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EN
The present study focused on understanding the seasonality of the phytoplankton biomass (chlorophyll a) distribution in the oligotrophic, Equatorial, and Southern Tropical Indian Ocean (ESTIO; 0–30°S and 60–90°E). The long-term satellite data analyses (2003–2020) showed a strong seasonality in sea surface temperature (SST), wind, currents, mean sea level anomaly (MSLA), photosynthetically available radiation (PAR), euphotic depth (ZEU) and mixed layer depth (MLD). As a response to the hydrographical changes, the phytoplankton biomass showed noticeable seasonal variation with the highest biomass during the Austral Winter (AW; June–September; avg. 0.11 ± 0.03 mg/m³) and lowest during the Austral Summer (AS; November–February; avg. 0.07 ± 0.03 mg/m). High chlorophyll patches (>0.1 mg/m³) were found between 0°–8°S during the AS and expanded over 0°–18°S during the AW. As multi-year mean chlorophyll a was higher (>0.1 mg/m³) in the northern part of the ESTIO (north of ∼13°S; HCD: high chlorophyll a domain) than the southern side (LCD: low chlorophyll a domain), the study area was divided into two domains and all the variables were analysed. In the HCD, enhancement of chlorophyll a was positively correlated with variables such as wind speed, wind stress, Ekman pumping, stronger northward and westward winds, as well as the presence of cyclonic eddies. These features are likely to stimulate primary production by uplifting the thermocline and enhancing nutrient supply. In the LCD, mixed layer depth also showed a strong positive correlation with elevated chlorophyll a, apparently because it is deep throughout the year (thereby keeping lower biomass) and deepens more strongly in winter than in the HCD. Another contrast with the HCD is that the cyclonic eddies appear to be insufficiently abundant to influence its chlorophyll a. Pearson's multivariable correlation analysis and principle component analysis confirmed the statistical significance of the above parameters on the enhancement of chlorophyll a in the ESTIO.
EN
In order to investigate temporal variations in phytoplankton connected with hydrography, high-resolution (twice a week) samplings were carried out between January and December 2018 at a single, shallow water station in the Dardanelles. Diatoms dominated in early and mid-winter, late spring and early summer, and between August and October. Whereas dinoflagellates dominated in the period from mid-February to the end of the third week of May, mid-summer, and late autumn. Other groups were generally more abundant in the early summer and mid-autumn than any other period. Late spring and early summer, mid-autumn and middle winter were the important bloom periods. The average contribution of diatom abundance (5.00 × 105±7.80 × 105 cells L−1) to average total phytoplankton abundance (9.63 × 105±7.88 × 105 cells L−1) was above 50% (average: 51.88%) during the year except spring (34.32%). However, the average contribution of dinoflagellates (43.32±20.69%) and others (4.81±6.99%) to the total phytoplankton abundance were lower than the abundance of the diatoms (51.88±21.61%). The study revealed a decrease both in the total number of algal blooms which also included HABs and their densities in the region compared to the previous findings. These observations seem to evidence environmental status improvement of the investigated area, manifested in an average chlorophyll a concentration (0.71±0.52 µg L−1) and quantitative phytoplankton structure (103 to 105 cells L−1).
EN
The present study investigated the phytoplankton assemblage and diversity with physicochemical parameters of Diu coastal waters in different seasons during 2018–19. During the study period, 61 phytoplankton species comprising diatoms (50 sp.), dinoflagellates (8 sp.), and cyanophyceae (3 sp.) were recorded. Diatom was found to be a major community and contributed 79 to 99% of total phytoplankton abundance. Reduction in dinoflagellate and dominance of pennate-diatoms were observed during the monsoon. Chlorophyll-a concentration also showed a similar trend and decreased during the monsoon. However, the phytoplankton abundance was low particularly during the monsoon which might be due to the elevated total suspended solids (TSS) load. Canonical correspondence analysis revealed that diatoms were able to survive in high TSS with the support of high nutrients; while dinoflagellates were limited due to those conditions. Overall, the reduction in phytoplankton abundance, diversity, and biomass was recorded due to the elevated TSS input along the coastal waters of Diu.
EN
Phytoplankton composition, abundance and carbon biomass were investigated at monthly intervals during 2006–2007 at a coastal site, “Acqua Alta” an oceanographic tower, in the northern Adriatic Sea. Results were compared with chlorophyll a concentrations of phytoplankton classes attributed by HPLC-CHEMTAX analysis. Changes in the taxonomic structure were associated with environmental parameters. The total carbon biomass of phytoplankton was positively correlated with the temperature and negatively correlated with silicate concentrations. Nutrient concentrations were higher in the winter–spring period than in the summer-autumn period. The highest carbon biomass and abundance of phytoplankton were observed during summer–autumn months. Diatoms were the group that had the highest contribution to the total carbon biomass during the sampling period. Small flagellates, which were the major contributors to the total cell counts were dominant during the summer period. There was a significant correlation between carbon biomass and CHEMTAX-derived Chl a values of diatoms and dinoflagellates. However, the total carbon biomass of phytoplankton was not correlated with Chl a, which seemed to be related to seasonal changes in the ratios of C:Chl a of all taxonomic classes. This ratio was higher during the summer-autumn period (73 ± 33) than during the winter–spring period (17 ± 20).
EN
This study delineates the role of small and medium river inputs, Low Saline Plume Advection (LSPA) and eddies in hydrography alteration and Chlorophyll a (Chl. a) in the Western Bay of Bengal. Samples were collected across five transects viz: Hooghly (HO), Mahanadi (MN), Rushikulya (RK), Visakhapatnam (VSKP) and Godavari (GD) during Fall Intermonsoon. Each transect consists of 7 or 8 locations from inshore to offshore. LSPA propagates southward concordance with the East India Coastal Current (EICC) and its southward flow strengthened by a cold-core eddy. LSPA results in the intermittent low salinity in the cross-shore section of HO, MN and RK. Upper layer Chl. a is 2-3 folds higher in inshore and in LSP-influenced locations than in its adjacent stations. The present study identified Double Chlorophyll a Maxima (DoCM) in LSPA-influenced slope regions of MN and RK. DoCM is less known in the BoB. DoCM has both the Surface Chl. a Maxima (SCM) and Subsurface Chl. a Maxima (SSCM). SSCM layer is relatively shallow and intense in slope and offshore regions of MN and RK due to their closeness with cold-core eddy. The present study highlights that freshwater discharge from small and medium rivers impacts hydrobiology around 10-50 km from the shore depends on the magnitude of river influx. LSPA is away from the local inputs and impacts hydrobiology (>500 km) along the path. EICC and eddies together regulated the direction of LSPA. Existing eddies nature alters vertical hydrobiology in slope and offshore regions.
EN
The response of phytoplankton community to the co-existing events of coastal upwelling and mud banks in the nearshore waters of Alappuzha (15 m depth), located in the southwest coast of India from April to November 2016, is described based on size-fractionated phytoplankton biomass (chlorophyll a), primary production and community composition. The study region exhibited well-distinct spatio-temporal hydrological changes because of the influence of wind-driven coastal upwelling, prevalent during the southwest monsoon (SWM) period. However, the formation of mud banks, in addition to coastal upwelling, was observed at station M2, which facilitated the substantial increase of water column turbidity and inorganic nutrients (ammonium, phosphate, and silicate) during and after the peak SWM period compared to the non-mud bank reference stations (M1 and M3). The prevailing hydrological changes were complemented the corresponding phytoplankton productivity patterns, in which profound domination of nanophytoplankton (2-20 µm) chlorophyll a and primary production was observed throughout the study region, irrespective of seasons. The SIMPER analysis, based on phytoplankton (mostly >20 µm) species composition data (microscopy), revealed the formation of certain characterizing species, mainly comprised of diatoms and dinoflagellates. The consistent predominance of the nanophytoplankton, established under variable hydrological scenarios, showed that the inorganic nutrient (specifically ammonium) availability was instrumental in defining the widespread growth of nanophytoplankton community compared to the prevailing light levels. The present study thus revealed that even the small-sized phytoplankton community could survive in the nutrient-enriched coastal waters, characterised by the co-existing upwelling and mud banks.
EN
This study investigates the concentration of chlorophyll-a (chl-a) using the data of field observation and MODISAqua imagery. The field observation data were retrieved by using a conventional method and processed using spectrometric analysis. This study covers the coastal and near land areas which have different levels of anthropogenic activity. The results showed that the coastal waters of Semarang with a high level of anthropogenic activity persistently show a concentration of chlorophyll a (chl-a) twice as large as Jepara coastal waters. This comparison value is obtained based on imagery and field data. Meanwhile, the ratio of chl-a field data in each region shows a value of ±5 times greater than the MODIS data. Field observation data shows a higher value than the MODISAqua imagery data. The use of imagery data can be employed as a method of monitoring the eutrophication process on the coast. On the basis of the chlorophyll a classification and field observations, the coastal water of Semarang are classified as eutropic waters and Jepara is categorized as mesotropic category. The classification results will be different if monitoring is carried out using the image data with a location far from the mainland, the Semarang waters are included in the mesotropic category (> 2 mg•m-3) and Jepara is included in the oligotropic water category (< 2 mg•m-3).
EN
Pelargonium graveolens belongs to Geraniaceae family. It is an aromatic and hairy herbaceous shrub that can reach up to 1.2 m height and a spread of 1 m. Its leaves are deeply incised, soft to the touch and strongly scented, while flowers are small and usually pink. P. graveolens is native to South Africa, but it is now widely cultivated in many countries, e.g. Reunion Island, Egypt, Russia, China, and Morocco, mainly for the production of essential oil. It is used in many different industries, e.g. perfumery, cosmetic, food and beverages industry as well as in veterinary drugs and medicine. Literature data shows that chloroplasts content in leaves reflects a whole plant condition, as they are able to produce chemical energy from the solar energy. Most important of all pigments are chlorophylls that can be found in almost every green part of a plant. However, during plant senescence, photosynthetic pigments are degraded. This research was carried out to determine a chlorophyll a, chlorophyll b and also total chlorophylls content in Pelargonium graveolens at different age: one year old, two years old and three years old plants. To prepare samples, fresh leaves from each cultivation have been harvested, than homogenized in a chilled mortar with organic solvent 80% (v/v) acetone and then centrifuged. The absorbance of supernatants was immediately measured at 647 and 663 nm in a spectrophotometer. The outcome shows that in a first stage (first year) of plant growth, when it absorbs nutrients and synthesizes proteins to achieve efficient photosynthesis and undergo rapid expansion, chlorophyll a and b content is the lowest from all studied plants. The best quality pelargoniums are these at the age of two in which there is the biggest amount of green photosynthetic pigments.
PL
Pelargonium graveolens należy do rodziny Geraniaceae. Roślina ta jest aromatycznym, owłosionym krzewem, sięgającym 1,2 metra wysokości i osiągającym 1 m szerokości. Jej liście są mocno powcinane, miękkie w dotyku i wydzielają intensywny zapach, natomiast kwiaty są małe, zwykle różowe, zebrane w baldachy. Ojczyzną P. graveolens jest Afryka Południowa, ale uprawia się ją obecnie w wielu krajach świata, np. wyspie Reunion, Egipcie, Rosji, Chinach czy Maroko, głównie z przeznaczeniem na produkcję olejku eterycznego. Wykorzystywany jest on w wielu gałęziach przemysłu, m.in. perfumiarstwie, kosmetyce, przemyśle spożywczym czy medycynie. Dane literaturowe pokazują, że o kondycji całej rośliny świadczy zawartość chloroplastów w jej liściach, ponieważ te produkują niezbędną do wzrostu i rozwoju energię chemiczną z dostarczanej przez słońce energii cieplnej. To właśnie w chloroplastach znajdują się chlorofile, które są najważniejszymi pigmentami fotosyntetyzującymi. Jednakże podczas starzenia rośliny pigmenty te ulegają degradacji. Obecne badanie zostało przeprowadzone w celu ustalenia zawartości chlorofilu a i chlorofilu b w jedno-, dwu- i trzyletnich roślinach z gatunku Pelargonium graveolens. Zebrane zostały świeże liście z każdej ww. upraw, następnie zhomogenizowane w schłodzonym moździerzu w obecności 80% acetonu, a później odwirowane. Absorbancja uzyskanych supernatantów została niezwłocznie zmierzona w spektrofotometrze przy dł. fal 647 i 663 nm. Uzyskane dane pokazały, że w pierwszym stadium (pierwszym roku) wzrostu rośliny, kiedy pobiera ona składniki odżywcze i syntetyzuje białka, aby osiągnąć wydajną fotosyntezę i kiedy przechodzi gwałtowny rozwój, zawartość chlorofilu a i chlorofilu b była najmniejsza w porównaniu z pozostałymi roślinami. Najlepszą jakością wykazały się pelargonie dwuletnie, w których ilość chlorofilu była największa.
9
Content available remote Oznaczanie chlorofilu a w wodach ze zbiorników antropogenicznych
PL
Przedstawiono możliwość wykorzystania metody spektrofotometrycznej do monitorowania stężenia chlorofilu a w próbkach wód ze zbiorników antropogenicznych. Na podstawie wyników badań określono wartości podstawowych cech jakościowych i ilościowych zastosowanejmetody, takich jak: granica wykrywalności (0,366 mg/m3), granica oznaczalności (1 mg/m3), precyzja (CV<15% wyrażona jako wartość współczynnika zmienności) i poprawność (błąd względny <10% na podstawie wyników z badania biegłości Aquacheck).
EN
Spectrophotometric method was used for determination of chlorophyll a in waters from anthropogenic reservoir to establish the applicability limits of the method. The detection limit reached 0.366 mg/m3, the quantification limit is 1 mg/m3, the precision <15% and accuracy <10%.
EN
The laboratory experiments have been found that soaking seeds Galega orientalis L. (Fodder galega) in nanoaquacitrates solutions of Mn (10 and 20 mg/dm3), Mo (4 mg/dm3) and Mg (2 and 4 mg/dm3), has been lead to germination energy rise, while Mn (10 and 20 mg/dm3) and Mo (4 mg/dm3) concentrations has been influenced germinating ability. At the same time, the soaking seeds in solution of nanoaquacitrates Mn (20 mg/dm3) had the biggest stimulatory effect on the accumulation 7 daily sprouts mass (on 18%). It has been shown that soaking seeds in nanoparticles Mn and Mo solutions leads to the increase of catalase activities (especially under the influence of manganese) and peroxidase activities (under molybdenum influence). Applying the method of chlorophyll a fluorescence in the field and greenhouse experiments with Galega orientalis L. plants, artificial infected with phytoplasma Acholeplasma laidlawii var. granulum st. 118 the following changes in the photosynthetic apparatus has been indicated: reduction in the length of the light-antenna, blocking transport of electrons in plastoquinone pool PSII with reducing the pool of electron acceptors. It has also been indicated that photochemical activity resistance of the photosynthetic apparatus decreases while its stability increases, as result of described above effects the concentration of chlorophyll a and b in plants leaves decreases. The above-mentioned negative effects have been deactivated through foliar treatment of infected Galega orientalis L. plants with nanoaquacitrates solution Mo (4 mg/dm3) that allow increasing of photochemical resistance of photosynthetic apparatus as well as chlorophyll content in leaves. The foliar treatment with Mn (20 mg/dm3) solution of the infected plants, in compared with infected plants without treatment, resulted in more significant increase of Ki value (which correlate to the ribulose-1,5-bisphosphate carboxylase/oxygenase activity), which is explaining anti-mycoplasma effect of this solution.
EN
The experiments testing the toxicity of glyphosate Roundup® formulation were conducted on the natural microphytobenthic communities collected from the Gulf of Gdansk. The toxic effect of glyphosate was assessed by changes in the biomass of microphytobenthos cells [mm3 ∙ ml-1], chlorophyll a concentration and reduction of efficiency of photosystem II. Negative impact of glyphosate on microphytobenthic communities, both at the cellular and population scale, was determined. Hence it can be concluded that certain concentrations of the herbicide Roundup (glyphosate – active substance), in the marine environment may adversely impact natural microphytobenthic communities, and in consequence also other elements of the ecosystem.
EN
The comparison of the latest and previous data on the structure of phytoplankton and chlorophyll a concentration in Lake Charzykowskie indicated long-term changes and fluctuations. The main objective of this study was to assess the phytoplankton communities in the lake with reference to hydrochemical conditions. Detailed hydrobiological studies were carried out in 2014-2015 to explain the improvement in the trophic status of the lake observed in 2008-2009. The research has shown that the phytoplankton community structure does not change significantly during the limnological cycle. The spring/ autumn season is characterized by the highest contribution of diatoms and cryptophytes. Massive development of dinoflagellates was observed during the summer. Relative abundance of cyanobacteria (Aphanizomenon, Dolichospermum and Microcystis) was significantly lower compared to the previous years. In August 2014, cyanobacteria accounted for 100% of the total phytoplankton at site 2. In the following year, cyanobacteria represented only 13% in the summer phytoplankton. The current research has confirmed the favorable trophic changes in the phytoplankton of the lake. Unfortunately, very poor oxygen conditions will continue to affect the trophic status of the lake through mobilization of the internal nutrient supply. The current conditions of the lake require further monitoring of changes in the ecosystem.
13
Content available remote Diurnal and seasonal DOC and POC variability in the land-locked sea
EN
Organic matter is a minor yet important component of the marine environment. The aim of this study was to investigate the diurnal and seasonal changes in dissolved and particulate organic carbon (DOC and POC, respectively). Thus, DOC and POC as well as chlorophyll a (Chl a), δ13C, NO3−, NO2−, NH4+, PO43-, salinity, pH, and temperature were regularly measured in samples collected for 24 h (2-h resolution) in the Gdańsk Deep (54°44.730′N, 19°08.531′E) at three water depths (1, 10, and 40 m) during sampling campaigns in 2011 (May), 2014 (May), and 2015 (January, March, May, July, September, November). Seasonal variations in DOC and POC followed the seasonality of Chl a (proportional trend) and nutrients (reverse trend) concentrations. Diurnal oscillations were detected in six out of the eight measurement series. The strongest diurnal variability in both POC and DOC occurred in May 2011 and March 2015, when phytoplankton activity was highest (high Chl a). The surprisingly low δ13C values (range: −28‰ to −24‰) measured over the course of the study revealed the gaps in our knowledge of the isotopic characteristics of terrestrial- vs. marine-derived particulate organic matter.
EN
The present study focused on the determination of the baseline data and correlations between biological and physicochemical variables, including the assessment of trophic conditions in Lake Qarun. The concentrations of nutrients were high, with the maxima usually in the east subarea (total nitrogen 6.40 mg dm-3, mineral nitrogen 2.34 mg dm-3, orthophosphates 0.22 mg dm-3). A total of 134 phytoplankton species were recorded. Bacillariophyceae and Dinophyceae co-dominated spatially and seasonally in phytoplankton assemblages. The highest phytoplankton density (935 × 104 cells dm-3) and chlorophyll a content (69.3 μg dm-3) were recorded in the east subarea of the lake, whereas the largest total and dominant fish (Mugil cephalus and Solea spp.) were in the west. Tilapia zillii and Engraulis encrasicolus were most abundant in the east and in the middle part, respectively. When phytoplankton density decreased from the east toward the west subarea, the Secchi disk depth increased. The TLI-based assessment indicated hypereutrophic waters at most sites of Lake Qarun. Statistically significant positive or negative correlations were found between the dominant fish species: T. zillii and Solea spp., and the phytoplankton density, Dinophyceae density, concentrations of TP, chlorophyll a, ammonium, nitrite and nitrate. Such correlations may be helpful to better understand how to enhance the sustainable fish production.
EN
This study shows the influence of eutrophication pressure on the phytoplankton community structure, abundance and biodiversity in the investigated bays with different hydromorphological features. Šibenik Bay is a highly stratified estuary of the karstic river Krka; Kaštela Bay is a semi-enclosed coastal bay, which is influenced by the relatively small river Jadro; and Mali Ston Bay is located at the Neretva River estuary, the largest river on the eastern part of the Adriatic Sea. All of the areas are affected by urban pressure, which is reflected in the trophic status of the waters. The greatest anthropogenic influence was found in Kaštela Bay while the lowest influence was found in Mali Ston Bay. In this study, the highest biomass concentration and maximum abundance of phytoplankton were recorded at the stations under the strongest anthropogenic influence. Those stations show a dominance of abundance compared to the biomass and a dominance of opportunistic species, which is reflected in the lower biodiversity of phytoplankton community. Diatoms were the most represented group of the phytoplankton community in all three bays, followed by the dinoflagellates. Diatoms that were highlighted as significant for the difference between the bays were Skeletonema marinoi in Šibenik Bay, Leptocylindrus minimus in Kaštela Bay and the genus Chaetoceros spp. in Mali Ston Bay. Dinoflagellates were more abundant at the stations under the strongest anthropogenic influence, and most significant were Prorocentrum triestinum in Kaštela Bay and Gymnodinium spp. in Šibenik Bay and Mali Ston Bay.
PL
Proces eutrofizacji zbiorników zaporowych jest bardzo istotnym problemem środowiskowym i ze względu na ich ważne funkcje gospodarcze musi być stale monitorowany. Trudności prognozowania stanu trofii wód oraz ograniczona możliwość sterowania procesem powodują potrzebę systematycznej kontroli przebiegu eutrofizacji w celu wczesnego reagowania. Wiarygodnej oceny dostarczają wskaźniki wieloparametrowe, odznaczające się wieloaspektowym podejściem do problemu. W badaniach przedstawionych w artykule do oceny stanu trofii wód zbiorników Jeziorsko i Sulejowskiego zastosowano integralny wskaźnik troficzności (ang. Index of Trophic State - ITS), który odzwierciedla bilans procesów produkcji i rozkładu substancji organicznej produkowanej przez glony oraz bazuje na wartościach pH i nasycenia wody tlenem, a więc standardowych pomiarach monitoringowych. Pozwala on dzięki temu w szybki i tani sposób ocenić stan trofii. W celu weryfikacji wyników uzyskanych z zastosowaniem integralnego wskaźnika troficzności (ITS) przeprowadzono również ocenę według wartości granicznych koncentracji fosforu całkowitego i chlorofilu „a” ustalonych przez Vollenweidera i OECD. Ocena stanu troficznego wód obu zbiorników dokonana na podstawie różnych metod charakteryzuje się bardzo zbliżonymi wynikami, co potwierdziło zasadność zastosowania wskaźnika ITS do oceny stanu troficznego wód.
EN
The natural eutrophication process can be accelerated as the result of anthropogenic activity. The intensification of eutrophication process leads to destroying of the balance between synthesis and destruction of organic compounds that in turn results in the disturbance of ecological equilibrium of whole aquatic ecosystem. Taking into account the high dynamics of eutrophication process and its negative consequence, the continuous monitoring of water trophic state is necessary for early detecting the changes and taking appropriate action. The aim of the paper was the assessment of water trophic state of two dam reservoirs: Jeziorsko and Sulejowski on the base of long-term monitoring within analyzed period 2010-2014. The localization of the reservoirs is borderland between the Małopolska Upland and Środkowopolska Lowland, administrative localization is Łódź Province and they are managed by Regional Water Management Authority in Poznań and by Regional Water Management Authority in Warszawa. The monitoring of Jeziorsko Reservoir was carried out in one measurement-control point above the dam. The monitoring of Sulejowski Reservoir was carried out in three measurement-control points: near to the Pilica river inflow, in the middle of reservoir and above the dam. The database includes monitoring measurements realized in 2011 and 2014 on Jeziorsko Reservoir and in 2010, 2011, 2012, 2014 on Sulejowski Reservoir. The values of reservoirs’ water quality parameters were obtained from Province Environmental Protection Inspectorate in Łódź, which realizes the surface water monitoring including artificial lakes, as a part of the State Environment Monitoring Program. The assessment of water trophic state was carried out using the Index of Trophic State (ITS) which is based on the existing of linear relationship between pH and oxygen content in water, the parameters indirectly expressing the balance of oxygen and carbon dioxide in water. Eutrophication is a consequence of the disturbance of the balance between synthesis and destruction of organic compounds produced by water vegetation, which leads to the changes in content of oxygen and carbon dioxide in water. The results of water trophic state assessment obtained on the base of ITS index indicated the eutrophic and mesoeutrophic level in both reservoirs. The results obtained with the help of ITS were verified by the results obtained on the base of total phosphorus and chlorophyll “a” threshold values determined by Vollenweider and OECD. The assessment of water trophic state on the base of multiparametric Index of Trophic State (ITS) was confirmed by assessment based on threshold values of single parameters. This proves that ITS index is useful and justified. High trophic state of both reservoirs within whole research period showed that this trend is enduring for multi-year period.
EN
Chlorophyll (chl a) concentration in coastal seas exhibits variability on various spatial and temporal scales. Resuspension of particulate matter can somewhat limit algal growth, but can also enhance productivity because of the intrusion of nutrient-rich pore water from sediments or bottom water layers into the whole water column. This study investigates whether characteristic changes in net phytoplankton growth can be directly linked to resuspension events within the German Bight. Satellite-derived chl a were used to derive spatial patterns of net rates of chl a increase/decrease (NR) in 2003 and 2004. Spatial correlations between NR and mean water column irradiance were analysed. High correlations in space and time were found in most areas of the German Bight (R2 > 0.4), suggesting a tight coupling between light availability and algal growth during spring. These correlations were reduced within a distinct zone in the transition between shallow coastal areas and deeper offshore waters. In summer and autumn, a mismatch was found between phytoplankton blooms (chl a > 6 mg m−3) and spring-tidal induced resuspension events as indicated by bottom velocity, suggesting that there is no phytoplankton resuspension during spring tides. It is instead proposed here that frequent and recurrent spring-tidal resuspension events enhance algal growth by supplying remineralized nutrients. This hypothesis is corroborated by a lag correlation analysis between resuspension events and in-situ measured nutrient concentrations. This study outlines seasonally different patterns in phytoplankton productivity in response to variations in resuspension, which can serve as a reference for modelling coastal ecosystem dynamics.
EN
Large numbers of Mallard Anas platyrhynchos (max. 10,490 ind.), Black-headed Gull Chroicocephalus ridibundus (max. 3,430 ind.) and Great Cormorant Phalacrocorax carbo (max. 1,449 ind.) were recorded on the Goczałkowice Reservoir, Poland (2,754 ha). Most of the waterbirds occurred in the backwater of this reservoir. The amount of phosphorus and nitrogen loaded by the most numerous waterbirds into Goczałkowice Reservoir was estimated at 958 kg and 2,621 kg, respectively in 2011 and 1,043 kg and 2,793 kg, respectively in 2012. In 2011 and 2012, the waterbirds introduced a considerable amount of phosphorus, nitrogen and a large number of coliforms into the backwater of the reservoir. The concentration of different forms of phosphorus and nitrogen, chlorophyll-a and bacteria coli in the water was not greater at the site of birds’ concentration (except dissolved organic nitrogen). The concentration of nitrates in the water at the site near the breeding colony of gulls in comparison with the reference site was not different. The amounts of P-tot and N-tot in the sediment were similar at the site affected by waterbirds and at the reference site. The dynamics of water masses was not the reason for the lack of differences between the studied sites.
EN
According to the general classification of shallow eutrophic lakes, two alternative types are distinguished: phytoplankton-dominated and macrophyte-dominated lakes. The latter type is rare and currently endangered by human activity. In order to determine the effect of reduced inflow of surface water by an earth dyke on the lake trophic state, certain biological and physico-chemical parameters were evaluated. This work focuses on two lakes of similar morphometric characteristics situated in the agricultural landscape. The effect of the earth dyke on the trophic state was positively verified. The lake situated in the catchment basin, in which the inflow of surface water was reduced, was defined as meso-eutrophic, with a small amount of phytoplankton and high water transparency. The reference lake was highly eutrophic, with low water transparency and a large amount of phytoplankton. The water body surrounded by the earth dyke was macrophytes dominated (65% of the lake area), whereas the reference lake was a phytoplankton-macrophyte type (42% of the lake area). The trophic evaluation of a lake can be underestimated because of a significant amount of biogenic compounds accumulated in plant tissues. Thus, the values of Carlson’s indices in macrophyte-dominated lakes may not account for the total amount of nutrients in the water body.
PL
W ogólnej klasyfi kacji płytkich jezior eutrofi cznych można wyróżnić dwa alternatywne typy zbiorników: zdominowane przez fitoplankton i zdominowane przez makrofity. Ten drugi typ jezior jest rzadki i obecnie zagrożony działalnością człowieka. W celu określenia wpływu zredukowanego dopływu wód powierzchniowych przez ziemną groblę na stan troficzny jeziora, poddano ocenie wybrane parametry biologiczne i fizyczno-chemiczne dwóch zbiorników o podobnej morfometrii, położonych w krajobrazie rolniczym. Efekt oddziaływania grobli na jakość ekosystemu jeziornego oceniono jako znaczący. Jezioro położone w zlewni, w której dopływ wód powierzchniowych był ograniczony, zostało zaklasyfikowane jako mezo-eutroficzne, z małą ilością fitoplanktonu i o dużej przezroczystości wody. Jezioro porównawcze było silnie eutroficzne, z dużą ilością fitoplanktonu i o niskiej przezroczystości wody. Zbiornik otoczony przez groblę reprezentował typ makrofitowy (65% powierzchni jeziora pokryta przez roślinność), a stan jeziora porównawczego, w którym roślinność zajmowała 42% misy jeziornej, mieścił się między typem fitoplanktonowym i makrofitowym. Ocena trofii jezior może być jednak niedoszacowana, ponieważ znaczna część nutrientów może być zakumulowana w tkankach roślin. Stąd, wartości wskaźników Carlsona w przypadku jezior makrofitowych mogą nie uwzględniać ogólnej ilości nutrientów w jeziorze.
EN
Most scenarios of the predicted climate change in Europe imply that the increasing temperature trend will be maintained in winter seasons. The presence or absence of the ice cover in winter can impact on the functioning of lake ecosystems. The research was carried out in two mesotrophic and dimictic lakes in winter with and without ice cover. The biomass and phytoplankton and its composition was analysed with reference to physical factors (PAR and temperature). The research proved that poor thermal-light conditions under the ice/snow cover favoured the development of nanoplanktonic species from the genus Cryptomonas (Cryptophyta) or Stephanodiscus (Bacillariophyceae), whereas microplanktonic species of dinoflagellates, diatoms or green algae prevailed during the ice-free winter. The highest phytoplankton biomass and species richness were recorded during ice-free winter, which affected a higher Shannon-Wiener diversity index and evenness. It has been shown that the mild winter creates good conditions for the development of phytoplankton species characteristic for the mixing periods. The lack of inverse thermal stratification during winter can lead to disturbance in the functioning of the water ecosystems throughout the year.
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