scholarly journals Phytoplankton Pigments Reveal Size Structure and Interannual Variability of the Coastal Phytoplankton Community (Adriatic Sea)

Water ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 23
Author(s):  
Vesna Flander-Putrle ◽  
Janja Francé ◽  
Patricija Mozetič
Keyword(s):  
Interannual Variability ◽  
Phytoplankton Biomass ◽  
Adriatic Sea ◽  
Size Structure ◽  
Seasonal Pattern ◽  
Bottom Layer ◽  
Trophic Relationships ◽  
Phytoplankton Pigments ◽  
Size Classes ◽  
Phytoplankton Communities

In coastal seas, a variety of environmental variables characterise the average annual pattern of the physico-chemical environment and influence the temporal and spatial variations of phytoplankton communities. The aim of this study was to track the annual and interannual variability of phytoplankton biomass in different size classes in the Gulf of Trieste (Adriatic Sea) using phytoplankton pigments. The seasonal pattern of phytoplankton size classes showed a co-dominance of the nano and micro fractions during the spring peak and a predominance of the latter during the autumn peak. The highest picoplankton values occurred during the periods with the lowest total phytoplankton biomass, with chlorophytes dominating during the colder months and cyanobacteria during the summer. The highest number of significant correlations was found between phytoplankton taxa and size classes and temperature, nitrate and nitrite. The most obvious trend observed over the time series was an increase in picoplankton in all water layers, with the most significant trend in the bottom layer. Nano- and microplankton showed greater variation in biomass, with a decrease in nanoplankton biomass in 2011 and 2012 and negative trend in microplankton biomass in the bottom layer. These results suggest that changes in trophic relationships in the pelagic food web may also have implications for biogeochemical processes in the coastal sea.

Differences between Nearshore and Offshore Phytoplankton Communities in Lake Ontario

1987 ◽  
Vol 44 (12) ◽  
pp. 2155-2163 ◽  
Author(s):  
I. M. Gray
Keyword(s):  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Algal Biomass ◽  
Phytoplankton Community ◽  
Seasonal Pattern ◽  
Principal Component ◽  
Lake Ontario ◽  
Dominant Group ◽  
Phytoplankton Communities ◽  
Eutrophic Species

Differences between nearshore and offshore phytoplankton biomass and composition were evident in Lake Ontario in 1982. Phytoplankton biomass was characterized by multiple peaks which ranged over three orders of magnitude. Perhaps as a consequence of the three times higher current velocities at the northshore station, phytoplankton biomass ranged from 0.09 to 9.00 g∙m−3 compared with 0.10 to 2.40 g∙m−3 for the midlake station. Bacillariophyceae was the dominant group at the northshore station until September when Cyanophyta contributed most to the biomass (83%). Although Bacillariophyceae was the principal component of the spring phytoplankton community at the midlake station, phytoflagellates (49%) and Chlorophyceae (25%) were responsible for summer biomass, with the Chlorophyceae expanding to 80% in the fall. The seasonal pattern of epilimnetic chlorophyll a correlated with temperature. While chlorophyll a concentrations were similar to values from 1970 and 1972, algal biomass had declined and a number of eutrophic species (Melosira binderana, Stephanodiscus tenuis, S. hantzschii var. pusilla, and S. alpinus) previously found were absent in 1982.

scholarly journals Spatial and seasonal variability of fractionated phytoplankton biomass and primary production in the frontal region of the Northern Adriatic Sea

2005 ◽  
Vol 6 (1) ◽  
pp. 5 ◽  
Author(s):  
M.R. VADRUCCI ◽  
G. CATALANO ◽  
A. BASSET
Keyword(s):  
Primary Production ◽  
Phytoplankton Biomass ◽  
Adriatic Sea ◽  
Size Structure ◽  
Nutrient Concentrations ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Frontal System ◽  
Dissolved Phosphorus ◽  
Point Total

Spatial and seasonal patterns of variation of fractionated phytoplankton biomass and primary production and their relationships with nutrient concentrations were analyzed along an inshore - offshore gradient and in relation to the presence of a frontal system in the Northern Adriatic Sea. Sampling was carried out in winter and summer during four oceanographic cruises (June 1996 and 1997, February 1997 and 1998) as part of the PRISMA II project. Water samples for determining nutrient concentrations, phytoplankton biomass (as Chla) and primary production (as 14 C assimilation) were collected at five optical depths. Sampling stations were located along 2 or 4 parallel transects arranged perpendicularly to the shoreline and the frontal system. The transects were located at such a distance from the coast that the frontal system crossed them at their halfway point. Total dissolved nitrogen (TDN) and total dissolved phosphorus concentrations (TDP) were 12.41 ± 3 .95 mM and 0.146 ± 0 .070 mM, respectively. The values in the two seasonal periods were similar, decreasing along the inshore-offshore gradient. Values for phytoplankton biomass and primary productionwere higher in the winter than the summer cruises, and decreased, in both seasonal periods, along the inshore / offshore gradient. Moreover, in both seasonal periods, picophytoplankton dominated both biomass and productivity, (56% and 44%, respectively) at stations beyond the frontal system, while microphytoplankton was more important at stations inside it (44% and 44%, respectively). Total phytoplankton biomass and primary production were directly related to nutrient concentrations. Regarding size classes, significant patterns of variation with nutrients were observed particularly for biomass. The results indicate that the size structure and function of phytoplankton guilds seem to be mediated by nutrient inflow, as well as by competitive interaction among size fractions.

scholarly journals Scyphomedusae and Ctenophora of the Eastern Adriatic: Historical Overview and New Data

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 186
Author(s):  
Branka Pestorić ◽  
Davor Lučić ◽  
Natalia Bojanić ◽  
Martin Vodopivec ◽  
Tjaša Kogovšek ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Seasonal Pattern ◽  
Geographical Location ◽  
Distribution Patterns ◽  
Mnemiopsis Leidyi ◽  
Future Studies ◽  
Phenological Data ◽  
Pelagia Noctiluca ◽  
Regional Trends ◽  
Clear Seasonal Pattern

One of the obstacles to detecting regional trends in jellyfish populations is the lack of a defined baseline. In the Adriatic Sea, the jellyfish fauna (Scyphozoa and Ctenophora) is poorly studied compared to other taxa. Therefore, our goal was to collect and systematize all available data and provide a baseline for future studies. Here we present phenological data and relative abundances of jellyfish based on 2010–2019 scientific surveys and a “citizen science” sighting program along the eastern Adriatic. Inter-annual variability, seasonality and spatial distribution patterns of Scyphomedusae and Ctenophore species were described and compared with existing historical literature. Mass occurrences with a clear seasonal pattern and related to the geographical location were observed for meroplanktonic Scyphomedusae Aurelia solida, Rhizostoma pulmo, and to a lesser extent Chrysaora hysoscella, Cotylorhiza tuberculata and Discomedusa lobata. Holoplanktonic Pelagia noctiluca also formed large aggregations, which were seasonally less predictable and restricted to the central and southern Adriatic. Four species of Ctenophora produced blooms limited to a few areas: Bolinopsis vitrea, Leucothea multicornis, Cestum veneris and the non-native Mnemiopsis leidyi. However, differences between Adriatic subregions have become less pronounced since 2014. Our results suggest that gelatinous organisms are assuming an increasingly important role in the Adriatic ecosystem, which may alter the balance of the food web and lead to harmful and undesirable effects.

Implementation of Self-Organizing Maps (SOM) to analyses of environmental parameters and phytoplankton biomass in a macrotidal estuary and artificial lake

2012 ◽  
Vol 93 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Roksana Jahan ◽  
Hyu Chang Choi ◽  
Young Seuk Park ◽  
Young Cheol Park ◽  
Ji Ho Seo ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Algal Blooms ◽  
Suspended Solids ◽  
Inorganic Nitrogen ◽  
Environmental Parameters ◽  
Ecological Data ◽  
Self Organizing Maps ◽  
Macrotidal Estuary ◽  
Phytoplankton Communities ◽  
Self Organizing

Self-Organizing Maps (SOM) have been used for patterning and visualizing ten environmental parameters and phytoplankton biomass in a mactrotidal (>10 m) Gyeonggi Bay and artificial Shihwa Lake during 1986–2004. SOM segregated study areas into four groups and ten subgroups. Two strikingly alternative states are frequently observed: the first is a diverse non-eutrophic state designated by three groups (SOM 1–3), and the second is a eutrophic state (SOM 4: Shihwa Lake and Upper Gyeonggi Bay; summer season) characterized by enhanced nutrients (3 mg l−1 dissolved inorganic nitrogen, 0.1 mg l−1 PO4) that act as a signal and response to that signal as algal blooms (24 µg chlorophyll-a l−1). Bloom potential in response to nitrification is affiliated with high temperature (r = 0.26), low salinity (r = −0.40) and suspended solids (r = –0.27). Moreover, strong stratification in the Shihwa Lake has accelerated harmful algal blooms and hypoxia. The non-eutrophic states (SOM 1–3) are characterized by macro-tidal estuaries exhibiting a tolerance to pollution with nitrogen-containing nutrients and retarding any tendency toward stratification. SOM 1 (winter) is more distinct from SOM 4 due to higher suspended solids (>50 mg l−1) caused by resuspension that induces light limitation and low chlorophyll-a (<5 µg l−1). In addition, eutrophication-induced shifts in phytoplankton communities are noticed during all the seasons in Gyeonggi Bay. Overall, SOM showed high performance for visualization and abstraction of ecological data and could serve as an efficient ecological map that can specify blooming regions and provide a comprehensive view on the eutrophication process in a macrotidal estuary.

Size structure of phytoplankton biomass and photosynthesis in subtropical Hawaiian waters

1983 ◽  
Vol 76 (2) ◽  
pp. 203-211 ◽  
Author(s):  
M. Takahashi ◽  
P. K. Bienfang
Keyword(s):  
Phytoplankton Biomass ◽  
Size Structure

scholarly journals SIZE STRUCTURE OF PHYTOPOPULATIONS AND ITS QUANTITATIVE EVALUATION

2016 ◽  
Vol 1 ◽  
pp. 9-15
Author(s):  
Victoria Skliar ◽  
Maryna Sherstuk
Keyword(s):  
Pinus Sylvestris ◽  
Quantitative Evaluation ◽  
Size Structure ◽  
Size Classes ◽  
Ledum Palustre ◽  
Forest Phytocenoses ◽  
Index Index ◽  
High Level ◽  
Original Approach

There was elucidated the original approach to the evaluation of phytopopulation size structure. For its characteristics it was offered to use the special index - index diversity of size structure (ІDSS). There are presented methods and algorithm of its determination. There was demonstrated that index diversity of size structure can be used at populational studies of species that belong to the different living forms. Especially phanerophytes (Pinus sylvestris) and hamephytes (Ledum palustre). As to Pinus sylvestris and Ledum palustre with help of index diversity of size structure was objectively proved that its cohorts and ontogenetic groups that growth in composition of forest phytocenoses typical for Ukrainian Polissya are not characterized with high level diversity of size structure. The value of index diversity of size structure is mainly less than 20 %. In phytopopulation the specific and phytocenotic peculiarity is demonstrated by diversity of size structure and also by representation of plants of certain size classes.

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