Vertical Distribution Of Plankton Research Articles

Distributions of environmental parameters and Plankton’s volume backscattering strength at Yos Sudarso Bay, Jayapura, Indonesia

The present study combined the data of environmental parameters and plankton distribution using hydroacoustic technology with the purpose to map the horizontal and vertical distribution of plankton in Yos Sudarso Bay, Jayapura, Indonesia. Hydroacoustic data were processed using a threshold in the range of −90 dB to −70 dB which was used for plankton detection at a depth range of 5–100 m. The results of the current study showed that the surface temperature changed from 30 °C on the outside to 18 °C on the inside of the bay. Similarly, the salinity of the surface outside the bay was 36‰ while it was 18‰ inside the bay. The distribution of chlorophyll had also decreased, where the value outside the bay was 0.32 mg/m3 and inside the bay was 0.02 mg/m3. The horizontal distribution of the values of plankton's volume backscattering strength (Sv) had a range of −82 dB to −75 dB with an average of −76.63 dB. When the distribution of plankton's Sv was detected vertically, it showed that the value of plankton’s Sv decreased with increasing the water depth.

Complex Analysis of the Plankton Community of two Brown-Water Bog Lakes in the European Part of Russia

The composition and vertical distribution of plankton of two polyhumic bog lakes on the territory of the Volga-Kama State Natural Biosphere Reserve were studied. It was found that the anaerobic conditions were formed in the water column at a depth deeper than 2 m due to stratification and lack of light. Phyto- and zooplankton (including ciliates) prevailed in the upper aerobic layers of water, heterotrophic bacteria and green sulfur bacteria (Chlorobiaceae) – in the anaerobic zone. Rotifers dominated the metazooplankton in the whole water column (>95% of the biomass); prevailing genera were Asplanchna, Polyarthra, and Bipalpus. Heterotrophic organisms formed 70 ± 10% of the plankton biomass in both lakes. A high proportion of ciliates (on average 3%, maximum up to 18%) and heterotrophic bacteria (on average 49 ± 25%) was also revealed. The invasive species algae Gonyostomum semen (Raphidophyta) was first registered in the lakes of the Republic of Tatarstan. It formed 28-80% of the phytoplankton biomass in the studied lakes. It was found that at least one of the ciliate species (Frontonia cf. leucas) is able to feed on G. semen cells in situ.

Influence of wind events on larval fish mortality rates in the southern California Current Ecosystem

Wind-induced mixing can affect the vertical distribution of plankton in the upper water column, influencing the prey available for larval fishes. The stable ocean hypothesis proposes that periods of calm winds facilitate the development of plankton layers at concentrations sufficient for successful larval foraging and increased survival. Conversely, storm events redistribute prey, leading to reduced foraging success. Here, we investigate this hypothesis by comparing larval fish mortality rates estimated from 37 years of ichthyoplankton data against metrics of wind events defined as storms and calm periods. Contrary to expectations, we found that mortality for Pacific hake (Merluccius productus) significantly decreased as storm events increased in the southern California Current Ecosystem. Mortality rates for northern anchovy (Engraulis mordax), Pacific sardine (Sardinops sagax), Pacific mackerel (Scomber japonicus), and jack mackerel (Trachurus symmetricus) had no relationship to storms, and no species’ mortality rates were related to the number of calm events. Our results highlight the differing sensitivities of larval survival among fishes in the region and indicate that responses to atmospheric processes are species-dependent.

Disruption of the vertical distribution of plankton in the tributary mouth of a plains reservoir in the summer period of a hot year

A stratification site was detected according to the water conductivity in the frontal zone of the mouth part of the tributary of a plains reservoir. The “second bottom” effect is shown to occur in the lower, denser layer of river waters, where the zooplankton, whose structural and functional characteristics differ from those in overlying and underlying water layers, live. The growth of bacterioplankton is controlled by the zooplankton. The “second bottom” effect is disrupted under an oxygen deficiency caused by abnormally high water temperatures.

The Rise and Fall of Plankton: Long-Term Changes in the Vertical Distribution of Algae and Grazers in Lake Baikal, Siberia

Both surface water temperatures and the intensity of thermal stratification have increased recently in large lakes throughout the world. Such physical changes can be accompanied by shifts in plankton community structure, including changes in relative abundances and depth distributions. Here we analyzed 45 years of data from Lake Baikal, the world's oldest, deepest, and most voluminous lake, to assess long-term trends in the depth distribution of pelagic phytoplankton and zooplankton. Surface water temperatures in Lake Baikal increased steadily between 1955 and 2000, resulting in a stronger thermal gradient within the top 50 m of the water column. In conjunction with these physical changes our analyses reveal significant shifts in the daytime depth distribution of important phytoplankton and zooplankton groups. The relatively heavy diatoms, which often rely on mixing to remain suspended in the photic zone, shifted downward in the water column by 1.90 m y-1, while the depths of other phytoplankton groups did not change significantly. Over the same time span the density-weighted average depth of most major zooplankton groups, including cladocerans, rotifers, and immature copepods, exhibited rapid shifts toward shallower positions (0.57–0.75 m y−1). As a result of these depth changes the vertical overlap between herbivorous copepods (Epischura baikalensis) and their algal food appears to have increased through time while that for cladocerans decreased. We hypothesize that warming surface waters and reduced mixing caused these ecological changes. Future studies should examine how changes in the vertical distribution of plankton might impact energy flow in this lake and others.

Across-shore variability in plankton layering and abundance associated with physical forcing in Monterey Bay, California

The purpose of this study was to further our understanding of the role of the coastal physical oceanographic environment as a dynamic and constantly evolving habitat for plankton. Over a 3-week period in the summer of 2010, an array of moorings were deployed and shipboard and autonomous underwater vehicle (AUV) surveys were conducted to investigate the association between physical processes and plankton distributions over the Monterey Bay, California inner shelf. Acoustic backscatter, chlorophyll-a fluorescence, and high-resolution zooplankton imagery data collected during the shipboard surveys were used to map the distributions of phytoplankton and zooplankton; and profiles of temperature, salinity, oxygen, and nitrate from the AUV characterized the physical and chemical environment. A synthesis of underway and moored time series data provided insight into the histories of water masses in the area, and facilitated tracking of internal wave groups as they propagated towards shore. A near-bottom intrusion of recently-upwelled water was found to be strongly influenced by the diurnal tide, resulting in daily across-shelf excursions past the mooring array at the 20-m isobath. Behind the leading edge of the intrusion, the water column was highly stratified in temperature, salinity, oxygen, and nitrate; and thin layers of phytoplankton and zooplankton persisted at the upper boundary of the intrusion. In ambient waters shoreward of the intrusion, stratification was weak; copepod, appendicularian, and gelatinous zooplankton abundances were relatively low; and phytoplankton and acoustic backscatter were broadly distributed throughout the lower half of the water column. The arrival of two shoreward-propagating internal wave groups observed during the shipboard survey corresponded with disparate responses in plankton distribution. In the wake of the first wave group, phytoplankton and zooplankton layers thinned or converged; in the wake of the second wave group, an eight-fold increase in gelatinous zooplankton was observed. These findings reveal a strong coupling between physical processes and the abundance and vertical distribution of plankton. It is necessary to understand the underlying physical environment in order to understand the complex distribution of organisms in the sea.

Effects of a blue mussel Mytilus edulis bed on vertical distribution and composition of the pelagic food web

The impact of a mussel bed on the neighbouring pelagic food web is investigated by a comparative study of the vertical distribution of plankton above a mussel bed with that above a bare sandy bottom. The use of conventional water bottles did not reflect the near-bed dynamics. However, use of a high-resolution water sampler in the bottom 1 m of the water column above the sea floor revealed statistically significant differences. The results document for the first time in situ grazing on all major components of the pelagic food web. The vertical distributions of phytoplankton, bacteria, protozoa, meroplankton and copepods were statistically significantly different above the mussel and sand beds. The mussel bed recycled nutrients back to the water column as waste products. The pre- sent investigation stresses the need for a more diverse view of the trophic role of suspension-feeding bivalves in shallow coastal ecosystems.

Characterization of the zooplankton community, size composition, and distribution in relation to hydrography in the Japan/East Sea

Abstract The Japan/East Sea (JES) may be thought of as a model or microcosm of larger oceanic systems where biogeographic boundaries juxtapose at highly dynamic boundaries. The northern and southern portions of the JES are hydrographically and biologically distinct, with the southern portion being more tropical/oligotrophic and the northern portion being more boreal/eutrophic. Regional zooplankton taxonomic and size compositions and abundance and the high-resolution vertical distribution of plankton, fluorescence, and coincident hydrography were described using the Video Plankton Recorder (VPR), equipped with high- and low-magnification cameras and environmental sensors and mounted on a vertically profiling towed vehicle, in the upper 80 m of the JES during the summer of 1999. A survey was conducted over both the northern and southern regions, including the Subpolar Front (SPF), that spanned 10–12° of latitude and longitude and covered an along track distance of 7000 km. Plankton also were collected at 15 selected stations using a ring net for silhouette analysis of taxa and size. Distributional patterns in abundance (#/liter) of plankton taxa from the VPR were quantified at sea in real time, identifying plankton automatically using a neural network classifier. The most abundant taxa identified were copepods, Oithona spp., Calanus spp., copepod nauplii, protozoa, and diatoms, with copepods the dominant taxon. The northern JES, southern JES, and North Korean Cold Current were distinct based on based on temperature-salinity properties. The hydrography was complex and characterized by multiple mesoscale features including currents and the meandering of the SPF. Different taxonomic and size compositions were observed in the three hydrographic regions. The vertical distributions of copepods and fluorescence were associated with hydrographic structure, especially at fronts. Plankton abundances varied with regional hydrographic region and environmental conditions, although strong associations were not always observed. The extremely dynamic nature of the JES may effectively mix the plankton and obscure strong gradients or differences between regions.

Lake Shira, a Siberian salt lake: ecosystem structure and function

The specific composition, vertical distribution and daily migration of plankton in a meromictic salt lake, Lake Shira, have been investigated. The main structural components of the ecosystem are bacteria, algae and crustaceans. Since the late 1970s, blue-green algae are reported as dominant. Nowadays the phytoplankton is dominated byLyngbya contorta, Microcystis ichtyoblabe (Cyanophyta),Cyclotella tuberculata (Bacillariophyta) andDictyosphaerium tetrachotomum (Chlorophyta). The zooplankton of Lake Shira comprisesArctodiaptomus salinus (Copepoda),Brachionus plicatilis andHexarthra oxiuris (Rotatoria). Investigation revealed a stratified vertical distribution of all dominant species exceptCyclotella with a maximum at a depth of 12–15 m during the summer growth period. Zooplanktons differ in the pattern of distribution and daily migration, but most zooplankton tend to concentrate near the surface. The possible reasons for the vertical distribution of the plankton are discussed.

Visual observations of the vertical distribution of plankton throughout the water column above Broken Spur vent field, Mid-Atlantic Ridge

Visual observations were made in September 1997 during the 39 cruise of R/V “Akademik Mstislav Keldysh” with 2 deep-sea manned submersibles “Mir” aboard. During 4 dives the following plankton countings were made: 3 vertical throughout the water column during the day, 2 vertical in the upper 1000 m at night, and 1 oblique in the plume area during the day. Biomass profiles are represented for each dive for all abundant animal groups: copepods, euphausiids+decapods+mysids, chaetognaths, medusae, ctenophores, siphonophores, cyclothones, myctophides, radiolarians, and the total zooplankton. Plankton distribution shows 2 aggregations, one within the main pycnocline and the other near the plume; Gelatinous animals and radiolarians dominate in both aggregations by biomass and make a significant contribution to the plankton biomass throughout the water column. Oblique counting indicates the presence of aggregations of animals near the upper and lower borders of the plume and biomass depletion within the plume core.

Lake Shira, a Siberian salt lake: ecosystem structure and function. 1. Major physico-chemical and biological features

The specific composition, vertical distribution and daily migration of plankton in a meromictic salt lake, Lake Shira, have been investigated. The main structural components of the ecosystem are bacteria, algae and crustaceans. Since the late 1970s, blue-green algae are reported as dominant. Nowadays the phytoplankton is dominated by Lyngbya contorta, Microcystis ichtyoblabe (Cyanophyta), Cyclotella tuberculata (Bacillariophyta) and Dictyosphaerium tetrachotomum (Chlorophyta). The zooplankton of Lake Shira comprises Arctodiaptomus salinus (Copepoda), Brachionus plicatilis and Hexarthra oxiuris (Rotatoria). Investigation revealed a stratified vertical distribution of all dominant species except Cyclotella with a maximum at a depth of 12--15 m during the summer growth period. Zooplanktons differ in the pattern of distribution and daily migration, but most zooplankton tend to concentrate near the surface. The possible reasons for the vertical distribution of the plankton are discussed.

Spatial and temporal changes in the partitioning of organic carbon in the plankton community of the Sargasso Sea off Bermuda

The vertical distribution of plankton (bacteria, nanozooplankton, microzooplankton, mesozooplankton, macrozooplankton and salps) biomass in the photic zone near the JGOFS time series station off Bermuda was examined during 2–3 week periods in August 1989 and in March/April 1990. The amount of phytoplankton carbon in the photic zone was lower in August as compared to March/April (398 and 912 mg C m−2, respectively). Total heterotrophic biomass in the photic zone was also lower in August as compared to March/April (1106 and 1795 mg C m−2, respectively). Taken together, bacteria and nanozooplankton constituted approximately 70% of the total heterotrophic carbon in the photic zone on both cruises. Considering their high weightspecific carbon demand relative to micro-, meso-, and macrozooplankton, it is clear that most of the carbon in the surface waters of the Sargasso Sea near Bermuda cycles through bacteria and flagellates—the “microbial loop”. However, both seasonal (August vs. March/April) and withincruise variations in the vertical flux of organic material were related to the biomass of macrozooplankton. Macrozooplankton biomass was lower in August than March/April (93 and 267 Mg C m−2, respectively). There was more non-living carbon (detritus) than living carbon in the photic zone during the August cruise (70% of total organic matter) but about equal amounts of detritus and living carbon in March/April.

Vertical distribution of plankton in the Skagerrak in relation to doming of the seasonal thermocline

Vertical distribution of plankton in the Skagerrak in relation to doming of the seasonal thermocline

Vertical distribution of plankton in the skagerrak in relation to doming of the seasonal thermocline

In the central Skagerrak between Norway and Denmark, the seasonal thermocline tends to be relatively shallow (10 to 15 m) probably due to geostrophic effects. An investigation of phytoplankton distribution in this region in late August 1981 showed the presence of an intense subsurface chlorophyll maximum (up to 30 γ 1 − Chl a) at a temperature of <6°C, dominated by coccolithophores and the dinoflagellate, Prorocentrum minimum. Data are presented on the vertical distribution of zooplankton in relation to these phytoplankton populations.

The vertical distribution and diurnal migration of copepods at different stations in the Irish Sea

The vertical distribution of plankton and hydrographic factors was studied at five stations within the Irish Sea, differing in depth, strength of tidal currents and location with respect to non-tidal currents. Neither the plankton nor the hydrographic factors showed vertical homogeneity at any station, even when there were strong tidal currents. The day depth of bothPseudocalanus elongatus andMicrocalanus pusillus varied considerably at different stations and at different seasons at the same station.P. elongatus showed diurnal migrations on some but not all occasions. No clear diurnal migration was shown byM. pusillus. Some of the vertical distributions of both species, both by day and over 24 h, could be correlated with physical or chemical factors. These included stratification involving differences in temperature or salinity, but in some cases only differences in nutrient concentration were detected. Although layers of seawater of similar density are unlikely to maintain their identity for very long periods they are probably more common than is generally realized and sufficiently persistent to have important effects on the distribution of plankton. The determination of nutrient concentrations provides a convenient and effective means of detecting such layers.

Qualitative and Quantitative Variation of Net Plankton of Craighead Lake

This study describes the horizontal, vertical, and seasonal variation qualitatively and quantitatively of net plankton in Craighead Lake and the co-existing physicochemical characteristics. Further, this information is compared qualitatively with the results obtained by Barton (1963) concerning the same lake. Craighead Lake is a soft water lake with generally adequate oxygen values throughout the year, maintaining a fairly constant carbon dioxide level and neutral pH in the upper strata. The lake is biologically poor and the 55 genera of net plankton identified constituted a mean annual standing crop of only 710 organisms/1. Total organisms varied numerically from 168/1 to 2254/1 on 4 January and 26 April 1969, respectively. Difflugia, Ceratium, Diaptomus, and Keratella were the dominant genera, in that order. Vertical distribution of plankton was generally characterized by fewer taxa and greater numbers/1 with increased depth. The most striking change in net plankton since 1962-63 has been a drastic change in the composition of the dominant forms. This change, and the overall paucity of plankton organisms in the present study, is largely attributed to the softness of the water and the enlargement of the lake in 1962 by extensive dredging. Craighead Lake is located on Crowley's Ridge 9.7 km S of Jonesboro, Craighead County, Arkansas. Developed initially as a recreational area with primary emphasis upon boating and skiing, the lake was enlarged in 1962 and now serves as a fishing area as well. Barton's (1963) investigation of the seasonal variation in surface net plankton has been the only limnological study made of the lake. This study describes the horizontal, vertical and seasonal variation qualitatively and quantitatively of plankton in Craighead Lake and the co-existing physicochemical characteristics. Further, this information is compared qualitatively with the results obtained by Barton (1963) to report any change in the plankton composition. Preliminary observations indicated that a reversal of succession was to be anticipated, due to the dredging and enlargement of the lake in 1962. DESCRIPTION OF AREA. Craighead County lies within the alluvial valley of the Mississippi River beginning near Cape Girardeau, Missouri, and extends southward to the deltaic plain in Louisiana. A thick veneer of loess overlies the bedrock of the valley walls, particularly on its east side.

Le rôle de la prospection sous-marine autonome dans les recherches de biologie marine et d'océanographie biologique

At the present time the autonomous exploration of the sea may be divided into three main fields: airScuba down to 60 m; diving saucers down to 1200 m; bathyscaph down to the greatest depths of the ocean. In the near future, theScuba with special gas mixtures, excluding nitrogen, and the underwater permanent laboratories, will open a new field for biological investigations; progress in metallurgy may also allow diving with engines, without a floating tank, down to 2000 m. The ability of the deep-sea vehicles to stop and remain at a definite depth below the surface needs further research. TheScuba is interesting for investigating the biotopes where the usual devices cannot be used from a surface vessel, for instance in submarine caves. Very special biocoenoses have been found in the totally dark parts of these caves with impoverished stocks and sometimes relict species; the sampling may be perfect both on soft and hard bottoms. With the deep-sea vehicles, investigations may be carried out on the behaviour and distribution of the bottom epifauna. The bathyscaph also allows a general view of the vertical distribution of plankton much better than using plankton samplers, because the plankton nets or pumps are always working on a discontinuous scale. Unfortunately the sampling is much more difficult, especially as far as the plankton is concerned. It is necessary that the engineers pay more attention to the biological devices; very good data have been obtained for temperature, pressure, sound-velocity, etc., but in many instances the biologist diving with a deep-sea vehicle cannot do more than look at the animals and take photographs.

山形県大鳥池におけるプランクトンの鉛直分布

山形県大鳥池におけるプランクトンの鉛直分布

石狩灣に於けるプランクトンの垂直分布の一例

石狩灣に於けるプランクトンの垂直分布の一例

Notes on Cyanea Caught in the Ring-trawl in the Plymouth Area during the Years 1925 to 1930

Duringthe researches on the vertical distribution of plankton and on the-seasonal abundance of young fish, a record was kept of allCyanea lamarckiPéron and Lesueur occurring in the catches of the 2-metre stramin ring-trawl. This was primarily for correlation with the abundance of such fish as the young whiting,Gadus merlangus, which at certain stages in. their development shelter under the umbrella of the medusa. Since it is only with the larger Cyanea that this association of the young whiting exists it was necessary to keep a record of the sizes of the Cyanea occurring in the catches. These were only rough measurements and denote the diameter of the flattened disc of the medusa usually to the nearest half-inch.