Biomanipulation of Lake 221 in the Experimental Lakes Area (ELA): Effects on Phytoplankton and Nutrients

1994 ◽  
Vol 51 (12) ◽  
pp. 2794-2807 ◽  
Author(s):  
D. L. Findlay ◽  
S. E. M. Kasian ◽  
L. L. Hendzel ◽  
G. W. Regehr ◽  
E. U. Schindler ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Bacterial Population ◽  
Phytoplankton Community ◽  
Nutrient Recycling ◽  
Experimental Lakes Area ◽  
Piscivorous Fish ◽  
Pike Perch ◽  
Trophic Changes ◽  
Phytoplankton Cell ◽  
Daphnia Catawba

Lake 221 was dominated by omnivorous perch (Perca flavescens); the addition of northern pike (Esox lucius) resulted in trophic changes that eventually affected the phytoplankton community. Two years following the introduction of pike, perch were greatly reduced. Subsequently, Chaoborus abundance increased, rotifer and cladoceran abundance and biomass decreased, and the large-bodied cladoceran Daphnia catawba increased. The phytoplankton community shifted from chlorophyte to cyanophyte codominance with dinoflagellates. Phytoplankton biomass and phosphorus (P) increased because of nutrient recycling and excretion by pike and zooplankton. In years three and four, algal biomass and the ratio of suspended to dissolved P decreased because a larger portion of dissolved P was bound in an increased bacterial population. Phytoplankton cell size and production decreased, but the production:biomass ratio increased. In year five, chrysophytes dominated as phytoplankton biomass and production increased and bacterial abundance declined. Phytoplankton responses were primarily an indirect result of the introduction of piscivorous fish, which altered internal nutrient recycling.

Differences between Nearshore and Offshore Phytoplankton Communities in Lake Ontario

1987 ◽  
Vol 44 (12) ◽  
pp. 2155-2163 ◽  
Author(s):  
I. M. Gray
Keyword(s):  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Algal Biomass ◽  
Phytoplankton Community ◽  
Seasonal Pattern ◽  
Principal Component ◽  
Lake Ontario ◽  
Dominant Group ◽  
Phytoplankton Communities ◽  
Eutrophic Species

Differences between nearshore and offshore phytoplankton biomass and composition were evident in Lake Ontario in 1982. Phytoplankton biomass was characterized by multiple peaks which ranged over three orders of magnitude. Perhaps as a consequence of the three times higher current velocities at the northshore station, phytoplankton biomass ranged from 0.09 to 9.00 g∙m−3 compared with 0.10 to 2.40 g∙m−3 for the midlake station. Bacillariophyceae was the dominant group at the northshore station until September when Cyanophyta contributed most to the biomass (83%). Although Bacillariophyceae was the principal component of the spring phytoplankton community at the midlake station, phytoflagellates (49%) and Chlorophyceae (25%) were responsible for summer biomass, with the Chlorophyceae expanding to 80% in the fall. The seasonal pattern of epilimnetic chlorophyll a correlated with temperature. While chlorophyll a concentrations were similar to values from 1970 and 1972, algal biomass had declined and a number of eutrophic species (Melosira binderana, Stephanodiscus tenuis, S. hantzschii var. pusilla, and S. alpinus) previously found were absent in 1982.

scholarly journals Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

2010 ◽  
Vol 7 (12) ◽  
pp. 3941-3959 ◽  
Author(s):  
I. Marinov ◽  
S. C. Doney ◽  
I. D. Lima
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Sea Ice ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Vertical Mixing ◽  
Phytoplankton Community Structure ◽  
Marginal Sea ◽  
Small Phytoplankton ◽  
The Impact

Abstract. The response of ocean phytoplankton community structure to climate change depends, among other factors, upon species competition for nutrients and light, as well as the increase in surface ocean temperature. We propose an analytical framework linking changes in nutrients, temperature and light with changes in phytoplankton growth rates, and we assess our theoretical considerations against model projections (1980–2100) from a global Earth System model. Our proposed "critical nutrient hypothesis" stipulates the existence of a critical nutrient threshold below (above) which a nutrient change will affect small phytoplankton biomass more (less) than diatom biomass, i.e. the phytoplankton with lower half-saturation coefficient K are influenced more strongly in low nutrient environments. This nutrient threshold broadly corresponds to 45° S and 45° N, poleward of which high vertical mixing and inefficient biology maintain higher surface nutrient concentrations and equatorward of which reduced vertical mixing and more efficient biology maintain lower surface nutrients. In the 45° S–45° N low nutrient region, decreases in limiting nutrients – associated with increased stratification under climate change – are predicted analytically to decrease more strongly the specific growth of small phytoplankton than the growth of diatoms. In high latitudes, the impact of nutrient decrease on phytoplankton biomass is more significant for diatoms than small phytoplankton, and contributes to diatom declines in the northern marginal sea ice and subpolar biomes. In the context of our model, climate driven increases in surface temperature and changes in light are predicted to have a stronger impact on small phytoplankton than on diatom biomass in all ocean domains. Our analytical predictions explain reasonably well the shifts in community structure under a modeled climate-warming scenario. Climate driven changes in nutrients, temperature and light have regionally varying and sometimes counterbalancing impacts on phytoplankton biomass and structure, with nutrients and temperature dominant in the 45° S–45° N band and light-temperature effects dominant in the marginal sea-ice and subpolar regions. As predicted, decreases in nutrients inside the 45° S–45° N "critical nutrient" band result in diatom biomass decreasing more than small phytoplankton biomass. Further stratification from global warming could result in geographical shifts in the "critical nutrient" threshold and additional changes in ecology.

scholarly journals A MULTI-SPECIES MICROALGAE BLOOM IN BAHIA DE LA PAZ, GULF OF CALIFORNIA, MEXICO (JUNE 2008)

2009 ◽  
Vol 24 (1) ◽  
pp. 15 ◽  
Author(s):  
I. Gárate-Lizárraga ◽  
C. J. Band-Schmidt ◽  
F. Aguirre-Bahena ◽  
T. Grayeb del Alamo
Keyword(s):  
Phytoplankton Biomass ◽  
Gulf Of California ◽  
Phytoplankton Community ◽  
Red Tide ◽  
Total Density ◽  
La Paz ◽  
Gyrodinium Instriatum ◽  
High Species Richness ◽  
Myrionecta Rubra ◽  
Ecological Importance

Red tide patches were observed in Bahía de La Paz in June 17 and 18 of 2008. According to temperature and wind data this bloom occurred under upwelling-like conditions. Examination of the red tide samples showed the ciliate Myrionecta rubra and the naked dinoflagellates Gyrodinium instriatum and Katodinium glaucum as the main species responsible for this bloom. Total density (microalgae and ciliate) at the sampling stations was similar on both days, varying from 4607 × 103 cells L-1 to 4976 × 103 cells L-1 on the first day, and from 4172 × 103 cells L-1 to 5024 × 103 cells L-1 on the second day. Phytoplankton biomass (chlorophyll a) observed during the first day of the bloom was 1.5 mg m-3. Dinoflagellates and diatoms were the most numerically important phytoplankton groups. The phytoplankton community showed a high species richness, particularly heterotrophic dinoflagellates and ebridians. The ecological importance of the heterotrophic component of naked dinoflagellates and the ebriids for this bay is discussed. Florecimiento multiespecífico de microalgas en la Bahía de La Paz, Golfo de California, México (Junio, 2008) Durante los días 17 y 18 de junio de 2008, se observó una marea roja en la Bahía de La Paz. De acuerdo con los datos de temperatura y de vientos, este florecimiento ocurrió bajo condiciones muy similares a las de una surgencia. El examen de las muestras de marea roja revelaron que el ciliado Myrionecta rubra y los dinoflagelados desnudos Gyrodinium instriatum y Katodinium glaucum fueron las principales especies responsables de esta proliferación. La densidad total (microalgas y ciliado) fue similar en ambos días, variando de 4607 × 103 céls L-1 a 4976 × 103 céls L-1 durante el primero y entre 4172 × 103 céls L-1 y 5024 × 103 céls L-1 el segundo día, respectivamente. La biomasa fitoplanctónica (clorofila a) medida durante el primer día del florecimiento fue de 1.5 mg m3. Los dinoflagelados y las diatomeas fueron los dos grupos del fitoplancton numéricamente más importantes. Se observó una comunidad fitoplanctónica con una alta riqueza de especies, particularmente de dinoflagelados y ebriidos heterotróficos. Se discute la importancia del componente heterotrófico de los dinoflagelados desnudos y ebriidos.

scholarly journals Effects of nitrogen enrichment on zooplankton biomass and N:P recycling ratios across a DOC gradient in northern-latitude lakes

Hydrobiologia ◽  
2021 ◽  
Author(s):  
A.-K. Bergström ◽  
A. Deininger ◽  
A. Jonsson ◽  
J. Karlsson ◽  
T. Vrede
Keyword(s):  
Community Composition ◽  
Resource Use ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
N Fertilization ◽  
Zooplankton Biomass ◽  
Nitrogen Enrichment ◽  
C:N:P Stoichiometry ◽  
Food Quantity ◽  
N Enrichment

AbstractWe used data from whole-lake studies to assess how changes in food quantity (phytoplankton biomass) and quality (phytoplankton community composition, seston C:P and N:P) with N fertilization affect zooplankton biomass, community composition and C:N:P stoichiometry, and their N:P recycling ratio along a gradient in lake DOC concentrations. We found that despite major differences in phytoplankton biomass with DOC (unimodal distributions, especially with N fertilization), no major differences in zooplankton biomass were detectable. Instead, phytoplankton to zooplankton biomass ratios were high, especially at intermediate DOC and after N fertilization, implying low trophic transfer efficiencies. An explanation for the observed low phytoplankton resource use, and biomass responses in zooplankton, was dominance of colony forming chlorophytes of reduced edibility at intermediate lake DOC, combined with reduced phytoplankton mineral quality (enhanced seston N:P) with N fertilization. N fertilization, however, increased zooplankton N:P recycling ratios, with largest impact at low DOC where phytoplankton benefitted from light sufficiently to cause enhanced seston N:P. Our results suggest that although N enrichment and increased phytoplankton biomass do not necessarily increase zooplankton biomass, bottom-up effects may still impact zooplankton and their N:P recycling ratio through promotion of phytoplankton species of low edibility and altered mineral quality.

Experimental culling of minnows suppresses cyanobacterial bloom under low-nutrient conditions

2019 ◽  
Vol 76 (11) ◽  
pp. 2102-2109 ◽  
Author(s):  
Blake R. Stuparyk ◽  
Mark Graham ◽  
Jenna Cook ◽  
Mitchell A. Johnsen ◽  
Karen K. Christensen-Dalsgaard ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Trophic Cascade ◽  
Phytoplankton Biomass ◽  
Management Practices ◽  
Phytoplankton Community ◽  
Cyanobacterial Bloom ◽  
Nutrient Status ◽  
Cyanobacterial Blooms ◽  
Phytoplankton Blooms ◽  
Cascade Effect

Cyanobacterial blooms in lakes of low nutrient status are recent ecological surprises. Culling of planktivorous fish may help suppress phytoplankton blooms via a trophic cascade effect. To test this hypothesis, we conducted a 90-day experiment adjacent to a shallow oligomesotrophic lake increasingly beset by midsummer cyanobacterial blooms in the presence of high abundances of minnows and sparse herbivorous zooplankton. The single-factor (± three spottail shiners, Notropis hudsonius) experimental design was replicated 10 times for a total of twenty 1200 L capacity mesocosms. Contrary to the trophic cascade hypothesis, minnow removal decreased the abundance of bosminids capable of grazing cyanobacteria. Nevertheless, removal of the minnows significantly both suppressed phytoplankton biomass and offset the development of cyanobacteria, such as Gloeotrichia echinulata. Lower concentrations of phosphorus and nitrogen in the fishless relative to stocked mesocosms best explained these differences in the phytoplankton community. Our findings highlight how fisheries management practices that enhance minnow populations in lakes of low productivity may inadvertently contribute to cyanobacterial blooms through increased nutrient cycling.

scholarly journals Biogeochemical versus ecological consequences of modeled ocean physics

2017 ◽  
Vol 14 (11) ◽  
pp. 2877-2889 ◽  
Author(s):  
Sophie Clayton ◽  
Stephanie Dutkiewicz ◽  
Oliver Jahn ◽  
Christopher Hill ◽  
Patrick Heimbach ◽  
...  
Keyword(s):  
Primary Production ◽  
Ocean Circulation ◽  
Mixed Layer ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Resource Competition ◽  
Nutrient Supply ◽  
Zooplankton Biomass ◽  
Global Ocean ◽  
Competition Theory

Abstract. We present a systematic study of the differences generated by coupling the same ecological–biogeochemical model to a 1°, coarse-resolution, and 1∕6°, eddy-permitting, global ocean circulation model to (a) biogeochemistry (e.g., primary production) and (b) phytoplankton community structure. Surprisingly, we find that the modeled phytoplankton community is largely unchanged, with the same phenotypes dominating in both cases. Conversely, there are large regional and seasonal variations in primary production, phytoplankton and zooplankton biomass. In the subtropics, mixed layer depths (MLDs) are, on average, deeper in the eddy-permitting model, resulting in higher nutrient supply driving increases in primary production and phytoplankton biomass. In the higher latitudes, differences in winter mixed layer depths, the timing of the onset of the spring bloom and vertical nutrient supply result in lower primary production in the eddy-permitting model. Counterintuitively, this does not drive a decrease in phytoplankton biomass but results in lower zooplankton biomass. We explain these similarities and differences in the model using the framework of resource competition theory, and find that they are the consequence of changes in the regional and seasonal nutrient supply and light environment, mediated by differences in the modeled mixed layer depths. Although previous work has suggested that complex models may respond chaotically and unpredictably to changes in forcing, we find that our model responds in a predictable way to different ocean circulation forcing, despite its complexity. The use of frameworks, such as resource competition theory, provides a tractable way to explore the differences and similarities that occur. As this model has many similarities to other widely used biogeochemical models that also resolve multiple phytoplankton phenotypes, this study provides important insights into how the results of running these models under different physical conditions might be more easily understood.

scholarly journals Spatial autocorrelation of phytoplankton biomass is weak in the rivers of Lake Taihu Basin, China

2019 ◽  
pp. 35
Author(s):  
Zhaoshi Wu ◽  
Ming Kong ◽  
Yamin Fan ◽  
Xiaolong Wang ◽  
Kuanyi Li
Keyword(s):  
Community Structure ◽  
Spatial Autocorrelation ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Lake Taihu ◽  
Total Biomass ◽  
Phytoplankton Community Structure ◽  
River Systems ◽  
Toxic Cyanobacteria ◽  
The Mean

We investigated the characteristic of phytoplankton community structure across the entire Lake Taihu Basin (LTB), one of the most developed areas in China. A morphologically based functional group (MBFG) proposed by Kruk et al. (2010), especially potential toxic cyanobacteria (group III and VII), was also illustrated. Samples were collected at 96 sites along main rivers throughout the four seasons from September 2014 to January 2016. Significant differences in the phytoplankton community structure were observed at spatial (particularly between Huangpu/Tiaoxi and the other 4 river systems) and seasonal scales. On a spatial basis, high variability was observed in the mean phytoplankton biomass, with a relatively high value of 3.13 mg L−1 in Yanjiang system and a relatively low value in Huangpu (1.23 mg L−1) and Tiaoxi (1.44 mg L−1) systems. The mean biomass of potential toxic cyanobacteria accounted for 18.28% of the mean total biomass spatially, which was more abundant in Nanhe and Yanjiang systems. Spatial autocorrelation was weak for the total biomass and its four main components (bacillariophyta, chlorophyta, euglenophyta, and cyanobacteria) at whole basin scale regardless of season. Regarding the river system, significant autocorrelation was scarcely observed in all the river systems except Huangpu, especially in the inflows. The characteristic in terms of hydrological and environmental conditions may determine the community structure of the 6 river systems. Our study highlighted the importance of monitoring based on a large spatial scale, and more attention should be paid to potential toxic cyanobacteria for water quality management purposes.

Effects of zooplankton and nutrients on phytoplankton: an experimental analysis in a eutrophic tropical reservoir

2017 ◽  
Vol 68 (6) ◽  
pp. 1061 ◽  
Author(s):  
Juliana dos Santos Severiano ◽  
Viviane Lúcia dos Santos Almeida-Melo ◽  
Enaide Marinho de Melo-Magalhães ◽  
Maria do Carmo Bittencourt-Oliveira ◽  
Ariadne do Nascimento Moura
Keyword(s):  
Experimental Analysis ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
N:P Ratio ◽  
Molar Ratio ◽  
Zooplankton Species ◽  
Tropical Reservoir ◽  
Total Phytoplankton Biomass ◽  
Taxonomic Class ◽  
Total Phytoplankton

Experiments were conducted to evaluate the N:P ratio, as well as the effects of the interaction between this ratio and zooplankton, on phytoplankton in a tropical reservoir. Three experiments were performed in the presence (+Z) or absence (–Z) of zooplankton and the addition of N and P in different ratios (N:P molar ratio of 5, 16 and 60).In Experiment I, the total phytoplankton biomass and biomass by taxonomic class and species of the N:P 16–Z treatment did not differ significantly from that of the control, whereas for N:P 16+Z, there was a reduction in total phytoplankton. In Experiment II, there was a significant increase in Bacillariophyceae and the biomass of two species in the N:P 60–Z treatment. For the N:P 60+Z treatment, a significant reduction was observed in the total phytoplankton biomass and the biomass of three phytoplankton classes and three species. In Experiment III, there was an increase in the biomass of Dinophyceae with the N:P 5–Z treatment. In the N:P 5+Z treatment, there was a significant reduction in total phytoplankton biomass and the biomass of the phytoplankton class and five species. The findings of the present study reveal that zooplankton species native to a tropical reservoir can change the structure of the phytoplankton community and the response of these organisms to variations in nutrients.

The Prediction of Lacustrine Phytoplankton Diversity

1981 ◽  
Vol 38 (5) ◽  
pp. 524-534 ◽  
Author(s):  
Bruce D. LaZerte ◽  
Susan Watson
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Good Predictor ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Taxonomic Composition ◽  
Phytoplankton Community Structure ◽  
Trophic Gradient ◽  
Phytoplankton Diversity ◽  
Total Phytoplankton

We tested the hypothesis that total phytoplankton biomass can predict phytoplankton community structure independent of its taxonomic composition. From a 2-yr study on Lake Memphremagog, Quebec, which exhibits a marked axial trophic gradient, 133 samples were rarefied to uniform count sizes and a range of diversity numbers, based on proportional biomass, was calculated for each. Biomass is a good predictor of evenness (0.7 < R < 0.9), but not species richness (0.1 < R < 0.3), and this prediction is independent of changes in taxonomic composition. Species richness is more directly related to season and changes in taxonomic composition.Key words: diversity, evenness, species richness, phytoplankton

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