The results of a study on morphological features and reproductive phenology of the brown alga
Cystoseira foeniculacea f. tenuiramosa
(Ercegović) A. Gómez Garreta, M.C. Barceló, M.A. Ribera & J. Rull ...Lluch from the marine lagoon of Strunjan (Gulf of Trieste), are reported. Based on monthly samplings carried out during one year period, it was observed that this species shows considerable seasonal morphological variations. The Strunjan marine lagoon appears to be the only location of the Slovenian coast where population of this taxon occur. Based on the high associated biodiversity, we propose the inclusion of this population in the conservation management plans in the area.
Prikazani su rezultati istraživanja morfoloških značajki i reproduktivne fenologije smeđe alge
Cystoseira foeniculacea f. tenuiramosa
(Ercegović) A. Gómez Garreta, M.C. Barceló, M.A. Ribera & J. Rull Lluch u morskoj laguni Strunjan (Tršćanski zaljev). Na temelju mjesečnih uzorkovanja, provedenih tijekom jedne godine, utvrđeno je kako ova vrsta pokazuje značajne sezonske morfološke varijacije. Strunjanska morska laguna vjerojatno je jedina lokacija na slovenskoj obali gdje obitava populacija ove svojte. Na temelju velike povezane bioraznolikosti, predlažemo uključivanje ove populacije u planove upravljanja očuvanja na tom području.
The occurrence of unattached spherical (aegagropilous) populations of the green alga Cladophora prolifera in the marine lagoon of Strunjan (Gulf of Trieste) is reported. Species identification was ...based on molecular and morphological data, and the distribution, ecology and morphological features of the aegagropilous populations are described. The ball-shaped form of this species differs from the typical upright attached form found on open shores by the radial arrangement of the branches and the absence of cells and rhizoids with clear annular constrictions. The formation of the aegagropilous form of C. prolifera likely results from specific hydrodynamic conditions in the human-mediated environment of the marine lagoon, in combination with morphological development of the species. The Strunjan marine lagoon appears to be the only location in the Mediterranean Sea, or even worldwide, where aegagropilous forms of C. prolifera occur in large abundance. Based on the high associated biodiversity, we propose the inclusion of these populations to be considered in conservation management plans in the area.
Gli autori riportano la prima segnalazione dell'alga bruna Cystoseira aurantia Kützing, trovata nella Laguna Schiusa di Strugnano (Golfo di Trieste, Slovenia). Durante le indagini sul campo, condotte ...nel marzo 2021, sono state osservate delle dense masse di quest'alga fluttuanti sulla superficie dell'acqua lungo il margine orientale della laguna, a profondita non superiore a 0,5 m. Le masse acropleustofitiche liberamente flottanti in superficie, si presentano composte da singoli talli abbondantemente ramificati e saldamente intrecciati. Non sono stati riscontrati esemplari fertili. Tra i possibili fattori responsabili della formazione delle masse fluttuanti di C. aurantia, assume un carattere particolarmente rilevante la costante variazione delle correnti superficiali, all'interno della Laguna, dovuta alla marea. Vengono descritti l'habitat e i caratteri morfologici degli esemplari studiati.
The occurrence of an aegagropilous form of the red alga Rytiphlaea tinctoria in the Stjuža marine lagoon of Strunjan (Gulf of Trieste) has been reported for the first time. The distribution, mean ...diameter, mean density and morphological structure of this population of R. tinctoria are here described. During the study, it was observed that the ball-like form of this species differs from the attached form found on open shores, lacking a holdfast, having a radial arrangement of the branches, and a curled distal part of the branches. No reproductive structures were observed in any of the collected samples. The ball-like form of Rytiphlaea tinctoria can be considered as an ecotype.
This study reports the occurrence of the non-native red alga Caulacanthus okamurae, previously unknown on the Slovenian coast (Gulf of Trieste, northern Adriatic Sea). The distribution of the ...species, its abundance, morphological characteristics and reproductive phenology are described. The study is based on seasonal sampling conducted during one year, from winter to autumn 2021, on two different substrates (limestone and sandstone) of the midlittoral zone, and showed a moderate variation in the biomass of C. okamurae populations between the winter-spring and summer-autumn periods. The native algal assemblages of the two substrates impacted by C. okamurae were characterized by generally limited species diversity and consisted mainly of small-sized species with simple morphology. During the study, in addition to non-fertile thalli of C. okamurae, tetrasporophytic thalli with tetrasporocysts and female gametophytes with cystocarps were found.
Ovo istraživanje prikazuje nalaz alohtone crvene alge Caulacanthus okamurae, dosad nepoznate na području slovenske obale (Tršćanski zaljev, sjeverni Jadran). U radu se opisuje rasprostranjenost vrste, njezina brojnost, morfološke karakteristike te reproduktivna fenologija. Istraživanje se temelji na sezonskom uzrokovanju provedenom tijekom jedne godine, od zime do jeseni 2021., na dvije različite podloge (vapnenac i pješčenjak) mediolitoralne zone, a istim je utvrđena umjerena promjenjivost u biomasi naselja C. okamurae između zimsko-proljetnog i ljetno-jesenskog razdoblja. Zajednice zavičajnih algi dvaju supstrata pod utjecajem C. okamurae općenito su okarakterizirane ograničenom raznolikošću vrsta, uglavnom onih malih dimenzija s jednostavnom morfologijom. Tijekom istraživanja, osim sterilnih talusa C. okamurae, pronađeni su tetrasporofitni talusi s tetrasporocistama i ženski gametofiti s cistokarpima.
The paper presents the results of the study on the populations of Patella caerulea of the Bay of Koper (Gulf of Trieste, northern Adriatic). The coast in the bay of Koper is composed of different ...types of substrata-limestone, marl and sandstone-making an ideal opportunity to study the influence of these substrata on the vertical distribution, density and morphological characteristics of this species. The observation revealed that the Patella population was distributed on all selected substrata in the midlittoral zone of this region. The density (individuals per 400 cm^sup 2^) was the highest on sandstone and the lowest on marl. The shells of individuals from the upper midlittoral zone were greater in size than those from the lower midlittoral, in all the investigated substrata. The surface sea temperature, salinity and chlorophyll a, that could explain increase of P. caerulea populations, have been analyzed.
The zonation of midlittoral mainly based on macroalgal communities was studied at six sites of the Bay of Koper (Slovenian south-east part of the Gulf of Trieste) in spring (April) and autumn ...(November) 2010. The study, using the random selection method, involved different types of substrate (limestone, marl and sandstone). It was surveyed from the upper midlittoral to the infralittoral fringe (from the mean higher high water to the mean lower low water), the upper limit of the occurrence of the brown macroalgae Cystoseira compressa. The zonation of the midlittoral zone was divided into three horizons (upper, middle and lower) by biotic (leader species) and abiotic (sea level) criteria. By using multivariate technique the main dissimilarity was found between the macroalgal communities of the upper and lower horizon. The species that most contributed to this difference was Blidingia minima. The main differences in species composition in different substrates were found between limestone and marl. The species Chaetomorpha linum mainly characterized such differences, while the species Fucus virsoides was the main contributor to dissimilarity among the middle horizons on limestone and sandstone.Original Abstract: Podjela tj. zonacija mediolitoralnog pojasa pretezito se temelji na istrazivanjima zajednica makroalgi na sest postaja u zaljevu Koper (slovenski jugoistocni dio trscanskog zaljeva) provedenih u proljece (travanj) i jesen (studeni) 2010. godine. Studija provedena metodom slucajnog odabira, ukljucuje razlicite vrste podloga (vapnenac, lapor i pjescenjak). Uzorkovano je podrucje od gornjeg mediolitoralnog pojasa do ruba infralitorala (izmedu srednje gornje razine plime do srednje donje razine oseke), te gornje granice prisustva smede alge cystoseira Compressa. Zonacijom je mediolitoral podijeljen u tri sloja (visi, srednji i nizi) prema biotickim (vodece vrste) i abiotickim kriterijima (razina mora). Primjenom multivarijatne tehnike glavna razlicitost je ustanovljena izmedu zajednica makroalgi gornjeg i donjeg sloja. Vrsta koja je najvise doprinijela ovakvoj razlicitosti je Blidingia minima.Glavne razlike u sastavu vrsta u razlicitim podlogama su pronadene izmedu vapnenca i lapora. Vrsta Chaetomorpha linum uglavnom karakterizira takve razlike, dok je vrsta Fucus virsoides bila glavni pridonositelj razlicitosti medu srednjim slojem na vapnencu i pjescenjaku.
The paper presents the results of the study on the populations of Patella caerulea of the Bay of Koper (Gulf of Trieste, northern Adriatic). The coast in the bay of Koper is composed of different ...types of substrata-limestone, marland sandstone-making an ideal opportunity to study the infl uence of these substrata on the vertical distribution, density and morphological characteristics of this species. The observation revealed that the Patella population was distributed on all selected substrata in the midlittoral zone of this region. The density (individuals per 400 cm2 ) was the highest on sandstone and the lowest on marl. The shells of individuals from the upper midlittoral zone were greater in size than those from the lower midlittoral, in all the investigated substrata. The surface sea temperature, salinity and chlorophyll a, that could explain increase of P. caerulea populations, have been analyzed.
At the end of 2010, a significant decline in populations of Fucus virsoides was observed in the Slovenian coast (Gulf of Trieste, northern Adriatic), which prompted the undertaking of a direct ...observation assessment of changes in the occurrence of these populations along the Slovenian coast over the period 2010-2015. The paper presents a comparison between historical and current data on the presence of F. virsoides along the Slovenian coast, gathered through in situ surveys and from literature, and proposes the possible causes that have led to the decline and disappearance of F. virsoides populations along the Slovenian coastline.
Fucus virsoides
is a glacial relict-species endemic to the Adriatic that was widespread from northern Italy to southern Albania. In recent decades, however, it has suffered an alarming decline. In ...this study, all available records were reviewed to reconstruct its historical and current occurrence and to investigate the possible causes of its decline. Comprehensive mapping revealed a continuing decline with a significant shift, leaving only about 20 fragmented populations. While the species is already classified as critically endangered in Albania,
F. virsoides
could be considered functionally extinct in Istria (Croatia), critically threatened with extinction in Italy and Montenegro and locally extinct in Slovenia. The status of the species in the rest of Croatia is still unclear. The remaining populations are located in areas characterised by low temperatures, low salinity and high nutrient concentrations. Long-term analyses of these key abiotic factors revealed profound changes that suggest a link to the species' decline. This study provides a thorough assessment of the overall status of
F. virsoides
and argues for its inclusion on the IUCN Red List. Immediate conservation measures are needed for the long-term survival of this species.
PDF
