scholarly journals Phytoplankton community responses to temperature fluctuations under different nutrient concentrations and stoichiometry

Ecology ◽  
2019 ◽  
Vol 100 (11) ◽  
Author(s):  
Miriam Gerhard ◽  
Apostolos Manuel Koussoroplis ◽  
Helmut Hillebrand ◽  
Maren Striebel
Keyword(s):  
Phytoplankton Community ◽  
Temperature Fluctuations ◽  
Nutrient Concentrations ◽  
Community Responses

scholarly journals Whole-Ecosystem Experiments Reveal Varying Responses of Phytoplankton Functional Groups to Epilimnetic Mixing in a Eutrophic Reservoir

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 222 ◽  
Author(s):  
Mary Lofton ◽  
Ryan McClure ◽  
Shengyang Chen ◽  
John Little ◽  
Cayelan Carey
Keyword(s):  
Community Composition ◽  
Green Algae ◽  
Phytoplankton Community ◽  
Water Reservoir ◽  
Ecosystem Dynamics ◽  
Bubble Plume ◽  
Community Responses ◽  
Drinking Water Reservoir ◽  
Biological Variables ◽  
Lakes And Reservoirs

Water column mixing can influence community composition of pelagic phytoplankton in lakes and reservoirs. Previous studies suggest that low mixing favors cyanobacteria, while increased mixing favors green algae and diatoms. However, this shift in community dominance is not consistently achieved when epilimnetic mixers are activated at the whole-ecosystem scale, possibly because phytoplankton community responses are mediated by mixing effects on other ecosystem processes. We conducted two epilimnetic mixing experiments in a small drinking water reservoir using a bubble-plume diffuser system. We measured physical, chemical, and biological variables before, during, and after mixing and compared the results to an unmixed reference reservoir. We observed significant increases in the biomass of cyanobacteria (from 0.8 ± 0.2 to 2.4 ± 1.1 μg L−1, p = 0.008), cryptophytes (from 0.7 ± 0.1 to 1.9 ± 0.6 μg L−1, p = 0.003), and green algae (from 3.8 to 4.4 μg L−1, p = 0.15) after our first mixing event, likely due to increased total phosphorus from entrainment of upstream sediments. After the second mixing event, phytoplankton biomass did not change but phytoplankton community composition shifted from taxa with filamentous morphology to smaller, rounder taxa. Our results suggest that whole-ecosystem dynamics and phytoplankton morphological traits should be considered when predicting phytoplankton community responses to epilimnetic mixing.

scholarly journals Influences of Nutrient Sources on the Alternation of Nutrient Limitations and Phytoplankton Community in Jiaozhou Bay, Southern Yellow Sea of China

2020 ◽  
Vol 12 (6) ◽  
pp. 2224
Author(s):  
Jie Shi ◽  
Qian Leng ◽  
Junying Zhu ◽  
Huiwang Gao ◽  
Xinyu Guo ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Phytoplankton Community ◽  
Inorganic Nitrogen ◽  
Marine Ecosystem ◽  
Jiaozhou Bay ◽  
Nutrient Concentrations ◽  
River Input ◽  
Aquaculture Wastewater ◽  
The 1960S ◽  
Yellow Sea Of China

A marine ecosystem box model was developed to reproduce the seasonal variations nutrient concentrations and phytoplankton biomasses in Jiaozhou Bay (JZB) of China. Then, by removing each of the external sources of nutrients (river input, aquaculture, wastewater discharge, and atmospheric deposition) in the model calculation, we quantitatively estimated its influences on nutrient structure and the phytoplankton community. Removing the river input of nutrients enhanced silicate (SIL) limitation to diatoms (DIA) and decreased the ratio of DIA to flagellates (FLA); removing the aquaculture input of nutrients decreased FLA biomass because it provided less dissolved inorganic nitrogen (DIN) but more dissolved inorganic phosphate (DIP) as compared to the Redfield ratio; removing the wastewater input of nutrients changed the DIN concentration dramatically, but had a relatively weaker impact on the phytoplankton community than removing the aquaculture input; removing atmospheric deposition had a negligible influence on the model results. Based on these results, we suppose that the change in the external nutrients sources in the past several decades can explain the long-term variations in nutrient structure and phytoplankton community. Actually, the simulations for the 1960s, 1980s, and 2000s in JZB demonstrated the shift of limiting nutrients from DIP to SIL. A reasonable scenario for this is the decrease in riverine SIL and increase in DIP from aquaculture that has reduced DIA biomass, promoted the growth of FLA, and led to the miniaturization of the phytoplankton.

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 Responses of Marine Diatom-Dinoflagellate Competition to Multiple Environmental Drivers: Abundance, Elemental, and Biochemical Aspects

2021 ◽  
Vol 12 ◽  
Author(s):  
Rong Bi ◽  
Zhong Cao ◽  
Stefanie M. H. Ismar-Rebitz ◽  
Ulrich Sommer ◽  
Hailong Zhang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Algal Blooms ◽  
Phytoplankton Community ◽  
Additive Models ◽  
Prorocentrum Minimum ◽  
Marine Phytoplankton ◽  
Marine Diatom ◽  
Environmental Drivers ◽  
Nutrient Concentrations ◽  
High Nutrient

Ocean-related global change has strongly affected the competition between key marine phytoplankton groups, such as diatoms and dinoflagellates, especially with the deleterious consequency of the increasing occurrence of harmful algal blooms. The dominance of diatoms generally shifts toward that of dinoflagellates in response to increasing temperature and reduced nutrient availability; however, contradictory findings have also been observed in certain sea areas. A key challenge in ecology and biogeochemistry is to quantitatively determine the effects of multiple environmental factors on the diatom-dinoflagellate community and the related changes in elemental and biochemical composition. Here, we test the interplay between temperature, nutrient concentrations and their ratios on marine diatom-dinoflagellate competition and chemical composition using bi-algal competition experiments. The ubiquitous diatom Phaeodactylum tricornutum and dinoflagellate Prorocentrum minimum were cultivated semi-continuously, provided with different N and P concentrations (three different levels) and ratios (10:1, 24:1, and 63:1 molar ratios) under three temperatures (12, 18, and 24°C). The responses of diatom-dinoflagellate competition were analyzed by a Lotka-Volterra model and quantified by generalized linear mixed models (GLMMs) and generalized additive models (GAMs). The changes in nutrient concentrations significantly affected diatom-dinoflagellate competition, causing a competitive superiority of the diatoms at high nutrient concentrations, independent of temperature and N:P supply ratios. Interestingly, the effect amplitude of nutrient concentrations varied with different temperatures, showing a switch back toward a competitive superiority of the dinoflagellates at the highest temperature and at very high nutrient concentrations. The ratios of particulate organic nitrogen to phosphorus showed significant negative correlations with increasing diatoms/dinoflagellates ratios, while lipid biomarkers (fatty acids and sterols) correlated positively with increasing diatoms/dinoflagellates ratios over the entire ranges of temperature, N and P concentrations and N:P ratios. Our results indicate that the integration of phytoplankton community structure and chemical composition provides an important step forward to quantitatively understand and predict how phytoplankton community changes affect ecosystem functions and biogeochemical cycles in the ocean.

scholarly journals Phytoplankton Community Responses to Interactions Between Light Intensity, Light Variations, and Phosphorus Supply

2020 ◽  
Vol 8 ◽  
Author(s):  
Vanessa Marzetz ◽  
Elly Spijkerman ◽  
Maren Striebel ◽  
Alexander Wacker
Keyword(s):  
Light Intensity ◽  
Green Algae ◽  
Nutrient Supply ◽  
High Light Intensity ◽  
High Light ◽  
Nutrient Concentrations ◽  
Community Responses ◽  
Phytoplankton Communities ◽  
Light Variability ◽  
Nutrient Conditions

In a changing world, phytoplankton communities face a large variety of challenges including altered light regimes. These alterations are caused by more pronounced stratification due to rising temperatures, enhanced eutrophication, and browning of lakes. Community responses toward these effects can emerge as alterations in physiology, biomass, biochemical composition, or diversity. In this study, we addressed the combined effects of changes in light and nutrient conditions on community responses. In particular, we investigated how light intensity and variability under two nutrient conditions influence (1) fast responses such as adjustments in photosynthesis, (2) intermediate responses such as pigment adaptation and (3) slow responses such as changes in community biomass and species composition. Therefore, we exposed communities consisting of five phytoplankton species belonging to different taxonomic groups to two constant and two variable light intensity treatments combined with two levels of phosphorus supply. The tested phytoplankton communities exhibited increased fast reactions of photosynthetic processes to light variability and light intensity. The adjustment of their light harvesting mechanisms via community pigment composition was not affected by light intensity, variability, or nutrient supply. However, pigment specific effects of light intensity, light variability, and nutrient supply on the proportion of the respective pigments were detected. Biomass was positively affected by higher light intensity and nutrient concentrations while the direction of the effect of variability was modulated by light intensity. Light variability had a negative impact on biomass at low, but a positive impact at high light intensity. The effects on community composition were species specific. Generally, the proportion of green algae was higher under high light intensity, whereas the cyanobacterium performed better under low light conditions. In addition to that, the diatom and the cryptophyte performed better with high nutrient supply while the green algae as well as the cyanobacterium performed better at low nutrient conditions. This shows that light intensity, light variability, and nutrient supply interactively affect communities. Furthermore, the responses are highly species and pigment specific, thus to clarify the effects of climate change a deeper understanding of the effects of light variability and species interactions within communities is important.

scholarly journals Seasonal and interannual variability of phytoplankton abundance and community composition on the Central Coast of California

2020 ◽  
Vol 637 ◽  
pp. 29-43 ◽  
Author(s):  
A Barth ◽  
RK Walter ◽  
I Robbins ◽  
A Pasulka
Keyword(s):  
Interannual Variability ◽  
Phytoplankton Community ◽  
Coastal Upwelling ◽  
Current System ◽  
Ecosystem Dynamics ◽  
Nutrient Concentrations ◽  
Ecosystem Structure ◽  
Phytoplankton Abundance ◽  
California Current System ◽  
Seasonal And Interannual Variability

Variations in the abundance and composition of phytoplankton greatly impact ecosystem structure and function. Within the California Current System (CCS), phytoplankton community structure is tightly coupled to seasonal variability in wind-driven coastal upwelling, a process that drives changes in coastal water temperatures and nutrient concentrations. Based on approximately a decade (2008-2018) of weekly phytoplankton measurements, this study provides the first characterization of the seasonal and interannual variability of phytoplankton abundance and composition in San Luis Obispo (SLO) Bay, an understudied region within the CCS. Overall, the seasonality of phytoplankton in SLO Bay mirrored that of the larger CCS; diatoms dominated the community during the spring upwelling season, whereas dinoflagellates dominated the community during the fall relaxation period. While we observed considerable interannual variability among phytoplankton taxa, of particular note was the absence of a fall dinoflagellate-dominated period from 2010 through 2013, followed by the return of the fall dinoflagellate-dominated period in 2014. This compositional shift coincided with a major phase shift of both the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO). In addition to exerting a strong influence on the seasonality of phytoplankton community succession and transition between diatom- and dinoflagellate-dominated periods, the state of both the PDO and NPGO also influenced the extent to which environmental conditions (temperature and upwelling winds) could predict community type. These results highlight the importance of long-term datasets and the consideration of large-scale climate patterns when assessing local ecosystem dynamics.

Spatial variations of phytoplankton community structure in a highly eutrophicated coast of the Western Mediterranean Sea

1995 ◽  
Vol 32 (9-10) ◽  
pp. 313-322 ◽  
Author(s):  
E. Soler Torres ◽  
J. G. del Río
Keyword(s):  
Phytoplankton Community ◽  
Sea Water ◽  
Western Mediterranean ◽  
Nutrient Concentrations ◽  
Western Mediterranean Sea ◽  
Open Sea ◽  
Southern Side ◽  
Well Differentiated ◽  
Abundance And Diversity ◽  
Physical And Chemical

Pinedo is a small beach placed at the southern side of Valencia (Eastern Spain). This coastal area has became highly eutrophicated because of the discharge of a large flow of urban wastewaters at the shore line. In order to assess the environmental impact of a new sea outfall and to study the phytoplankton and nutrients dynamics of this eutrophicated system a broad survey was conducted between May 1989 and April 1990. Physical and chemical parameters were measured through a transect laying between the wastewater discharge point and the open sea. In this paper we report preliminary results about the variations observed in the phytoplankton community along this sharp environmental gradient. Three main zones with particular phytoplankton structure appear well differentiated. The first is an inshore zone very influenced by continental loadings where brackish and polluted waters were found. Phytoplankton shows relatively low numbers being dominated by Chlorophyceae and a few other eurihaline species. An intermediate zone has salinities close to sea water but nutrient concentrations are high enough to allow maximum development of phytoplankton, which reaches its highest abundance and diversity values. Diatoms, dinoflagellates and some flagellates (Prymnesiophyceae and Cryptophyceae) dominate the eukaryotic community of this zone. Gradual impoverishment of sea water is accompanied by a rapid decrease of phytoplankton biomass, which is reduced to scarce flagellates populations at the open sea stations.

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