The impact of two Chaoborus species on a zooplankton community

1990 ◽  
Vol 68 (5) ◽  
pp. 981-985 ◽  
Author(s):  
Neil A. MacKay ◽  
Stephen R. Carpenter ◽  
Patricia A. Soranno ◽  
Michael J. Vanni
Keyword(s):  
Chlorophyll A ◽  
Daphnia Pulex ◽  
Zooplankton Community ◽  
Chlorophyll A Concentration ◽  
Chaoborus Flavicans ◽  
Chaoborus Americanus ◽  
Diaptomus Oregonensis ◽  
Herbivore Responses ◽  
The Impact

The responses of a zooplankton community to Chaoborus predation were studied in large in situ mesocosms in Peter Lake. Chaoborus flavicans, the native chaoborid, significantly reduced the density of the dominant grazer, Daphnia pulex, in relation to controls that lacked Chaoborus. Chaoborus americanus, a species found only in fishless bogs, reduced Da. pulex densities far more than the chaoborid found in Peter Lake, C. flavicans. Chaoborus americanus also significantly reduced the dominant copepod, Diaptomus oregonensis, in relation to both the control and the C. flavicans treatment. Chlorophyll a concentration did not differ among treatments, indicating that herbivore responses could not be explained by changes in food levels. Our results show that Chaoborus predation can greatly affect a zooplankton community, especially daphnids.

scholarly journals OPTMIZATION OF BIO-OPTICAL MODEL PARAMETERS FOR TURBID LAKE WATER QUALITY ESTIMATION USING LANDSAT 8 AND WASI-2D

2020 ◽  
Vol XLII-3/W11 ◽  
pp. 67-72
Author(s):  
A. Manuel ◽  
A. C. Blanco ◽  
A. M. Tamondong ◽  
R. Jalbuena ◽  
O. Cabrera ◽  
...  
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
The Philippines ◽  
Quality Data ◽  
Model Parameters ◽  
Landsat 8 ◽  
Water Quality Data ◽  
Chlorophyll A Concentration ◽  
In Situ Data

Abstract. Laguna Lake, the Philippines’ largest freshwater lake, has always been historically, economically, and ecologically significant to the people living near it. However, as it lies at the center of urban development in Metro Manila, it suffers from water quality degradation. Water quality sampling by current field methods is not enough to assess the spatial and temporal variations of water quality in the lake. Regular water quality monitoring is advised, and remote sensing addresses the need for a synchronized and frequent observation and provides an efficient way to obtain bio-optical water quality parameters. Optimization of bio-optical models is done as local parameters change regionally and seasonally, thus requiring calibration. Field spectral measurements and in-situ water quality data taken during simultaneous satellite overpass were used to calibrate the bio-optical modelling tool WASI-2D to get estimates of chlorophyll-a concentration from the corresponding Landsat-8 images. The initial output values for chlorophyll-a concentration, which ranges from 10–40 μg/L, has an RMSE of up to 10 μg/L when compared with in situ data. Further refinements in the initial and constant parameters of the model resulted in an improved chlorophyll-a concentration retrieval from the Landsat-8 images. The outputs provided a chlorophyll-a concentration range from 5–12 μg/L, well within the usual range of measured values in the lake, with an RMSE of 2.28 μg/L compared to in situ data.

Estimation of chlorophyll‐a concentration in Lake Tai, China using in situ hyperspectral data

2006 ◽  
Vol 27 (19) ◽  
pp. 4267-4276 ◽  
Author(s):  
H. B. Jiao ◽  
Y. Zha ◽  
J. Gao ◽  
Y. M. Li ◽  
Y. C. Wei ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Hyperspectral Data ◽  
Chlorophyll A Concentration

Variations in chlorophyll-a concentration and the impact on Sardinella lemuru catches in Bali Strait, Indonesia

2010 ◽  
Vol 87 (1-4) ◽  
pp. 168-174 ◽  
Author(s):  
Aida Sartimbul ◽  
Hideaki Nakata ◽  
Erfan Rohadi ◽  
Beni Yusuf ◽  
Hanggar Prasetyo Kadarisman
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll A Concentration ◽  
The Impact

scholarly journals Mesoscale, cyclonic eddies as larval fish habitat along the southeast United States shelf: a Lagrangian description of the zooplankton community

2009 ◽  
Vol 67 (3) ◽  
pp. 403-411 ◽  
Author(s):  
J. J. Govoni ◽  
J. A. Hare ◽  
E. D. Davenport ◽  
M. H. Chen ◽  
K. E. Marancik
Keyword(s):  
United States ◽  
Chlorophyll A ◽  
Larval Fish ◽  
Fish Habitat ◽  
Zooplankton Community ◽  
The United States ◽  
Continuous Series ◽  
Lagrangian Description ◽  
Southeast United States ◽  
Chlorophyll A Concentration

Abstract Govoni, J. J., Hare, J. A., Davenport, E. D., Chen, M. H., and Marancik, K. E. 2010. Mesoscale, cyclonic eddies as larval fish habitat along the southeast United States shelf: a Lagrangian description of the zooplankton community. – ICES Journal of Marine Science, 67: 403–411. The Charleston Gyre region is characterized by continuous series of cyclonic eddies that propagate northeastwards before decaying or coalescing with the Gulf Stream south of Cape Hatteras, NC, USA. Over 5 d, chlorophyll-a concentration, zooplankton displacement volume, and zooplankton composition and abundance changed as the eddy moved to the northeast. Surface chlorophyll-a concentration decreased, and zooplankton displacement remained unchanged as the eddy propagated. Zooplankton taxa known to be important dietary constituents of larval fish increased in concentration as the eddy propagated. The concurrent decrease in chlorophyll-a concentration and static zooplankton displacement volume can be explained by initial stimulation of chlorophyll-a concentration by upwelling and nutrient enrichment near the eddy core and to possible grazing as zooplankton with short generation times and large clutch sizes increased in concentration. The zooplankton community did not change significantly within the 5 d that the eddy was tracked, and there was no indication of succession. Mesoscale eddies of the region are dynamic habitats as eddies propagate northeastwards at varying speeds within monthly periods. The abundance of zooplankton important to the diets of larval fish indicates that the region can provide important pelagic nursery habitat for larval fish off the southeast coast of the United States. A month of feeding and growth is more than half the larval duration of most fish spawned over the continental shelf of the southeastern United States in winter.

scholarly journals CHLOROPHYLL SPECIFIC ABSORPTION COEFFICIENTS AND THE IMPACT OF PHYTOPLANKTON TAXONOMIC GROUP OF SURFACE WATERS IN THE NORTHEASTERN GULF OF MEXICO

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Bisman Nababan
Keyword(s):  
Gulf Of Mexico ◽  
Absorption Coefficient ◽  
Chlorophyll A ◽  
Mississippi River ◽  
Specific Absorption Coefficient ◽  
Specific Absorption ◽  
Chlorophyll A Concentration ◽  
Average Value ◽  
Northeastern Gulf Of Mexico ◽  
The Impact

<p>The chlorophyll-specific absorption coefficient at 440 nm (a*<br />ph(440)) of surface water in the Northeastern Gulf of Mexico varied by a factor of 7 (0.02-0.15 m2 mg-1) with the of chlorophyll-a concentration of 0.06-12.25 mg m-3. In general, lower values of a*ph(440) (&lt;0.06 m2 mg-1) were observed in the inshore particularly in the major river mouths. During summer, lower values of a*ph(440) were also observed offshore associated with low-salinity waters of the Mississippi River plume. Higher values of a*ph(440) (&gt;0.1 m2 mg-1) were otherwise observed outside the river plumes in the outer<br />shelf and slope, where lower chlorophyll-a concentration occurred. Based on phytoplankton taxonomic groups, the average value of a*ph(440), of microphytoplankton group was significantly lower than that of nanophytoplankton and picophytoplantkon groups, suggesting that an increase in cell optical size (pigment packaging) resulted in decreasing a*<br />ph(440) values. The relationship between a*ph(440) and chlorophyll-a concentration was also not linear, indicating pigment composition played an important role in determining a*ph(440) variability.</p><p>Keywords: chlorophyll-specific absorption coefficient, microphytoplankton, nanophytoplankton,<br />picophytoplankton, Gulf of Mexico, pigment, packaging effect</p>

scholarly journals The fate of a southwest Pacific bloom: gauging the impact of submesoscale vs. mesoscale circulation on biological gradients in the subtropics

2017 ◽  
Vol 14 (14) ◽  
pp. 3471-3486 ◽  
Author(s):  
Alain de Verneil ◽  
Louise Rousselet ◽  
Andrea M. Doglioli ◽  
Anne A. Petrenko ◽  
Thierry Moutin
Keyword(s):  
Chlorophyll A ◽  
Large Scale ◽  
Subtropical Gyre ◽  
Mesoscale Circulation ◽  
Mesoscale Structures ◽  
Subsequent Decrease ◽  
Time Period ◽  
Low Concentrations ◽  
The Impact

Abstract. The temporal evolution of a surface chlorophyll a bloom sampled in the western tropical South Pacific during the 2015 Oligotrophy to UlTra-oligotrophy PACific Experiment (OUTPACE) cruise is examined. This region is usually characterized by largely oligotrophic conditions, i.e. low concentrations of inorganic nutrients at the surface and deep chlorophyll a maxima. Therefore, the presence of a surface bloom represents a significant perturbation from the mean ecological state. Combining in situ and remote sensing datasets, we characterize both the bloom's biogeochemical properties and the physical circulation responsible for structuring it. Biogeochemical observations of the bloom document the bloom itself, a subsequent decrease of surface chlorophyll a, significantly reduced surface phosphate concentrations relative to subtropical gyre water farther east, and a physical decoupling of chlorophyll a from a deep nitracline. All these characteristics are consistent with nitrogen fixation occurring within the bloom. The physical data suggest surface mesoscale circulation is the primary mechanism driving the bloom's advection, whereas balanced motions expected at submesoscales provide little contribution to observed flow. Together, the data provide a narrative where subtropical gyre water can produce significant chlorophyll a concentrations at the surface that is stirred, deformed, and transported great distances by the mesoscale circulation. In this case, for the time period considered, the transport is in an easterly direction, contrary to both the large-scale and mean mesoscale flow. As a result, future studies concerning surface production in the region need to take into account the role complex mesoscale structures play in redistributing subtropical gyre water.

Vertical distributions and zooplankton predation in a small temperate pond

1981 ◽  
Vol 59 (9) ◽  
pp. 1720-1725 ◽  
Author(s):  
Guy E. Melville ◽  
Edward J. Maly
Keyword(s):  
Daphnia Pulex ◽  
Predation Rate ◽  
Invertebrate Predation ◽  
Chaoborus Americanus ◽  
Vertical Distributions ◽  
Zooplankton Communities ◽  
The Impact ◽  
Predation Rates

Depth-specific sampling in a small Quebec pond between April and October 1977 revealed that instars of Daphnia pulex less than 1.41 mm in length and instars of Diaptomus leptopus greater than 0.64 mm in length consistently had vertical distributions which were different from those of late instars of their predator Chaoborus americanus. Experiments were done to determine to what extent these distributions affected the rate of predation by Chaoborus. Vertical and horizontal 25-L enclosures, 1.4 m long, and 2.5-L enclosures, all containing Chaoborus–prey pairs, were introduced into a pond for 3-day periods weekly from July to September. Predation rates in vertical enclosures were considerably lower than those in small and horizontal enclosures. These results suggest that distributions of Diaptomus and Daphnia in vertical enclosures significantly reduce predation on them by Chaoborus. In horizontal and small enclosures where overlap of predator and prey was increased, predation rate of Chaoborus was higher. Results are discussed in relation to the impact of invertebrate predation on zooplankton and the structure of zooplankton communities.

scholarly journals Bio-Optical Characteristics of the Black Sea Coastal Waters near Sevastopol: Assessment of the MODIS and VIIRS Products Accuracy

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
E. Yu. Skorokhod ◽  
T. Ya. Churilova ◽  
T. V. Efimova ◽  
N. A. Moiseeva ◽  
V. V. Suslin ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Black Sea ◽  
Coastal Waters ◽  
Light Absorption ◽  
Ecological Monitoring ◽  
Optically Active ◽  
The Black Sea ◽  
Active Components ◽  
Chlorophyll A Concentration

Purpose. The purpose of the work is to evaluate accuracy of the satellite products for the coastal waters near Sevastopol, reconstructed by the standard algorithms based on the MODIS and VIIRS (installed at the artificial Earth satellites Aqua and Terra, and at Suomi NPP, respectively) data. Methods and Results. In situ sampling was carried out at the station (44°37'26" N and 33°26'05" E) located at a distance of two miles from the Sevastopol Bay. The chlorophyll a concentration was measured by the spectrophotometric method. The spectral light absorption coefficients by optically active components were measured in accordance with the current NASA protocol. The spectroradiometers MODIS and VIIRS Level 2 data with spatial resolution 1 km in nadir around the in situ station (44°37'26"±0°00'32" N and 33°26'05"±0°00'54" E) were used. The satellite products were processed by the SeaDAS 7.5.3 software developed in NASA. The research showed that the standard NASA algorithms being applied to the MODIS and VIIRS data, yielded incorrect values of the optically active components’ content in the Black Sea coastal waters near Sevastopol as compared to the data of in situ measurements in the same region: the satellite-derived “chlorophyll a concentration” was on average 1.6 times lower in spring, and 1.4 times higher in summer; the contribution of phytoplankton pigments to total light absorption at 443 nm was underestimated in 8.7 times; the light absorption by colored detrital organic matter was overestimated in 2.2 times. Conclusions. The NASA standard algorithms are inapplicable to calculating bio-optical indices in the coastal waters of the Black Sea near Sevastopol since they provide incorrect values of the satellite products (Ca-s, aph-s(443) and aCDM-s(443)). Operative ecological monitoring based on satellite data requires development of a regional algorithm taking into account the seawater optical features in the region and in the coastal zone, in particular.

scholarly journals Long-Term Presence of the Island Mass Effect at Rangiroa Atoll, French Polynesia

2021 ◽  
Vol 7 ◽  
Author(s):  
Carleigh Vollbrecht ◽  
Paula Moehlenkamp ◽  
Jamison M. Gove ◽  
Anna B. Neuheimer ◽  
Margaret A. McManus
Keyword(s):  
Chlorophyll A ◽  
Marine Ecosystem ◽  
Mass Effect ◽  
French Polynesia ◽  
Driving Frequency ◽  
Ocean Water ◽  
Chlorophyll A Concentration ◽  
Wave Forcing ◽  
Tropical Oceans

Enhancement of phytoplankton biomass near island and atoll reef ecosystems—termed the Island Mass Effect (IME)—is an ecologically important phenomenon driving marine ecosystem trophic structure and fisheries in the midst of oligotrophic tropical oceans. This study investigated the occurrence of IME at Rangiroa Atoll in the French Polynesian Tuamotu archipelago, and the physical mechanisms driving IME, through the analysis of satellite and in situ data. Comparison of chlorophyll-a concentration near Rangiroa Atoll with chlorophyll-a concentration in open ocean water 50 km offshore, over a 16-year period, showed phytoplankton enhancement as high as 130% nearshore, over 75.7% of the study period. Our statistical model examining physical drivers showed the magnitude of IME to be significantly enhanced by higher sea surface temperature (SST) and lower photosynthetically active radiation (PAR). Further, in situ measurements of water flowing through Tiputa Channel revealed outflowing lagoon water to be warmer, lower in salinity, and higher in particulate load compared to ocean water. We suggest that water inside Rangiroa’s lagoon is enriched in nutrients and organic material by biological processes and advected as a result of tidal and wave forcing to coastal ocean waters, where it fuels primary production. We suggest that a combination of oceanographic and biological mechanisms is at play driving frequency and magnitude of IME at Rangiroa Atoll. Understanding the underlying processes driving IME at Rangiroa is essential for understanding future changes caused by a warming climate and changing environmental conditions for the marine ecosystem.

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