General features of phytoplankton communities and primary production in the Gulf of Naples and adjacent waters

1984 ◽  
pp. 89-100 ◽  
Author(s):  
D. Marino ◽  
M. Modigh ◽  
A. Zingone
Keyword(s):  
Primary Production ◽  
Gulf Of Naples ◽  
Phytoplankton Communities

scholarly journals Seasonal dynamics influencing coastal primary production and phytoplankton communities along the southern Myanmar coast

2017 ◽  
Vol 73 (3) ◽  
pp. 345-364 ◽  
Author(s):  
Maung-Saw-Htoo-Thaw ◽  
Shizuka Ohara ◽  
Kazumi Matsuoka ◽  
Tatsuya Yurimoto ◽  
Shota Higo ◽  
...  
Keyword(s):  
Primary Production ◽  
Seasonal Dynamics ◽  
Phytoplankton Communities

scholarly journals Declining silica availability – a challenge in the North Atlantic region?

2020 ◽  
Author(s):  
Kriste Makareviciute-Fichtner ◽  
Birte Matthiessen ◽  
Heike K. Lotze ◽  
Ulrich Sommer
Keyword(s):  
Primary Production ◽  
Food Webs ◽  
Silicic Acid ◽  
North Atlantic ◽  
North Atlantic Region ◽  
Atlantic Region ◽  
The North ◽  
Phytoplankton Communities ◽  
Limiting Nutrient ◽  
The North Atlantic

<p>Understanding how changes in limiting nutrient availability affect life in the oceans requires interdisciplinary efforts. Here we illustrate this with an example of silicon, one of the most common elements on land which bioavailable form, silicic acid (Si(OH)<sub>4</sub>), is a limiting nutrient for silicifying primary producers, such as diatoms.</p><p> Silicic acid concentrations in the pelagic polar and subpolar North Atlantic have declined by 1-2 μM during spring pre-bloom conditions over the past 25 years. Many coastal areas of the North Atlantic region also face decreased relative availability of silicon due to increased riverine supply of nitrogen and phosphorus and stable or declining loads of silicon. Both declining silicic acid concentrations and declining silicon to nitrogen (Si:N) ratios limit the growth of diatoms, which are major primary producers contributing up to a quarter of global primary production.</p><p>To assess the effects of declining silicon availability on phytoplankton communities we conducted a mesocosm experiment manipulating Si:N ratios and copepod grazing pressure on phytoplankton communities from the Baltic Sea. Declining Si:N ratio affected not only diatom abundance and relative biomass but also their species composition and overall plankton diversity. Our results illustrate the importance of silicon in structuring community composition at the base of temperate marine food webs. Changes in silicic acid concentrations and Si:N ratios, therefore, may have far-reaching consequences on oceanic primary production and planktonic food webs.</p><p>The decline in silicon concentrations in polar and subpolar North Atlantic waters is attributed to natural multi-decadal variability but is likely amplified by reduced ocean mixing due to increased water temperatures, illustrating the need of international efforts to curb global climate change. The decline in Si:N ratios in coastal oceans also highlights the need for further reduction of nutrient pollution and improved river basin management. This may require interdisciplinary and international approaches to manage anthropogenic perturbations of the silicon cycle.</p>

scholarly journals Hippos (Hippopotamus amphibius): The animal silicon pump

2019 ◽  
Vol 5 (5) ◽  
pp. eaav0395 ◽  
Author(s):  
Jonas Schoelynck ◽  
Amanda L. Subalusky ◽  
Eric Struyf ◽  
Christopher L. Dutton ◽  
Dácil Unzué-Belmonte ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Primary Production ◽  
Detailed Analysis ◽  
River Sediment ◽  
Savannah River ◽  
River Continuum ◽  
Lake Ecosystems ◽  
Phytoplankton Communities ◽  
Hippopotamus Amphibius ◽  
Dissolution And Precipitation

While the importance of grasslands in terrestrial silicon (Si) cycling and fluxes to rivers is established, the influence of large grazers has not been considered. Here, we show that hippopotamuses are key actors in the savannah biogeochemical Si cycle. Through a detailed analysis of Si concentrations and stable isotope compositions in multiple ecosystem compartments of a savannah-river continuum, we constrain the processes influencing the Si flux. Hippos transport 0.4 metric tons of Si day−1 by foraging grass on land and directly egesting in the water. As such, they bypass complex retention processes in secondary soil Si pools. By balancing internal processes of dissolution and precipitation in the river sediment, we calculate that hippos affect up to 76% of the total Si flux. This can have a large impact on downstream lake ecosystems, where Si availability directly affects primary production in the diatom-dominated phytoplankton communities.

scholarly journals Phytoplankton dynamics in contrasting early stage North Atlantic spring blooms: composition, succession, and potential drivers

2015 ◽  
Vol 12 (8) ◽  
pp. 2395-2409 ◽  
Author(s):  
C. J. Daniels ◽  
A. J. Poulton ◽  
M. Esposito ◽  
M. L. Paulsen ◽  
R. Bellerby ◽  
...  
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
North Atlantic ◽  
Phytoplankton Community ◽  
Spring Bloom ◽  
Early Stage ◽  
Biological Factors ◽  
Phytoplankton Composition ◽  
Bloom Formation ◽  
Phytoplankton Communities

Abstract. The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little consensus as to the main drivers of spring bloom formation, exacerbated by a lack of in situ observations of the phytoplankton community composition and its evolution during this critical period. We investigated the dynamics of the phytoplankton community structure at two contrasting sites in the Iceland and Norwegian basins during the early stage (25 March–25 April) of the 2012 North Atlantic spring bloom. The plankton composition and characteristics of the initial stages of the bloom were markedly different between the two basins. The Iceland Basin (ICB) appeared well mixed down to >400 m, yet surface chlorophyll a (0.27–2.2 mg m−3) and primary production (0.06–0.66 mmol C m−3 d−1) were elevated in the upper 100 m. Although the Norwegian Basin (NWB) had a persistently shallower mixed layer (<100 m), chlorophyll a (0.58–0.93 mg m−3) and primary production (0.08–0.15 mmol C m−3 d−1) remained lower than in the ICB, with picoplankton (<2 μm) dominating chlorophyll a biomass. The ICB phytoplankton composition appeared primarily driven by the physicochemical environment, with periodic events of increased mixing restricting further increases in biomass. In contrast, the NWB phytoplankton community was potentially limited by physicochemical and/or biological factors such as grazing. Diatoms dominated the ICB, with the genus Chaetoceros (1–166 cells mL−1) being succeeded by Pseudo-nitzschia (0.2–210 cells mL−1). However, large diatoms (>10 μm) were virtually absent (<0.5 cells mL−1) from the NWB, with only small nano-sized (<5 μm) diatoms (i.e. Minidiscus spp.) present (101–600 cells mL−1). We suggest microzooplankton grazing, potentially coupled with the lack of a seed population of bloom-forming diatoms, was restricting diatom growth in the NWB, and that large diatoms may be absent in NWB spring blooms. Despite both phytoplankton communities being in the early stages of bloom formation, different physicochemical and biological factors controlled bloom formation at the two sites. If these differences in phytoplankton composition persist, the subsequent spring blooms are likely to be significantly different in terms of biogeochemistry and trophic interactions throughout the growth season, with important implications for carbon cycling and organic matter export.

scholarly journals High CO2 Under Nutrient Fertilization Increases Primary Production and Biomass in Subtropical Phytoplankton Communities: A Mesocosm Approach

2018 ◽  
Vol 5 ◽  
Author(s):  
Nauzet Hernández-Hernández ◽  
Lennart T. Bach ◽  
María F. Montero ◽  
Jan Taucher ◽  
Isabel Baños ◽  
...  
Keyword(s):  
Primary Production ◽  
High Co2 ◽  
Phytoplankton Communities ◽  
Nutrient Fertilization

scholarly journals Phytoplankton distribution in the Western Arctic Ocean during a summer of exceptional ice retreat

2011 ◽  
Vol 8 (4) ◽  
pp. 6919-6970 ◽  
Author(s):  
P. Coupel ◽  
H. Y. Jin ◽  
D. Ruiz-Pino ◽  
J. F. Chen ◽  
S. H. Lee ◽  
...  
Keyword(s):  
Primary Production ◽  
Ice Melting ◽  
Phytoplankton Distribution ◽  
Pacific Waters ◽  
Phytoplankton Communities ◽  
Ice Retreat ◽  
Western Arctic ◽  
Canadian Basin ◽  
Chukchi Borderland ◽  
Chukchi Shelf

Abstract. A drastic ice decline in the Arctic Ocean, triggered by global warming, could generate rapid changes in the upper ocean layers. The ice retreat is particularly intense over the Canadian Basin where large ice free areas were observed since 2007. The CHINARE 2008 expedition was conducted in the Western Arctic (WA) ocean during a year of exceptional ice retreat (August–September 2008). This study investigates whether a significant reorganization of the primary producers in terms of species, biomass and productivity has to be observed in the WA as a result of the intense ice melting. Both pigments (HPLC) and taxonomy (microscopy) acquired in 2008 allowed to determine the phytoplanktonic distribution from Bering Strait (65° N) to extreme high latitudes over the Alpha Ridge (86° N) encompassing the Chukchi shelf, the Chukchi Borderland and the Canadian Basin. Two different types of phytoplankton communities were observed. Over the ice-free Chukchi shelf, relatively high chl-a concentrations (1–5 mg m−3) dominated by 80 % of diatoms. In the Canadian Basin, surface waters are oligotrophic (<0.1 mg m−3) and algal assemblages were dominated by haptophytes and diatoms while higher biomasses (~0.4 mg m−3) related to a deep Subsurface Chlorophyll Maximum (SCM) are associated to small-sized (nano and pico) phytoplankton. The ice melting onset allows to point out three different zones over the open basin: (i) the ice free condition characterized by deep and unproductive phytoplankton communities dominated by nanoplankton, (ii) an extended (78°–83° N) Active Melting Zone (AMZ) where light penetration associated to the stratification start off and enough nutrient availability drives to the highest biomass and primary production due to both diatoms and large flagellates, (iii) heavy ice conditions found north to 83° N allowing light limitation and consequently low biomass and primary production associated to pico and nanoplankton. To explain the poverty (Canadian Basin) and the richness (Chukchi shelf) of the WA, we explore the role of the nutrient-rich Pacific Waters, the bathymetry and two characteristics linked to the intense ice retreat: the stratification and the Surface Freshwater Layer (SFL). The freshwater accumulation induced a strong stratification limiting the nutrient input from the subsurface Pacific waters. This results in a biomass impoverishment of the well-lit layer and compels the phytoplankton to grow in subsurface. The phytoplankton distribution in the Chukchi Borderland and north Canadian Basin, during the summer of exceptional ice retreat (2008), suggested when compared to in-situ data from a more ice covered year (1994), recent changes with a decrease of the phytoplankton abundance while averaged biomass was similar. The 2008 obtained phytoplankton data in the WA provided a state of the ecosystem which will be useful to determine both past and future changes in relation with predicted sea ice decline.

Structure of the phytoplankton communities and primary production in the Ob River estuary and over the adjacent Kara Sea shelf

Oceanology ◽  
2010 ◽  
Vol 50 (5) ◽  
pp. 743-758 ◽  
Author(s):  
I. N. Sukhanova ◽  
M. V. Flint ◽  
S. A. Mosharov ◽  
V. M. Sergeeva
Keyword(s):  
Primary Production ◽  
River Estuary ◽  
Kara Sea ◽  
Ob River ◽  
Phytoplankton Communities

scholarly journals Phytoplankton dynamics in contrasting early stage North Atlantic spring blooms: composition, succession, and potential drivers

2015 ◽  
Vol 12 (1) ◽  
pp. 93-133 ◽  
Author(s):  
C. J. Daniels ◽  
A. J. Poulton ◽  
M. Esposito ◽  
M. L. Paulsen ◽  
R. Bellerby ◽  
...  
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
North Atlantic ◽  
Phytoplankton Community ◽  
Spring Bloom ◽  
Early Stage ◽  
Biological Factors ◽  
Phytoplankton Composition ◽  
Bloom Formation ◽  
Phytoplankton Communities

Abstract. The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little consensus as to the main drivers of spring bloom formation, exacerbated by a lack of in situ observations of the phytoplankton community composition and its evolution during this critical period. We investigated the dynamics of the phytoplankton community structure at two contrasting sites in the Iceland and Norwegian Basins during the early stage (25 March–25 April) of the 2012 North Atlantic spring bloom. The plankton composition and characteristics of the initial stages of the bloom were markedly different between the two basins. The Iceland Basin (ICB) appeared well mixed to > 400 m, yet surface chlorophyll a (0.27–2.2 mg m–3) and primary production (0.06–0.66 mmol C m–3 d–1) were elevated in the upper 100 m. Although the Norwegian Basin (NWB) had a persistently shallower mixed layer (< 100 m), chlorophyll a (0.58–0.93 mg m–3) and primary production (0.08–0.15 mmol C m–3 d–1) remained lower than in the ICB, with picoplankton (> 2 μm) dominating chlorophyll a biomass. The ICB phytoplankton composition appeared primarily driven by the physicochemical environment, with periodic events of increased mixing restricting further increases in biomass. In contrast, the NWB phytoplankton community was potentially limited by physicochemical and/or biological factors such as grazing. Diatoms dominated the ICB, with the genus Chaetoceros (1–166 cells mL–1) being succeeded by Pseudo-nitzschia (0.2–210 cells mL–1). However, large diatoms (> 10 μm) were virtually absent (< 0.5 cells mL–1) from the NWB, with only small nanno-sized (< 5 μm) diatoms present (101–600 cells mL–1). We suggest micro-zooplankton grazing, potentially coupled with the lack of a seed population of bloom forming diatoms, was restricting diatom growth in the NWB, and that large diatoms may be absent in NWB spring blooms. Despite both phytoplankton communities being in the early stages of bloom formation, different physicochemical and biological factors controlled bloom formation at the two sites. If these differences in phytoplankton composition persist, the subsequent spring blooms are likely to be significantly different in terms of biogeochemistry and trophic interactions throughout the growth season, with important implications for carbon cycling and organic matter export.

Spatial variability of photophysiology and primary production rates of the phytoplankton communities across the western Antarctic Peninsula in late summer 2013

2018 ◽  
Vol 149 ◽  
pp. 99-110 ◽  
Author(s):  
Arnaldo D.’Amaral Pereira Granja Russo ◽  
Márcio Silva de Souza ◽  
Carlos Rafael Borges Mendes ◽  
Virginia Maria Tavano ◽  
Carlos Alberto Eiras Garcia
Keyword(s):  
Spatial Variability ◽  
Primary Production ◽  
Antarctic Peninsula ◽  
Late Summer ◽  
Western Antarctic Peninsula ◽  
Production Rates ◽  
Phytoplankton Communities
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