Title

Phytoplankton species abundance in Lake Kasumigaura (Japan) monitored monthly or biweekly since 1978

AUTHORS

Noriko Takamura and Megumi Nakagawa

Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies

*Author for correspondence: Noriko Takamura

National Institute for Environmental Studies

Email: cebes.data@nies.go.jp

Telephone number: +81-298-50-2471, Fax number: +81-298-50-2577

Address: National Institute for Environmental Studies, Onogawa 16-2, Tsukuba 305-8506, Japan

ABSTRACT

This data paper reports the abundance of phytoplankton species in monthly or biweekly samples collected from May 1978 through March 2010 at two stations on Lake Kasumigaura, a shallow lake that is the second-largest lake in Japan. The data set of quantitatively over several decades is unique among the available published data papers concerning lakes or plankton and continues to be freely available. The monitoring has been performed as a component of the Lake Kasumigaura Long-term Environmental Monitoring program, conducted by the National Institute for Environmental Studies (NIES) since 1977. The data set details 173 phytoplankton species (or taxa), that can be identified by using an optical microscope and records their abundance. The abundance of each species is expressed in units of volume ( µm³) per milliliter of lake water. This approach allows quantitative comparisons among taxa because the cell size of phytoplankton varies by several orders of magnitude among taxa. The phytoplankton data include 39 species (taxa) of Cyanophyta, 67 Chlorophyceae (Chlorophyta), 3 Prasinophyceae (Chlorophyta), 1 Raphidophyceae (Heterokontophyta), 6 Euglenophyceae (Euglenozoa), 4 Dinophyceae (Dinophyta), 38 Bacillariophyceae (Heterokontophyta), 6 Chrysophyceae (Heterokontophyta), 7 Xanthophyceae (Heterokontophyta), 1 Cryptophyceae (Cryptophyta) and 1 Prymnesiophyceae (Haptophyta). The data have been used for ecological and environmental studies and for studies on lake management.

KEYWORDS

Lake Kasumigaura, phytoplankton species (taxa), abundance, biomass, seasonal change, water bloom, eutrophication

INTRODUCTION

There are 478 natural lakes of ≥1 ha in area in Japan (Ministry of Environment of Japan 1993). In most of these lakes, eutrophication occurred during the 1960s and 1970s with the increase in Japan’s economic growth. Therefore, in 1972, the Ministry of Environment Agency began monitoring the water quality (chemical oxygen demand, pH, suspended solids, and dissolved oxygen) of lakes and reservoirs greater than 10 million m³ in volume; the total nitrogen and total phosphorus were added to the variables monitored in 1982. As of 2010, there were 259 lakes and reservoirs in this data set (NIES 2010). In addition, two collections of long-term fishery statistics are provided by the Statistics and Information Department of the Japanese Ministry of Agriculture, Forestry and Fisheries: the Annual Report of Catch Statistics on Fishery and Aquaculture (since 1954) and the Fisheries Census (since 1949) (Katano and Matsuzaki 2012). Thus, both the water quality and commercial fish catch, which indicate two important freshwater ecosystem services, have been prioritized and monitored for many years by the Japanese government.

As a consequence of eutrophication, certain phytoplankton species form conspicuous nuisance algal blooms, which cause hypoxic conditions that kill fish, cause taste and odor problems in drinking water, and produce toxins that affect mammals and other aquatic organisms. Therefore, changes in phytoplankton species composition have become a major concern for both the public and lake managers.

Phytoplankton comprises micro-organisms with high turnover rates and is a unique primary producer in a pelagic ecosystem; therefore even without anthropogenic impacts, the species composition of phytoplankton is variable in response to seasonal changes in the physicochemical environment of the water. Furthermore, the natural and fairly regular seasonality of the phytoplankton community has been easily destroyed by eutrophication, similar to the unexpected outbreaks of some algal blooms, because phytoplankton species react directly to the quantity and quality of their main resources: nitrogen and phosphorus. In addition to eutrophication, global warming, the invasion of alien fish, the degradation and/or loss of the littoral area, and water level control are the main stressors that cause the current biodiversity loss in Japanese lakes (Takamura 2012). These possible stressors gradually or indirectly influence the seasonality of the phytoplankton community over a long period of time and may cause a shift or a discontinuous change in a lake ecosystem through changes in the phytoplankton community. To understand these changes, it is essential to study the data set compiled from long-term monitoring.

This study reports the changes in the abundance of phytoplankton species (taxa) monitored monthly from May 1978 to March 2010 at two stations on Lake Kasumigaura, a shallow and the second largest lake in Japan. The data set is unique among the available published data papers concerning lakes or plankton and continues to be freely available. The abundance of phytoplankton species was expressed as bio-volume (&mirco;m³) per milliliter of lake water. This approach allowed quantitative comparisons among taxa.

The monitoring was performed as a component of the Lake Kasumigaura Long-term Environmental Monitoring program conducted by NIES since 1977. The program includes the collection of data on the water quality, plankton, benthos, and the primary production, and the data set is part of the database of the Lake Kasumigaura Long-term Environmental Monitoring program. Lake Kasumigaura is registered as a core site of the Japan Long-term Ecological Research Network (JaLTER), a member of the International Long-term Ecological Research Network (ILTER). This data set can be used for ecological and environmental researches and contributes information for use in further studies.

METADATA

1. Title

Phytoplankton species abundance in Lake Kasumigaura (Japan) monitored monthly or biweekly since 1978

2. Identifier

ERDP-2012-02

3. Contributors

A. Principal investigators

Morihiro Aizaki, Senichi Ebise, Takehiko Fukushima, Toshio Iwakuma, Takayoshi Kawai, Noriko Takamura, Takayuki Hanazato, Yukihiro Nojiri, Masaaki Hosomi, Takanobu Inoue, Hideaki Ozawa, Akira Otsuki, Masayuki Yasuno, Akio Imai, Kazuho Inaba, Noriko Tomioka, Kazuhiro Iwasaki, Ayato Kohzu, Takayuki Satou, Kazuhiro Komatsu, Masami Koshikawa, Kazuo Matsushige, Shin-ichiro Matsuzaki, Megumi Nakagawa, Ryuhei Ueno, Junko Yamamura and Tomiji Hagiwara performed the field survey.

B. Data set Owners

The National Institute for Environmental Studies, Japan and the following individuals are the owners of the data.

C. Data set Creators

Noriko Takamura, Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies

Megumi Nakagawa, Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies

4. Program

A. Title

Lake Kasumigaura Long-term Environmental Monitoring program

B. Personal

Organization: National Institute for Environmental Studies

Address: Onogawa 16-2, Tsukuba 305-8506, Japan

Phone: +81-298-50-2471 (Voice)

Phone: +81-298-50-2577 (fax)

Web Address: http://www.nies.go.jp/

C. Funding

National Institute for Environmental Studies (NIES), Japan

D. Objectives

The National Institute for Environmental Studies (NIES) has conducted monthly monitoring of the water quality, plankton/benthos biomass, and primary production in Lake Kasumigaura since 1977. The monitoring was initiated by several lake scientists of the NIES with the intention of sharing fundamental limnological data for their own research. The monitoring has subsequently been continued for more than 30 years to promote environmental and ecological studies aimed at the recovery of lake environments.

5. Geographic coverage

A. Geographic Description

Nishi-ura of Lake Kasumigaura, Japan

B. Geographical Position

Station 3: 36°07.302′ 140°22.652′ (WGS84)

Station 9: 36°02.142′ 140°24.222′ (WGS84)

6. Temporal coverage

A. Begin

May 1978

B. End

March 2012

7. Taxonomic coverage

The data include 39 species (taxa) of Cyanophyta, 71 Chlorophyceae (Chlorophyta), 3 Prasinophyceae (Chlorophyta), 1 Raphidophyceae (Heterokontophyta), 6 Euglenophyceae (Euglenozoa), 4 Dinophyceae (Dinophyta), 38 Bacillariophyceae (Heterokontophyta), 6 Chrysophyceae (Heterokontophyta), 7 Xanthophyceae (Heterokontophyta) , 1 Cryptophyceae (Cryptophyta) and 1 Prymnesiophyceae (Haptophyta).

8. Methods

A. Study sites

Lake Kasumigaura (Figure 1) is located approximately 60 km northeast of the Tokyo metropolitan area. It is the second-largest lake in Japan (surface area of 220 km², a total volume of 0.85 billion m³) and is shallow (mean depth of 4 m, maximum depth of 7 m), with a catchment area of 2157 km². The lake is composed of three parts: Nishi-ura, Kita-ura and Sotonasaka-ura. Nishi-ura, the largest part of the lake, has a surface area of 167.7 km² and a total volume of 662 million m³. This part of the lake has 29 inflows and 1 major outflow. The Lake Kasumigaura Long-term Environmental Monitoring program is conducted at 10 sites in Nishi-ura, and the phytoplankton species abundance is monitored at 2 sites. The annual means of the transparency and the concentrations of the total phosphorus (TP), total nitrogen (TN), chlorophyll a (Chl.a), and suspended solids (SS) at the two sites from 1978 and 2009 are shown in Figure 2. The history of the lake alterations by recent human activities and the associated environmental problems are summarized in Takamura (2012).

Fig.1. Sampling sites in Lake Kasumigaura (Nishi-ura).

Fig.2. Changes in the annul means of the a) transparency, b) concentrations of the total phosphorus (TP), c) total nitrogen (TN), d) chlorophyll a (Chl.a), and e) suspended solids (SS) at Sta.3 and Sta.9.

B. Sampling, sample preservation and counting methods

Water samples were taken monthly or biweekly with a Van Dorn sampler at a depth of 0.5 m until March 1981, but the sampling method changed in April 1981 to the use of a column sampler from the surface to a depth of 2.0 m. The sample was immediately fixed with Lugol’s iodine solution. We counted the cells or units of each phytoplankton taxon under an inverted microscope with a Utermöhl chamber (1958) and then multiplied the volumes of the cell or unit of each taxon, making differential measurement for approximately 30 cells or units, according to Wetzel and Likens (1990). Microcystis cells were counted with a hemocytometer after dispersal of the colonial cell by ultrasonic disintegration (20 kHz, 60 sec.).

C. Taxonomy and systematics

The textbooks used for identification were Geitler (1932) and Watanabe (1999) for Cyanophyceae, Ettl (1978) for Xanthophyceae, Starmach (1985) for Chrysophyceae and Haptophyceae, Krammer and Lange-Bertalot (1986; 1988; 1991a, b) for Bacillariophyceae, Popovský and Pfiester (1990) for Dinophyceae, Mizuno and Tahahashi (2000) for Prasinophyceae, Raphidophyceae, Cryptophyceae, and Vovocales, Huber-Pestalozzi (1955) for Euglenophyceae, and Komárek and Fott (1983) for Chlorophyceae without Vovocales.

The alga belonging to the genus Anabaena can be identified based on akinates’ shape and the alignment of akinates and heterocysts inside its colony or filament. Therefore, when we did not encounter such a colony or filament with akinates and heterocysts in the sample, we identified it as Anabaena spp.

D. Data verification procedures

The data were manually digitized and checked for typographical errors by the investigators. If any unreliable value remained, it was recorded as an error (see section11.D).

9. Data Status

A. Latest Update

7 March 2012

The dates of the data collection span the period May 1978 - March 2012. Data will be collected continuously after March 2012 and the database will be updated as the data are verified.

B. Metadata status

Metadata are complete for this period and stored with the data

10. Accessibility

A. License and Usage Rights

1) Acceptable use. The data set should not be used for illegal purpose or to violate the rights of the others. Use of the data set will be restricted to academic, research, educational, government, or other not-for-profit professional purposes. Data users need to agree to the terms of use for NIES Lake Kasumigaura Database (http://db.cger.nies.go.jp/gem/moni-e/inter/GEMS/database/kasumi/contents/terms.html). Please make sure to contact the data manager of Lake Kasumigaura Database by email (cebes.data@nies.go.jp) before using the dataset.

2) Citation. Data users should properly cite this data paper in any publications or in the metadata of any derived data products that were produced using the data set. As the metadata and the data set can be updated at any time, the date of update should be shown in bibliography.

3) Acknowledgement. To support this long-term monitoring activity, data users should write acknowledgements in any publications to whose content the data set contributed as follows: “Data for XXX was provided by the Lake Kasumigaura Long-term Environmental Monitoring program of the National Institute for Environmental Studies, Japan.”

4) Notification. Data users should notify the Data set Contact when any derivative work or publication based on or derived from the Data set is distributed. Inform the Data set Contact with two reprints or a PDF file of any publications resulting from the use of the data set.

5) Collaboration. Data users are strongly encouraged to consider consultation, collaboration and/or co-authorship with the data owners.

6) Disclaimer. In no event shall the authors, data owners, or the National Institute for Environmental Studies be liable for a loss of profits or for any indirect, incidental damages arising from the use or interpretation of the data.

B. Contact

Data set Contact

Noriko Takamura or Megumi Nakagawa

Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba 305-8506, Japan

Telephone number: +81-298-50-2471

Email: cebes.data@nies.go.jp

E. Storage location

http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2012-02.1/default

The data owners and the National Institute for Environmental Studies store the original data.

11. Data Structure

A. Data tables

B. Format type

The data files are in ASCII text, comma delimited (csv).

C. Header information

Headers corresponding to variable names (see section 11.D) are included in the first row in the data files.

D. Variable definitions

The variables are listed in the order they appear in the data file. The variable names are headers included as the first row in the data file. “.” indicates that we did not encounter species during our counting procedure. This means that the bio-volume of the species was less than the minimum numerical value in the range of numerical values shown in the below table.

12. Supplementary information

The data in this data paper represent part of the database of the Lake Kasumigaura Long-term Environmental Monitoring program. This monitoring program has been conducted by NIES since 1977, and the data in this data paper are therefore, fully identical to the data reported on the Japanese ( http://db.cger.nies.go.jp/gem/inter/GEMS/database/kasumi/index.html ) and English ( http://db.cger.nies.go.jp/gem/moni-e/inter/GEMS/database/kasumi/index.html ) websites of NIES, Japan.

The Lake Kasumigaura Long-term Environmental Monitoring program measures selected environmental variables (water temperature, water depth, transparency, dissolved oxygen, pH, and light intensity in the water), water quality (EC, COD, Chl.a, SS, POC, PON, TP, DTP, SRP, TN, DTN,NH₄-N, NO₂-N+NO₃-N, Al, B, Ba, Ca, Fe, K, Mg, Mn, Na, Si, Sr, and Cu), plankton (bacteria, HNFs, ciliates, picocyanobacteria, eukaryotic picoplankton, phytoplankton, rotifer, crustacean zooplankton, and mysids), benthos (chironomids and oligochaetes), and primary production. The data of the densities of bacteria, picophytoplankton, heterotrophic nanoflagellates and ciliates monitored monthly since 1996 were published as a data paper by Takamura and Nakagawa (2012).

A list of publications associated with the Lake Kasumigaura Long-term Environmental Monitoring program is shown on the website http://db.cger.nies.go.jp/gem/inter/GEMS/database/kasumi/contents/research.html .

13. Acknowledgements

The publication of this data paper was encouraged by the partial support of J-BON (Japan Biodiversity Observation Network) and the Environmental Research and Technology Development Fund (S9) of the Ministry of the Environment, Japan.

14. Literature cited

Ettl H (1978) Xanthophyceae. In: Ettl H, Gerloff J, Heynig H (eds) Süβwasserflora von Mitteleuropa, 3. Gustav Fischer Verlag, Stuttgart

Geitler L (1932) Cyanophyceae. In: Rabenhorst L (ed) Kryptogamenflora von Deutschland, Österreich und der Schweiz, 14. Academische Verlagsgesellschaft, Leipzig

Huber-Pestalozzi G (1955) Euglenophyceen. In: Huber-Pestalozzi G (ed) Das Phytoplankton des Süβwassers, 4. Schweizerbart’sch Verlagsbuchhandlung, Stuttgart

Katano O, Matsuzaki SS (2012) Biodiversity of freshwater fishes in Japan in relation to inland fisheries. In: Nakano S, Yahara T, Nakashizuka T (eds) Biodiversity Observation Network in Asia-Pacific region: Towards further development of monitoring activities, Springer, Tokyo

Komárek J, Fott B (1983) Chlorophyceae Ordnung: Chlorococcales. In: Huber-Pestalozzi G (ed) Das Phytoplankton des Süβwassers, 7. Schweizerbart’sch Verlagsbuchhandlung, Stuttgart

Krammer K, Lange-Bertalot H (1986) Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl H, Gerlo J, Heynig H (eds) Süβwasserflora von Mitteleuropa, 2/1. Gustav Fischer Verlag, Stuttgart

Krammer K, Lange-Bertalot H (1988) Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. In: Ettl H, Gerlo J ,Heynig H (eds) Süβwasserflora von Mitteleuropa, 2/2. Gustav Fischer Verlag, Stuttgart

Krammer K, Lange-Bertalot H (1991a) Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In: Ettl H, Gerlo J, Heynig H (eds) Süβwasserflora von Mitteleuropa, 2/3. Gustav Fischer Verlag, Stuttgart

Krammer K, Lange-Bertalot H (1991b) Bacillariophyceae. 4. Teil: Acnanthaceae. In: Ettl H, Gerlo J, Heynig H (eds) Süβwasserflora von Mitteleuropa, 2/4. Gustav Fischer Verlag, Stuttgart

Ministry of Environment of Japan (1993) The 4^th National Survey on the Natural Environment. Accessed 1 July 2010 http://www.biodic.go.jp/reports2/4th/kosho/4_kosho_all.pdf

Mizuno T, Tahakashi E (2000) An Illustrated Guide to Freshwater Zooplankton in Japan (in Japanese). Tokai University Press, Tokyo

National Institute for Environmental Studies (2010) Data of water quality in rivers, lakes and sea. Accessed 31 July 2010. http://www.nies.go.jp/igreen/index.html

Popovský J, Pfiester LA (1990) Dinophyceae. In: Ettl H, Gerloff J, Heynig H (eds) Süβwasserflora von Mitteleuropa. 6, Gustav Fischer Verlag, Stuttgart

Starmach K (1985) Chrysophyceae und Haptophyceae. In: Ettl H, Gerloff J, Heynig H, Mollenhauer D (eds) Süβwasserflora von Mitteleuropa, 1. Gustav Fischer Verlag, Stuttgart

Takamura N (2012) The status of biodiversity loss in lakes and ponds in Japan. In: Nakano S, Yahara T, Nakashizuka T (eds) Biodiversity Observation Network in Asia-Pacific region: Towards further development of monitoring activities, Springer, Tokyo

Takamura N, Nakagawa M (2012) The densities of bacteria, picophytoplankton, heterotrophic nanoflagellates and ciliates in Lake Kasumigaura (Japan) monitored monthly since 1996.Ecol. Res. (printing)

Utermöhl H (1958): Zur Vervollkommung der quantitative phytoplankton-Methodik. Internationale Vereinigung für theoretishe und angewandte Limnologie, Mitteilungen 9:1-38

Watanabe M (1999) Nihon-no Aoko (in Japanese). National Museum of Nature and Science, Tokyo

Wetzel RG, Likens GE (1990) Limnological Analyses. Springer-Verlag, New York