19.5° 20.0° 20.5° 21.0° CLIMATECLIMATE CHANGE:CHANGE: HOWHOW DOESDOES THISTHIS INFLUENCEINFLUENCE ONON HARMFULHARMFUL Klaipeda ALGALALGAL BLOOMSBLOOMS ININ THETHE LAGOONLAGOON OFOF THETHE BALTICBALTIC SEA?SEA? 12 11 55.5° AtlanticAtlantic ResearchResearch InstituteInstitute ofof MarineMarine FisheriesFisheries andand OceanographyOceanography SergeSergeii AleksandrovAleksandrov 13 10 5 Dm. Donskoy St., 236022, Kaliningrad, Russia, e-mail: [email protected] 16 9 8 17 7 17,0 t, °C Curonian Lagoon 14 11 10 12 INTRODUCTION 23 6 18 The Curonian and Vistula Lagoons are the largest 16,5 Vistula Lagoon 15 7 6 9 8 5 1 5 lagoons of the Baltic Sea. These Lagoons are similar in 2 3 419 1 2 3 55.0° 16,0 Baltic Sea (coastal area) 4 temperature regimes, however different in continental 22 Zelenogradsk 15,5 Polessk runoff and salinity. The Curonian Lagoon is choke mostly 20 21 Primorsk Kaliningrad freshwater lagoon, while the Vistula Lagoon is restricted 15,0 4 Baltiysk 2 1 brackish water lagoon. 9 10 3 14,5 6 5 RUSSIA In XX century in the Baltic Sea and its coastal areas and 7 54.5° lagoons the nutrients loading increased and warming trend 14,0 is observed (Fig. 1). Reduction of industrial production and 13,5 fertilizers during the economic crisis in Russia resulted in a POLAND decrease of the external nutrients loading by 3-4 times. 13,0 Fig. 2. The mean for the growing season However, in the Lagoons, unlike many inland and coastal 12,5 Fig. 2. The mean for the growing season Fig. 1. Monitoring stations in the Baltic Sea, marine waters, eutrophication of water continues. (April - October) temperature of water 12,0 Vistula and Curonian Lagoons Ongoing eutrophication is one of the most important problems for the lagoon. Eutrophication of the lagoons 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 MATERIAL AND METHODS affects all trophic levels and primarily the intensity of The researches (primary production, phytoplankton development and also at benthic Fig. 2. CAUSES of HARMFUL ALGAL BLOOMS chlorophyll a (Chl), phytoplankton, nutrients communities and fishery. The environmental factors determining level of and others) were carried out monthly from biological production and the trophic status of the lagoon «close type» (Curonian Lagoon). March-April to November at 12 stations in the I) CURONIAN LAGOON Curonian Lagoon and at 9 stations in the The Curonian Lagoon may be characterized as Hypertrophic water body Vistula Lagoon since 1991 to 2014. Location of PP = 360-680 gC·m-2·year-1, hypertrophic water body with "poor" water quality. 3 this stations corresponds to hydrological and Chl = 36-210 mg/m In this choked lagoon the water temperature is key Weak hydrochemical division and covers the environmental factor determining the level of primary water Russian waters (Fig. 2). The database includes production and algae blooms. Climate change in 1990s- Fresh- «Hyperbloom» exchange 3250 stations for the period from 1991 to 2014. water on most 2000s combined with other factors (freshwater conditions, 10 S >2‰ 60 дней of Cyanobacteria 6 3 Long-term data on the water temperature were slow-flow exchange, high nutrients concentrations) creates (0.1 ‰) (Aph. flos-aquae) part of estimated on the basis of daily observations at Salinity of water (the Water exchange (from conditions for Cyanobacteria “hyperblooms” (Fig. 3, 4). data from Ferrarin et al., 2008) lagoon -1 Ferrarin et al., 2008) standard stations in the lagoons. “Hyperblooming” of Cyanobacteria is observed at water (<3 year ) warming-up to 20-22С and the mean water temperature High concentrations of Strong summer 210 Chl a, µg/l 1 2 A t, °C 16,0 above 14.5 С for the growing season. Small fluctuations of total phosphorus (87-260 warming-up μgР/l) and total nitrogen 180 15,5 the mean summer water warming-up (in 2-3ºС) resulted in of water 150 2-4-fold variations of the trophic status indices and (939-3214 μgN/l) (до 22-24 °С) 15,0 120 affected considerably the ecological state (Fig. 5, 6). 14,5 90 14,0 Silts with High external Local 60 During the latest decades the trend towards increase Shallow high nut- nutrients loading (mean climate 13,5 2 30 number of “warm” years has been observed. The water rients (0.8- 2.3 gP/m , depth warming in 2 0 13,0 temperature above 14.5С, typical to “hyperblooming”, was concent- 21-40 gN/m 3.8 m) 1990-2000 observed 3 times in 1970s, 4 times in 1980s, 6 times in Grounds and zones of transit rations in year) Bathymetrical map and accumulation (Ferrarin et al., 2008) (Gudelis, 1959) 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 1990s, and 13 times in 2000s. So, the “hyperblooming” (Chl 260 TP, µg/l t, °C 16,0 1 2 B “a” > 100 µg/l) was observed during 3 years in 1980s in the Fig. 3. The environmental factors determining level of 230 15,5 period of the most intensive nutrients loading, while 11 biological production and the trophic status of the lagoon 200 15,0 years “hyperblooming” were observed in 1990s and 2000s 5 (а) 140 (б) 170 14,5 when the nutrients loading from lagoon watershed area , multiple decreased owing to the economic crisis in Russia. ΣA = 0,045 · t1,41 120 140 14,0 4 1,43 2 ΣA = 1,33 · t R = 0,86, n = 68 100 110 13,5 2 -1 R = 0,86, n = 68 80 13,0 700 А 22 16 B 22 3 80 20 20 ·сут ·мес 600 14 -2 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 18 -1 18 2 60 500 16 12 16 Fig. 5. The mean for the growing season (April - гС·м гС·м 14 ?day 14 40 -3 10 October) Chl “a” (A), total phosphorus (B) and 400 12 t, °С t, 12 1 8 °С t, temperature of water in the Curonian Lagoon 300 10 10 20 °С °С 8 6 8 PP,gС?m Chlorophyll, µg/l . µg/l Chlorophyll, 200 6 6 0 0 Mean annual primary production in 2010- 4 4 2014 (≈600 gC·m-2·year-1) is considerable 100 4 0 3 6 9 12 15 18 21 24 0 3 6 9 12 15 18 21 24 2 2 2 - 0 0 higher, than in the middle of 1970s (300 gC·m 0 0 Fig. 4. Correlation primary production per day (a) and monthly (b) 2·year-1) in the Curonian Lagoon (Fig. 7). The IV V VI VII VIII IX X XI Month IV V VI VII VIII IX X XI and average monthly water temperature local climate warming in the Baltic region Month caused ongoing eutrophication and harmful Fig. 6. The temperature of water and A) concentration of chlorophyll “a”, 700 Vistula Lagoon Curonian Lagoon algae blooms in the Curonian Lagoon despite B) primary production in 2002 (1, 3) and 2003 (2, 4) 650 of significant reduction of nutrients loading. 600 Hypertrophic Harmful algal blooms (Aphanizomenon flos-aquae, -1 550 Microcystis aeruginosa) in July-October (Chl to 700-3400 μg/l) 500 ·year result in deterioration of the water chemical parameters, death -2 450 of fish in the coastal zone of the Curonian Lagoon (Fig. 8, 400 Eutrophic table 2). Algal toxins detected in water, mussels and fish, and gС·m 350 the concentrations of microcystins (0.1-134 μg/l) may exceed Primary production, 300 safe level. Hyperblooms" of Cyanobacteria is the most 250 dangerous for coastal towns (Polessk, Zelenogradsk) and 200 Table 2. Effects of algal blooms in the Southeastern tourist resorts (UNESCO National Park "Curonian Spit"). 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Baltic Sea (including coastal water, lagoons) Fig. 7. Primary production of phytoplankton in lagoons Year Water Type Trophic Effects of Eutrophication and Algal Blooms in the Baltic Sea Table 1. Trophic classification for II) VISTULA LAGOON body status 1) Baltic Sea (including coastal Also, effects of climate change and eutrophication have 1 Curonian Choked Hyper- 1. Hyperblooming of freshwater Cyanobacteria is observed long waters) ( Wasmund et al., 2001) been observed in restricted Vistula Lagoon (Fig. 7). Mean 2) lakes (2OECD, 1982), lagoons Lagoons lagoon trophic period (July-October). Dominant species of Cyanobacteria is the annual temperature increased by 1.4С for 40 years, and toxic and the concentrations of toxins may exceed safe levels. water warming combined with other factors created Trophic 1Chl a 2Chl a PP, Type 2. Accumulation and decomposition of Cyanobacteria results in conditions for phytoplankton “hyperblooms” (70-80 μg status μg/l μg/l gC·m-2·year-1 oxygen deficiency and death of fish in the coastal zone. Chl/l) in 1995-2010. Mean annual primary production in Oligotrophic < 0.8 < 2.5 < 100 3. The pathological changes in zooplankton and fish were similar to 2000s (430 gC·m-2·year-1) is considerable higher, than in Mesotrophic 0.8-4,0 2.5-8 100 – 200 the symptoms of affected by toxins of Cyanobacteria. -2 -1 the middle of 1970s (300 gC·m ·year ). The climate Eutrophic 4.1-10 8-35 250 – 400 4. Phytoplankton production (≈600 gС/(m2·year) exceeds mineraliza- warming was cause ongoing eutrophication and harmful tion of organic matter (on 60%).