scholarly journals Mesozooplankton grazing minimally impacts phytoplankton abundance during spring in the western North Atlantic

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9430
Author(s):  
Francoise Morison ◽  
James Joseph Pierson ◽  
Andreas Oikonomou ◽  
Susanne Menden-Deuer
Keyword(s):  
Growth Rate ◽  
Particle Size ◽  
North Atlantic ◽  
Phytoplankton Growth ◽  
Phytoplankton Production ◽  
Grazing Impact ◽  
Phytoplankton Abundance ◽  
Phytoplankton Primary Production ◽  
Phytoplankton Growth Rate ◽  
Net Phytoplankton

The impacts of grazing by meso- and microzooplankton on phytoplankton primary production (PP) was investigated in the surface layer of the western North Atlantic during spring. Shipboard experiments were performed on a latitudinal transect at three stations that differed in mixed layer depth, temperature, and mesozooplankton taxonomic composition. The mesozooplankton community was numerically dominated by Calanus finmarchicus at the northern and central station, with Calanus hyperboreus also present at the northern station. The southern station was >10 °C warmer than the other stations and had the most diverse mesozooplankton assemblage, dominated by small copepods including Paracalanus spp. Microzooplankton grazing was detected only at the northern station, where it removed 97% of PP. Estimated clearance rates by C. hyperboreus and C. finmarchicus suggested that at in-situ abundance these mesozooplankton were not likely to have a major impact on phytoplankton abundance, unless locally aggregated. Although mesozooplankton grazing impact on total phytoplankton was minimal, these grazers completely removed the numerically scarce > 10 µm particles, altering the particle-size spectrum. At the southern station, grazing by the whole mesozooplankton assemblage resulted in a removal of 14% of PP, and its effect on net phytoplankton growth rate was similar irrespective of ambient light. In contrast, reduction in light availability had an approximately 3-fold greater impact on net phytoplankton growth rate than mesozooplankton grazing pressure. The low mesozooplankton grazing impact across stations suggests limited mesozooplankton-mediated vertical export of phytoplankton production. The constraints provided here on trophic transfer, as well as quantitative estimates of the relative contribution of light and grazer controls of PP and of grazer-induced shifts in particle size spectra, illuminate food web dynamics and aid in parameterizing modeling-frameworks assessing global elemental fluxes and carbon export.

A modeling approach to simulate impact of climate change in lake water quality: phytoplankton growth rate assessment

1998 ◽  
Vol 37 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Hany Hassan ◽  
Keisuke Hanaki ◽  
Tomonori Matsuo
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Growth Rate ◽  
Dissolved Oxygen ◽  
Lake Water ◽  
Phytoplankton Growth ◽  
Quality Data ◽  
Model Parameters ◽  
Lake Water Quality ◽  
Phytoplankton Growth Rate

Global climate change induced by increased concentrations of greenhouse gases (especially CO2) is expected to include changes in precipitation, wind speed, incoming solar radiation, and air temperature. These major climate variables directly influence water quality in lakes by altering changes in flow and water temperature balance. High concentration of nutrient enrichment and expected variability of climate can lead to periodic phytoplankton blooms and an alteration of the neutral trophic balance. As a result, dissolved oxygen levels, with low concentrations, can fluctuate widely and algal productivity may reach critical levels. In this work, we will present: 1) recent results of GCMs climate scenarios downscaling project that was held at the University of Derby, UK.; 2) current/future comparative results of a new mathematical lake eutrophication model (LEM) in which output of phytoplankton growth rate and dissolved oxygen will be presented for Suwa lake in Japan as a case study. The model parameters were calibrated for the period of 1973–1983 and validated for the period of 1983–1993. Meterologic, hydrologic, and lake water quality data of 1990 were selected for the assessment analysis. Statistical relationships between seven daily meteorological time series and three airflow indices were used as a means for downscaling daily outputs of Hadley Centre Climate Model (HadCM2SUL) to the station sub-grid scale.

Aspects of Estimating Zooplankton Production from Phytoplankton Production

1969 ◽  
Vol 26 (2) ◽  
pp. 199-220 ◽  
Author(s):  
C. D. McAllister
Keyword(s):  
Growth Rate ◽  
Primary Productivity ◽  
Secondary Production ◽  
Relative Effect ◽  
Plant Production ◽  
Phytoplankton Production ◽  
Continuous Grazing ◽  
Different Types ◽  
Phytoplankton Growth Rate ◽  
Zooplankton Production

Primary productivity and zooplankton data from Ocean Station P are used to compare estimates of phytoplankton and herbivore production calculated on the assumption of continuous grazing by the animals with estimates obtained on the assumption of three different types of nocturnal grazing. Effective plant production, that corrected for the effects of grazing on the size of the phytoplankton stock and hence on the magnitude of the plant respiratory loss, was less than the measured production and was least under the assumption of continuous grazing. The small differences in effective production resulting from the choice of different grazing schemes resulted in large differences in estimates of secondary production. The relative effect of assuming different grazing schemes on the estimate of secondary production varied markedly with zooplankton respiration and with the phytoplankton growth rate.

Phytoplankton growth rate and zooplankton grazing in the western part of the Black Sea in the autumn period

Oceanology ◽  
2009 ◽  
Vol 49 (1) ◽  
pp. 83-92 ◽  
Author(s):  
L. V. Stel’makh ◽  
I. I. Babich ◽  
S. Tugrul ◽  
S. Moncheva ◽  
K. Stefanova
Keyword(s):  
Growth Rate ◽  
Black Sea ◽  
Phytoplankton Growth ◽  
The Black Sea ◽  
Zooplankton Grazing ◽  
Autumn Period ◽  
Phytoplankton Growth Rate

An early spring bloom of large diatoms in the ice-covered Saroma-ko Lagoon, Hokkaido, Japan

2011 ◽  
Vol 92 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Akihiro Shiomoto ◽  
Koji Asakuma ◽  
Han-Dong Hoon ◽  
Koichi Sakaguchi ◽  
Kimihiko Maekawa
Keyword(s):  
Growth Rate ◽  
Global Warming ◽  
Primary Production ◽  
Spring Bloom ◽  
Early Spring ◽  
Phytoplankton Growth ◽  
Bloom Period ◽  
Ice Coverage ◽  
Phytoplankton Growth Rate ◽  
Free Area

Saroma-ko Lagoon, the largest body of water that has complete ice coverage during winter in Japan, was not completely covered by ice in the winter of 2009. This condition is considered to be a result of the progression of global warming. A bloom of large diatoms was observed in the ice-free area between February and April. This early spring bloom seemed to have started in the latter part of January, and lasted for about three months. The maximum chlorophyll-a (Chl a) concentration of about 10 mg m−3 was observed in March, and was similar to the level of 5–20 mg m−3 previously reported for the ordinary spring bloom in Saroma-ko Lagoon. The maximum primary production of 786 mgC m−2 day−1 and the maximum Chl a-specific primary production, an index of the phytoplankton growth rate, were also found in March. Species changes from Thalassiosira spp. to Chaetoceros spp. were observed during the bloom. This early spring bloom could extend into the ordinary spring bloom period. Its duration was obviously longer than that of the spring bloom, which is typically about one month. These results show the phytoplankton condition that could be expected during winter and spring as global warming progresses.

Dominance of phosphorus over nitrogen as the limiter to phytoplankton growth rate

Hydrobiologia ◽  
1978 ◽  
Vol 57 (3) ◽  
pp. 209-215 ◽  
Author(s):  
E. B. Welch ◽  
P. Sturtevant ◽  
M. A. Perkins
Keyword(s):  
Growth Rate ◽  
Phytoplankton Growth ◽  
Phytoplankton Growth Rate

Multivariate control of heterotrophic bacterial abundance and zooplankton grazing in Labrador fjords (northeastern Canada)

2020 ◽  
Vol 84 ◽  
pp. 105-120
Author(s):  
AG Simo-Matchim ◽  
M Gosselin ◽  
C Belzile
Keyword(s):  
Growth Rate ◽  
Heterotrophic Bacteria ◽  
Abiotic Factors ◽  
Mean Value ◽  
Phytoplankton Growth ◽  
Heterotrophic Nanoflagellates ◽  
Organic Substrates ◽  
Bacterial Growth Rate ◽  
Phytoplankton Growth Rate ◽  
Substantial Control

This study was conducted in 4 Labrador fjords (Nachvak, Saglek, Okak, and Anaktalak) during the summers of 2007 and 2013, early fall 2010, and late fall 2009. Our results show that water temperature combined with the availability of nutrients and organic substrates are the main abiotic factors controlling the abundance of heterotrophic bacteria in Labrador fjords. Bacterivory also played a crucial role, with heterotrophic bacteria exerting a significant bottom-up control on the abundance of heterotrophic nanoflagellates (r = 0.35, p < 0.05) and ciliates (r = 0.70, p < 0.01). During summer 2013, the intrinsic phytoplankton growth rate varied between <0 and 0.64 d-1, with a mean value of 0.36 d-1. The herbivory rate was highly variable, ranging from 0.01 to 0.86 d-1, with a mean value of 0.31 d-1. Grazing mortality was 6-fold higher than phytoplankton growth rate. Mean phytoplankton growth and herbivory rates in Labrador fjords were comparable to the Barents and Bering seas. The intrinsic growth rate of total heterotrophic bacteria ranged between <0 and 0.68 d-1, with a mean value of 0.30 d-1. Bacterivory varied from 0.01 to 0.95 d-1, with a mean of 0.30 d-1. Mortality due to grazing was up to 2.3 times higher than total bacterial growth rate. This study improves our understanding of the factors influencing the dynamics of heterotrophic bacteria and indicates that herbivory and bacterivory exert substantial control on microbial communities in Labrador fjords.

Phytoplankton Ecology of Vancouver Harbor

1979 ◽  
Vol 36 (1) ◽  
pp. 1-10 ◽  
Author(s):  
John G. Stockner ◽  
David D. Cliff
Keyword(s):  
Mixed Layer Depth ◽  
Phytoplankton Growth ◽  
Industrial Wastes ◽  
Tidal Mixing ◽  
Phytoplankton Production ◽  
Daily Production ◽  
Inlet System ◽  
Phytoplankton Primary Production ◽  
Phytoplankton Ecology ◽  
Coastal Marine

Phytoplankton production and distribution were examined over a 2-yr period in the Burrard Inlet system, which includes a true fiord (Indian Arm), a shallow blind inlet (Port Moody Arm), and a turbulent narrows region that is contiguous to the Port of Vancouver. Greatest annual production occurred in Port Moody Arm with a mean of 532 g C∙m−2∙yr−1 while the lowest values were in Indian Arm and the Narrows region, averaging about 260 g C∙m−2∙yr−1. Nitrate and zooplankton grazing were the main factors limiting phytoplankton production in Indian Arm, while flushing and poor light conditions influenced phytoplankton growth in the Narrows and outer Burrard Inlet. Most of the discharges of domestic and industrial wastes have been diverted to the Fraser River, and Vancouver Harbor can be considered relatively clean and pollution-free because of strong tidal mixing and seaward flushing. The only sign of eutrophication in the inlet is in Port Moody Arm where sufficient nutrients from sewage discharges and a relatively stable mixed-layer depth create near optimal conditions for phytoplankton growth. Daily production here is among the highest recorded in the literature for Pacific coastal marine waters. Key words: Phytoplankton, primary production, coastal marine embayment, fiord, phytoplankton succession and distribution, chlorophyll a

The Redfield Ratio and Phytoplankton Growth Rate

1985 ◽  
Vol 65 (2) ◽  
pp. 487-504 ◽  
Author(s):  
P. Tett ◽  
M. R. Droop ◽  
S. I. Heaney
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Surface Waters ◽  
Growth Rates ◽  
Phytoplankton Growth ◽  
Maximal Growth ◽  
Redfield Ratio ◽  
Phytoplankton Growth Rate ◽  
Marine Surface ◽  
Natural Phytoplankton

Goldman, McCarthy & Peavey (1979b) argued that growth rates of phyto-plankton in apparently oligotrophic ocean waters may near maximal. Their hypothesis was succinctly restated by Goldman (1980): ‘…the chemical composition of phytoplankton is extremely variable under exacting laboratory conditions of nutrient limitation and approaches the ‘Redfield’ proportions (C:N:P of 106:16:1) when neither nitrogen nor phosphorus is limiting so that near maximal growth rates are attained. In marine surface waters the chemical composition of particular matter often is in the Redfield proportions, thus implying that natural phytoplankton growth rates may be close to maximal.’ We argue on theoretical, experimental and observational grounds that this implication may not necessarily be correct.

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