ICES Annual Science Conference Baltic Committee meeting Maastricht

ICES Annual Science Conference Baltic Committee meeting Maastricht, September 18 -23, 2006 Modern development of barrier salinity zones relativity and plurality conception N. V. Aladin, I. S. Plotnikov, M. B. Dianov Zoological Institute of Russian Academy of Sciences, St. Petersburg

Water salinity is one of major environmental factors influencing hydrobionts. Ascertainment of specificity of the attitude of aquatic animals and plants to this factor is important to understand both autoecological and synecologilal rules. Conception of relativity and plurality of water barrier salinity zones was formulated more than 20 years before in the frames of V. V. Khlebovich’s school of thought (Aladin, 1986). Its main theses were published in the Journal of General Biology (Aladin, 1988). Two main theses were stated: 1. Zones of barrier salinities are relative, on the one hand, to the degree of perfection of hydrobionts osmoregulatory capacities and, on the other hand, to the water chemical composition. 2. There are several zones of barrier salinities and they are unequal by their importance.

Zones of barrier salinities and tolerance ranges of hydrobionts from marine and continental waters : horizontal axis – salinity, ‰; over horizontal axis are given salinity tolerance ranges of hydrobionts from marine waters; below horizontal axis – for those from continental waters. Osmoconformers: 1 – I, 2 – II, 3 – III; confohyperosmotics: 4 – I, 5 – II; 6 – hyperosmotics I, 7 –hyperosmotics II or secondary confohyperosmotics; amphiosmotics: 8 – I, 9 – II, 10 – III, 11 – IV; 12 – hypoosmotics; Barrier salinities of marine waters: I M – first, 5 – 8‰, II M – second, 16– 20‰, III M – third, 26– 30‰, IV M – fourth, 36– 40‰, V M – fifth, 50– 55‰; barrier salinities of continental waters : I c – first, 5– 20‰, II c – second, 50– 60‰, III c – third, 100– 300‰ and more; A – marine brackish waters; A* – before “critical salinity” 5– 8‰, A** – after “critical salinity” 5– 8‰, B – typical marine waters, C – marine hyperhaline waters, D – fresh waters, E – continental brackish waters, E*– in the “critical salinity” zone 5– 20‰, E**– after the “critical salinity” zone, F – continental hyperhaline waters. Summarized from: Journal of General Biology, 1988, vol. 67(7): 974 -982.

All the hydrosphere of our planet could be conditionally divided into freshwater, brackish water, marine and hyperhaline zones. Marine zone occupies about 95% of the hydrosphere surface. Freshwater zone occupies about 3%. Brackish water and hyperhaline zones occupy about 0. 5% each. Between these four basic zones there are transitional ones occupying less than 0. 5% each. Approximate boundaries and corresponding barrier salinities are found for all of these basic and transitional zones of the hydrosphere are defined.

Following main principles of conception of relativity and plurality of salinity barrier zones (Aladin, 1986, 1988; Aladin, Plotnikov, 2007) the following salinity zones were suggested for oceanic, Caspian and Aral waters. Zones Ocean Caspian Aral Basic freshwater 0 -2 ‰ 0 -2. 5 ‰ 0 -3 ‰ Transitional freshwater-brackishwater 2 -5 ‰ 2. 5 -7 ‰ 3 -8 ‰ Basic brackishwater 5 -8 ‰ 7 -11 ‰ 8 -13 ‰ Transitional brackishwater-marine 8 -26 ‰ 11 -28 ‰ 13 -29 ‰ Basic marine 26 -40 ‰ 28 -41 ‰ 29 -42 ‰ Transitional marine-hyperhaline 40 -50 ‰ 41 -50. 5 ‰ 42 -51 ‰ Basic hyperhaline > 50 ‰ > 50. 5 ‰ > 51 ‰

Following the main principles of conception of relativity and plurality of salinity barrier zones (Aladin, 1986, 1988; Aladin, Plotnikov, 2007) the following salinity zones were suggested for oceanic, Caspian and Aral waters.

Revealing barrier salinity zones in the hydrosphere supposes studying osmoregulatory capacities of hydrobionts first of all. It is to reveal types of osmotic relations of internal media with the environment, to find experimentally limits of salinity tolerant ranges, to analyze data on salinity boundaries of hydrobionts distribution in the nature.

Classification of osmoconformers and osmoregulators Aquatic organisms Osmoregulators Osmoconformers I Confohyperosmotics Osmoconformers II Hyperosmotics Hypoosmotics Amphyosmotics Osmoconformers III Confohyperosmotics II Hyperosmotics I Amphyosmotics I Hyperosmotics II Amphyosmotics III Amphyosmotics IV

General table of osmoconformers and osmoregulators Osmoconformers Confohyperosmotics Hyperosmotics Amphyosmotics Hypoosmotics I I II II III IV Osmoconformers – majority of recent primary marine hydrobionts: Coeletnterata, Vermes, Mollusca, Arthropoda, Echinodermata, etc. Confohyperosmotics – majority of recent widely euryhaline primary marine hydrobionts: Polychaeta, Gastropoda, Crustacea, etc. Hyperosmotics – majority of recent freshwater hydrobionts: Oligochaeta, Rotatoria, Mollusca, Crustacea, Insecta, freshwater Pisces, etc. Amphyosmotics – some Crustacea, some Insecta, anadrom Pisces. Hypoosmotics – some secondary marine Crustacea, majority of recent secondary marine Pisces.

Evolution of all known types of osmoregulation A 0 – Hypothetic ancestral osmoconformer A 1 – Stenohaline marine hydrobionts (osmoconformers I) A 2 – Marine hydrobionts (osmoconformers II) A 3 – Euryhaline marine hydrobionts (osmoconformers III) B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) C 1 – Freshwater hydrobionts (hyperosmotics I) C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) D 1 – Some Caspian brackish water hydrobionts (amphiosmotics I) D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics)

Different levels of Ostracoda and Branchiopoda occurrence in marine and continental waters (by: Aladin, 1986) Marine waters Levels of occurrence Continental waters Typical marine waters Brackish waters Hyperhaline waters Fresh waters Brackish waters Hyperhaline waters Mass A 1, A 2, E A 3, B 1, B 2, E B 1, E C 1 C 2, D 1, D 3 D 4 Rare A 3, B 1, B 2 - - C 2, D 1, D 3, D 4 - Bringing / invasion D 3, D 4 C 1, C 2, D 1, D 3, D 4 B 1, B 2 A 3, B 1, B 2, E -

The position and width of barrier salinities ranges cannot depend on water physicochemical properties only. The values of barrier salinities can change following evolution of salinity adaptations and osmoregulation capacities of aquatic plants and animals.

α-, β- and g- horohalinicums in the waters classified by salinity (by: Aladin, 1986, 1988; Khlebovich, 1989 )

Special attention needs to be given on comparative analysis of oceanic (thalassic) zones of hydrosphere and those continental (athalassic).

Critical salinity shift to higher concentrations in water of Caspian and Aral seas as compared with oceanic water (by: Aladin, 1986, 1989)

We shall review some water bodies where we had our studies.

Aral Sea before 1960 - Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwater-marine ecosystems

Aral Sea in 1989 - Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwatermarine ecosystems - Marine ecosystems

Aral Sea in 2006 - Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwatermarine ecosystems - Hyperhaline ecosystems

Caspian Sea - Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwatermarine ecosystems - Marine ecosystems - Transitional marinehyperhaline ecosystems - Hyperhaline ecosystems

- Freshwater ecosystems - Transitional freshwater-brackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwater-marine ecosystems - Marine ecosystems - Transitional marine-hyperhaline ecosystems - Hyperhaline ecosystems Sea of Azov

Black Sea - Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwatermarine ecosystems

- Freshwater ecosystems - Transitional freshwaterbrackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwatermarine ecosystems - Marine ecosystems Baltic Sea

- Freshwater ecosystems - Transitional freshwater-brackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwater-marine ecosystems - Marine ecosystems White Sea

- Freshwater ecosystems - Transitional freshwater-brackishwater ecosystems - Brackishwater ecosystems - Transitional brackishwater-marine ecosystems - Marine ecosystems Barentz Sea

Sea of Japan - Marine ecosystems

Ladoga Lake - Freshwater ecosystems

Baltic Sea Caspian Sea of Azov Aral Sea prior 1960 in 2006

Area of different salinity zones in different brackish water seas and lakes

Percentage of water areas of different salinity zones in different brackish water seas and lakes Aral Sea Caspian Black Sea Baltic Zones (in 2006) (prior 1960) Sea of Azov Sea Basic freshwater 0. 01 0. 93 5. 02 0. 25 2. 26 5. 63 Transitional freshwater-brackishwater 0. 04 2. 58 6. 52 0. 03 3. 33 14. 89 Basic brackishwater 0. 23 88. 65 13. 42 0. 02 7. 87 61. 54 20. 71 7. 84 70. 87 99. 70 82. 90 4. 10 Basic marine 0. 00 0. 04 0. 00 1. 15 13. 84 Transitional marine-hyperhaline 0. 00 0. 03 0. 00 0. 53 0. 00 79. 01 0. 00 4. 11 0. 00 1. 96 0. 00 Transitional brackishwater-marine Basic hyperhaline At present Baltic Sea is the only sea where basic brackishwater zone is occupying more than half of its area (> 60%)

There are offered some hypotheses on which basis position of paleo-barrier salinities in water bodies of Parathetys and ancient Baltic Sea is discussed. An attempt is made to apply main principles of the conception to forecast future scenarios of evolution of water bodies anew formed on the place of divided Aral Sea.

1 2 3 4 5 6 7 8 Water bodies of Paleo-Baltic Sea (by Zenkevich, 1963, with corrections and additions) 1 – maximal phase of the last glaciation; 2 - Danish glaciation (15 ths B. P. ); 3 – Baltic Glacial Lake (14 ths B. P. ); 4 – Yoldia Sea (12 ths B. P. ); 5 – Ancylus Lake-Sea (7 ths B. P. ); 6 – last phase of Ancylus Lake-Sea (5 ths B. P. ); 7 – Littorina Sea (4 ths B. P. ); 8 – modern phase (since 2 ths B. P. ) Indicated only average salinity without salinity gradient in the Baltic Sea

Water bodies of the Palaeocaspian A — Balakhansky (5 mil B. P. ); B — Akchagylsky (3 mil B. P. ); C — Postakchagylsky (> 2 mil B. P. ); D — Apsheronsky (2 mil B. P. ); E — Tyurkyansky (< 2 mil B. P. ); F — Bakinsky (1. 7 mil B. P. ); G — Venedsky or Ushtalsky (0. 5 mil B. P. ); H — the Early Khazarsky (400 ths B. P. ); I — the Late Khazarsky; J — Atelsky (> 50 ths B. P. ); K — the Early Khvalynsky; L — Enotaevsky; M — the Late Khvalynsky; N — Mangyshlaksky (7. 5 ths B. P. ); O — the New Caspian (5 ths B. P. ); P — the present. Indicated only average salinity without salinity gradient

Aral Sea: from 9000 to 1600 years BP

Aral Sea: from 450 years BP, till now and in the future

Changing of the species number in the Baltic Sea following salinity gradient

Scheme of aquatic fauna pattern change in water bodies with different salinities (by: Remane, 1934; Khlebovich, 1962; Kinne, 1971; with additions and corrections) 1 – freshwater, 2 – brackish-water, 3 – marine, 4 – hyperhaline and ultrahaline species

Changing of the species number following salinity gradient in the Baltic Sea

Number of fishes, free-living invertebrates and plants without micro-Metazoa, Protozoa and Bacteria in the Baltic Sea By A. Alimov's formula (n=199. 21*S 0. 155) From scientific literature by expert evaluation Baltic Sea Proper 1370 700 Gulf of Finland 982 1000 Bay of Bothnia 1021 1100 Bothnian Sea 1144 1200 Gulf of Riga 896 900 Kattegat 985 4000

Decreasing of marine species biodiversity following decreasing of the Baltic Sea salinity

Scheme of halopathy of main types of aquatic fauna of Azov and Black Seas basin (by: Mordukhai-Boltovskoi, 1953) Abscissa – salinity, ‰; ordinate axis – number of species

Scheme of aquatic fauna pattern change in the Caspian and Aral seas (by: Zenkevich, 1977; Andreeva, Andreev, 2001 with additions and corrections) 1 – freshwater, 2 – brackish-water, 3 – marine species

Percentage of different types of osmoconformers and osmoregulators in the World Ocean and fully saline seas as Barents Sea, Sea of Japan, etc. A 1 – Stenohaline marine hydrobionts (osmoconformers I) – 30% A 2 – Marine hydrobionts (osmoconformers II) - 25% A 3 – Euryhaline marine hydrobionts (osmoconformers III) – 15% B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) – 5% B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) – 3% C 1 – Freshwater hydrobionts (hyperosmotics I) – 0% C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) – 1% D 1 – Some Caspian Brackish water hydrobionts (amphiosmotics I) – 0% D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) – 0% D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) – 1% D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) – 0% E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics) – 20%

Percentage of different types of osmoconformers and osmoregulators in the World Ocean and fully saline seas as Barents Sea, Sea of Japan, etc.

Percentage of different types of osmoconformers and osmoregulators in brackish water seas as Black Sea, Sea of Azov, etc. A 1 – Stenohaline marine hydrobionts (osmoconformers I) – 3% A 2 – Marine hydrobionts (osmoconformers II) - 5% A 3 – Euryhaline marine hydrobionts (osmoconformers III) – 10% B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) – 10% B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) – 15% C 1 – Freshwater hydrobionts (hyperosmotics I) – 5% C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) – 10% D 1 – Some Caspian Brackish water hydrobionts (amphiosmotics I) – 5% D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) – 0% D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) – 5% D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) – 2% E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics) – 30%

Percentage of different types of osmoconformers and osmoregulators in brackish water seas as Black Sea, Sea of Azov, etc.

Percentage of different types of osmoconformers and osmoregulators in freshwater lakes as Ladoga, Onega, etc. A 1 – Stenohaline marine hydrobionts (osmoconformers I) – 0% A 2 – Marine hydrobionts (osmoconformers II) - 0% A 3 – Euryhaline marine hydrobionts (osmoconformers III) – 0% B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) – 0% B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) – 0% C 1 – Freshwater hydrobionts (hyperosmotics I) – 98% C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) – 1% D 1 – Some Caspian Brackish water hydrobionts (amphiosmotics I) – 1% D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) – 0% D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) – 0% D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) – 0% E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics) – 0%

Percentage of different types of osmoconformers and osmoregulators in freshwater lakes as Ladoga, Onega, etc.

Percentage of different types of osmoconformers and osmoregulators in the Baltic Sea A 1 – Stenohaline marine hydrobionts (osmoconformers I) – 0% A 2 – Marine hydrobionts (osmoconformers II) - 0% A 3 – Euryhaline marine hydrobionts (osmoconformers III) – 5% B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) – 15% B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) – 24% C 1 – Freshwater hydrobionts (hyperosmotics I) – 14% C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) – 9% D 1 – Some Caspian Brackish water hydrobionts (amphiosmotics I) – 9% D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) – 0% D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) – 10% D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) – 0% E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics) – 14%

Percentage of different types of osmoconformers and osmoregulators in the Baltic Sea

World Ocean and full-saline seas Brackish water seas as Black Sea, Sea of Azov, etc. Freshwater lakes as Ladoga, Onega, etc. The Baltic Sea

Percentage of different types of osmoconformers and osmoregulators in the Western Baltic, Baltic Sea proper and Archipelago Sea A 1 – Stenohaline marine hydrobionts (osmoconformers I) – 0% A 2 – Marine hydrobionts (osmoconformers II) - 0% A 3 – Euryhaline marine hydrobionts (osmoconformers III) – 10% B 1 – Widely euryhaline marine hydrobionts (confohyperosmotics I) – 20% B 2 – Brackish water hydrobionts of marine origin (confohyperosmotics II) – 25% C 1 – Freshwater hydrobionts (hyperosmotics I) – 2% C 2 – Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) – 5% D 1 – Some Caspian Brackish water hydrobionts (amphiosmotics I) – 10% D 2 – Some euryhaline Australian hydrobionts of freshwater origin (amphiosmotics II) – 0% D 3 – Euryhaline hydrobionts of freshwater origin (amphiosmotics III) – 10% D 4 – Widely euryhaline hydrobionts of freshwater origin (amphiosmotics IV) – 0% E – Euryhaline marine hydrobionts of freshwater origin (hypoosmotics) – 23%

Percentage of different types of osmoconformers and osmoregulators in the Western Baltic, Baltic Sea proper and Archipelago Sea

World Ocean and full-saline seas Brackish water seas as Black Sea, Sea of Azov, etc. Freshwater lakes as Ladoga, Onega, etc. Western Baltic, Baltic Sea proper and Archipelago Sea

The Baltic Sea Kattegat and the Sound Bothnian Bay and Bothnian Sea Gulf of Riga Gulf of Finland Neva bay

Recent invader to the Baltic Sea Evadne anonyx Parthenogenetic female with developing embryos on initial stages in the closed brood pouch

Some Caspian Brackish water hydrobionts (amphiosmotics I) This recent invader could spread all over the Baltic Sea, except of strongly freshened areas of estuaries

Recent invader to the Baltic Sea Evadne anonyx Parthenogenetic female with developing embryos on final stages in the closed brood pouch

“Old” invader to the Baltic Sea Cercopagis pengoi (Photo by Dr. Flinkman)

Brackish water hydrobionts of freshwater origin (hyperosmotics II or secondary confohyperosmotics) This old invader already spread over nearly all the Baltic Sea including estuaries, but excluding saline areas such as the Sound and Kattegat

In the nearest future one more Cladocera could appear in the Baltic Sea: Podonevadne camptonyx. It has the same type of osmoregulation as Evadne anonyx.

Dike in Berg’s strait funded by GEF and Kazakhstan government allowed to improve brackish water environment of Small (Northern) Aral Sea 1960 1989 2006 2011

Prior Ordovician life was only in the ocean. So, barrier salinities in this geological time could be distinguished in thalassic waters only. Athalassic waters in this period were still lifeless and there is no sense to speak about barrier salinities in them. Cambrian thalassic waters were inhabited by trilobites, brachiopods, monoplacophors, hyolithids, and archaeocyatha. However in the late Paleozoic seas crinoids, Echinodermata, brachiopods, graptolites, tabulates and rugose corals. So, the world of marine invertebrates was highly representative and we suppose the in Ordovician in oceanic water there were at least 3 barrier salinities: α-, β- and γ-horohalinicums. As for Precambrian, in Archaean and Proterozoic in oceanic waters possibly there was only one barrier salinity (α- horohalinicum).

In the late Ordovician life left thalassic waters and got into athalassic ones. The process was started by plants and in Silurian invertebrates and in the late Devonian also vertebrates were next to them. So, to speak about barrier salinities in athalassic waters is possible only since Ordovician. Maximal number of barrier salinities in athalassic waters is since Cenozoic apparently. Ancient Caspian can be an example. Up to this time specific fauna of continental brackish waters has been formed. However, even in the early Cenozoic, in thalassic waters there were more barrier salinities (at least 7) while in the athalassic waters they were not more than 5. Because man contributed to invasion of some representatives of thalassic fauna and flora into athalassic waters, now in continental closed water bodies also it is possible to find more that 5 barrier salinities. So, in the Caspian Sea due to invasion of marine invertebrates and fishes number of barrier salinities has exceeded initial 5.

All above-said argumentations are based on evolutionary conception by V. V. Khlebovich (1974, published in Russian)

Perfection of osmoregulation capacities in Ostracoda and Branchiopoda in the evolution process Abscissa – geological time; ordinate – extent of hemolymph osmoregulation perfection (by: Aladin, 1986)

Nowadays conception of relativity and plurality of salinity barrier zones is originally being developed by Prof. S. I. Andreeva. While positions of her barrier salinities are slightly differ from ours, nevertheless we consider her approach to be constructive. (Andreeva, Andreev, 2001, in Russan)

At the conference on the Baltic Sea next year in March (Rostock, Germany) our German colleagues (Steffen Bleich, Martin Powilleit, Torsten Seifert, Gerhard Graf) will report about existence of some barrier salinities (29. 5‰, 18. 5‰, 10‰, 7. 5‰, и 4. 5‰) what also testifies to correctness of our approach. We hope that in the nearest future some barrier salinities will be found in the very narrow range of fresh waters. Conquering by hydrobionts salinity range from 1‰ to almost distilled water was as hard as conquering hyperhaline waters. There are no doubts that it is important to define precisely lower as well as upper barrier salinities confining distribution of hydrobionts in the hydrosphere.

• Authors consider that under umbrella of the responsible organizations new meeting should be held in order to reconsider Global Water Classification regarding salinity. • Since last meeting in Venice more than half of century has gone. New data and hypotheses appeared since than. New brain-storm is needed. • Another international meeting is needed. It should be devoted to aquatic ecosystems classification regarding salinity. Such type of meeting was never held before. It is right time to have it.

Thank you for your attention