Phytoplankton dynamics in relation to physicochemical conditions in large, stratified Lake Charzykowskie (Northern Poland)

Figure 1

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Figure 4

Selected physicochemical parameters of water in Lake Charzykowskie in 2014-2015

parameter	2014			2015
	mean	range	±SD	mean	range	±SD
	Secchi depth (m)	2.8	1.9-5.5	1.2	2.4	1.7-4.1	0.7
Dissolved oxygen (mg l-1)	8.3	4.8-10.6	2.1	9.3	7.5-11.4	1.2
Water temperature (°C)	20.0	15.4-25.0	3.6	18.4	15.0-21.3	2.7
pH	8.0	6.7-8.5	0.6	7.9	6.8-8.5	0.6
Electrolytic conductivity (µS cm-1)	329	317-348	9.3	332	302-357	14.9
Chlorophyll a (µg l-1)	25.41	2.27-78.32	21.80	12.44	2.9-21.31	5.26
TP (mg l-1)	0.101	0.015-0.300	0.10	0.149	0.045-0.496	0.12
TN (mg l-1)	3.45	1.65-5.25	1.2	3.49	0.33-8.73	2.07

Statistically significant values of Pearson correlation between environmental parameters and phytoplankton biomass (p≤0_05, bold p≤ 0_001)

	WT	SD	EC	pH	DO	N-NH4	N-NO2	N-NO3	TN	P-PO4	Chl a	Dino	Eugl
SD	-0.5113
EC		0.4992
pH	0.6326	-0.5742
DO			0.5258
N-NH4	0.6409	-0.4101		0.5970
N-NO2			0.5213		0.6334
N-NO3					-0.4384		-0.5323
TN			-0.4358
P-PO,								0.3837
Chl a				0.4079		0.5159
Cyano			-0.5017	0.3930	-0.5295		-0.5646		0.3757
Crypto	1-0.4153
Dino	0.7098	-0.4801				0.4615
Eugl										0.4925
Chryso									0.5305				0.7463
Bacill												-0.3932
Chloro						0.5316					0.6312
B phyto	0.6959	-0.6359	-0.3842	0.4268		0.4338						0.8959

Structural changes in phytoplankton of Lake Charzykowskie in 1947-2015

Date of studies Authors	Chl a (µg l-1)	Biomass (µg l-1)	Dominants and subdominants	Strategy	FGs	Traits of phytoplankton	Trophic status
1947(Cabejszek 1950)		0.72	Aulacoseira granulataAphanizomenon HosaquaeMicrocystis aeruginosa	RSS	PH1LM	diatomaceous and cyanobacterial	β-mesotrophy
1954-1955(Solski 1962)	4.5-73.5						?eutrophy
1968(Szulkowska-Wojaczek 1978)		2.44	Fragilaria crotonensisMicrocystis aeruginosa	R	P	cyanobacterial and diatomaceous	eutrophy
1976(Szulkowska-Wojaczek 1978)		1.26	Microcystis aeruginosa Oscillatoria n.det.	S	LM	cyanobacterial bloom	eutrophy
1987-1990(Wiśniewska 1994)	1.33-90.8	0.5-43.4	Aulacoseira granulataCyclotella sp. div.Microcystis aeruginosaAphanizomenon flos-aquae	RCRSS	P-LMH1	diatomaceous and cyanobacterial bloom	hypertrophy
1999(Wiśniewska 2000)	4.2-28.3	0.06-10.4	Fragilaria crotonensisCeratium hirundinellaAphanizomenon flos-aquaeMicrocystis aeruginosa	RSSS	PLMH1LM	diatoms, dinoflagellates, cyanobacteria	eutrophy
2004(Wiśniewska 2005)	8.3-49.4	1.8-107.4	Asterionella formosaFragilaria crotonensisCeratium hirundinellaAulacoseira granulataMicrocystis aeruginosa	RRSRS	CPLMHPLM	diatoms, dinoflagellates, cyanobacteria	hypertrophy
2008(Luścińska & Wiśniewska 2012)		1.1-11.0	Stephanodiscus neoastrea, S. alpinusAulacoseira islandicaCeratium hirundinellaAphanothece minutissima	CCSCS	CPLML	diatoms and dinoflagellates	meso-eutrophy
2009(Luścińska & Wiśniewska 2012)		3.3-7.6	Plagioselmis sp.Microcystis wesenbergiiCeratium hirundinella	CSS	X2LMLM	cryptophytes, cryptophytes, dinoflagellates	meso-eutrophy
2014(Wiśniewska & Dembowska this article)	2.27-78.32	0.3-37.82	Stephanodiscus neoastrea, S. alpinusAulacoseira islandicaCeratium hirundinella	CSS	CPLM	diatoms and dinoflagellates	meso-eutrophy
2015 (Wiśniewska & Dembowska this article)	2.9-21.31	0.5-11.3	Plagioselmis sp.Microcystis wesenbergiiCeratium hirundinellaFragilaria crotonensis	CSSR	X2LMLMP	cryptophytes, cyanobacteria, dinoflagellates	meso-eutrophy

Main functional groups in Lake Charzykowskie and representative species in each group (after Reynolds et al_ 2002; Padisák et al_ 2009) FG Representative species

FG	Representative species	Physiological characteristics
B	Aulacoseira islandica Stephanodiscus neoastraea	Mixed, mesotrophic small- and medium-sized lakes, sensitive to the onset of stratification, adapted to low light, sensitive to pH increase, Si depletion, stratification
C	Asterionella formosa	Mixed, eutrophic small- and medium-sized lakes with species sensitive to the onset of stratification, sensitive to Si depletion
o	Fragilaria crotonensis Aulacoseira granulata A. granulata var. angustissima Staurastrum gracile S. chaetoceras Staurastrum sp.	Eutrophic epilimnia, tolerant of carbon dioxide depletion, more eutrophic waters, sensitive to Si depletion, stratification
LM	Microcystis sp. Ceratium hirundinella C. furcoides	Summer epilimnia in eutrophic lakes, low light and very low C tolerant, sensitive to mixing and poor stratification
H2	Gloeotrichia echinulata Anabaena lemmermanii	Oligo-mesotrophic, deep, stratified lakes, with good light conditions, tolerant to low nitrogen, sensitive to mixing, poor light
HI	Aphanizomenon spp. Dolichospermum spiroides	Eutrophic, both stratified and shallow lakes with low nitrogen and low carbon, sensitive to mixing, poor light and low phosphorus
X2	Plagioselmis	Shallow, clear, mixed layers in meso-eutrophic lakes, tolerance to stratification, sensitive to mixing and filter-feeding grazers, reduced grazing leads to high relative biomass
G	Eudorina Volvox	Nutrient-rich conditions in stagnant water columns, small eutrophic lakes and very stable phases in larger river-fed basins and storage reservoirs
K (L)?	Aphanothece Aphanocapsa	Aphanothece and Aphanocapsa colonies are often found late summer in epilimnion of oligotrophic, deep lakes