Biogeochemical influences on the carbon isotope signatures of Lake Ontario biota

1999 ◽  
Vol 56 (11) ◽  
pp. 2211-2218 ◽  
Author(s):  
M F Leggett ◽  
M R Servos ◽  
R Hesslein ◽  
O Johannsson ◽  
E S Millard ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Primary Productivity ◽  
Benthic Invertebrates ◽  
Food Source ◽  
Spring Bloom ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Sediment Surface ◽  
Food Web Interactions ◽  
Primary Consumers

Particulate organic matter (POM), zooplankton, and benthic invertebrates were sampled seasonally at a midlake and east basin site in Lake Ontario. The δ13C values of POM samples were compared with measurements of chlorophyll a concentrations, areal rates of primary productivity, concentrations of dissolved free CO2 (CO2(aq)), and the δ13C of zooplankton and benthic invertebrates. The δ13C of POM was significantly correlated with the concentration of CO2(aq) at the east basin site. No correlation was found between chlorophyll a concentrations, areal rates of primary productivity, and the δ13C of POM. The δ13C of zooplankton was not always similar to the δ13C of the POM fraction collected, indicative of the complexity of food web interactions within the lower trophic levels. The δ13C of benthic invertebrates feeding on the sediment surface was similar to that of POM produced prior to stratification, indicating the importance of the spring bloom as a food source for benthic primary consumers.

The Lake Ontario Life Support System

1987 ◽  
Vol 44 (12) ◽  
pp. 2230-2240 ◽  
Author(s):  
D. R. S. Lean ◽  
H-J. Fricker ◽  
M. N. Charlton ◽  
R. L. Cuhel ◽  
F. R. Pick
Keyword(s):  
Primary Productivity ◽  
Life Support ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Phosphorus Concentration ◽  
Nutrient Regeneration ◽  
Particulate Carbon ◽  
Calcium Carbonate Precipitation ◽  
Mixing Processes ◽  
Aquatic Food

Primary productivity provides most of the energy to support aquatic food chains. The rate is not only influenced by available solar radiation but also by temperature, availability of phosphorus, and the influence of physical mixing processes. The special features of Lake Ontario such as changes in phosphorus concentration, calcium carbonate precipitation, and silica deficiency on primary productivity, concentration of particulate carbon, and chlorophyll are discussed. Our lack of understanding of food chain and nutrient regeneration processes is illustrated through our failure to balance carbon production with losses through zooplankton grazing and sedimentation. It was demonstrated, however, that bacteria are not responsible for nutrient regeneration through "mineralization" but nutrients are effectively recycled in the water column at the second and third trophic levels.

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 Phytoplankton Increase Along the Kuroshio Due to the Large Meander

2021 ◽  
Vol 8 ◽  
Author(s):  
Daniel Andres Lizarbe Barreto ◽  
Ricardo Chevarria Saravia ◽  
Takeyoshi Nagai ◽  
Takafumi Hirata
Keyword(s):  
Chlorophyll A ◽  
Mixed Layer Depth ◽  
Local Environment ◽  
Trophic Levels ◽  
Large Meander ◽  
The Mean ◽  
Western Side ◽  
The Kuroshio ◽  
Cold Core ◽  
Kuroshio Region

The Kuroshio Large Meander (LM) is known to be highly aperiodic and can last from 1 to 10 years. Since a stationary cold core formed between the Kuroshio and the southern coast of Japan off Enshu-Nada and approaching warm saltier water on the eastern side of the LM changes the local environment drastically, many commercially valuable fish species distribute differently from the non-LM period, impacting local fisheries. Despite this importance of the LM, the influences of the LM on the low trophic levels such as phytoplankton and zooplankton have still been unclear. In this study, satellite daily sea surface chlorophyll data are analyzed in relation to the LM. The results show positive anomalies of the chlorophyll-a concentration along the Kuroshio path during the LM periods, 2004–2005 and 2017–2019, from the upstream off Shikoku to the downstream (140°E). These positive anomalies are started by the triggering meander generated off south of Kyushu, which then slowly propagates to the downstream LM region in both the LM periods. Even though the detailed patterns along the Kuroshio region in the two LM periods were different, similar formations of the positive anomalies on the western side of the LM with shallower mixed layer depth are observed. Furthermore, we found clear relationships between the minimum distance from several stations along the coast to the Kuroshio axis and the mean chlorophyll-a anomaly, with significant correlations with the distance from different stations.

Long-term, seasonal and spatial trends in nutrients, chlorophyll a and light attenuation in Lake Ontario

2003 ◽  
pp. 97-132
Author(s):  
E.S. Millard ◽  
O.E Johannsson ◽  
M.A. Neilson ◽  
A.H. El-Shaarawi
Keyword(s):  
Chlorophyll A ◽  
Light Attenuation ◽  
Lake Ontario ◽  
Spatial Trends

scholarly journals Estimation of the Particulate Organic Carbon to Chlorophyll-a Ratio Using MODIS-Aqua in the East/Japan Sea, South Korea

2020 ◽  
Vol 12 (5) ◽  
pp. 840 ◽  
Author(s):  
Dabin Lee ◽  
SeungHyun Son ◽  
HuiTae Joo ◽  
Kwanwoo Kim ◽  
Myung Joon Kim ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Seasonal Variability ◽  
Japan Sea ◽  
Global Ocean ◽  
Phytoplankton Communities

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.

scholarly journals Towards an improved organic carbon budget for the western Barents Sea shelf

2014 ◽  
Vol 10 (2) ◽  
pp. 569-587 ◽  
Author(s):  
I. Pathirana ◽  
J. Knies ◽  
M. Felix ◽  
U. Mann
Keyword(s):  
Organic Carbon ◽  
Sea Ice ◽  
Primary Productivity ◽  
Carbon Budget ◽  
Barents Sea ◽  
Carbon Accumulation ◽  
The Arctic ◽  
Sediment Surface ◽  
Organic Facies ◽  
Facies Modelling

Abstract. There is generally a lack of knowledge on how marine organic carbon accumulation is linked to vertical export and primary productivity patterns in the Arctic Ocean. Despite the fact that annual primary production in the Arctic has increased as a consequence of shrinking sea ice, its effect on flux, preservation, and accumulation of organic carbon is still not well understood. In this study, a multi-proxy geochemical and organic-sedimentological approach is coupled with organic facies modelling, focusing on regional calculations of carbon cycling and carbon burial on the western Barents Shelf between northern Scandinavia and Svalbard. OF-Mod 3-D, an organic facies modelling software tool, is used to reconstruct and quantify the marine and terrestrial organic carbon fractions and to make inferences about marine primary productivity changes across the marginal ice zone (MIZ). By calibrating the model against an extensive set of sediment surface samples, we improve the Holocene organic carbon budget for ice-free and seasonally ice-covered areas in the western Barents Sea. The results show that higher organic carbon accumulation rates in the MIZ are best explained by enhanced surface water productivity compared to ice-free regions, implying that shrinking sea ice may reveal a significant effect on the overall organic carbon storage capacity of the western Barents Sea shelf.

Phosphorus Flux through Epilimnetic Zooplankton from Lake Ontario: Relationship with Body Size and Significance to Phytoplankton

1984 ◽  
Vol 41 (11) ◽  
pp. 1702-1712 ◽  
Author(s):  
W. D. Taylor
Keyword(s):  
Body Size ◽  
Phosphorus Uptake ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Phytoplankton Production ◽  
Unit Size ◽  
Release Rates ◽  
Zooplankton Size ◽  
Uptake Rates ◽  
Phosphorus Flux

The flux of phosphate through epilimnetic zooplankton from Lake Ontario was measured by adding 32PO4 into whole lakewater, monitoring its accumulation by zooplankton over 48 h, and then measuring its release when animals were returned to unlabelled lake water. Phosphorus uptake was calculated as the sum of accumulation and release rates. The 10 species examined ranged in size from 36-μm Codonella cratera to 1-mm Daphnia retrocurva. Phosphorus uptake rates of herbivorous zooplankton ranged about 200-fold and increased with body size both within and among species, although not proportionally. Among species, there was a pronounced allometry, with smaller species having much higher rates per unit size. This allometry is similar to that described for other metabolic parameters and body size. There was no tendency for smaller species to release a greater fraction of the label they took up. These results suggest that the biomass of zooplankton consuming a given phytoplankton production will be much smaller if small zooplankton dominate, and therefore, this phosphorus sink will be much smaller. Further, the flow of phosphorus to higher trophic levels may be reduced. The result of changing the zooplankton size-distribution may be to change the amount of spring total phosphorus available to summer phytoplankton.

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