Long-term changes in the benthic communities of the Pomeranian Bay (Southern Baltic Sea)

Helgoland Marine Research, May 2019

Long-term changes in the macrofauna of the Pomeranian Bay were studied by comparing survey data from the 1950s, 1980s, and 1990s. The study area has undergone significant eutrophication during the period of investigation. Biomass of filter-feeding bivalves increased significantly. Spatial distribution patterns of several species have changed. Strong decreases in species richness were caused by oxygen depletion at stations deeper than 15 m.Saduria entomon, Monoporeia affinis, andPontoporeia femorata vanished entirely between 1981 and 1993. Although a causal relationship between simultaneous increases of nutrient levels and macrobenthic biomass cannot be verified, eutrophication is proposed to be the major process affecing changes in macrofauna assemblages. In addition, changes in hydrography and climate increased frequency and severity of oxygen depletion events in the Pomeranian Bay since the mid 1980s.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://hmr.biomedcentral.com/track/pdf/10.1007/BF02908723

Long-term changes in the benthic communities of the Pomeranian Bay (Southern Baltic Sea)

HELGOLJ~NDER MI'ERESI.JNTERSUCHUNGEN Elelgol,~nder b,'leeresunters. Long-term c h a n g e s in the benthic c o m m u n i t i e s of the Pomeranian Bay (Southern Baltic S e a ) J. K u b e ~ F. G o s s e l c k M . P o w i l l e i t ~ J. W a r z o c h a Long-term changes in the macrofauna of the Pomeranian Bay were studied by comparing survey data from the 1950s, 1980s, and 1990s. The studv area has undergone significant eutrophication during the period of investigation. Biomass of filter-feeding blwdves increased signifi~antly. Spatial distribution patterns of several species have changed. Strong decreases in species richness were caused by oxygen depletion at stations deeper than 15 m. Saduria entomon, .Monoporeia u/finis, and Ponloporeiu femorata vanished entirely between t981 and 1993. Although a causal relationship between simultaneous increases of nutrient levels and macroben!hic biomass cannot be veri.~ied, eutrophicat!on is proposed to be the ma~or process affectip,~ changes in macrofauna assemblages. In addition, changes in hydrography dnd climate increased frequency and seventy of oxygen depletion events in the Pomeranian Bay since the mid 1980s. - ~Institute of Baltic S e a R e s e a r c h , S e e s t r a B e 15, D - I 8 I 19 Rostock, G e r m a n y 2Institute of A p p l i e d Ecology, L i n d e n w e g 2, D - 18184 N e u Broderstorf, G e r m a n y r F i s h e r i e s I n s t i t u t e G d y n i a , ul. Kollatoja 1, PL - 81-332 Gd~.'nia, P o l a n d J. Kube, K Gosse/ck, 3,1. Powillelt & .l. Warzocha This paper describes long-term changes in the macrozoobenthic c o m m u n i t i e s of the Pomeranian Bay (southern Baltic Seal by compdring the 1950s with the I980s and 1990s. The P o m e r a n i a n Bay is a shallow transition zone b e t w e e n the Oder Estuary and the d e e p e r Arkona and Bornholm Basins (Fig. 1). Due to its topography a n d hydrography, recent macrofauna communities are influenced by both an increase in organic riverine loads and severe oxygen depletions in the d e e p e r basins (Powilleit et al., 1995; Kube et al., 1996) . The aim of our study is to discuss the long-term c h a n g e s in the macrozoobenthos in relation to fluctuations and long-term trends in the e n v i r o n m e n t a l conditions. MATERIAL AN[) METHODS We c o m p a r e d original data sets from studies carried out from 1955 to 1958 (Lowe, 1963) , [rom I980 to 1982 (Gosselck, 1985; Warzocha, 1995) a n d in 1993 (Powilleit et a l , 1995]. In all studies a heavy, 0.1 m 2 Van Veen grab, a sieve with l-ram m e s h size, and 4% Formalin for storage were used. All investigators collected three s a m p l e s at each station and date. Unfortunately, we do not know how much grabs used d u r i n g different periods of investigation differed r e g a r d i n g the penetration depth and the strength of shock wave. The data sets compared here are based on 58 stations sampled by L6we (1963), 23 stations samp!ed by Gosselck (1985) and Warzocha (199.'5) and 35 stations sampled by Powilleit et al. (1995) . Although all three station grids covered the main habitat types of the study area, sampling sites diltered b e t w e e n investigation periods (Table 1, Fig. 5). The border b e t w e e n Germany and Poland runs through the middle ol the study area and, therelore, till investigations were restricted either to the G e r m a n or Polish part of the bay. Samples were mainly collected outside of the reproduction time in April/May and O c t o b e r / N o v e m b e r . About 20% of the samples were taken in July/August. However, the influence of high spat densities on species a b u n d a n c e s is almost negligible, because most of the juveniles pass through the m e s h e s of the l-ram sieve (Powilleit et al., 1995) . The Pomeranian Bay harbours about 40 different macrofauna species (Kube et al., 1996) but a b u n d a n c e s of only 14 species could be used for a cluster analysis. The patchiiy distributed biue mussel, lMytiM~ edulis, and all associated crustaceans were excluded from the cluster analysis because they cannot be sampled precisely with only three replicate grabs. Due to the patchy distribution of Mytilu.s-clunlps, relative 95%confidence limits were greater than 100% of the m e a n values (Powilleit et al., 1995) . We also had to exclude all small polychaetes and the mud snail HydrobJa ulvae from the cluster analysis because these species w e r e not counted by L6we (1963) and Warzocha (1995) . Furthermore, three infaunal species (Hediste diversicolor, ~Marenzelleria viridis, ,Mya arenaria), burying d e e p e r than 5 cm, w e r e excluded from the cluster analysis. Howe.ver, the species that could be used for the cluster analysis are r e p r e s e n t a t i v e s of all major habitat types of the study area. i.e. the d e e p e r parts along the slopes of the adjacent Arkon,J and Bornholm Basins, the e x p o s e d shallow sandy central parts, and the sheltered river mouth (Table 2). A b u n d a n c e data w e r e also used to plot species distribution maps. The maps w e r e c o m p u t e d by kriging (Cressie, 1991) . Biomass comparisons were restricted to the bivalves ,~1. edulis, NIacoma balthica, and NI. arenaria. T h e s e species account for more than 90% of the total z o o b e n t h i c biomass (Kube et al., 1996) . They are c h a r a c t e r i z e d by d longevity of more than ten years and a low P/B ratio (Kube, 1996b) . Bivalve biomass data at LOwe (1963) and Powilleit et al. (1995) w e r e recalculated by allometric shell length-ash free dry w e i g h t (AFDW) relationships for s a m p l e s taken ~ & ~ ~ ~ = = . . . . ~ S ~ ~ ~ o Long-term changes in the benthic communities ot the Pomeranian Bay in April 1993 (Kube, 1996b) . Biomass data of Gosselck (1985) and Warzocha (1995) w e r e e x c l u d e d from the analysis, b e c a u s e they h a d not m e a s u r e d the shell l e n g t h of bivalves. As already mentioned, the patchily distributed, mobile Mytilus-clumps c a n n o t be s a m p l e d precisely with less than 10 grab subsamples. The data set of L6we (1963) provided e n o u g h parallel grab samples per cluster group to estimate biomass means. Biomass data from Powilleit et al. (1995) w e r e v a l i d a t e d by additional d r e d g e samples and video observations (Kube, 1996b) . Biomass v a l u e s of NI. arenaria o b t a i n e d from Van Veen grab samples r e p r e s e n t only about 70% the standing stock (Powilleit et al., 1995) . L O N G - T E R M VARIABILITY OF E N V I R O N M E N T A L FACTORS O c e a n o g r a p h y The w a t e r column in the P o m e r a n i a n Bay is usually well mixed d o w n to a d e p t h of about 15 m by wind forcing, As a c o n s e q u e n c e , fresh water supplied by river runoff affects the entire w a t e r column (Trzosinska & Cyberska, 1992) . T h e r e is a strong n e g a Fig. 2. Intensity index of inflows of highly saline water into the Baltic Sea (annual maximum) between 1946 and I993 (redrawn from Franck & Matth~ius, 1992, see MatthSus & Franck, 1992 for calculation of the index) . Asterisks indicate benthos investigations. Values above the asterisks give the total number of major inflow events for the ten year periods preceding each benthos investigation tive relationship b e t w e e n runoff data of the O d e r River and annual salinity m e a n s (1950-1992, r = -0.7, p < 0.05, n = 41) . A n n u a l salinity m e a n s s h o w e d no trend within the last 40 years. Values fluctuated b e t w e e n 6-8','~ near the mouth of the O d e r and 7-97~ on its banks INehrinq, 1990; Cyberski, 1992). A strong vertical salinity gradient occurs at the steep northern e d g e s of the bay. The 10~, halocline is k n o w n to fluctuate there b e t w e e n 15-35 m depth n e a r the Arkona Basin and 40-60 m d e p t h ne.ar the Bornholm Basin. C h a n g e s in halocline d e p t h d e p e n d mainly on the f r e q u e n c y and intensity of the inflow of highly saline water from the Kattegat into the Baltic Sea (Nehring et al., 1994; Matthaus & Lass, 1995) . Occasionally, u p w e l l i n g - l i k e e v e n t s are responsible for an uprising of the halocline. As a result, d e e p water from the Arkona Basin p r o p a g a t e s into the bay via the Sassnitz Deep. Such u p w e l l i n g events s o m e t i m e s cause strong stratification in the western part of the P o m e r a n i a n Bay at d e p t h s b e t w e e n 10 and 15 m (Lass, pers. comm.). The o x y g e n of the highly saline d e e p water, inflowing from the North Sea during the winter, is d e p l e t e d during periods of stagnation. Hence, the oxygen concentration of the d e e p w a t e r b e l o w the halocline d e p e n d s on both, on biological activity and on the f r e q u e n c y and intensity of major inflows. Until the 1970s, major inflows were observed more or less regularly (Fig. 2). S e v e n t e e n major inflow events w e r e observed within a period of ten years p r e c e d i n g the investigations of L6we (1963), and e l e v e n inflows occurred within the ten years before the studies carried out by Gosselck (1985) and Warzocha (1995) . A long lasting stagnation period since 1983 resulted in e x t r e m e d e c r e a s e s of o x y g e n concentrations in the Bornholm Basin and, during summer, e v e n in the Arkona Basin (Franck & Matth~ius, 1992; N e h r i n g et al., 1994) . This stagnation period was interrupted in J a n u a r y 1993 (Matth~ius & Lass, 1995) . T e m p e r a t u r e Fluctuations of a n n u a l m e a n s of w a t e r t e m p e r a t u r e in the P o m e r a n i a n Bay are strongly related to the severity of the p r e c e d i n g winter season (Cyberska, 1992). Although the overall trend of the s e v e r e n e s s index of winter seasons is n e g a t i v e (1946-1993, r = -0.21, p >0.05, n = 49) , m e a n s of s e v e r e n e s s indices of a period of ten winter seasons before the b e g i n n i n g of the investigation did not differed (Fig. 3). Differences occurred in the course of the s e v e r e n e s s index over the three ten year periods. W h e r e a s the investigations of L6we (1963), Gosselck (1985), and Warzocha (1995~ followed a period of cold winters p r e c e d e d by a period of mild winters, opposite conditions p r e d a t e d the investigation of Powilleit et al. (1995) . F o o d s u p p l y The nitrogen input of the Oder River increased from 10000-20000 t 9a-1 in the 1960s to 70000-80000 t 9 a Z in the 1990s (Cyberska et al., 1992, 1993; Lampe, 1993) . Surface chlorophyll a concentrations have doubled in the whole study area b e t w e e n 1970 and 1990 (Scbulz & Kaiser, 1986; Nakonieczny et al., 1991; Renk, 1992) . The increase in phytoplankton biomass resulted in a decreasing water transparency and a heavy loss of macrophytobenthos in the adjacent Greifswalder Bodden (Messner & Von Oertzen, 1991}. Long-term changes in the benthic commumties of the Pomeranian Bay Fi(j. 3. Index ot the severity of the winter seasons between 1946/47 cind 1!)94/95 (sum of minus degrees Iddily meansl per winter season, data from the Meteorological Station Warnem/inde, F.R.G.). Thin horizontal line shows the long-term average. Thick horizontal lines show the average for the ten-year periods preceding ectch benthos investigation Furthermore, an increasing a c c u m u l a t i o n of organic matter was o b s e r v e d in sediments of the s h e l t e r e d Greifswalder B o d d e n and in the Sassnitz Deep (Lampe, 1993; Leipe et al., 1995; Nausch, pets. comm.) . However, no accumulation of organic matter was found for sandy sediments of the P o m e r a n i a n Bay a b o v e the 15 m isobath (Neum a n n & Bublitz, 1969; Koine, 1995) . RESULTS L o n g - t e r m c h a n g e s of t h e m a c r o z o o b e n t h o s a s s e m b l a g e s Eight groups of stations were s e p a r a t e d by cluster analysis at a 45% similarity threshold and were c o m p u t e d to spatial distribution maps for all three investigation periods (Figs 4 and 5). The first group c o m b i n e s stations with a high species richness in the southern Arkona Basin. The s e c o n d group covers shallow coastal locations near the O d e r Mouth and n e a r the G r e i f s w a l d e r Bodden. Group three is s e p a r a t e d into two main sub-groups 3a and 3b, r e p r e s e n t i n g e x p o s e d sandy stations on the shallow O d e r Bank and its d e e p e r surroundings, respectively. T h e fourth group contains d e e p e r sites in the southeast of the bay, which are c h a r a c t e r i s e d by low densities of characteristic Distribution pattern of several species u n d e r investigation h a v e c h a n g e d b e t w e e n 1958 and 1993. The crustaceans Monoporeia affinis and Pontoporeia fernorata v a n i s h e d entirely since 1981 (Fig. 6). Only a few single individuals of the isopod Saduria 14~0 J. Kube, ]:. G o s s e l c k , M. Powilleit & J. W a r z o c h a M o n o p o r e i a a f f i n i s P o n t o p o r e i a f e m o r a t a I ' ~ , : ' : i : : ' ~ o . ~ ~ 5 7 .... 9 entomon w e r e f o u n d since 1993. All o t h e r species, that w e r e a b u n d a n t in t h e s o u t h e r n part of the A r k o n a Basin a n d in the S a s s n i t z D e e p b e t w e e n 1955 and 1980 w e r e discove r e d to be v e r y s c a r c e in 1993. T h e c o c k l e C. lamurcki a n d the a m p h i p o d B. pilosa a l m o s t d i s a p p e a r e d from the s o u t h w e s t of t h e s t u d y area. T h e i r d e n s i t i e s r e m a i n e d stable only on the O d e r B a n k (Fig. 7). D e n s i t i e s of t h e a m p h i p o d Corophium volutator h a v e p r o b a b l y i n c r e a s e d n e a r the O d e r M o u t h . No c h a n g e s w e r e o b s e r v e d for the isop o d Cyathura carinata a n d t h e a m p h i p o d Leptocheirus pilosus (Fig. 8). Bathyporeia pilosa Cerastoderma lamarcki 4 " I ~ " . . ~ : ,~ ~ " , ~ i ~ :: ' , . :~:.;::!;; I~ooo ~ ~ooo C h a n g e s in the b i o m a s s d i s t r i b u t i o n p a t t e r n b e t w e e n the 1950s a n d 1990s a r e s h o w n for t h r e e b i v a l v e s p e c i e s in Fig. 9. T h e d i s t r i b u t i o n p a t t e r n of NI. e d u l i s a n d M. a r e n a r i a h a v e not c h a n g e d w i t h i n the p a s t 35 years. T h e b i o m a s s distribution p a t t e r n of M. b a l t h ica in 1993 l o o k e d a l m o s t like an i n v e r s e d p i c t u r e of its 1950s distribution. B i o m a s s v a l u e s of hi. b u l t h i c a h a v e d e c r e a s e d in the s o u t h w e s t a n d i n c r e a s e d north of t h e O d e r Bank. J. K u b e , F. G o s s e l c k , M. Powilleit & J. W a r z o c h a Corophiumvolutator Cyathuracarinata ~ ~ 1981 "'1 T h e m e a n b i o m a s s or M. edulis a n d M. arenaria w a s a b o u t e i g h t t i m e s h i g h e r in 1993 t h a n in t h e 1950s. T h e i n c r e a s e is s t r o n g l y s i g n i f i c a n t . M e a n b i o m a s s v a l u e s of M. balthica s h o w e d n o d i f f e r e n c e b e t w e e n t h e t w o i n v e s t i g a t i o n p e r i o d s ( T a b l e 3). To o b t a i n a m o r e d e t a i l e d v i e w , q u a n t i t a t i v e c h a n g e s in b i v a l v e b i o m a s s e s w e r e a l s o c a l c u l a t e d s e p a r a t e l y for c l u s t e r g r o u p s 3a, 3b, 4 a n d 6 ( T a b l e 3). L a r g e d i f f e r e n c e s o c c u r r e d b e t w e e n t h e c l u s t e r g r o u p s . W h e r e a s t h e b i o m a s s of M. edulis s t r o n g l y i n c r e a s e d in t h e s o u t h w e s t , b i o m a s s v a l u e s d i d n o t i n c r e a s e o n t h e O d e r ', j , ~ ~ - ~ i I ~ ~ g AFDW/m~ 13o 1993 I ~ .: :." g A F D W / m 2 L o n g - t e r m c h a n g e s in t h e b e n t h i c c o m m u n i t i e s of t h e P o m e r a n i a n Bay . ; ,,.i Mytilus edulis < ~ : . . . . " . . ~ ~ 9 . Macoma balthica ~ : , : ~ . J. Kube, F. G o s s e l c k , M. Powilleit & J. W a r z o c h a C o m p a r i n g d a t a that w e r e g a t h e r e d by clilferent samplin~.j m e t h o d s is a g e n e r a l p r o b l e m in e v a l u a t i n g p a s t a n d p r e s e n t d i s t r i b u t i o n p a t t e r n s in t h e b e n t h o s (Reise el al., 1989) . U n f o r t u n a t e l y , i o n f l - t e r m d a t a s e r i e s are o f t e n l a c k i n g for s u b l i t t o r d l m a r i n e a r e a s , d u e to the e n o r m o u s costs of s h i p b o a r d s a m p l i n g . As a c o n s e q u e n c e , a l m o s t all d o c u m e n t a t i o n s of l o n g - t e r m c h a n g e s in t h e m a c r o f a u n a ot t h e Baltic S e a a r e b a s e d on r e i n v e s t i g a t i o n s of a r e a s that h a d b e e n s t u d i e d i n t e n s i v e l y s e v e r a l d e c a d e s a g o {Rosenb e r g & M o l l e r , 1979; C e d e r w a l l & E l m g r e n , 1980; Brey, 19861. For s h a l l o w w a t e r s in the w e s t e r n a n d s o u t h e r n Baltic Sea, w e c o n s i d e r it u n i m p o r l a n t to r e s a m p l e e x a c t l y the s a m e sites in the s a m e s e a s o n , b e c a u s e : 1. R e p o s i t i o n i n 9 the r e s e a r c h v e s s e l on e x a c t l y t h e s a m e s t a t i o n t h a t h a d b e e n s a m p l e d d e c a d e s a g o is i m p o s s i b l e . O u r o w n e x a m i n a t i o n s of the p r e c i s i o n of t h e n a v i g a t i o n s y s t e m w h i c h w a s u s e d in t h e 1950s r e v e a l e d a m a x i m u m e r r o r of +_2 k m for off s h o r e a r e a s w i t h o u t visible l a n d m a r k s . 2. O f t e n , t h e r e are no g r e a t d i f f e r e n c e s in s p e c i e s c o m p o s i t i o n in s a n d y a r e a s , d u e to a very low s p e c i e s r i c h n e s s (Kube, 1992; Kube, 19966; this study) . 3. D e n s i t y v a r i a t i o n s c a n n o t b e r e l a t e d to s e a s o n a l oscillations, p r o v i d e d b y r e p r o d u c tive cycles. T h e y are s u p e r - i m p o s e d by s t o c h a s t i c v a r i a t i o n s in h y d r o g r a p h i c c o n d i tions (Arntz & Rumohr, 1986; Brey, 1986; K u b e , 1992) . 4. A b r a s i o n of s e d i m e n t a n d h e d l o a d t r a n s p o r t i n d u c e d by local w i n d s o f t e n c a u s e c h a n g e s in l a r g e - s c a l e p a t c h i n e s s w h i c h c a n n o t b e c o v e r e d by t a k i n g t h r e e p a r a l l e l g r a b s a m p l e s at a s i n g l e s t a t i o n (Kube, 1996a) . 5. T h e s a m p l i n g s e a s o n h a s n o s t r o n g e l f e c t on e s t i m a t e s of b i o m a s s v a l u e s c a l c u l a t e d from s t a n d a r d i z e d l e n g t h - w e i g h t r e l a t i o n s h i p s of b i v a l v e s w i t h a h i g h l o n g e v i t y a n d low P/B ratio. H e n c e , it s e e m s to us t h a t t h e c o v e r a g e of all i m p o r t a n t h a b i t a t t y p e s a n d a l a r g e n u m b e r of s a m p l e s is m o r e i m p o r t a n t for a s t a t i s t i c a l e v a l u a t i o n t h a n s p a t i a l a n d s e a s o n a l a c c u r a c y . T h e total n u m b e r o| s a m p l e s u s e d in this s t u d y w a s m u c h h i g h e r t h a n t h e s a m p l e s i z e s of t h e i n v e s t i g a t i o n s of C.ederwall & E l m g r e n (1980) a n d Brey (1986) . R e s p o n s e s to e u t r o p h i c a t i o n , a n d f l u c t u a t i o n s i n h y d r o g r a p h y a n d c l i m a t e Spatial variations in the biomass increase ol M. edulis demonstrate how strong limitations by other ecological factors can be. In the P o m e r a n i a n Bay, motile M y t i l u s clumps lay attached to Myaoshells on the sea floor. D e p e n d i n g on the current situation, single clumps can a g g r e g a t e to patches of several square meters or disperse. Perman e n t erosion a n d strong bedload transports on the shallow Oder Bank p r e v e n t a successful s e t t l e m e n t of mussel spat a n d e n c o u r a g e an a c c u m u l a t i o n of m u s s e l - c l u m p s in the d e e p e r southwest of the bay. As a c o n s e q u e n c e , distribution patterns of M. edulis have not c h a n g e d considerably d u r i n g the past 35 years. Below 15 m, all stations showed a decrease in species richness in the 1990s. These c h a n g e s were caused by an increase in oxygen depletion events in the A r k o n a Basin since 1983 and upwe.lling of deep water with lowered oxygen saturation from the Arkona Basin into the P o m e r a n i a n Bay via the Sassnitz Deep. Gosselck (1985) described a rate of increase in m a c r o b e n t h i c biomass of 16'7o - a -~ b e t w e e n the 1950s and 1980s. M. balthica d o m i n a t e d m a c r o b e n t h i c biomass in 1980. Its biomass had increased a n n u a l l y by 53% of the initial value. First signs of macrofauna death in the Arkona Basin were noticed in 1984 (HELCONI, 1990). A c h a n g e in the M. balthica population trom larger to smaller individuals was observed a n d its biomass decreased. The total n u m b e r of speci~;s decreased from ,10 to 20 b e t w e e n 1980 and 1986. T h e reduction in the n u m b e r s of the crustaceans P. fr and Diastylis rathkei was particularly striking. C h a n g e s in the species composition of the m a c r o f a u n a of the P o m e r a n i a n Bay does not result in an increasing proportion of deposit-feeders, as reported previously by other investigators (Help, 1995). Our analyses rather suggest an increase in the portion ot filter-feeders until 1993. A high rate of r e s u s p e n s i o n of p h y t o p l a n k t o n a n d particulate organic matter in the shallow parts of the bay might be the cause for these findings. This hypothesis is supported by the fact that no organic matter was a c c u m u l a t e d in the sediments. Besides eutrophication, some of the observed p h e n o m e n a seem also to be triggered by variations in o c e a n o g r a p h i c a n d climatic conditions. Although c h a n g e s d u e to eutrophication in the benthic c o m m u n i t i e s of the Baltic Sea become more a n d more obvious, we are still u n a b l e to quantify the observed effects. Events of oxygen depletion were found to increase in the southern Baltic Sea since the 1980s (Weigelt, 1991; Franck & Matthaus, 1992) . The large gap of i m p o r t a n t inflow events since 1983 might have b e e n an important cause for the o b s e r v e d drastic c h a n g e s in the oxygen regime of the A r k o n a Basin. Otherwise, the increase in b e n t h i c biomass until the 1980s might have accelerated the speed of oxygen d e p l e t i o n below the pycnocline d u r i n g s u m m e r stratification. Bivalves, the biomass d o m i n a n t s , show highly successful recruitment d u r i n g summers following a cold winter (Beukema, 1982; Kube, 1996a) . This positive effect can establish extraordinarily high biomasses after a series of severe winters d u e to the long life s p a n of bivalves and, therefore, accelerates the speed of biomass i n c r e a s e (Beukema, 1989). Indeed, the p o p u l a t i o n structure of M. arenaria differed strongly b e t w e e n the 1950s a n d the 1990s. W h e r e a s smaller size classes prevailed d u r i n g the late 1950s, the p o p u l a t i o n was d o m i n a t e d by large s p e c i m e n s in 1993 (Kube, 1996a) . This observation agrees with differences in the time course of the winter s e v e r e n e s s index d u r i n g the t e n - y e a r periods p r e c e d i n g both investigations. Acknowledgements. This is publication No. 262 of the Institut f/.ir O s t s e e f o r s c h u n g W a r n e m u n d e , G e r m a n y . This study w a s s u p p o r t e d by the Federal Ministry of Research and Technology (BMBF) u n d e r g r a n t n u m b e r 03F0105B. L I T E R A T U R E C I T E D Fig. 5. Maps showing the spatial pattern of different cluster groups during the investigation periods of L6we ( 1963 ), Gosselck ( 1985 ), Warzocha ( 1995 ), and Powilleit et al. ( 1995 ). Symbols are the same as in Fig. 4. See text for further explanations Andersin , A.-B. , Lassig , J. , Parkkonen , L. & Sandier , H. , 1978 . The decline of m a c r o f a u n a in the d e e p e r parts of the Baltic proper and the Gulf of Finland . - Kieler Meeresforsch . (Sonderh.) 4 , 23 - 52 . Arntz , W. E. & Rumohr , H. , 1986 . Fluctuations of benthic m a c r o l a u n a during s u c c e s s i o n and in e s t a b l i s h e d community . - Meerestorsch . 31 , 97 - 114 . Beukema , J. J. , 1982 . Annual variation in reproductive success and b i o m a s s of the major m a c r o z o o b e n t h i c species living in a tidal flat area of the W a d d e n Sea. - Neth . J. Sea R e s 16 , 37 - 45 . Beukema , J. J. , 1989 . Long-term c h a n g e s in m a c r o z o o b e n t h i c a b u n d a n c e on the tidal flats of the w e s t e r n ~art of the Dutch Wadden Sea . - He!gol~inder M e e r e s u n t e r s 43 405 - 4 ".5. B e u k e m a , J J. , 199l . C h a n g e s in composition of bottom f a u n a of a t i d a l - t l a t a r e a during a period of eutrophication . - Mar. Biol. 11 I , 293 - 301 . Brey , "E , 1986 . Increase in m a c r o z o o b e n t h o s a b o v e the halocline in Kiel Bay c o m p a r i n g the 1960s with the 1980s . - Mar . Ecol. Prog. Ser. 28 , 299 - 302 . Cederwall , H. & Elmgren , R. , 1980 . Biomass increase of benthic m a c r o f a u n a d e m o n s t r a t e s eutrophication of the Baltic Sea . - O p h e h a {Suppl .) 1 , 287 - 304 . Cressie , N . A . C . , 1991 . Statistics for spatial data Wiley, N e w York, 900 pp. C y b e r s k a , B ., 1992 . T h e r m o h a l i n e conditions . - Stud. Nlat. oceanol. 6 I , 73 - 92 . C y b e r s k a , B ., Lauer , Z. & Trzosinska , A. , 1992 . E n v i r o n m e n t a l conditions in the Polish zone ol the s o u t h e r n Baltic Sea during 1991 . Institute of Meterology and Water M a n a g e m e n t , Maritime Branch Materials , Gdynia, 257 p p C y b e r s k a , B ., Lauer , Z. & Trzosinska , A. , 1993 . t-! nvironmental conditions m the Polish zone of the s o u t h e r n Baltic Sea during 1992 . Institute of Meterology a n d Water Nlcmdgement , Maritime Branch Materials, Gdynia, 256 pp. Cyberski , J , 1992 . P,iver outi' low from Poland. - Stud. Mat. oceanol . 61 , 53 - 6b . F o n s e b u s , S. El ., 1972 . On eutrophication a n d pollution in the Baltic Sea . In: Marine pollution and sea life . Ed. by M. Ruivo . Fishing N e w s Books, London, 23 - 28 . Franck , H. & Mett ~-cius, W., ~992. T~'u ,~ bsence of e~'fective maior !ntlo,,,:s and the p r e s e n t c h a n g e s in the h y d r o g r a p h i c conditions of the central Baltic d e e p water . - Proceedings ol the 12th Baltic Nlanne Biologists Symposmnr , l telsingar, D e n m a r k , 25-30 A u g u s t 1991 . Olsen & Olsen, 53 - 60 . Gargas , E. , DahI-Nladsen , K. I. , Schroder, t L & R a s m u s s e n , , 1 ., 1978 . Dynamics of Baltic e c o s y s t e m s a n d c a u s e s of their variability . - Kieler Meeresforsch. (Sonderh.) 4 , 210 - 232 . G~rlach, S. A ., 1994 . O x y g e n conditions i m p r o v e w h e n the salinity in the Baltic Sea decreases . - Mar. Pollut. Bull . 98 , 413 - 416 . Gosselck , F. , 1985 . U n t e r s u c h u n g e n am M a k r o z o o b e n t h o s des A r k o n a b e c k e n s (sfidliche Ostsee) . - Fischerei-Forsch . 23 , 28 - 32 . Gosselck , F. & Georgi , F. , 1984 . Benthic recolonization of the Lfibeck Bay (Western Baltic ) in 1980 /81. - Limnologica 15 , 407 -- 414 . Heip , C. , 1995 . Eutrophication and z o o b e n t h o s dynamics . - O p h e l i a 41 , 113 - 136 . HELCOM , 1990 . S e c o n d periodic a s s e s s m e n t of the state of the m a r i n e e n v i r o n m e n t of the Bdltic Sea area 1984-1988 . Background D o c u m e n t . - Baltic Sea Environ . Proc. 35 B , 1 - 432 . Koine , B. , 1995 . S e d i m e n t u n t e r s u c h u n g e n in der P o m m e r s c h e n Bucht. l)ipl . Arb., T e c h n i s c h e F a c h h o c h s c h u I e Berlin , 50 pp. Kube , J. , 1992 . Das M a k r o z o o b e n t h o s des Windwatts am B o c k - Szenario des J a h r e s 1991. Dipl . Arb., Univ. Rostock, ! 5 ! pp. Kube , J. , 1996a . Spatial and temporal variations in the p o p u l a t i o n structure of the soft-shell clam, M vu arenaria, in the P o m e r a n i a n Bay (Southern Baltic Sea) . - J. Sea Res . 35 , 335 - 344 . Kube , .I, 1996b . The ecology of m a c r o z o o b e n t h o s a n d sea d u c k s in the P o m e r a n i a n Bay. - M e e r e s w i s s . Ber ., W a r n e m f i n d e I8 , 1 - 128 . Kube , J. , Powilleit , M. & Warzocha , J. , 1996 . T h e i m p o r t a n c e of h y d r o d y n a m i c p r o c e s s e s a n d food availability for the structure of m a c r o f a u n a a s s e m b l a g e s in the P o m e r a n i a n Bay. - Arch . Hydrobiol. 138 , 213 - 228 . Lampe , R. , 1993 . E n v i r o n m e n t a l state and material flux in the w e s t e r n part of the O d e r river estuary - results a n d c o n s e q u e n c e s . - P e t e r m a n n s geogr . Mitt . 137 , 275 - 282 . Leipe , T. , N e u m a n n , T . & Emeis , K.-C., 1995 . S c h w e r m e t a l l v e r t e i l u n g in holoziinen O s t s e e s e d i - m e n t e n . - G e o w i s s e n s c h a f t e n 13, 470 - 478 . LOwe , F. - K., 1963 . Quantitative B e n t h o s u n t e r s u c h u n g e n in der Arkonasee . - Mitt. zool. Mus. Berlin 39 , 247 - 349 . Matthaus , W. & Franck , H. , 1992 . Characteristics of major Baltic inflows - d statistical analysis . - Cont. Shelf Res. I2 , 1375 - 1400 . Matth ~ius, W. & Lass , H.-U., 1995 . The recent salt inflow into the Baltic Sea . - J. phys. Oceanogr . 25 , 280 - 286 . Messner , U. & yon Oertzen , J. A. , 1991 . L o n g - t e r m c h a n g e s in the vertical distribution of macrop h y t o b e n t h i c c o m m u n i t i e s in the G r e i f s w d l d e r Bodden. - Acta Ichtyol. Pisc . 21 ( Suppl .), 135 - 144 . Nakonieczny , J.. Ochocki , S. & Renk , H. , 199t . L o n g - t e r m c h a n g e s in primary p r o d u c t i o n and chlorophyll concentrations in the S o u t h e r n Baltic . - Acta Ichtyol . Pisc. 21 ( Suppl .), 145 - 152 . Nehring , D. , 1990 . Die h y d r o g r a p h i s c h - c h e m i s c h e n B e d i n g u n g e n in der westlichen u n d z e n t r a l e n O s t s e e im J a h r e 1989 . - F i s c h F o r s c h 28 , 35 - 44 . Nehring , I ) . Nlatth~ius, W., Lass , H.-U. & Nausch , G. , 1994 . t l y d r o g r a p h i s c h - c h e m i s c h e Z u s t d n d s - e i n s c h a t z u n g der Ostsee 1993 . - M e e r e s w i s s . Ber ., W a r n e m d n d e 7 , 1 - 68 . N e u m a n n , G . & Bublitz . G., 1969 . S e e g r u n d u n t e r s u c h u n g e n im w e s t l i c h e n Teil der Oder-Bucht . - Beitr . NIeeresk. 24/25 , 81 - 109 . Pearson , T. H. & Rosenberg , R. , 1978 . NIdcrohenthic succession in relation to o r g a n i c e n r i c h m e n t a n d pollution of the marine e n v i r o n m e n t . - O c e a n o g r . mar. Biol . 16 , 229 - 3l I. Powilleit , .%l., Kube , J. , Maslowski , J. & Warzocha , J. , 1995 . Distribution of m a c r o b e n t h i c invertebrates in the P o m e r a n i a n Bay (Southern Baltic Sea ) in 1993 /94. - Bull. Sea Fish. Inst. 3 , 75 - 87 . Prena. J. , 1994 . O x y g e n depletion in W i s m a r Bay (Western Baltic Sea ) 1988 . - Arch . Fish. mar. Res . 42 , 77 - 87 . Reise , K. , tIerre, E. & Sturm , NI. 1989 . Historical c h a n g e s in the b e n t h o s of the W a d d e n Se~ a r o u n d the island ot Sylt In the North Sea . - Helgolcinder Nleeresunters . 43 , 417 - 433 . Renk , l I. , 1992 . Primary production and the c o n c e n t r a t i o n of chlorophyll a. - Stud. . Mat. oceanol . 61 , 167 - 180 . Rosenberg , R. & M611er, P. , 1979 . Salinity stratilicated benthic m a c r o f a u n a l c o m m u n i t i e s a n d longterm m o n i t o r i n g along the west coast of S w e d e n . - J . exp. mar. BioI. Ecol 37 , 175 - 203 . Schulz , S. & Kaiser , W. , 1986 . Increasing trends in p l a n k t o n variables in the Baltic Sea - a further sign of eutrophication? - Ophelia (Suppl .) 4 , 249 -- 257 . Trzosinska , A . & C y b e r s k a , B ., 1992 . O x y g e n a n d h y d r o g e n s u l p h i d e . - Stud. Mat. oceanol. 61 , 93 - 100 . Warzocha , J. , 1995 . Classification a n d structure of m a c r o f a u n a l c o m m u n i t i e s in the s o u t h e r n Baltic: . - Arch. Fish. mar. Res . 42 , 225 - 237 . Weigelt , N |., 1991 . Short- and l o n g - t e r m c h a n g e s in the benthic c o m m u n i t y of the d e e p e r parts of Kiel Bay (Western Baltic) due to o x y g e n depletion a n d eutrophication . - M e e r e s t o r s c h u n g 33 , 297 - 311 . Weigelt , NI & Rumohr, H. , 1986 . Effects of w i d e - r a n g e o x y g e n depletion on b e n t h i c f a u n a and demersaL fish in Kiel Bay 1981- 1983 . - M e e r e s f o r s c h u n g 31 , 124 - 136 .


This is a preview of a remote PDF: https://hmr.biomedcentral.com/track/pdf/10.1007/BF02908723

J. Kube, F. Gosselck, M. Powilleit, J. Warzocha. Long-term changes in the benthic communities of the Pomeranian Bay (Southern Baltic Sea), Helgoland Marine Research, 399, DOI: 10.1007/BF02908723