HELGOLANDER MEERESUNTERSUCHUNGEN Helgol~nder Meeresunters. 49, 57-67 (1995)

120 y e a r s of i n v e s t i g a t i o n s o n z o o b e n t h o s in t h e s o u t h e r n Baltic

L. ~mudzinski Marine Biology Centre; Sw. Wojciecha Str. 5, 81-347 Gdynia, Poland and University of Education; Arciszewskiego Str. 22, 76-200 Slupsk, Poland

ABSTRACT: The scheme of macrozoobenthos research development in the southern region of the Baltic Proper is presented here. In the course of a 120-year-long investigation cycle, four different, partly overlapping periods can be distinguished: qualitative investigations, quantitative distribution studies, biomass investigations, and regular monitoring of zoobenthos.

INTRODUCTION The southern Baltic m a c r o b e n t h i c investigations w e r e initiated by a G e r m a n scientist, Karl M6bius, in 1871. The first h u n d r e d years w i t n e s s e d only irregular e x a m i n a t i o n s in wh i ch the y e a r and area w e r e r a n d o m l y chosen. As late as the 1970s, systematic observations of the Baltic m a c r o z o o b e n t h o s w e r e started, w h i ch w e r e partly co o r d i n at ed to m e e t the Helsinki C o n v e n t i o n regulations. M a c r o b e n t h o s research can be divided into four partly o v er l ap p i n g periods accordm g to b e n t h o s - s a m p l i n g performance methods: qualitative and quantitative investigations, biomass investigations, and r e g u la r monitoring.

QUALITATIVE I N V E S T I G A T I O N S T h e first investigation of the southern Baltic m a c r o b e n t h i c i n v e r t e b r a t e composition was carried out in 1871. During the e x p e d i t i o n of a G e r m a n research v e s s e l "Pomm e r a n i a " in 1871, Karl M6bius collected bottom m a c r o i n v e r t e b r a t e s aIong some profiles across s e l e c t e d Baltic Sea areas (Fig. 1). In the southern Baltic. however, the profiles run off the d e e p e s t parts of particular deeps, g o i n g along their e d g e s rather than across them. This i n c l u d e d some shallows important for the fisheries. T h e r e M6bius took benthos s am p l es from 55 stations (Table 1). In 1880, M e y e r and M6biu.s (1882) e x a m i n e d the species composition an d distribution of m a c r o z o o b e n t h o s in the w e s t e r n r e g i o n of the Gulf of Gdafisk, k n o w n as Puck Bay (Fig. 1). It is a shallow area; the d e e p e s t station fixed at the e d g e of the Gdafisk D e e p has a d ep t h of 67 m. Some years later (in 1893), Brandt collected bottom i n v e r t e b r a t e s from the Baltic Sea w h i c h included some areas from the southern Baltic. The n e x t bottom m a c r o f a u n a in v e s ti g a ti on in the o p e n waters of the s o u t h e r n Baltic Sea was carried out by Reibisch (1902) who, in 1901, took samples from o v e r 10 stations situated mainly on the shallower Baltic g r o u n d s important for the fishery (Fig. 2). 9 Biologische Anstalt Helgoland, Hamburg

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120 y e a r s of Baltic z o o b e n t h o s i n v e s t i g a t i o n s

Table 1. Number of macrobenthic stations during the period of qualitative investigations in the southern Baltic. x - up to 5 stations, xx - up to 15 stations, xxx - up to 25 stations, xxxx - over 25 stations Author

Years

Basins Arcona

M~Sbius Meier, M6bius Reibisch Heinen 9 Skorikow ~ Demel Demel Seifert Forsman Jazdzewski

1871 1880 1901 1903-10 1908 1924 1932-35 1936-37 1953-54 1961

Bornholm

Stupsk

xx

xx

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x x x

x

Gdafisk Gottand

xx xxx x

x x x

xxxx xxxx xxxx xx

Number of stations Below Total 40 m 18 5 5 3 4 10 15 13

xxxx

Total

73

55 18 14 7 5 44 64 36 14 26 283

9 The investigations refer only to worms, mainly Polychaetes

At t h e e n d of t h e 19th c e n t u r y a n d in t h e first d e c a d e of this c e n t u r y , t h r e e o t h e r qualitative investigations w e r e carried out on the z o o b e n t h o s . T h e s e dealt with the g e o g r a p h i c a l d i s t r i b u t i o n of w o r m s , m a i n l y p o l y c h a e t e s , in t h e Baltic Sea, a n d t h e y t h r o w s o m e l i g h t u p o n t h e i n t e r s p e c i f i c r e l a t i o n s h i p s at t h a t time. M i c h a e l s e n (1896), S k o r i k o w 11910) a n d H e i n e n (1919) a n a l y s e d t h e r a n g e of p a r t i c u l a r s p e c i e s in t h e Baltic Sea. i n c l u d i n g its s o u t h e r n r e g i o n , or at l e a s t t h e s o u t h w e s t e r n strip. In t h e 1920s a n d 1930s, r e l a t i v e l y t h o r o u g h f a u n a i n v e s t i g a t i o n s w e r e c a r r i e d o u t on t w o s h e l t e r e d c o a s t a l a r e a s , e s p e c i a l l y t h e G r e i f s w a i d e r B o d d e n ISeifert, 1938), a n d P u c k Bay I D e m e l . 1925, 1935), as far as a l o n g t h e s o u t h e a s t e r n r e g i o n of t h e Baltic S e a ( L u n d b e c k . 1929: S k l o w e r . 1930). S o m e w h a t later, v e r y i n t e r e s t i n g f a u n a r e s e a r c h w a s d o n e off t h e K a l m a r f j o r d a n d in t h e n e i g h b o u r i n g p a r t s of t h e B o r n h o l m B a s i n f F o r s m a n , 1956) as w e l l as in P u c k Bay ( J a z d z e w s k i . 1962, 19711. A s t h e e v i d e n c e s h o w s in t h e first r e s e a r c h p e r i o d - t h e q u a l i t a t i v e o n e - t h e s o u t h e r n Baltic z o o b e n t h o s i n v e s t i g a t i o n s w e r e s t a r t e d b y t h e G e r m a n s , w h o w e r e f o l l o w e d b y t h e R u s s i a n s , t h e P o l e s a n d finally t h e S w e d i s h r e s e a r c h e r s . A t t h e t i m e of t h e q u a l i t a t i v e r e s e a r c h , t h e b o t t o m f a u n a s a m p l e s w e r e c o l l e c t e d b y m e a n s of b o t t o m d r e d g i n g d e v i c e s of w h i c h n o p u b h s h e d d e s c r i p t i o n or d i a g r a m w a s i n c l u d e d . Karl M~ibius (1873, 1884) c a l l e d t h e d e v i c e " d i e K u r r e " Until t h e b e g i n n i n g of this c e n t u r y , n o e x a c t g e o g r a p h i c a l p o s i t i o n h a d b e e n s t a t e d ; o n l y s o m e i n d i r e c t l o c a t i o n h a d b e e n g i v e n a c c o r d i n g to t h e d i s t a n c e s f r o m h g h t h o u s e s or o t h e r d i s t i n c t o n s h o r e points. QUANTITATIVE INVESTIGATIONS T h e s e i n v e s t i g a t i o n s of b o t t o m m a c r o f a u n a b e g a n i n t h e first d e c a d e of t h i s c e n t u r y b y a D a n i s h s c i e n t i s t P e t e r s e n {1914~ - t h e i n v e n t o r of t h e first b o t t o m g r a b , l a t e r c a l l e d

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120 years of Baltic zoobenthos investigations

61

"Petersen's Bottom Grab". Petersen confined his research to Danish waters including only a tiny part of the Baltic Proper, i.e. the western edges of the Arcona Basin (Petersen & J e n s e n , 1911). The Swedish scientists, Thulin (1922) & Hessle (1924) conducted quantitative macrobenthic quantitative investigations which were e x t e n d e d to cover the whole of the Arcona Basin a n d northwest region of the Bornholm Basin (Fig, 2). During the years 1932-1938 Mulicki (1938) e x a m i n e d the quantitative distribution of bottom m a c r o f a u n a in the western part of the Gulf of Gdafisk (Fig, 3), h a v i n g o b t a i n e d samples from 72 stations (Table 2). Benthos samples were collected by m e a n s of a smaller bottom grab, k n o w n as the "Ekman Grab". At the e n d of the 1930s and in the second half of the 1940s, a team of Polish biologists were the first to e x a m i n e the Baltic Sea benthos u s i n g diving e q u i p m e n t , i.e. a diving helmet of their own construction. While diving several times in Puck Bay, they collected 40 samples per 0.25 m 2, each time taking them directly from the bottom surface (Bursa et al., 1939; Bursa, 1948; Wojtusiak et al., 1950, 1951). During these investigations one could take into account not only soft bottoms (sandy a n d muddy) but also rocky a n d stony ones, The research results were p r e s e n t e d in very picturesque illustrations, similar to those m a d e by Petersen, the pioneer of the b e n t h o s quantitative investigations (Fig. 4). It seems that, in the second research period of the Baltic Sea zoobenthos, various methods of b e n t h o s sampling were used, This period covered mainly the first decade, and the 1930s a n d 1940s of this century, significantly overlapping with the first a n d the third periods of the m a c r o b e n t h i c investigations.

BIOMASS INVESTIGATIONS The third period of southern Baltic zoobenthos research was started by a G e r m a n scientist H a g m e i e r (1926. 1930, 1987) a n d concentrated not only on species composition records but on the biomass a n d a b u n d a n c e of bottom macrofauna as well. In the years 1925. 1929 a n d 1931, H a g m e i e r collected samples of bottom macrofauna from about 200 stations in the southern Baltic Sea. reporting the total biomass of zoobenthos from each station IRumohr. 1987). Unfortunately, H a g m e m r was interested in a trendy problem at that time. The results of the zoobenthos species distribution often reported only the d o m i n a n t species at particular stations, not always stating the a b u n d a n c e , let aione the biomass of individual species or of the total macrobenthos. In 1948-1954. Demel & Mafikowski (1951), a n d Demel & Mulicki (1954, 1959J c o m m e n c e d a series of macrozoobenthic investigations in the southern Baltic Sea which was r e p e a t e d every couple of years. The results gave a great n u m b e r of samples collected from 272 stations located fairly evenly over all the area, 83 % of them distributed at the depth of over 4 0 m (Table 3) This resulted in a n u m b e r of maps showing the distribution of d o m i n a n t species a n d general macrobenthos biomass. Based on this material, Mulicki {1957, 1959, 1962) could establish the ecological d e m a n d s of basic bottom invertebrate species. He a n a l y s e d their occurrence related to temperature, salinity a n d oxygen in n e a r bottom water a n d also to depth r a n g e a n d bottom type. The research was a classical one. rarely to b e repeated. In 1956 and 1957. Mulicki & Zmudzifiski ~1969) r e t u r n e d to the p r o b l e m of distribution a n d biomass of bottom m a c r o f a u n a i n the southern Baltic Sea. thus discovering vast b e n t h o s deserts in the Bornholm Deed a n d the Gdarisk DeeD. L6we 11963) analvsed

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120 y e a r s of Baltic z o o b e n t h o s i n v e s t i g a t i o n s

63

Table 2. Number of macrobenthic stations during the period of quantitative investigations in the southern Baltic. For m e a n i n g of symbols see legend to Table 1 Author

Basins

Years Arcona

Petersen, J e n s e n 1911 Thulin 1921 Mulicki 1935-38 Bursa et al. 1938 Bursa et al. 1939 Wojtusiak et al. 1946 Wojtusiak et al. 1948

x xx

Bornholm

Slupsk

G d a h s k Gotland

x xxxx xx xx xx xx

Total

N u m b e r of stations Below Total 40 m

10 18

28

2 14 72 9 11 10 10 128

b o t t o m m a c r o f a u n a s t o c k s a t a b o u t t h e s a m e t i m e in t h e A r c o n a a n d i n p a r t of t h e B o r n h o l m B a s i n s b y d r a w i n g s a m p l e s f r o m 177 s t a t i o n s . T h i s e n c o m p a s s e d a h i g h d e n s i t y of s a m p l i n g p o i n t s , as t h e a r e a is n o t l a r g e ( T a b l e 3). In t h e 1960s a n d 1970s, i n t e r e s t i n g c h a n g e s in t h e o c c u r r e n c e of z o o b e n t h o s i n t h e B o r n h o l m D e e p w e r e o b s e r v e d b y L e p p ~ k o s k i (1969, 1975), a n d i n t h e w h o l e s o u t h e r n Baltic b y Z m u d z i f i s k i (1968, 1971, 19761. In t h e 1960s, Z m u d z i n s k i {1967, 1968, 1971, 1976, 1982) a n d O s t r o w s k i & Z m u d z i r i s k i (1982) p e r f o r m e d a h u g e job. i n v e s t i g a t i n g s o u t h e r n Baltic m a c r o z o o b e n t h o s b y t a k i n g s a m p l e s f r o m o v e r 900 s t a t i o n s : 4 1 % of t h e s a m p l e s w e r e t a k e n f r o m a d e p t h of o v e r 4 0 m ( T a b l e 3). T h i s r e s e a r c h w a s c o n t i n u e d i n t h e s e v e n t i e s b y a n u m b e r of s c i e n t i s t s i n c l u d i n g A n d e r s i n e t al. (1977. 1978}, J 6 r v e k f i l g (1979), Z m u d z i f i s k i & O s o w i e c k i (1991), a n d others.

REGULAR MONITORING T o w a r d s t h e e n d of t h e 1970s, s y s t e m a t i c e n w r o n m e n t a l m o n i t o r i n g w a s i n t r o d u c e d , m e e t i n g t h e r e g u l a t i o n s of t h e H e l s i n k i C o n v e n t i o n . T h i s m e a n t t h e c o n t r i b u t i o n of m a n y , p a r t l y a n o n y m o u s , s c i e n t i s t s to s o u t h e r n Baltic m a c r o b e n t h o s i n v e s t i g a t i o n s . M a c r o b e n t h o s s a m p l e s c o l l e c t e d t w i c e a y e a r , as w e l l a s o t h e r m a c r o b e n t h o s m a t e r i a l , e n a b l e d t h e i s s u e s of s e c t i o n s o n b e n t h o s i n " A s s e s s m e n t of t h e S t a t e of t h e Baltic S e a E n v i r o n m e n t " I H E L C O M , 1987, I990: A n d e r s i n e t al.. 1990: Z m u d z i f i s k i et al., 1987) a n d m a n y o t h e r publications.

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120 y e a r s of B a l t i c z o o b e n t h o s

investigations

65

T a b l e 3. N u m b e r of m a c r o b e n t h i c s t a t i o n s d u r i n g t h e e a r l y p e r i o d of b i o m a s s i n v e s t i g a t i o n s in the s o u t h e r n Baltic. For m e a n i n g of s y m b o l s s e e l e g e n d to T a b l e 1

Author

Hagmeier Hagmeier Hagmeier Demel, Mafikowski Demel, Mulicki Demel, Mulicki M u l i c k i , 7_,mudzifi. L6we Zrnudzifiski ~nudzifiski Tulkki Zmudzifiski ~nudzifiski

Years

1925 1929 1931 1948-50 1951-52 1952-54 1956-57 1955-58 1961 1962 1963-64 1963-66 1967-68

Basins Arcona

Bornholm

Slupsk

Gdansk Gotland

xx xx.x xx xx xx xx xxxx xxxx xx

xx xxxx xx xxxx xxxx xxx xxxx x xxx

xx xx x xxx xxxx xx xxxx

xx xx x xxxx xx xxx xxxx

x x x x xx x xxxx

xx

xx xxxx

x

xxx xxxx

xxx xxxx xxxx

xxxx xxxx

xxxx xxxx

Total

LITERATURE

xxx

N u m b e r of stations Below Tot a l 40 m 22 55 13 77 85 64 162 46 41 31 22 50 258

39 98 41 102 102 66 191 177 63 220 24 252 386

913

1722

CITED

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