Epilimnetic and Metalimnetic Primary Production in an Indiana Hardwater Lake

1983 ◽  
Vol 40 (6) ◽  
pp. 792-798 ◽  
Author(s):  
Allan Konopka
Keyword(s):  
Numerical Model ◽  
Solar Radiation ◽  
Vertical Distribution ◽  
Primary Production ◽  
Water Column ◽  
Primary Productivity ◽  
Water Transparency ◽  
Incident Solar Radiation ◽  
The Vertical Distribution ◽  
Made In

Primary productivity in an Indiana lake, which contained a metalimnetic layer of cyanobacteria, was calculated for the summers of 1979–81 by using a numerical model. Production estimates of 183 and 187 g C∙m−2 were obtained for 1979 and 1980; the estimate for 1981 was 50% higher. These values were two- to four-fold higher than estimates made in 1963 and 1964. Production in the metalimnion accounted for 29, 44, and 34% of the total during the three summers. Changes in the vertical distribution of biomass in the water column appeared to have had a greater effect upon metalimnetic production than differences in water transparency or incident solar radiation. The average values measured for the latter two variables were reasonably similar during the 3 yr, whereas the depth at which the metalimnetic layer of cyanobacteria stratified decreased from 9 m in 1979 to 5 m in 1981.

scholarly journals ESTIMACIÓN DE LA PRODUCTIVIDAD PRIMARIA EN DOS BAJOS DE LA PARTE SUR DEL GOLFO DE CALIFORNIA, MÉXICO

2008 ◽  
Vol 23 (1-2) ◽  
pp. 39
Author(s):  
G. Verdugo-Díaz ◽  
R. Cervantes Duarte ◽  
M. O. Albáñez-Lucero
Keyword(s):  
Surface Temperature ◽  
Water Column ◽  
Primary Productivity ◽  
Gulf Of California ◽  
Inorganic Nutrients ◽  
Water Transparency ◽  
Vertical Profiles ◽  
Subsurface Maximum ◽  
Natural Fluorescence ◽  
Productivity Estimation

Primary productivity estimation in two seamounts in the southern Gulf of California, México Vertical profiles of temperature and natural fluorescence from 100 m deep were made during February 2005. Water transparency was measured using Secchi’s disc, as well samples of superficial water and at maximum of fluorescence deep were collected to analyze inorganic nutrients. In “El Bajo Espiritu Santo” temperature (20 °C at surface) diminished gradually with depth, without significant stratification.Primary productivity shows superficial values close to 6 mg C m-3 h-1, recahing undetectable values at 20 m of depth. In “El Bajo Gorda” surface temperature reached 22 °C and the water column shows a thermocline between 35 m and 45 m of depth. The profiles of primary productivity presented a subsurface maximum (approximately 2 mg C m-3 h-1) associated with the thermocline.

Primary Productivity of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion

1984 ◽  
Vol 41 (4) ◽  
pp. 591-604 ◽  
Author(s):  
R. E. Hecky ◽  
S. J. Guildford
Keyword(s):  
Light Intensity ◽  
Primary Production ◽  
Water Column ◽  
Primary Productivity ◽  
Phosphorus Deficiency ◽  
Light Environment ◽  
Phytoplankton Production ◽  
Light Penetration ◽  
The Mean ◽  
Chlorophyll Concentrations

The primary productivity of seven regions of Southern Indian Lake and neighboring Wood Lake was measured during open-water seasons from 1974 to 1978. The lake had regional differences in chlorophyll concentrations and daily rates of integral primary production in 1974 and 1975 prior to impoundment of the lake. Regions receiving Churchill River flow tended to have higher chlorophyll concentrations and production rates than those regions marginal to the flow. Impoundment of the lake resulted in higher efficiencies of primary production in all regions, as indicated by higher light-saturated rates of carbon uptake per unit chlorophyll and by higher initial slopes of the hyperbolic light response relation of the phytoplankton. Many large basins of the lake had light penetration reduced by high concentrations of suspended sediment from eroding shorelines, while other areas had relatively unchanged light penetration. The increased efficiency of carbon fixation per unit chlorophyll resulted in higher rates of integral production in those regions where light penetration was not greatly affected. Daily rates of integral primary production in lake regions where light penetration had decreased markedly were not significantly different after impoundment because efficiencies of light utilization were higher. Comparison of the mean water column light intensities for those turbid regions with the values of Ik (light intensity at the onset of light saturation) for phytoplankton indicated that these turbid regions are now light deficient on average. Phosphorus deficiency, as indicated by alkaline phosphatase activity per unit ATP, which was present before impoundment, has been eliminated as the mean water column light intensity declined below 5 mEinsteins∙m−2∙min−1. The light environment of a new reservoir can be a significant determinant of integral production, and predicting the consequences of impoundment on phytoplankton production requires accurate prediction of the light environment.

scholarly journals Optimal estimation of catch by the continuous underway fish egg sampler based on a model of the vertical distribution of American plaice (Hippoglossoides platessoides) eggs

2006 ◽  
Vol 64 (1) ◽  
pp. 18-30 ◽  
Author(s):  
P. Pepin ◽  
K. A. Curtis ◽  
P. V. R. Snelgrove ◽  
B. de Young ◽  
J. A. Helbig
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Vertical Profile ◽  
Negative Binomial ◽  
Optimal Estimation ◽  
Eddy Diffusivity ◽  
Model Parameters ◽  
Error Structure ◽  
The Vertical Distribution ◽  
Hippoglossoides Platessoides

Abstract Pepin, P., Curtis, K.A., Snelgrove, P.V.R., de Young, B., and Helbig, J.A. 2007. Optimal estimation of catch by the continous underway fish egg sampler based on a model of the vertical distribution of American plaice (Hippoglossoides platessoides) eggs – ICES Journal of Marine Science, 64, 18–30. We investigate how the vertical stratification of the water column (specifically density) affects predictions of the catch of American plaice eggs (Hipploglossoides platessoides) from a fixed-depth sampler [the continuous underway fish egg sampler (CUFES)] relative to the integrated abundance in the water column measured in bongo tows. A steady-state model of the vertical distribution of fish eggs coupled with a simple model of the vertical profile of eddy diffusivity (i.e. mixing) is applied. Key model parameters are estimated through optimization of a one-to-one relationship between predicted and observed catches fit, using a generalized linear model with a Poisson, negative binomial, or gamma error structure. The incorporation of data on the vertical structure of the water column significantly improved the ability to forecast CUFES catches when using Poisson or negative binomial error structure, but not using a gamma distribution. Optimal maximum likelihood parameter estimates for eddy diffusivity and egg buoyancy fell within the range of expected values. The degree of uncertainty in the parameterization of eddy diffusivity suggests, however, that greater understanding of the forces that determine the vertical profile of mixing is critical to achieving strong predictive capabilities. The inverse problem of predicting integrated abundance from CUFES catches did not benefit from the environmental-driven model because of the high uncertainty in the catches from the CUFES.

Vertical distribution of pelagial zooplankton in a middle-sized dimictic valley reservoir

Biologia ◽  
2006 ◽  
Vol 61 (2) ◽  
Author(s):  
Martina Hudcovicová ◽  
Marian Vranovsky
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Seasonal Changes ◽  
Thermal Gradient ◽  
Summer Temperature ◽  
Zooplankton Abundance ◽  
Invertebrate Predation ◽  
Chaoborus Flavicans ◽  
Daphnia Cucullata ◽  
The Vertical Distribution

AbstractOur observations indicate the vertical distribution of zooplankton and its seasonal changes in Dubník II reservoir (Slovakia) are determined mainly by the thermal regime of the reservoir, by transparency, and by fish and invertebrate predation. During periods of circulation, zooplankton vertical distribution in the whole water column was more homogeneous, whilst during summer temperature stratification zooplankton concentrated in the epilimnion — rotifers in higher layers than crustaceans. During summer stagnation a steep thermal gradient occurred at the boundary of the epi-and hypolimnion and low temperature and low dissolved oxygen in hypolimnion offered a refuge for Chaoborus flavicans larvae against fish, enabling coexistence of vertebrate and invertebrate predation. This evidence supports our previous findings concerning dominance of rotifers in zooplankton and representation of crustaceans by small-bodied species in the study reservoir. Steep thermal gradient and the presence of Chaoborus larvae caused very low zooplankton abundance in the lower part of the water column and a reduction of cladocerans refuges against fish to layers of thermocline or closely under thermocline where Daphnia cucullata and Daphnia parvula were found. Our previous assumptions about the high density of zooplanktivorous fish in Dubník II reservoir are supported by the fact that these small cladocerans are represented by smaller individuals in the upper layers and bigger individuals in deeper layers.

Vertical Distribution of Northern Shrimp (Pandalus borealis) Larvae in the Gulf of St Lawrence; Implications for Trophic Interactions and Transport

1994 ◽  
Vol 51 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Patrick Ouellet ◽  
Denis Lefaivre
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Suspended Particle ◽  
Stage I ◽  
Vertical Position ◽  
Pandalus Borealis ◽  
Northern Shrimp ◽  
Residual Transport ◽  
Larval Emergence ◽  
The Vertical Distribution

In the northwestern Gulf of St. Lawrence in spring 1987 and 1988, stage I and II northern shrimp (Pandalus borealis) larvae were concentrated in the upper (<30 m) layers above the permanent pycnocline and coincident with subsurface chlorophyll a and suspended particle concentration maxima; this was above other macrozooplankton taxa in the daytime. Shrimp larvae maintained their vertical position relative to the maximum density gradient in the water column in daytime but moved towards the surface at night. Estimation of larval residual transport (~66 km) during the first developmental stage (12 d) corresponded to the horizontal scale of patches of stage I shrimp larvae in the northwest sector of the Gulf. The result is consistent with the suggestion of localized and short-duration larval emergence in the sector. The direction of mass transport and current speed were similar throughout the upper layers of the water column; consequently, the direction and magnitude of larval shrimp transport were not dependent on their vertical position. We suggest that the vertical distribution maintained by shrimp larvae is a mechanism to ensure maximum food availability and to optimize development time in the stratified water of the northwestern Gulf of St. Lawrence.

scholarly journals Photosynthetic production in the Central Arctic during the record sea-ice minimum in 2012

2015 ◽  
Vol 12 (3) ◽  
pp. 2897-2945 ◽  
Author(s):  
M. Fernández-Méndez ◽  
C. Katlein ◽  
B. Rabe ◽  
M. Nicolaus ◽  
I. Peeken ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Water Column ◽  
Primary Productivity ◽  
Ice Cover ◽  
Annual Production ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Eurasian Basin

Abstract. The ice-covered Central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated primary production and of the nutrient supply with increasing warming. This study presents results from the Central Arctic Ocean collected during summer 2012, when sea-ice reached a minimum extent since the onset of satellite observations. Net primary productivity (NPP) was measured in the water column, sea ice and melt ponds by 14CO2 uptake at different irradiances. Photosynthesis vs. irradiance (PI) curves were established in laboratory experiments and used to upscale measured NPP to the deep Eurasian Basin (north of 78° N) using the irradiance-based Central Arctic Ocean Primary Productivity (CAOPP) model. In addition, new annual production was calculated from the seasonal nutrient drawdown in the mixed layer since last winter. Results show that ice algae can contribute up to 60% to primary production in the Central Arctic at the end of the season. The ice-covered water column has lower NPP rates than open water due to light limitation. As indicated by the nutrient ratios in the euphotic zone, nitrate was limiting primary production in the deep Eurasian Basin close to the Laptev Sea area, while silicate was the main limiting nutrient at the ice margin near the Atlantic inflow. Although sea-ice cover was substantially reduced in 2012, total annual new production in the Eurasian Basin was 17 ± 7 Tg C yr-1, which is within the range of estimates of previous years. However, when adding the contribution by sub-ice algae, the annual production for the deep Eurasian Basin (north of 78° N) could double previous estimates for that area with a surplus of 16 Tg C yr-1. Our data suggest that sub-ice algae are an important component of the ice-covered Central Arctic productivity. It remains an important question if their contribution to productivity is on the rise with thinning ice, or if it will decline due to overall sea-ice retreat and be replaced by phytoplankton.

scholarly journals Sinking microplastics in the water column: simulations in the Mediterranean Sea

Ocean Science ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 431-453
Author(s):  
Rebeca de la Fuente ◽  
Gábor Drótos ◽  
Emilio Hernández-García ◽  
Cristóbal López ◽  
Erik van Sebille
Keyword(s):  
Vertical Distribution ◽  
Mediterranean Sea ◽  
Water Column ◽  
Large Scale ◽  
Circulation Model ◽  
Small Scale ◽  
The Mediterranean ◽  
Scale Turbulence ◽  
Non Gaussian ◽  
The Vertical Distribution

Abstract. We study the vertical dispersion and distribution of negatively buoyant rigid microplastics within a realistic circulation model of the Mediterranean sea. We first propose an equation describing their idealized dynamics. In that framework, we evaluate the importance of some relevant physical effects (inertia, Coriolis force, small-scale turbulence and variable seawater density), and we bound the relative error of simplifying the dynamics to a constant sinking velocity added to a large-scale velocity field. We then calculate the amount and vertical distribution of microplastic particles on the water column of the open ocean if their release from the sea surface is continuous at rates compatible with observations in the Mediterranean. The vertical distribution is found to be almost uniform with depth for the majority of our parameter range. Transient distributions from flash releases reveal a non-Gaussian character of the dispersion and various diffusion laws, both normal and anomalous. The origin of these behaviors is explored in terms of horizontal and vertical flow organization.

scholarly journals The Vertical Distribution of Marine Macroplankton. IX. The Distribution of the Pelagic Young of Teleostean Fishes in the Daytime in the Plymouth Area

1930 ◽  
Vol 16 (2) ◽  
pp. 639-676 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Vertical Distribution ◽  
Recording Instrument ◽  
Different Depths ◽  
The Vertical Distribution ◽  
Depth Recording ◽  
Made In

In continuation of the study of the vertical distribution of the pelagic young of Teleostean fishes, already reported on for 1924 and 1925 (1), a further fifteen stations were made with the two-metre stramin net in the daytime between April and September in 1926. The collections were made in a manner exactly similar to that for those of the previous years, hauls of ten minutes' duration being made almost always at six different depths with the net towed horizontally as near as possible at the same speed on each occasion. The Admiralty depth-recording instrument was used at every station, and the results for each haul are given in Figures 6 and 7 on pages 666 and 667, which show the graphic records of the path of the net through the water for each haul. (That for June 25th is not included, an unsatisfactory record being obtained on that day owing to the drum of the recorder not having been fully screwed down, see 4, p. 431.)

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