ALGOLÓGUS IRODALMAK
Phycological Publications
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Phycological Publications
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Stenger-Kovács et al (2016): Ecological Indicators
Stenger-Kovács, C., É. Hajnal, E. Lengyel, K. Buczkó, J. Padisák (2016): A test of traditional diversity measures and taxonomic distinctness indices on benthic diatoms of soda pans in the Carpathian basin. Ecological Indicators 64: 1-8.
A cikk elkérhető a szerzőktől.
Abstract:
Saline lakes are threatened all over the world and their conservation has been a key issue. Various diversity indices are available for ecological status assessments, however, with poorly explored relevance and applicability in saline, alkaline pans. Therefore, traditional diversity measures (species richness and Shannon diversity) and taxonomic distinctness indices (Average [AvTD] and Variance of Taxonomic Distinctness [VarTD]) were tested in more than 100 sampling sites of 39 soda pans in Central-Europe to find sufficient indicators of the ecological condition and simultaneously to facilitate their preservation according to the modern conservation practices. Results of the analyses showed that healthy soda pan ecosystems with high level of natural stress and reduced habitat heterogeneity are characterized by low diversity diatom assemblages. In soda pans where the stress can be extremely high from natural reasons, oligopoly of closely related species can develop: the average taxonomic distinctness appeared between genus and family level. The non-DNA-sequence based phylogenetic diversity measures (AvTD and VarTD), were generally sensitive to the trophic state of the lakes, in contrast to traditional diversity metrics, which were unequivocally indicative for the special physical and chemical parameters (e.g. conductivity, pH) of the soda pans. In some cases, when the response of the diversity measures for a given environmental variable (pH, temperature) overlapped, the AvTD was found to be a more precise indicator of the environmental changes (pH) than traditional ones. The decreasing tendency of the AvTD along the intensified natural impact may be explained by the long available time for the species to adapt to these special environments.
Keywords: Species richness; Shannon diversity; Taxonomic distinctness; Soda pans; Diatoms; Limnological features
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Stenger-Kovács & Lengyel (2015): STUDIA BOTANICA HUNGARICA Stenger-Kovács, C., & Lengyel, E. (2015). Taxonomical and distribution guide of diatoms in soda pans of Central Europe. STUDIA BOTANICA HUNGARICA, 46(Supl), 3-203.
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Abstract:
The 93 most characteristic and dominant diatom taxa (including varieties and forms) of soda pans are presented in this study with detailed information on their distribution. The taxonomical position of five taxa is still unclear. Altogether 1257 light and 180 scanning electron microscopic photos are shown from cleaned valves and frustules as well as from living cells (cultures isolated from these lakes).
Keywords: Carpathian Basin, Central Europe, diatoms, soda pans
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Török et al (2016): Functional Ecology
Török P., T-Krasznai E., B-Béres V., Bácsi I., Borics G., Tóthmérész B. (2016): Functional diversity supports the biomass-diversity humped-back relationship in phytoplankton assemblages.
A cikk elkérhető a szerzőktől.
Abstract:
1. Modelling the relationship between biomass and diversity in phytoplankton assemblages provides new insights into the mechanisms responsible for the coexistence of species, even in terrestrial ecosystems.
2. We tested the biomass-diversity relationship in lake phytoplankton along a wide biomass gradient using functional species groups. We hypothesized that changes in the taxonomic diversity of the phytoplankton along a biomass gradient are associated with altered functional diversity.
3. For the analyses, in total 768 samples were collected from 30 oxbows, reservoirs and lakes in the Hungarian Lowland Region and analysed between 1992 and 2002.
4. We found that the diversity and also the number of functional species groups showed a humped-back curve similar to the species richness. The changes in functional group composition act as a good proxy for phytoplankton species responses. We found that the peak of the number of strategy groups and their Shannon diversity was at a much lower biomass than that of species richness.
5. We revealed the fine-scale effects of increasing the dominance of respective species or species groups with increasing biomass. This increase was well reflected by the changes in the functional characteristics: first, the species evenness; then, the Shannon diversity; and finally, the species richness started to decrease with increasing biomass.
6. Cyanoprokaryota were positively correlated with increasing biomass and negatively with the increase in species richness; thus, the high increase both in their abundance and biomass can be responsible for the abruptly decreasing part of the humped-back curve.
7. We detected a humped-back curve between biomass and diversity, where the peak compared to terrestrial plant communities tended to be towards high biomass scores, that is, greater than 60% instead of the 20 to 60% of the biomass range typical for terrestrial plant communities. Marked differences in the structural and dynamic features of phytoplankton assemblages and terrestrial plant communities are likely responsible for this difference.
Keywords: algae, ecological strategy, functional redundancy, functional strategies, humpback model, species richness, unimodal curve
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B-Béres et al (2015): Ecological Indicators
B-Béres, V., Lukács, Á., Török, P., Kókai, Zs., Novák, Z., T-Krasznai, E., Tóthmérész, B. I. Bácsi (2016): Combined eco-morphological functional groups are reliable indicators of colonisation processes of benthic diatom assemblages in a lowland stream. Ecological Indicators 64: 31-38.
A cikk elkérhető a szerzőktől.
Abstract:
Classifying benthic diatom taxa based on ecological and morphological features became increasingly important in recent years due to the demand of understanding the dynamics and functioning of diatom assemblages. The great potential in using these functional classifications in diatom ecology involves further refinement of current classification. In our experimental study, colonisation processes of diatom assemblages were studied in a typical small lowland stream, using both diatom guilds and cell size categories. We also tested newly proposed combined eco-morphological functional groups (ecological guilds combined with cell size categories) in the study of the colonisation process in benthic diatom assemblages. We hypothesised that (i) there is a decrease in the proportion of low profile guild, while an increase in that of high profile and motile guilds in time with the decreasing rate of physical disturbance; (ii) the presence of small size categories will be pronounced at the beginning of the colonisation processes, while proportion of larger size categories will be higher in the latter phases of colonisation; and (iii) the relationship between taxa and environmental factors are better reflected by the use of combined eco-morphological functional groups than by the sole analyses of rough guilds or cell size categories. The first hypothesis was not confirmed, and our second hypothesis was only partially confirmed by the results. We found that the relationship between environmental factors and guilds, as well as cell size categories was not appropriate to reveal the relationship between abiotic factors and taxa composition. In contrast we found that compositional changes in colonisation were appropriately reflected by the newly defined combined eco-morphological functional groups. In the combined eco-morphological functional groups, such kind of taxonomical and ecological features can be prevailed which are hidden in guilds or cell size categories separately. Thus these combined eco-morphological functional groups could help to come one step closer to develop a widely used ecological classification in diatom researches.
Keywords: Eco-morphological functional groups; Diatom guilds; Cell size categories; Colonisation; Lowland stream
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Müller et al (2015): Ecological Indicators
Müller, F., Bergmann, M.,
Dannowski, R., Dippner, J. W., Gnauck, A., Haase, P., Jochimsen, M. C., Kasprzak, P., Kröncke, I., Kümmerlin, R., Küster, M., Lischeid, G., Meesenburg,H., Merz, C. , Millat, G., Müller, J., Padisák, J., Schimming, C.G., Schubert, H., Schult, M., Selmeczy, G., Shatwell, T., Stoll, S., Schwabe, M., Soltwedel, T., Straileg, D., Theuerkauf, M.. & Küster,
M. (2015). Assessing resilience in long-term ecological data sets. Ecological Indicators. DOI: 10.1016/j.ecolind.2015.10.066
A cikk elkérhető a szerzőktől.
Abstract:
In this paper the concept of resilience
is discussed on the base of 13 case studies from the German branch of
the International Long-Term Ecological Research Program. In the
introduction the resilience approach is presented as one possibility to
describe ecosystem dynamics. The relations with the concepts of
adaptability and ecological integrity are discussed and the research
questions are formulated. The focal research objectives are related to
the conditions of resilient behaviour of ecosystems, the role of
spatio-temporal scales, the differences between short- or long-term
dynamics, the basic methodological requirements to exactly define
resilience, the role of the reference state and indicators and the
suitability of resilience as a management concept. The main part of the
paper consists of 13 small case study descriptions, which demonstrate
phase transitions and resilient dynamics of several terrestrial and
aquatic ecosystems at different time scales. In the discussion, some
problems arising from the interpretation of the time series are
highlighted and discussed. The topics of discussion are the conceptual
challenges of the resilience approach, methodological problems, the role
of indicator selection, the complex interactions between different
disturbances, the significance of time scales and a comparison of the
case studies. The article ends with a conclusion which focuses on the
demand to link resilience with adaptability, in order to support the
long-term dynamics of ecosystem development.
Keywords: Long-term ecological research; LTER; Ecosystem resilience and adaptability; Spatio-temporal scales; Indicator selection
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Duleba et al (2015): Diatom Research
Duleba, M., Kiss, K. T., Földi, A., Kovács, J., Borojević, K. K., Molnár, L. F., Plenković-Moraj, A., Pohner, Zs., Solak, C.N., Tóth, B. & Ács, É. (2015). Morphological and genetic variability of assemblages of Cyclotella ocellata Pantocsek/C. comensis Grunow complex (Bacillariophyta, Thalassiosirales). Diatom Research, 1-24. DOI: 10.1080/0269249X.2015.1101402
A cikk elkérhető a szerzőktől.
Abstract:
Centric diatom taxa in the Cyclotella ocellata and C. comensis complexes show high morphological variability and often apparently continuous morphological transitions. In this study, we investigated natural assemblages of the C. ocellata/C. comensis complex from Hungarian and Croatian lakes and from Turkish streams using morphological and molecular methods. The studied assemblages contained cells with morphologies resembling C. ocellata as well as other, closely related, species: C. comensis, C. pseudocomensis, C. costei, and C. trichnoidea. The goal of our paper was to assess whether the observed morphological differences were due to intraspecific variability or suggest the existence of several, putatively distinct species.
Ten morphometric characters were measured, which, either individually, or in pairs, did not differentiate the nominal taxa in our assemblages. However, multivariate discriminant analysis has revealed a group including C. ocellata and C. trichonidea morphologies could be separated from another containing C. comensis, C. pseudocomensis and C. costei.
A nuclear (18S rDNA) and a chloroplast (rbcL) gene were amplified and partially sequenced from environmental DNA or from isolated cells. The sequences showed little variability among the assemblages and nominal species. Although general congruence of molecular and morphometric separation supports the species level separation of C. ocellata/trichonidea from the probably conspecific C. comensis/pseudocomensis/costei, sequence divergences between the groups are in the same range as within them, so that a conspecificity of all four taxa cannot be unequivocally excluded.
Keywords: Cyclotella ocellata, Cyclotella comensis, European and Turkish assemblages, morphometric analysis, 18S rDNA, rbcL
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Fuchs et al (2015): HydrobiologiaFuchs, A., Selmeczy, G. B., Kasprzak, P., Padisák, J., & Casper, P. Coincidence of sedimentation peaks with diatom blooms, wind, and calcite precipitation measured in high resolution by a multi-trap. Hydrobiologia, 1-16. DOI: 10.1007/s10750-015-2388-9
A cikk elkérhető a szerzőktől.
Abstract:
Organisms and processes in the epilimnion of lakes determine the rate of sedimentation. To investigate the impact of phyto- and zooplankton on the sedimentation rate, we sampled the sedimenting material in Lake Stechlin. Sedimenting matter was collected using a high-resolution multi-trap in three-day intervals during the thermally stratified seasons in 2011 (at 65 m depth) and 2012 (at 20 m depth). Dry weight of the sedimented material was related to chemical, physical, and biological data collected from the water column, as well as to meteorological data. The high-resolution trap showed two mass sedimentation peaks in 2011 and one in 2012. We found that diatom blooms in spring were followed by the highest sedimentation rate in 2011, but not in 2012. The sedimentation rates significantly correlated to low wind speed, followed by a rapid formation of the thermocline, as well as to high calcite concentrations in 2011. Our results suggest that the presence of some aggregation factors like calcite crystal exopolymers or fecal pellets support the sinking process. Furthermore, the high resolution of the trap used here allowed for obtaining precise correlations between sedimentation and the measured parameters indicating relevance of temporal coincidence of multiple environmental variables.
Keywords: Sedimentation trap, Wind speed, Calcite precipitation, Plankton
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Buczkó et al (2015): Studia Botanica Hungarica
Buczkó, K., Wojtal, A., Beszteri, B. & Magyari, E. (2015): Morphology and distribution of Navicula schmassmannii and its transfer to genus Humidophila. Studia Botanica Hungarica 46: 25-41.
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Abstract:
A small diatom with a peculiar shape is often identified as Navicula schmassmannii in samples collected from alpine lakes and the Arctic region. Due to its characteristic outline, it is relatively well-identifiable, but scanning electron microscope (SEM) confirmation is essential for proving species identity. This species likely has a palaeoecological indicator value of warming climate in mountain lakes, although it is generally a minor component of the diatom assemblages. Here we re-investigate its type material to clarify its identity and taxonomic position. We provide an emended description based on SEM observation, including new information on girdle morphology. Furthermore, another population of N. schmassmannii was studied. Detailed morphological observations using light microscope (LM) and SEM were done on specimens from a sediment core obtained from Lake Brazi in the Southern Carpathian Mountains. Late-glacial and early Holocene populations of the diatom resembling N. schmassmannii showed high morphological variability in comparison with the type material. On the basis of details of type material and the different morphotypes from Lake Brazi, the transfer of N. schmassmannii Hustedt to the genus Humidophila is proposed as H. schmassmannii (Hustedt) Buczkó et Wojtal.
Keywords: taxonomy, type material, new combination, bioindication, Humidophila, Navicula schmassmannii, oligotrophy, palaeolimnology, Retezat Mountains
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Nadja Georgieva Ognjanova-Rumenova, KRISZTINA BUCZKÓ, AGATA Z. WOJTAL, REGINE JAHN: Staurosirella rhombus (Ehrenberg), Ognjanova-Rumenova, Buczkó, Wojtal & R. Jahn, comb. nov.—Typification, morphology and biostratigraphic significance. Phytotaxa 218(3): 279-288. DOI: http://dx.doi.org/10.11646/phytotaxa.218.3.6
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Abstract:
A new combination Staurosirella rhombus (Ehrenberg), comb. nov., is based of Fragilaria rhombus. Using light and scanning electron microscopy, the type material from Jastrabá, Slovak Republic was studied. The taxonomic description and typification was done on the basis of the original line drawings, mica preparations and on raw materials, which are housed in the Ehrenberg Collection, Museum für Naturkunde, Humboldt Universität zu Berlin (BHUPM). Comments are presented regarding possible synonyms, described for the Neogene sediments in the realm of Central Slovakia.
Keywords: Fragilaria rhombus, fossil, Jastrabá, Ehrenberg collection, typification, Algae, Slovakia
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Lengyel Edina, Attila W. Kovács, Judit Padisák, Csilla Stenger-Kovács (2015): Photosynthetic characteristics of the benthic diatom species Nitzschia frustulum (Kützing) Grunow isolated from a soda pan along temperature-, sulfate- and chloride gradients. Aquatic Ecology. DOI: 10.1007/s10452-015-9533-4
A cikk elkérhető a szerzőktől.
Abstract:
The Carpathian Basin hosts a number of small, shallow, saline, alkaline ponds. As being endorheic basins, they are highly threatened by the climate change and response of biota to changing climate has been largely unexplored. We investigated the effects of salinity changes on the photosynthetic activity of Nitzschia frustulum, which is one of the main dominant taxa of the saline lakes in the Fertő-Hanság Region of the Carpathian Basin. The photosynthetic activity of the species was measured along temperature (5, 10, 15, 20, 25, 30, 35, 40 °C), light (0–8–35–70–110–200–400–800–1200 µmol m−2 s−1), SO4 2− (0–50–600–1200–2400–3600–4800 mg L−1) and Cl− (0–36–437.5–875–1750–3500–5250 mg L−1) gradients under laboratory conditions in photosynthetron. The conductivity optimal of N. frustulum was around 5600 µS cm−1 with wide salinity tolerance. The species preferred the HCO3 −–SO4 2−-type waters since its photosynthetic activity (3.62 mg C mg Chl-a −1 h−1) was more than twice higher than in HCO3 −–Cl−-type media. Its photosynthesis saturated at very low-light intensity, and photoinhibition was not observed during the experiments. The maximal photosynthesis was measured at 28–29 °C. However, above 30 °C, the decline of photosynthesis of N. frustulum can be forecasted.
Keywords: Nitzschia frustulum, Photosynthetic activity, Salinity, Temperature, Light, Saline lakes
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Görgényi et al (2015): HydrobiologiaGörgényi, J., Boros, G., Vitál, Z., Mozsár, A., Várbíró, G., Vasas, G., & Borics, G. The role of filter-feeding Asian carps in algal dispersion. Hydrobiologia, 1-12. DOI: 10.1007/s10750-015-2285-2
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Abstract:
The gut contents of filter-feeding fish often contain considerable amounts of viable phytoplankton cells; thus, these animals can act as vectors in the horizontal and vertical transport of algae. In this study, the potential role of the introduced filter-feeding Asian carps (hybrids of silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis) in algal dispersion was studied in the oligo-mesotrophic Lake Balaton (Hungary). We examined the algal composition in the lake water, gut contents (foregut and hindgut), and occasionally in the filtered suspensions collected directly from the gill rakers (filtering apparatus) of fish. Microscopic analyses revealed that the phytoplankton composition of the ingested food differed considerably from what we found in the lake water. Cryptophytes, dinoflagellates, and euglenophytes were observed in both the lake water and foregut samples but were absent in the hindgut samples. However, in the cultured hindgut samples, we found viable cells of several phytoplankton taxa (e.g., diatoms, blue-greens, desmids, volvocalean, and chlorococcalean green algae), which managed to survive the physical and chemical digestion. These results imply that the presence of these filter-feeding fish can alter the phytoplankton species composition and promote the dominance of taxa that are able to resist digestion.
Keywords: Phytoplankton, Digestibility, Biogeography, Asian carps
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Hu et al (2015): Hydrobiologia
Ren Hu, Qiuhua Li, Bo-Ping Han, Luigi Naselli-Flores, Judit Padisak, Nico Salmaso (2015): Tracking management-related water quality alterations by phytoplankton assemblages in a tropical reservoir. Hydrobiologia. DOI: 10.1007/s10750-015-2366-2
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Abstract:
Water quality improvement and suppression of cyanobacterial blooms were planned in a eutrophic reservoir in southern China through ecological engineering measures from 2006 to 2011. This consisted in (i) a hydraulic resetting of inflows and outflows to increase the distance between inlet and outlet and the water residence time in the reservoir, and in (ii) the installation of floating frames hosting wetland vegetation to promote an alteration in phytoplankton composition. The environmental changes were therefore followed through the analysis of biotic responses in phytoplankton assemblages. Ecological engineering was effective in reducing phytoplankton total biomass, in re-establishing more diversified phytoplankton assemblages and in avoiding cyanobacterial blooms. These changes may be considered as an improvement of the reservoir water quality. However, trophic state parameters and the dynamics of dominant species were not sensitive enough in describing the environmental changes that had occurred when the eco-engineering measures were implemented. These were more effectively tracked by the dynamics followed by phytoplankton Morpho-Functional-Groups and by their classification based on Competitors, Stress tolerants and Ruderals strategies. Although providing immediate positive effects, the eco-engineering was temporally limited, highlighting the importance of constant management in the context of long-term oriented remediation techniques.
Keywords: Phytoplankton, Morpho-functional groups, C–S–R-model, Generalized additive modelling, Ecological engineering, Reservoir
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Buczkó et al (2015): Phytotaxa
Buczkó Krisztina, Ognjanova-Rumenova Nadja, Z. Wojtal Agata, Stenger-Kovács Csilla (2015): Ultrastructure and taxonomic position of Cymbella latestriata Pantocsek (Bacillariophyta). Phytotaxa. DOI: http://dx.doi.org/10.11646/phytotaxa.207.2.3A cikk elkérhető a szerzőktől.
Abstract:
A rare Neogene species, Cymbella latestriata, was studied by light and
scanning electron microscopy. Cymbella latestriata was found to have
apical pore fields on both apices, although these are simple, very
small. Because of the presence of apical pore fields APF the transfer of
this species to the genus Cymbopleura is not justified as previously
was suggested by Krammer. Thus, the study confirms Pantocsek’s original
assignment of the taxon as Cymbella latestriata.
Keywords: apical pore fields, Cymbella, Cymbopleura, diatoms, fossil, Neogene, Pantocsek collection, type material, Algae, Slovakia
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Selmeczy et al (2015): Hydrobiologia
Selmeczy G. B., Tapolczai K., Casper P., Krienitz L., J.Padisák (2015): Spatial- and niche segregation of DCM-forming cyanobacteria in Lake Stechlin (Germany). Hydrobiologia. DOI: 10.1007/s10750-015-2282-5
A cikk elkérhető a szerzőktől.
Abstract:
At low trophic state, stable stratified water columns may provide favorable conditions for adapted phytoplankton species to form deep chlorophyll maxima (DCM). Such maxima occur regularly in Lake Stechlin, mainly contributed by the cyanobacterial species Cyanobium sp. and occasionally by Planktothrix rubescens. In the early twenty-first century, a rapid invasion by nostocalean cyanobacteria occurred in the lake and a number of Dolichospermum species together with Aphanizomenon flos-aquae appeared. As revealed by both microscopic and fluorimetric methods, during the summer stratification of 2013, a multispecific DCM was formed by Cyanobium, Planktothrix rubescens, and A. flos-aquae, however with spatial segregation. Planktothrix occurred in the upper hypolimnion, Aphanizomenon and Cyanobium dominated in the metalimnetic layer. Coexistence of these three cyanoprokaryota is possibly the consequence of different environmental factors limiting them (light, availability of N and P). This study represents a rare case when spatial niche segregation of phytoplankton species occurs in close to equilibrium conditions. DCM formed by Aphanizomenon and Cyanobium was detected by the fluoroprobe; Planktothrix with its different pigment compositions remained largely hidden. Our results indicate the necessity of parallel microscopic investigations and
Keywords: Aphanizomenon flos-aquae; Planktothrix rubescens; Cyanobium sp.; Deep chlorophyll maximum
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B-Béres et al (2015): Acta Botanica CroaticaB-Béres V., Bácsi I., T-Krasznai E., Kókai Zs., K. Buczkó (2015): First report of Navicula jakovljevicii Hustedt (Bacillariophyta) from Hungary: distribution, comparative morphology and a related species. Acta. Bot. Croat. 74(2). DOI: 10.1515/botcro-2015-0027
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Abstract:
In Hungary Navicula jakovljevicii was firstly recorded in biofilm of Elodea nuttallii in 2005 in an oxbow of the catchment area of the River Danube. Subsequently, in 2006, N. jakovljevicii was also found in the same oxbow on reed stems as well. In the following years it appeared in another oxbow, suggesting an expanding distribution in the tributaries of the Danube in Hungary. The Hungarian population can be characterised as having mixed morphological features in comparison with other known N. jakovljevicii populations of Europe. When the morphological study was expanded, a similar, but 'giant form' was detect ed in fossil material. We found similarities and a possible connection between N. jakovljevicii and Navicula lucida, a diatom taxon described from a Neogene deposit in the Carpathian Basin. Despite the morphological similarities in the shape, apices, striae pattern and raphe structure of these two species, there are significant differences in valve dimensions: the valves of N. lucida are larger and more heavily silicified than N. jakovljevicii.
Keywords: biofilm; Danube; Elodea nuttalli; Navicula jakovljevicii; Navicula lucida; oxbow; Pantocsek collection
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Kókai et al (2015): Acta Botanica Croatica
Kókai Zs., Bácsi I., Török P., Buczkó K., T-Krasznai E., Balogh Cs., Tóthmérész B., B-Béres V. (2015): Halophilic diatom taxa are sensitively indicating even the short term changes in lowland lotic systems. Acta. Bot. Croat. 74(2). DOI: 10.1515/botcro-2015-0025
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Abstract:
The occurrence and spread of halophilic diatom taxa in freshwater lotic ecosystems are influenced both by natural processes and anthropogenic pollution. Diatom assemblages were regularly monitored in lowland lotic systems in Hungary (Central Europe) during the unusually dry year of 2012. Highly pronounced changes in diatom composition were observed from spring to autumn. Halophilic taxa (especially Nitzschia sensu lato species) appeared in the dry autumn. In addition, the total relative abundances of halophilic species also increased up to autumn. Abundance of Nitzschia cf. lorenziana and Nitzschia tryblionella showed a positive correlation with chloride and phosphate concentration, while that of other taxa like Tryblionella apiculata or Tryblionella calida showed a positive correlation with the concentration of nitrate. Our findings clearly demonstrated that these halophilic and mesohalophilic diatom taxa were sensitive indicators of even short-term changes in lowland lotic ecosystems, such as the increasing salt concentration from spring to autumn caused by the lack of rainfall and/or environmental loads.
