Seasonal Variations of Phytoplankton Production in an Estuary in Relation to Coastal Water Movements

1979 ◽  
Vol 30 (4) ◽  
pp. 449 ◽  
Author(s):  
BD Scott
Keyword(s):  
Primary Production ◽  
Coastal Waters ◽  
Solar Irradiance ◽  
Phytoplankton Biomass ◽  
Annual Variation ◽  
Light Attenuation ◽  
Nutrient Concentrations ◽  
Phytoplankton Production ◽  
Fluorescence Measurements

Primary production and phytoplankton biomass in Port Hacking, an estuary 24 km south of Sydney, were measured at 2-4 day intervals for one year. Primary production was measured by in situ 14C uptake, and phytoplankton biomass by 14C uptake at constant irradiance and in vivo chlorophyll fluorescence. Measurements of solar irradiance and light attenuation by the water column were also obtained. Nutrient concentrations were measured both in the estuary and in the coastal waters adjacent to Port Hacking. The short-term variations of phytoplankton biomass were found to be due to both estuarine hydrological events resulting in the release of regenerated nutrients, and to coastal hydrological events, where slope water intrusions enriched the coastal waters and were introduced into the estuarine basins by tidal exchange. The annual variation of primary production in Port Hacking was related to the annual variation of solar irradiance. A minor part of the annual variation appeared to be due to temperature, but the nature of this relationship was uncertain.

In Vivo Fluorescence of Chlorophyll A: Estimation of Phytoplankton Biomass and Activity in Římov Reservoir (Czech Republic)

1993 ◽  
Vol 28 (6) ◽  
pp. 29-33 ◽  
Author(s):  
V. Vyhnálek ◽  
Z. Fišar ◽  
A. Fišarová ◽  
J. Komárková
Keyword(s):  
Czech Republic ◽  
Chlorophyll Fluorescence ◽  
Primary Production ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
In Vivo Fluorescence ◽  
Fluorescence Of Chlorophyll A ◽  
Římov Reservoir ◽  
Natural Phytoplankton

The in vivo fluorescence of chlorophyll a was measured in samples of natural phytoplankton taken from the Římov Reservoir (Czech Republic) during the years 1987 and 1988. The fluorescence intensities of samples either with or without addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron, DCMU) were found reliable for calculating the concentration of chlorophyll a during periods when cyanobacteria were not abundant. The correction for background non-chlorophyll fluorescence appeared to be essential. No distinct correlation between a DCMU-induced increase of the fluorescence and primary production of phytoplankton was found.

scholarly journals Spatial and seasonal variability of fractionated phytoplankton biomass and primary production in the frontal region of the Northern Adriatic Sea

2005 ◽  
Vol 6 (1) ◽  
pp. 5 ◽  
Author(s):  
M.R. VADRUCCI ◽  
G. CATALANO ◽  
A. BASSET
Keyword(s):  
Primary Production ◽  
Phytoplankton Biomass ◽  
Adriatic Sea ◽  
Size Structure ◽  
Nutrient Concentrations ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Frontal System ◽  
Dissolved Phosphorus ◽  
Point Total

Spatial and seasonal patterns of variation of fractionated phytoplankton biomass and primary production and their relationships with nutrient concentrations were analyzed along an inshore - offshore gradient and in relation to the presence of a frontal system in the Northern Adriatic Sea. Sampling was carried out in winter and summer during four oceanographic cruises (June 1996 and 1997, February 1997 and 1998) as part of the PRISMA II project. Water samples for determining nutrient concentrations, phytoplankton biomass (as Chla) and primary production (as 14 C assimilation) were collected at five optical depths. Sampling stations were located along 2 or 4 parallel transects arranged perpendicularly to the shoreline and the frontal system. The transects were located at such a distance from the coast that the frontal system crossed them at their halfway point. Total dissolved nitrogen (TDN) and total dissolved phosphorus concentrations (TDP) were 12.41 ± 3 .95 mM and 0.146 ± 0 .070 mM, respectively. The values in the two seasonal periods were similar, decreasing along the inshore-offshore gradient. Values for phytoplankton biomass and primary productionwere higher in the winter than the summer cruises, and decreased, in both seasonal periods, along the inshore / offshore gradient. Moreover, in both seasonal periods, picophytoplankton dominated both biomass and productivity, (56% and 44%, respectively) at stations beyond the frontal system, while microphytoplankton was more important at stations inside it (44% and 44%, respectively). Total phytoplankton biomass and primary production were directly related to nutrient concentrations. Regarding size classes, significant patterns of variation with nutrients were observed particularly for biomass. The results indicate that the size structure and function of phytoplankton guilds seem to be mediated by nutrient inflow, as well as by competitive interaction among size fractions.

scholarly journals Seaglider observations of variability in daytime fluorescence quenching of chlorophyll-<i>a</i> in Northeastern Pacific coastal waters

2008 ◽  
Vol 5 (4) ◽  
pp. 2839-2865 ◽  
Author(s):  
B. S. Sackmann ◽  
M. J. Perry ◽  
C. C. Eriksen
Keyword(s):  
Fluorescence Quenching ◽  
Continental Shelf ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Particle Concentration ◽  
Near Surface ◽  
Fluorescence Measurements ◽  
Pacific Waters ◽  
Northeastern Pacific

Abstract. The use of new autonomous and Lagrangian platforms (e.g. gliders, drifters, etc.) has revolutionized sampling of the ocean. The incorporation of in vivo chlorophyll-a fluorometers into these platforms for characterizing chlorophyll-a concentrations and phytoplankton biomass has reinforced the need for a thorough understanding of the variability and biases associated with basic fluorescence measurements. Seaglider, a long-range autonomous glider, has been deployed routinely in Northeast Pacific waters off the Washington coast, USA. Measurements of chlorophyll-a fluorescence (proxy for chlorophyll-a concentration) and optical backscattering (proxy for particle concentration) were collected on the continental shelf and along a V-shaped transect that extended 200 km from the continental shelf into deep oceanic waters. Daytime fluorescence quenching (i.e. the reduction in the fluorescence quantum yield often observed during daylight hours) could be detected throughout the dataset, with near-surface daytime fluorescence quenched by as much as 80% during summer. Quenching was observed throughout the region, at all times of year, and to depths greater than 50 m. The degree of quenching was positively correlated with incoming solar radiation and the observed pattern was remarkably similar to what has been observed in other areas, suggesting some degree of universality for the underlying relationship.

Nearshore–offshore comparison of chlorophyll a and phytoplankton production in the dreissenid-colonized eastern basin of Lake Erie

2006 ◽  
Vol 63 (5) ◽  
pp. 1115-1129 ◽  
Author(s):  
David C Depew ◽  
Stephanie J Guildford ◽  
Ralph E.H Smith
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Lake Erie ◽  
Light Attenuation ◽  
Phytoplankton Production ◽  
Light Climate ◽  
Production Rates ◽  
Chl A ◽  
Underwater Light Climate

Planktonic primary production, chlorophyll a (chl a), underwater light climate, and total phosphorus were measured at 18 stations during 2001 and 2002 in eastern Lake Erie to characterize spatial and seasonal patterns in this system colonized by dreissenid mussels (Dreissena spp.). Areal production rates and chl a displayed a seasonal pattern typical of the Laurentian Great Lakes, with highest production in the early and late summer. Daily and seasonal (May–October) primary production was significantly lower nearshore than offshore. Although light attenuation was similar between nearshore and offshore, the nearshore light climate was generally more favorable for phytoplankton because of shallower mixing depths. However, chl a was significantly lower nearshore, which accounted for most of the depression in production rates. Nearshore chl a was lower than predicted from relationships with total phosphorus in comparable dreissenid-free systems. Offshore, subepilimnetic communities contributed up to 67% of daily production but only up to 19% of seasonal production. The depression of chl a and primary production in the nearshore was a reversal from historic patterns in eastern Lake Erie and from the pattern traditionally expected in large lakes. Decreased external nutrient loading and dreissenid colonization may both have contributed to this new spatial pattern, but dreissenids appear to be key agents.

Importance of Latitude and Organic Color on Phytoplankton Primary Productivity in Florida Lakes

1991 ◽  
Vol 48 (7) ◽  
pp. 1145-1150 ◽  
Author(s):  
John R. Beaver ◽  
Thomas L. Crisman
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Phytoplankton Biomass ◽  
Nutrient Concentrations ◽  
Empirical Equations ◽  
Strongly Correlated ◽  
Florida Lakes ◽  
Vegetative Season

A characterization of primary productivity patterns in subtropical Florida lakes along increasing gradients of both dissolved organic color and phytoplankton biomass is presented. Volumetric expression of gross primary productivity was more strongly correlated with chlorophyll a and nutrient concentrations than was areal expression. Primary production in clearwater (<75 Pt units) lakes was more predictable than colored (>75 Pt units) lakes. Areal production in Florida lakes was intermediate to the tropical and temperate regions, although volumetric productivity during the vegetative season (May–September) was not significantly different from temperate zone lakes for the same period. Predictive abilities of empirical equations describing primary productivity in Florida lakes are improved by distinguishing colored and clear lakes.

Phytoplankton Primary Production and Light Attenuation Responses to the Experimental Acidification of a Small Canadian Shield Lake

1987 ◽  
Vol 44 (S1) ◽  
pp. s83-s90 ◽  
Author(s):  
J. A. Shearer ◽  
E. J. Fee ◽  
E. R. DeBruyn ◽  
D. R. DeClercq
Keyword(s):  
Primary Production ◽  
Light Attenuation ◽  
Distinct Pattern ◽  
Phytoplankton Production ◽  
Phytoplankton Primary Production ◽  
Apparent Reduction ◽  
Production Increase ◽  
Pre Treatment ◽  
Experimental Acidification ◽  
Ph Level

Phytoplankton primary production and light attenuation were monitored over a 10-yr period in Lake 223, a small, softwater, shield, lake. After 2 yr with no treatment, the lake was treated for 8 yr with sulfuric acid to decrease the epilimnetic pH from about 6.7 to 5.0. Primary production, integrated over time and depth, varied considerably during the 2 pre-treatment years. However, it increased steadily during the first 6 yr of treatment, with a total increase of more than 250%. This production increase was coincident with a decrease in epilimnetic light attenuation. After the 6th year of treatment, the production of the lake decreased although the pH level was held relatively constant during this period. Nearby control lakes tended to show a similar, though less distinct, pattern during this 10-yr period. Thus, it is difficult to separate the effects of acidification from long-term natural variation. However, there was no apparent reduction in community phytoplankton production as a consequence of the acidification and the hypothesis that acidification causes oligotrophication was not supported.

Time-series of direct primary production and phytoplankton biomass in the southeastern Bering Sea: responses to cold and warm stanzas

2020 ◽  
Vol 642 ◽  
pp. 39-54 ◽  
Author(s):  
MW Lomas ◽  
LB Eisner ◽  
J Gann ◽  
SE Baer ◽  
CW Mordy ◽  
...  
Keyword(s):  
Primary Production ◽  
Bering Sea ◽  
Phytoplankton Biomass ◽  
Net Primary Production ◽  
Phytoplankton Growth ◽  
Trophic Levels ◽  
Global Ocean ◽  
Phytoplankton Production ◽  
Phytoplankton Growth Rate ◽  
The Bering Sea

Sub-Arctic and Arctic regions are warming faster than nearly all other areas of the global ocean, leading to significant changes in ice quality and the duration of ice-covered periods. The impacts of this warming and sea ice variability on higher trophic levels in the Bering Sea is well documented, but the effects on lower trophic levels are less well understood. Phytoplankton biomass (as chlorophyll a [chl a]) and primary and nitrogen production measurements in the Bering Sea are presented from 2006-2016, a period that covers relatively colder (2007-2012) and warmer (2014-2016) temperature regimes. In warm spring periods, relative to cold spring periods, the frequency of subsurface chl a maxima increased, but with no significant differences in integrated chl a inventories. In contrast, cold fall periods were characterized by greater integrated chl a inventories than warm fall periods. Integrated net primary production (NPP) increased from the cold period (2007-2011) to the warm period (2014-2016). The difference in patterns in chl a and NPP resulted in higher phytoplankton growth rates during warm periods. Nitrate uptake rates increased from spring to fall during cold periods, while rates decreased from spring to fall during warm periods, suggesting changes in the balance of new versus regenerated production. While changes in phenological timing cannot be ruled out, changes in phytoplankton growth rate appear more important than changes in chl a biomass underlying increasing daily NPP. This distinction directly impacts our understanding of the linkages between warming temperatures and phytoplankton production and its implications in evaluating and understanding energy flow to higher trophic levels.

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