Gelatinous Species Dynamics in the Black Sea: Environmental Influences & Species Interactions

1. Native and non-native gelatinous species in the Black Sea Tamara Shiganova P.P.Shirshov Institute of Oceanology RAS Moscow, Russia shiganov@ocean.ru

2. 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

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

4. Euryterm species Warm-water species Cold-water species Euryterm species 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)

5. 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 Warm water species Cold water species Subdivision of the gelatinous species in their relation to mean seasonal, annual and minimal winter SST: analyses offield data according to main component method)

6. Chronolody of the gelatinous species blooms 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)

7. Vertical distribution Termocline Mnemiopsis leidyi and Beroe ovata Noctiluca scintillans Aurelia aurita P. pileus

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

9. Map of first Mnemiopsis leidyi findings 2008 2006 2007 2007 2007 2006 2006 2006 2005 1988 2013 2009 2005 1982 1982 2009 1999 2009 2004-08 1990 1988? 1992 1993 2009

10. 2014 2010 1999 2005 1997 2004 2000 Beroeovata Beroecucumis Beroeforskalii 2011-12 Beroegracilis Shiganova et al, in preparation

11. 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).

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

13. Phenological stages of M.leidyi andB.ovata After Shiganova et al., 2000, 2003; Vinogradov et al., 2001-2006.

14. Seasonal distribution of M.leidyi and B.ovata larvae in warm (2001) and cool (2003) year Shiganova et al., 2000, 2003; Vinogradov et al., 2001-2004.

15. Expansion of gelatinous species from the Mediterranean Sea Bolinopsis vitrea (2009) 2 Chrysaora hysoscella (2009) 8 Chrysaora hysoscella (2002) Cassiopea andromeda(2008) Cotylorhiza tuberculata Chrysaora hysoscella 4 Rhopilema nomadica Cassiopea andromeda Shiganova, Ozturk,2010; Ozturk, Shiganova,2010

16. Mnemiopsis leidyi Beroe ovata Bolinopsis vitrea Pleurobrachia pileus

17. Native species Aurelia aurita Rhisostoma pulmo Possible invader Chrysaura hysoscella

19. 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 “badenvironmental status”