Wyniki wyszukiwania - BazTech

1

Monitoring of the trophic ecology of pipefish species (Syngnathus abaster, Syngnathus acus) in an alluvial lake habitat (Lake Bafa, Turkey)

Gurkan Sule, Innal Deniz, Gulle Iskender

Oceanological and Hydrobiological Studies

|

2021

|

Vol. 50, No. 1

24--32

EN

The present study investigated the trophic ecology of two species living in an alluvial lake ecosystem in terms of season, length groups, sex, and mouth morphology. The fish were caught in a coastal lake area between December 2014 and March 2016 using a seine. In general, C. aquaedulcis was the most important prey for S. abaster, accounting for 10.99% of all prey, while amphipods accounted for 54.04% of the S. acus diet. Amphipods were the most frequently consumed prey in autumn, while C. aquaedulcis was the most important prey in spring. This result indicates that the species preferred similar prey groups and generated food competition depending on the season. The short-length group contained samples of S. abaster with empty guts, whereas S. acus in the same group consumed C. aquaedulcis. Length group II and III of individuals indicated that both species consumed amphipods and juvenile Syngnathus sp. Thus, the two species had statistically different preferences in terms of prey length. The mouth width of S. abaster was larger than that of S. acus. In conclusion, zooplankton constituted the main prey for both species in the lake and the morphological differences between the mouth apparatus of the species were due to the differences in feeding habits.

2

Mycobiota of Dead Ulmus glabra Wood as Breeding Material for the Endangered Rosalia alpina (Coleoptera : Cerambycidae)

Bartnik Czesław, Michalcewicz Jakub, Ledwich Dominika, Ciach Michał

Polish Journal of Ecology

|

2020

|

Vol. 68, nr 1

13--22

EN

The presence in wood of saprotrophic fungi is crucial for xylophagous insects, as they modify its chemical composition, moisture content and structure, and thus govern the survival and growth rate of larvae. Little is known about the mycobiota colonising the breeding material of saproxylic species. This paper focuses on the mycobiota of dead wych elms Ulmus glabra as breeding material for the endangered Rosalia alpina. Fungal isolates from wood fragments of the breeding material were identified using molecular techniques. A total of 24 taxa of wood-decay fungi were found (16 Ascomycota, 6 Basidiomycota, 1 Zygomycota, 1 unidentified) – saprotrophs and facultative parasites, saprotrophic fungi, fungal parasites and tree parasites. Six taxa were isolated from both the surface and deeper layers of the wood, and also from the wood dust and frass left in R. alpina foraging sites: Cladosporium cladosporioides, Cladosporium sp., Hypoxylon macrocarpum, Phaeoacremonium fraxinopennsylvanicum, Sistotrema brinkmannii and Stereum hirsutum. These fungi may be crucial in enabling R. alpina to colonise dead or dying trees and affect its larval development. Ph. fraxinopennsylvanicum, H. macrocarpum and Daldinia childiae are reported for the first time from Poland.

3

Change in metazooplankton abundance in response to flood dynamics and trophic relations in Danubian floodplain lake (Kopački Rit, Croatia)

Palijan G., Galir A.

Polish Journal of Ecology

|

2012

|

Vol. 60, nr 4

777--787

EN

This study investigated relationships of hydrological variability and potential food resources for metazooplankton groups: rotifers, cladocerans, copepods and nauplii. Samples were collected monthly during ice-free season from March until November in 2006. Two sampling stations were chosen, the one located in Lake Sakadaš, as a segment of Kopački Rit floodplain (Croatia), and the other in the River Danube. Due to hydrological conditions we divided our samples into two hydrological groups which corresponded to: 1/ increased water level i.e. disturbed phase and 2/ decreased water level representing a more stable phase. Abundance of metazooplankton was not significantly different between hydrological groups in the River Danube. However, it was significantly different between hydrological groups in Lake Sakadaš (one-way ANOSIM R = 0.688, P = 0.024), where during a decreased water level higher abundance of metazooplankton was recorded. Rotifers were the most abundant metazooplankton group during the whole investigated period at both stations and between both hydrological groups comprising almost 99% of total metazooplankton abundance. Rotifers were significantly positively correlated with the total number of bacteria, as well as with ammonium and total phosphorous concentrations. The metazooplankton community in Lake Sakadas was negatively influenced by flooding, but not in the River Danube. Compared to the River Danube the investigated floodplain lake showed potential as a storage zone for metazooplankton development during more stable hydrological periods. During that time abundance of rotifers was related to the heterotrophic component of microbial food web. Hence, this investigation adds to the understanding of the metazooplankton dynamics in river-floodplain systems as well as of their relations with trophic levels under variable hydrological conditions.

4

Biomass distribution and dynamics and food web relations in psammon community of a eutrophic lake

Kalinowska K., Ejsmont-Karabin J., Gorelysheva Z., Rybak J.

Polish Journal of Ecology

|

2012

|

Vol. 60, nr 3

443-453

EN

Organisms living in submerged sand along the shore and below the water's edge in freshwater lake beaches create community called hydropsammon (see Fig. 1 in Preface). Trophic relations between psammon food web components are essential in energy flow, nutrient cycling and functioning of aquatic environments. The seasonal changes in algal, bacterial, nanoflagellate, ciliate, rotifer and crustacean biomass were investigated in hydroarenal (submerged sand) of the eutrophic Lake Mikołajskie (Poland). Sampling cores were taken once or twice a month since April till October 2005 from three layers: adjacent water layer (AWL), layer of water and sand from the transitory level (EPIH - epihydroarenal) and slice of sand (ENDOH . endohydroarenal). The mean annual phytopsammon biomass was extremely high in all microlayers. Bacterial biomass was the highest in the ENDOH. Biomass of nanoflagellates was 4 to 8 times lower than that of bacteria and was the highest in the AWL. The highest mean annual biomass of ciliates was recorded in the EPIH, whereas rotifers dominated in the ENDOH. In contrast, average biomass of Crustacea was the highest in the AWL. Crustaceans dominated heterotrophic biomass in the AWL and EPIH (92 and 54% of the total biomass, respectively) whereas bacteria definitely prevailed in the ENDOH (57%). The ratios of autotrophic to heterotrophic biomass and prey to predator biomass as well as trophic relations between the studied groups of psammon organisms differed clearly among microlayers. The AWL was characterised by the lowest autotrophic/heterotrophic and predator/prey biomass ratios (about 2) and significant positive correlations between nanoflagellates and ciliates as well as between protists and both rotifers and copepods. The highest autotrophic/heterotrophic and predator/prey biomass ratio (14 and 40, respectively) and lack of correlations was found in the ENDOH. These results may suggest that the pressure of consumers was weaker in the hydroarenal layers than in the AWL. In addition, it seems that psammon ciliates, rotifers and crustaceans inhabiting the ENDOH were probably limited by factors other than food availability. In contrast to the pelagic ecosystems, autotrophic biomass exceeded heterotrophic biomass, especially in the ENDOH.