Školjkaš korbula, Corbula gibba (Olivi, 1792) (Bivalve Mollusks), otporna vrsta na poremećaje u okolišu. Pregledan rad

Structural changes in bottom communities in many coastal and offshore areas result from enhanced eutrophication and are characterized by the presence of species that are tolerant to a wide range of environmental disturbances. In soft bottom communities that are degraded or recovering from stress, Corbula gibba appears to be a highly abundant, ecologically important species and, therefore, an interesting subject for investigation. The literature compiled in this review reveals that, Corbula is a short-lived species with high fecundity, enormous production of small eggs, and a prolonged spawning season. The fertilization of spawned eggs in open waters is followed by pelagic development of larvae, accompanied by dispersal sometimes far from the mother population. High larvae settlement frequently appears as a “recruitment boom” in a new community after a catastrophe, making Corbula a short-term dominant species until the perished invertebrate species repopulate. As a dominant suspension feeder with rapid juvenile and adult growth, Corbula becomes an important element in the food chain as a transferor of organic matter from plankton to benthos. In a relatively stable soft-bottom community, the size of the Corbula population is mainly limited by the activity of competitors and predators. Dense Corbula populations may occur in a community with low species diversity in constantly and occasionally eutrophic areas. Generally, Corbula is considered an indicator of environmental instability caused by pollution, low oxygen content, or increased turbidity.Školjkaš korbula, Corbula gibba (Olivi, 1792), je rasprostranjena vrsta u evropskim morima i često je obilna u nestabilnim i eutrofiziranim sredinama. Zapažena kao ekološki važna vrsta u obnovi pridnenih zajednica u sjevernom Jadranu, nakon učestalih ugibanja vrsta makrobentosa uzrokovanih nestašicama kisika, korbula se smatrala zanimljivom vrstom za istraživanja populacijskih karakteristika. Pregled do sada objavljenih radova o korbuli ukazuje da je to mala kratko živuća vrsta visokog reprodukcijskog potencijala s obilnom proizvodnjom malih spolnih stanica tijekom produžene sezone mriješćenja. Oplodnja jajnih stanica i razvoj ličinki u planktonskoj zajednici omogućuje njeno širenje u nova područja, kao i u područja osiromašena vrstama nakon katastrofalnih ugibanja. Slobodni prostori, nastali nakon ugibanja brojnih vrsta u pridnenoj zajednici, omogućuju korbuli intenzivno naseljavanje novacima, u prvoj fazi obnove makrobentosa. Tada kao dominirajuća «suspension feeding» vrsta korbula postaje važnim prenosnikom proizvedene organske tvari iz fitoplanktona u bentos. U kasnijem periodu obnove pridnenih zajednica znatno se smanjuje veličina populacije korbule. Čini se da tome pridonosi kratak životni vijek korbule kao i obnova predatorskih vrsta. Sažeto rečeno korbula se zbog svoje otpornosti prema učestalim promjenama sredine smatra indikatorom nestabilnosti, najčešće uzrokovanim sniženjem slanoće morske vode, te pojačanim turbiditetom i zagađivačima, u okolišu snižene bioraznolikosti

Response to oxygen deficiency (depletion): Bivalve assemblages as an indicator of ecosystem instability in the northern Adriatic Sea

Benthic communities represent a powerful tool for the detection of natural and anthropogenic disturbances, as well as for the assessment of marine ecosystem stability. This paper shows that bivalve assemblages could serve as excellent indicators of disturbance and ecosystem instability. The goal of this study was to compare two sets of data in order to determine the differences between two different periods belonging to bivalve assemblage in the muddy detritic bottom of the northern Adriatic Sea in the post-anoxic period during December 1989, 1990, 1991 and quite a while later, during 2003, 2004 and 2005. Abundances of some indicator species such as Corbula gibba, Modiolarca subpicta and Timoclea ovata were detected during the post-anoxic period. Recruitment in the quality of bivalve assemblages was proved by the ecologic and biotic indexes during 2003, 2004 and 2005, during a period of relatively stable ecological conditions. Fluctuation in bivalve diversity due to the ecological quality of the marine ecosystem in the eastern part of the northern Adriatic Sea is also discusse

Prilog poznavanju raznolikosti školjkaša u Malostonskom zaljevu (Jadran)

Although Mali Ston Bay is an important bivalve aquaculture area and one of the most studied areas in the Adriatic Sea, very little is known about its biodiversity. The goal of the present study was to estimate bivalve diversity in Mali Ston Bay according to the spatial distribution of live bivalves and empty shells. Samples were collected with a 0.1-m2 van VEEN grab at twelve sampling stations in the bay during June 2000. Species were determined in the laboratory and the bivalve assemblage was analyzed using the PRIMER software package. Eighty-two bivalve species were identified, indicating that Mali Ston Bay is an area of high bivalve diversity.Iako je Malostonski zaljev važno područje za akvakulturu školjkaša i jedno od naj- istraživanih područja u Jadranskom moru, vrlo malo je poznato o njegovoj biološkoj raznolikosti. Ovo istraživanje je pokrenuto s ciljem procjene raznolikosti školjkaša u Malostonskom zaljevu na osnovi prostorne raspodjele živih školjkaša i praznih ljuštura. Uzorci su prikupljani sa 0.1 m2 van VEEN grabilom na 12 postaja uzorkovanja smještenih u Malostonskom zaljevu tijekom lipnja 2000. Vrste su određene u laboratoriju i sastav zajednice školjkaša je analiziran pomoću PRIMER programa. Ukupno su određene 82 vrste školjkaša što upućuje da je Malostonski zaljev područje sa visokom raznolikošću školjkaša

Pregled vrsta školjkaša u istočnom Jadranu. III. Pteriomorpha (Glycymerididae)

The bivalve species Glycymeris bimaculata (Poli, 1795), G. glycymeris (Linnaeus, 1758) and G. violacescens (Lamarck, 1819) of the family Glycymerididae (Pteriomorpha) are reviewed. Literature citations, specimens deposited in collections, and unpublished data were consulted. For each species the valid name, Adriatic Sea synonyms, shell sizes, general and eastern Adriatic distribution, collection depths, habitat and biocenological characters, ecological significance, abundance, bivalve collections and additional relevant data are recorded. The results are discussed, and further study of certain species is suggested.Nastavljena je obrada skupine školjkaša i to vrste Glycymeris bimaculata (Poli, 1795), G. glycymeris (Linnaeus, 1758), and G. violacescens (Lamarck, 1819) iz porodice Glycymerididae (Pteriomorpha). U radu su korišteni navodi iz literature, malakoloških zbirki, kao i do sada neobjavljeni podaci. Za svaku vrstu uz važeći naziv zabilježene su istoznačnice za Jadran, veličine ljuštura, opća i jadranska rasprostranjenost, dubine nalaza, obitavališta i biocenološke karakteristike, ekološka značajnost, obilnost nalaza, pohranjenost u zbirkama i drugi važniji navodi. Rezultati istraživanja pojedinih vrsta su raspravljeni, te je naglašena potreba daljnjih istraživanja

LONG-TERM CHANGES IN THE TRANSITIONAL COMMUNITY OF DETRITIC BOTTOMS IN THE NORTHERN ADRIATIC SEA: DYNAMICS OF BIVALVE ASSEMBLAGES

WOS: 000320829200001Benthic fauna is an important component in marine ecosystems. Due to their relatively sessile habit, benthic macrofauna can serve as an indicator of changes in the marine environment caused by natural or anthropogenic disturbances. This study is primarily focused on the long-term natural variability of the diversity, biotic and multimetric indices, through the use of prolonged data collection (1989-1991 and 2003-2009) on bivalve assemblages in the transitional community of detritic bottoms in the northern Adriatic Sea. With regards to faunistic composition, Cluster and Abundance Comparison analyses were used to assess the recruitment and fluctuations in the quality of bivalve assemblages during the investigated periods. The results of univariate and multivariate analyses clearly distinguished three separate groups (1990-1991, 2003-2006 and 2007-2009) from aforementioned periods during which the research was conducted. Furthermore, this study also discusses the temporal variability in bivalve diversity, which is due to the ecological status of the investigated area in the northern Adriatic Sea.Ministry of Science, Education and Sport of the Republic of CroatiaMinistry of Science, Education and Sports, Republic of Croatia [0098111, 098-0982705-2732]This research study was supported by the Ministry of Science, Education and Sport of the Republic of Croatia in the frame of the projects: Mechanisms of long-term changes in the Adriatic Sea ecosystem (no. 0098111); and Biodiversity of benthic communities in the Adriatic - natural and human impacts (no. 098-0982705-2732). Dr. Andrej Jaklin is acknowledged for providing the data collected during the first sampling period (December 1989 to December 1991)