Tamara Shiganova P.P.Shirshov Institute of Oceanology RAS Moscow, Russia

Main large scale events, which changed ecosystem functioning and provoked first gelatinous species blooms runoff regulation of the major rivers; increase in the input of dissolved mineral forms of phosphates and nitrates from large rivers accompanied by reduced silicate supply. This resulted in a decrease in the Si : P and Si : N ratios, which are important for the functioning of phytoplankton; changes in the composition of phytoplankton species and dominance of dinoflagellates instead of dominance of diatoms, significant growth in the phytoplankton biomass and outburst of harmful algae; Subsequent eutrophication overfishing of large predator fish and dolphins, resulted in decrease of top-down control

Enterannual changes mean summer temperature upper and intermedial layers Data of Hydrophysics lab SB IORAS

Subdivision of the Black Sea fish, zoo- and gelatinous plankton species in their relation to mean seasonal, annual and minimal winter SST: blue-cold water, red-warm water, between euryterm species (analyses own field data according to method main components) Cold-water species Warm-water species Euryterm species

With respect to their origin native gelatinous species belong to moderately cold-water species: the ctenophore Pleurobrachia pileus, scyphomedusa Aurelia aurita, and the pyrophyte alga Noctiluca scintillans. Two warm water invasive ctenophores arrived and established in upper layer Cold water species Warm water species Subdivision of the gelatinous species in their relation to mean seasonal, annual and minimal winter SST: analyses of field data according to main component method )

Noctiluca scintillans increased abundance in late 1970s (eutrophication and cold period) Aurelia aurita increased abundance in late 1970s (eutrophication and cold period) Ctenophore Mnemiopsis leidyi arrived in 1982 and its huge population development started in 1988 (eutrophication and warm period) ctenophore Beroe ovata arrived and its development started around the sea in 1999 (warm period) Chronolody of the gelatinous species blooms

Vertical distribution Noctiluca scintillansAurelia aurita Mnemiopsis leidyi and Beroe ovata Termocline P. pileus

Interannual Mnemiopsis leidyi and surface water temperature variabilities in the Black Sea B.ovata In spring In summer Mnemiopsis leidyi Beroe ovata

? Map of first Mnemiopsis leidyi findings

Shiganova et al, in preparation Beroe ovata Beroe cucumis Beroe forskalii Beroe gracilis

Haplotype distribution and frequency map for Mnemiopsis leidyi. Allele (inner circle for ITS) and haplotype (outer donut for COI) distribution map of Mnemiopsis leidyi. Each color indicates a different allele/haplotype. Private alleles/haplotypes are highlighted in grey (Ghabooli et al.2013).

Morphological differences of M. leidyi individuals from the Black, Azov, Caspian and Aegean seas Upper row of our data below after Mayer (1912). Black Sea Sea of AzovAegean Sea М.leidyi M.gardeni M.mccradyi

Phenological stages of M.leidyi and B.ovata After Shiganova et al., 2000, 2003; Vinogradov et al.,

Seasonal distribution of M.leidyi and B.ovata larvae in warm (2001) and cool (2003) year Shiganova et al., 2000, 2003; Vinogradov et al.,

Expansion of gelatinous species from the Mediterranean Sea Rhopilema nomadica Cassiopea andromeda Cassiopea andromeda (2008) Chrysaora hysoscella Chrysaora hysoscella (2002) Cotylorhiza tuberculata Chrysaora hysoscella (2009) Bolinopsis vitrea (2009) Shiganova, Ozturk,2010; Ozturk, Shiganova,2010

Mnemiopsis leidyi Beroe ovata Bolinopsis vitrea Pleurobrachia pileus

Aurelia aurita Rhisostoma pulmo Chrysaura hysoscella Native species Possible invader

Conclusion During the last three decades, first native than invasive gelatinous species have become the main drivers of the Black Sea ecosystem functioning subjected to ecosystem disturbance With respect to their origin, all the Black Sea species may be subdivided into cold water (boreal) warm-water, eurythermal (Mediterranean species). Correspondingly, their spatial and vertical distribution, seasonal dynamics, and phenology depend on their origin. Three native gelatinous species belong to moderately cold- water species: the ctenophore Pleurobrachia pileus, scyphomedusa Aurelia aurita Warm water invader Mnemiopsis leidyi arrived and established in the upper layer of the Black Sea, where there was not any predator or gelatinous competitor. It could reach high abundance at optimal upper layer temperature in high prey concentration. Its predator warm water species Beroe ovata established in the same upper layer in conditions of high M.leidyi concentrations. According to indicator of GES abundance M.leidyi and A.aurita >5 ind.m-3 is characterizated as bloom and “bad environmental status”