Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

Abstract. The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October–November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m−2 for chlorophyll a 314 to 744 mmol m−2 for biogenic silica (BSi), 1106 to 2268 mmol m−2 for particulate organic carbon, 215 to 436 mmol m−2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m−2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the polar front zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size–fractionation and high performance liquid chromatography (HPLC) pigment signatures, whereas the iron-limited reference area was associated with a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from most previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9, respectively) in the iron-fertilized areas compared to the iron-limited reference station (0.13, 1.1, and 5.8, respectively). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From particulate organic carbon (POC), particulate organic nitrogen (PON), and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the phytoplankton community structure as well as major changes in the nutrient stocks progressively leading to silicic acid exhaustion at the end of the productive season. Our observations suggest that the specific response of phytoplankton communities under natural iron fertilization is much more diverse than what has been regularly observed in artificial iron fertilization experiments and that the elemental composition of the bulk particulate matter reflects phytoplankton taxonomic structure rather than being a direct consequence of iron availability.

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Pigments, elemental composition (C, N, P, Si) and stoichiometry of particulate matter, in the naturally iron fertilized region of Kerguelen in the Southern Ocean

Biogeosciences Discussions ◽

10.5194/bgd-11-8259-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 8259-8324 ◽

Cited By ~ 15

Author(s):

M. Lasbleiz ◽

K. Leblanc ◽

S. Blain ◽

J. Ras ◽

V. Cornet-Barthaux ◽

...

Keyword(s):

Particulate Matter ◽

Community Structure ◽

Elemental Composition ◽

Phytoplankton Community ◽

Reference Station ◽

Phytoplankton Community Structure ◽

Iron Fertilization ◽

Phytoplankton Communities ◽

Natural Iron ◽

Fertilization Experiments

Abstract. The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October–November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m−2 for chlorophyll a, 314 to 744 mmol m−2 for biogenic silica (BSi), 1106 to 2268 mmol m−2 for particulate organic carbon, 215 to 436 mmol m−2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m−2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the Polar Front Zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size–fractionation and HPLC pigment signatures, whereas the iron-limited reference area was associated to a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (respectively 0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9) in the iron-fertilized areas compared to the iron-limited reference station (respectively 0.13, 1.1, 5.8). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From POC, PON, and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the phytoplankton community structure as well as major changes in the nutrient stocks progressively leading to silicic acid exhaustion at the end of the productive season. Our observations suggest that the specific response of phytoplankton communities under natural iron fertilization is much more diverse than what has been regularly observed in artificial iron fertilization experiments and that the elemental composition of the bulk particulate matter reflects phytoplankton taxonomic structure rather than being a direct consequence of iron availability.

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Timing of sea ice retreat can alter phytoplankton community structure in the western Arctic Ocean

Biogeosciences ◽

10.5194/bg-11-1705-2014 ◽

2014 ◽

Vol 11 (7) ◽

pp. 1705-1716 ◽

Cited By ~ 35

Author(s):

A. Fujiwara ◽

T. Hirawake ◽

K. Suzuki ◽

I. Imai ◽

S.-I. Saitoh

Keyword(s):

Community Structure ◽

Sea Ice ◽

Arctic Ocean ◽

Phytoplankton Community ◽

Phytoplankton Community Structure ◽

Western Arctic Ocean ◽

Phytoplankton Communities ◽

Ice Retreat ◽

Western Arctic ◽

Sea Ice Retreat

Abstract. This study assesses the response of phytoplankton assemblages to recent climate change, especially with regard to the shrinking of sea ice in the northern Chukchi Sea of the western Arctic Ocean. Distribution patterns of phytoplankton groups in the late summers of 2008–2010 were analysed based on HPLC pigment signatures and, the following four major algal groups were inferred via multiple regression and cluster analyses: prasinophytes, diatoms, haptophytes and dinoflagellates. A remarkable interannual difference in the distribution pattern of the groups was found in the northern basin area. Haptophytes dominated and dispersed widely in warm surface waters in 2008, whereas prasinophytes dominated in cold water in 2009 and 2010. A difference in the onset date of sea ice retreat was evident among years–the sea ice retreat in 2008 was 1–2 months earlier than in 2009 and 2010. The spatial distribution of early sea ice retreat matched the areas in which a shift in algal community composition was observed. Steel-Dwass's multiple comparison tests were used to assess the physical, chemical and biological parameters of the four clusters. We found a statistically significant difference in temperature between the haptophyte-dominated cluster and the other clusters, suggesting that the change in the phytoplankton communities was related to the earlier sea ice retreat in 2008 and the corollary increase in sea surface temperatures. Longer periods of open water during the summer, which are expected in the future, may affect food webs and biogeochemical cycles in the western Arctic due to shifts in phytoplankton community structure.

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Phytoplankton community structure in Menjer Lake, Central Java

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/869/1/012037 ◽

2021 ◽

Vol 869 (1) ◽

pp. 012037

Author(s):

F Sulawesty ◽

G P Yoga ◽

L Subehi ◽

R Rosidah

Keyword(s):

Community Structure ◽

Phytoplankton Community ◽

Diversity Index ◽

Nutrient Content ◽

Cell Counting ◽

Phytoplankton Community Structure ◽

Nitrogen And Phosphorus ◽

Central Java ◽

Phytoplankton Communities ◽

Ecological Pressure

Abstract The occurrence of land changes around Lake Menjer, Central Java Province will affect the condition of water quality subsequently will affect biota, including phytoplankton. The purposes of study was to analyze the composition and abundance of phytoplankton in Menjer Lake regarding to nutrient content i.e. nitrogen and phosphorus. Observations on the phytoplankton community were conducted in July and October 2019 at six locations in Menjer Lake. Water samples were taken at the water surface as much as 10 L filtered using plankton net. Identification was carried out under the inverted microscope Diaphot 300. The abundance was calculated using the Sedgwick Rafter cell counting (SRCC) method. Analysis of the phytoplankton community structure was derived by calculating the Diversity Index, Evenness Index, and Simpson Dominance Index. The nutrient content in Menjer Lake influences the structure of phytoplankton communities quantitatively and qualitatively. Observation showed that the diversity of phytoplankton was low and there was one species dominanted, the result explained that the phytoplankton community in Menjer Lake is unstable and there is ecological pressure on the community. It can be concluded that the improvement of environmental conditions around Menjer Lake is the basis for the sustainable management of Menjer Lake.

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Impact of the 2009 extreme water level variation on phytoplankton community structure in Lower Amazon floodplain lakes

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x2012005000001 ◽

2012 ◽

Vol 23 (3) ◽

pp. 260-270 ◽

Cited By ~ 7

Author(s):

Simone Casali ◽

Maria do Carmo Calijuri ◽

Bernard Barbarisi ◽

Vivian Fróes Renó ◽

Adriana Gomes Affonso ◽

...

Keyword(s):

Community Structure ◽

Water Level ◽

Phytoplankton Community ◽

Diversity Index ◽

Water Level Fluctuations ◽

Phytoplankton Community Structure ◽

Extreme Water Level ◽

Hydrological Conditions ◽

Amazon Floodplain ◽

Phytoplankton Communities

AIM: This paper examines the effect of the extreme water level change in 2009 on the structure and diversity of the phytoplankton communities in lakes of the Lower Amazon Floodplain, and compares it to phytoplankton community structure data reported in the literature for 2002 and 2003 high water periods, closer to the normal hydrological conditions. METHODS: Sub-surface integrated water samples for phytoplankton and chlorophyll-a analyses were collected during high and low water phases in 2009. Water temperature (°C), pH, turbidity (NTU) and electrical conductivity (µS.m-1) were measured, and the Shannon diversity index was calculated. RESULTS: The results showed striking differences in taxonomic composition between phases (high and low) and also between normal (2002 and 2003) and extreme (2009) hydrological conditions, all related to the flood pulse intensity. CONCLUSIONS: Extreme water level fluctuations can result in shifts in phytoplankton community structure and diversity. This work represents a valuable contribution to phytoplankton research since presents the community structure under extreme hydrological events in the Amazon floodplain.

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Variation of phytoplankton community structure in Quang Ngai coastal waters during 2015–2019

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/15652 ◽

2021 ◽

Vol 20 (4A) ◽

pp. 21-33

Author(s):

Huynh Thi Ngoc Duyen ◽

Tran Thi Minh Hue ◽

Tran Thi Le Van ◽

Phan Tan Luom ◽

Nguyen Ngoc Lam ◽

...

Keyword(s):

Community Structure ◽

Environmental Impacts ◽

Coastal Waters ◽

Phytoplankton Community ◽

Environmental Changes ◽

Diversity Indices ◽

Species Number ◽

Phytoplankton Community Structure ◽

Phytoplankton Diversity ◽

Phytoplankton Communities

Phytoplankton in coastal waters are important for the evaluation of either biodiversity or environmental impacts because of this highly vulnerable ecosystem. Seasonal and annual changes in the phytoplankton community structure in Quang Ngai waters during the period 2015 to 2019 were analyzed to assess the phytoplankton diversity and reveal possible causes of these changes. A total of 366 phytoplankton taxa belonging to 10 classes were identified throughout this present study. The highest species number was found in 2019 with 295 taxa, followed by those in 2015 (247), 2017 (185), and 2018 (99). The waters of Ly Son transect showed the highest diversity and most stable phytoplankton communities in both dry and rainy seasons, whereas the stations of Quang Ngai coast revealed high variability of the communities. All diversity indices including Margalef, Pielou, Shannon, Simpson did not reflect well differences in average values but a certain degree of variances, indicating possible environmental impacts. During the study time, there were blooms of certain diatom species including Skeletonema spp. in 2015 and Pseudo-nitzschia spp. in 2019. Analysis of a diatoms index, Centric/Pennate ratio, indicated that the waters were in eutrophic status with a decreasing trend from the coast area to Ly Son island in 2015 and 2019. This research built up fundamental data on phytoplankton communities for Quang Ngai province. The Centric/Pennate diatom index and diversity would be used as indicators for environmental changes and their values provided warning of eutrophication in this coastal waters including the water surrounding Ly Son island.

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Timing of sea ice retreat can alter phytoplankton community structure in the western Arctic Ocean

Biogeosciences Discussions ◽

10.5194/bgd-10-15153-2013 ◽

2013 ◽

Vol 10 (9) ◽

pp. 15153-15180 ◽

Cited By ~ 1

Author(s):

A. Fujiwara ◽

T. Hirawake ◽

K. Suzuki ◽

I. Imai ◽

S.-I. Saitoh

Keyword(s):

Community Structure ◽

Sea Ice ◽

Arctic Ocean ◽

Phytoplankton Community ◽

Phytoplankton Community Structure ◽

Western Arctic Ocean ◽

Phytoplankton Communities ◽

Ice Retreat ◽

Western Arctic ◽

Sea Ice Retreat

Abstract. This study assesses the response of phytoplankton assemblages to recent climate change, especially with regard to the shrinking of sea ice in the northern Chukchi Sea of the western Arctic Ocean. Distribution patterns of phytoplankton groups in the late summers of 2008–2010 were analyzed based on HPLC pigment signatures and, the following four major algal groups were inferred via multiple regression and cluster analyses: prasinophytes, diatoms, haptophytes and dinoflagellates. A remarkable interannual difference in the distribution pattern of the groups was found in the northern basin area. Haptophytes dominated and dispersed widely in warm surface waters in 2008, whereas prasinophytes dominated in cold water in 2009 and 2010. A difference in the onset date of sea ice retreat was evident among years – the sea ice retreat in 2008 was 1–2 months earlier than in 2009 and 2010. The spatial distribution of early sea ice retreat matched the areas in which a shift in algal community composition was observed. Steel-Dwass's multiple comparison tests were used to assess the physical, chemical and biological parameters of the four clusters. We found a statistically significant difference in temperature between the haptophyte-dominated cluster and the other clusters, suggesting that the change in the phytoplankton communities was related to the earlier sea ice retreat in 2008 and the corollary increase in sea surface temperatures. Longer periods of open water during the summer, which are expected in the future, may affect food webs and biogeochemical cycles in the western Arctic due to shifts in phytoplankton community structure.

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Temporal Distribution Patterns of Phytoplankton Community Structure in a Large Shallow Lake, Lake Taihu, China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.1363 ◽

2014 ◽

Vol 955-959 ◽

pp. 1363-1367 ◽

Cited By ~ 1

Author(s):

Rui Ye ◽

Xin Qian ◽

Kun Shan ◽

Hai Long Gao

Keyword(s):

Community Structure ◽

Shallow Lake ◽

Phytoplankton Community ◽

Lake Taihu ◽

Cyanobacterial Bloom ◽

Temporal Distribution ◽

Distribution Patterns ◽

Phytoplankton Community Structure ◽

Monthly Basis ◽

Phytoplankton Communities

Temporal distribution phytoplankton community structure in a shallow lake, Lake Taihu, China, was investigated from 2010 to 2011 on a monthly basis at 9 sampling stations. The results showed that phytoplankton communities primarily consist of cyanobacteria, chlorophyta and bacillariophyta in Lake Taihu. A significant change in phytoplankton community was observed in both years: cyanobacteria hold an overwhelming dominance in summer and autumn, chloraphyta and bacillariophyta occupied the certain proportion only when the cyanobacterial bloom was declined in winter and early spring. The maximum abundance value of cyanobacteria, chlorophyta and bacillariophyta appeared at June, 2010, July, 2011 and Feb, 2011, respectively. The present study is a continuation and complement in long-term research of Lake Taihu, which provides scientific foundation for further research of the lake.

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Phytoplankton community structure in the Lena Delta (Siberia, Russia) in relation to hydrography

Biogeosciences ◽

10.5194/bg-10-7263-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 7263-7277 ◽

Cited By ~ 11

Author(s):

A. C. Kraberg ◽

E. Druzhkova ◽

B. Heim ◽

M. J. G. Loeder ◽

K. H. Wiltshire

Keyword(s):

Climate Change ◽

Community Structure ◽

Phytoplankton Community ◽

The Arctic ◽

Laptev Sea ◽

Phytoplankton Community Structure ◽

Lena River ◽

Phytoplankton Communities ◽

The Laptev Sea ◽

Lena Delta

Abstract. The Lena Delta in Northern Siberia is one of the largest river deltas in the world. During peak discharge, after the ice melt in spring, it delivers between 60–8000 m3 s−1 of water and sediment into the Arctic Ocean. The Lena Delta and the Laptev Sea coast also constitute a continuous permafrost region. Ongoing climate change, which is particularly pronounced in the Arctic, is leading to increased rates of permafrost thaw. This has already profoundly altered the discharge rates of the Lena River. But the chemistry of the river waters which are discharged into the coastal Laptev Sea have also been hypothesized to undergo considerable compositional changes, e.g. by increasing concentrations of inorganic nutrients such as dissolved organic carbon (DOC) and methane. These physical and chemical changes will also affect the composition of the phytoplankton communities. However, before potential consequences of climate change for coastal arctic phytoplankton communities can be judged, the inherent status of the diversity and food web interactions within the delta have to be established. In 2010, as part of the AWI Lena Delta programme, the phyto- and microzooplankton community in three river channels of the delta (Trofimov, Bykov and Olenek) as well as four coastal transects were investigated to capture the typical river phytoplankton communities and the transitional zone of brackish/marine conditions. Most CTD profiles from 23 coastal stations showed very strong stratification. The only exception to this was a small, shallow and mixed area running from the outflow of Bykov channel in a northerly direction parallel to the shore. Of the five stations in this area, three had a salinity of close to zero. Two further stations had salinities of around 2 and 5 throughout the water column. In the remaining transects, on the other hand, salinities varied between 5 and 30 with depth. Phytoplankton counts from the outflow from the Lena were dominated by diatoms (Aulacoseira species) cyanobacteria (Aphanizomenon, Pseudanabaena) and chlorophytes. In contrast, in the stratified stations the plankton was mostly dominated by dinoflagellates, ciliates and nanoflagellates, with only an insignificant diatom component from the genera Chaetoceros and Thalassiosira (brackish as opposed to freshwater species). Ciliate abundance was significantly coupled with the abundance of total flagellates. A pronounced partitioning in the phytoplankton community was also discernible with depth, with a different community composition and abundance above and below the thermocline in the stratified sites. This work is a first analysis of the phytoplankton community structure in the region where Lena River discharge enters the Laptev Sea.

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Herbivory in variable environments: an experimental test of the effects of vertical mixing and Daphnia on phytoplankton community structure

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-080 ◽

2001 ◽

Vol 58 (7) ◽

pp. 1371-1379 ◽

Cited By ~ 9

Author(s):

Beatrix E Beisner

Keyword(s):

Community Structure ◽

Phytoplankton Community ◽

Size Structure ◽

Vertical Mixing ◽

Community Diversity ◽

Temporal Heterogeneity ◽

Phytoplankton Community Structure ◽

Phytoplankton Composition ◽

Encounter Rates ◽

Phytoplankton Communities

Phytoplankton communities in lakes are exposed to different within-season frequencies of heterogeneity in resource supply because of wind-induced vertical mixing. Effects of such heterogeneity, in conjunction with herbivory, on phytoplankton community structure have rarely been simultaneously examined, despite the fact that each factor can have large effects on phytoplankton composition and diversity. This study uses replicated oligotrophic mesocosms to examine the effects of herbivory and different scales of temporal heterogeneity in deepwater mixing. The pattern of vertical mixing alone had minor effects on phytoplankton community diversity and composition. The herbivore Daphnia caused a shift in phytoplankton composition to less edible types, based mainly on morphological features (spiny shapes and trichomes on cell walls) rather than size structure alone. Phytoplankton richness depended jointly on mixing frequency and large Daphnia biomasses. When systems were well mixed, with high encounter rates between predator and prey populations, phytoplankton community richness was lowest. By contrast, the systems that were least often mixed had highest richness. These results are related to limited encounter rates with infrequent mixing and to the availability of refuges from predation. Responses to different scales of temporal heterogeneity in these oligotrophic phytoplankton communities depend more on Daphnia feeding than on resource pulsing.

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