increase in light favored the diatom growth but suppressed the cryptophyte growth. Thus, water quality improvements shift the dominant group in the coastal ecological niche from cryptophytes to diatoms.

Modification of phytoplankton group diversity over submesoscale fronts

<p>Over large parts of the ocean, submesoscale fronts are known to enhance total phytoplankton abundance because they are the location of intense vertical transport of nutrients. Disparate in situ observations suggest that such frontal dynamics not only affects the total biomass of phytoplankton, but also significantly modifies its composition. Here we make use of a newly developed algorithm able to distinguish a set of phytoplankton-specific pigments to statistically explore the change in phytoplankton community composition over basin-wide regions. We use 15 years of SST and reflectance data from the MODIS sensor on the Aqua satellite, at 1km and daily resolutions and focus on the oligotrophic North Atlantic subtropical gyre and on the more productive gulf stream region. We locate submesoscale fronts by computing an index quantifying SST patchiness. Our results confirm that submesoscale fronts are collocated with elevated Chlorophyll-a concentration and show significant changes in phytoplankton composition. These results underline the influence of submesocale dynamics on phytoplankton diversity, and stress the need to better understand the underlying mechanisms.</p>

Seasonal Shift of a Phytoplankton (>5 µm) Community in Bohai Sea and the Adjacent Yellow Sea

In order to better understand the seasonal variations in the phytoplankton community structure in the Bohai Sea (BS) and the North Yellow Sea (NYS), we carried out three cruises during 12 to 24 April 2019, 8 to 18 June 2019, and 12 to 22 October 2019. A total of 212 taxa (75 genera and three phyla) were identified, among which 83 taxa in 40 genera, 96 taxa in 43 genera, and 151 taxa in 62 genera were found in spring, summer, and autumn, respectively. Diatoms including Paralia sulcata and Coscinodiscus granii were the most dominant phytoplankton group during the three seasons, while several species of dinoflagellates, e.g., Scrippsiella troichoidea, Tripos massiliensis f. armatus, Gyrodinium spirale, and Prorocentrum minimum were found in warmer, saltier, and nutrient-poor waters. The diversity index of phytoplankton community was highest in autumn and lowest in summer. Based on cluster and multidimensional scaling analyses, the phytoplankton community of the BS and the NYS was divided into three ecological provinces: the BS, the coastal area, and the NYS. These three ecological provinces differed in physicochemical properties induced by the complicated water masses and circulations. Due to the influence of nutrient concentration, the phytoplankton diversity had the highest value in autumn, followed by spring, and the smallest in summer.

Assessment of water quality in Shitalakhya river insights from phytoplankton and nutrient regimes

The present study assessed the water quality parameter insights from phytoplankton and nutrientregimes of the Shitalakhya River based on three sampling stations. The ranges of water temperature,transparency, dissolved oxygen, pH, TDS, phosphate-phosphorus, nitrite-nitrogen, nitrate-nitrogen, andsilicate were 27.86±0.249 °C to 29.83±0.612 °C, 42.33±0.471 to 31.33±0.942 cm, 6.35±0.232 to5.88±0.066 mg/L, 7.62±0.008 to 7.52±0.018, 63.33±4.714 to 40±8.164 mg/L, 0.52±0.020 to0.34±0.016 mg/L, 0.06±0.012 to 0.01±0.004 mg/L, 0.12±0.008 to 0.05±0.004 mg/L, and 0.12±0.004to 0.07±0.001 mg/L respectively. The values of transparency, TDS, nitrite, nitrate, and silicate variedsignificantly while other parameters showed non-significant (p>0.05) among three stations. The results alsoindicated the presence of 27 genera belonging to five major groups- Bacillariophyceae (9), Chlorophyceae(8), Euglenophyceae (5), Dinophyceae (3), and Cyanophyceae (2). The dominant phytoplankton group wasthe Bacillariophyceae (38%), followed in order by Chlorophyceae (26%), Euglenophyceae (19%),Dinophyceae (12%), and Cyanophyceae (5%). Shannon-Weiner species diversity index (H?) ranged from 2.31to 2.99 (phytoplankton) indicating the water body is moderately polluted. Overall, maximum density(46.66×103 cells L-1) of phytoplankton was observed at S2 followed by S3 (35.23×103 cells L-1) and S1(20.95×103 cells L-1). The fluctuation of the physico-chemical parameters and phytoplankton density of theriver could be attributed to the high influx of nutrients into the river as a result of discharging nutrient reachwater from. Monitoring of these activities within the river and education on the wise use of the water isrecommended.

Cyclic evolution of phytoplankton forced by changes in tropical seasonality

The effect of global climate cycles driven by Earth’s orbital variations on evolution is poorly understood because of difficulties achieving sufficiently-resolved records of past evolution. The fossil remains of coccolithophores, a key calcifying phytoplankton group, enable an exceptional assessment of the impact of cyclic orbital-scale climate change on evolution because of their abundance in marine sediments, and because coccolithophores demonstrate extreme morphological plasticity in response to the changing environment1,2. Recently, evolutionary genetic analyses linked broad changes in Pleistocene fossil coccolith morphology to species radiation events3. Here, using high-resolution coccolith data, we show that during the last 2.8 million years coccolithophore evolution was forced by Earth’s orbital eccentricity with rhythms of ~100,000 years and 405,000 years - a distinct spectral signature to that of coeval global climate cycles4. Simulations with an Earth System Model5 including the marine carbon cycle6 demonstrate that eccentricity directly impacts the diversity of ecological niches occurring over the annual cycle in the tropical ocean. Reduced seasonality favours species with mid-size coccoliths that bloom year-round, increasing coccolith carbonate export and burial. We posit that eccentricity pacing of phytoplankton evolution contributed to the strong 405,000-year pacing seen in records of the global carbon cycle.