Title

Global dataset for carbon and nitrogen stable isotope ratios of lotic periphyton

Authors

Naoto F. Ishikawa^{1, †, *}, Hideyuki Doi^{2, *}, Jacques C. Finlay³

¹Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5 8092 Zürich, Switzerland, naoto.f.ishikawa@gmail.com

²Graduate School of Simulation Studies, University of Hyogo, 7-1-28 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan, hideyuki.doi@icloud.com

³Department of Ecology, Evolution and Behavior, University of Minnesota, 140 Gortner Lab, 1479 Gortner Ave., St. Paul, MN 55108 USA, jfinlay@umn.edu

^†Corresponding author, present address: Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061 Japan

^*Equal contribution

Abstract

Carbon and nitrogen stable isotope ratios (δ¹³C and δ¹⁵ N) have been widely employed in food web analysis. In lotic environments, periphyton is a major primary producer that makes a large contribution to food web production as well as carbon and nitrogen cycling. While the δ¹³C and δ¹⁵N values have many advantages as a natural tracer, the controls over their high spatial and temporal variability in stream periphyton are not well known. Here, we present the global dataset of δ¹³C and δ¹⁵N values of lotic periphyton from 54 published and two unpublished sources, including 978 observations from 148 streams/rivers in 38 regions around the world, from arctic to tropical sites. The 54 published sources were articles recorded during the period of 1994–2016 in 25 academic journals. The two unpublished sources were from the authors’ own data. The dataset showed that δ¹³C and δ¹⁵N values of periphyton ranged from −47.3 to −9.3‰ and from −5.6 to +22.6‰, respectively. The dataset also includes physicochemical factors (altitude, coordinates, catchment area, width, depth, geology, vegetation, canopy coverage, biome, season, presence of anadromous salmon, temperature, pH, current velocity, and discharge), nutrient data (nitrate and ammonium concentrations), and algal attributes (chlorophyll a concentration, algal species compositions, and carbonates removal) in streams/rivers studied, all of which may help interpret the δ¹³C and δ¹⁵N values of periphyton. The metadata file outlines structure of all the data and with references for data sources, providing a resource for future food web studies in stream and river ecosystems.

Keywords

• δ¹⁵N
• δ¹³C
• algae
• food web
• stream
• river
• source
• fractionation
• environmental factors

Introduction

Periphytic algae attached to the surface of submerged substrates (hereafter, periphyton) play an important role as an energy base for lotic invertebrate and fish species. Carbon and nitrogen stable isotope ratios (δ ¹³C and δ¹⁵N) are often useful for distinguishing periphyton from other food sources such as terrestrial organic matters (Finlay 2001). However, considerable variation in both the δ¹³ C and δ¹⁵N values of periphyton (e.g., McCutchan and Lewis 2001; Chessman et al. 2009; Ishikawa et al. 2012) may complicate use of δ¹³C and δ¹⁵N in stream food web studies.

The δ¹³C and δ¹⁵N values of periphyton are largely dependent of fractionation (i.e., isotopic discrimination during uptake of inorganic carbon and nitrogen) and the δ¹³C and δ¹⁵N values of their resources (i.e., dissolved inorganic carbon and nitrogen). It has been suggested that environmental factors such as catchment area, canopy openness, and water current velocity strongly affect carbon isotopic fractionation during algal photosynthesis (Finlay et al. 1999; Doi et al. 2007; Ishikawa et al. 2012). On the other hand, nutrients discharged into streams from terrestrial and marine environments may affect δ¹⁵N values of inorganic nitrogen such as nitrate and ammonium (Harding et al. 2014; Pastor et al. 2014). Therefore, the controlling pathways on both the δ¹³C and δ¹⁵N values of periphyton are highly complicated, and no general model to predict their variability is currently available.

The aim of this data paper is to provide global dataset of the δ¹³C and δ¹⁵N values of periphyton as well as putative controlling variables, using worldwide data collected from a variety of sources including our own unpublished data. This dataset has fundamental information for aquatic ecologists who work on food web science.

Metadata

1. TITLE

Global dataset for carbon and nitrogen stable isotope ratios of lotic periphyton

2. IDENTIFIER

ERDP-2018-04

3. CONTRIBUTORS

A. Dataset Owner

Naoto F. Ishikawa
Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho Yokosuka 237-0061 Japan
+81 46 867 9812
naoto.f.ishikawa@gmail.com; ishikawan@jamstec.go.jp

B. Contact Person

Naoto F. Ishikawa
Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho Yokosuka 237-0061 Japan
+81 46 867 9812
naoto.f.ishikawa@gmail.com; ishikawan@jamstec.go.jp

4. GEOGRAPHIC COVERAGE

68°37’N–25°52.5’S, 151.5561°W–143°20.4’E

5. TEMPORAL COVERAGE

1989–2015 (calendar years when data were collected in the original papers)

6. METHODS

Data gathering

We searched for data from published sources using ISI Web of Science (http://www.isiknowledge.com). Search terms included ‘periphyt*’, ‘algae’, ‘isotope’, and ‘stream’, in accordance with our previous paper (Ishikawa et al. 2012). The search was conducted on 11 January 2016 and returned 256 studies. We also added studies found in the journals Limnology and Oceanography, Freshwater Biology, Journal of the North American Benthological Society, Canadian Journal of Aquatic and Fisheries Science, Hydrobiologia, and Ecology that were not detected in our Web of Science search. Also, we included unpublished data from our own studies.

We selected the studies that provided carbon and nitrogen stable isotope values of stream periphyton. Benthic algae, epilithic algae, filamentous algae, littoral algae, micro algae, epilithon, epiphyton, periphytic biofilms, phototrophic biofilms, and phytomicrobenthos were regarded as periphyton in this study.

Studies were screened according to the following criteria:

1. The study was conducted in a field setting.
2. The study provided periphyton δ¹³C and/or δ¹⁵N.
3. The study did not use ¹³C and ¹⁵N tracer additions.

After this screening, we ultimately selected 54 papers and used 978 data points (including unpublished 260 data points from Hideyuki Doi and Jacques C. Finlay). Materials and methods for the unpublished data are available in Finlay (2001) and Doi et al. (2007). When the papers presented their data in figures, we extracted the data using graph digitizing software PlotDigitizer X ver. 2.0.1 (http://www.surf.nuqe.nagoya-u.ac.jp/~nakahara/Software/PlotDigitizerX/index-e.html).

Putative control variables

Putative control variables for carbon and nitrogen isotopes of periphyton were extracted from individual studies or, for a small number of cases, provided directly by authors. We categorized the biome (alpine; arctic; boreal; subtropical; temperate; tropical) of the study sites from the location of rivers studied. For temperate regions, sampling periods were categorized into groups approximating four seasons (Spring: March-May; Summer: June-August; Autumn: September-November Winter: December-February for Northern hemisphere, Spring: September-November; Summer: December-February; Autumn: March-May; Winter: June-August for Southern hemisphere). Physicochemical factors (altitude, coordinates, catchment area, width, depth, geology, vegetation, canopy coverage, biome, season, presence of anadromous salmon, temperature, pH, current velocity, and discharge), nutrient data (nitrate and ammonium concentrations), and algal attributes (chlorophyll a concentration, algal species compositions, and carbonates removal) in streams/rivers studied, were also obtained.

7. LITERATURE CITED

Chessman BC, Westhorpe DP, Mitrovic SM, Hardwick L (2009) Trophic linkages between periphyton and grazing macroinvertebrates in rivers with different levels of catchment development. Hydrobiologia 625:135–150. doi: 10.1007/s10750-009-9702-3

Doi H, Takemon Y, Ohta T, Ishida Y, Kikuchi E (2007) Effects of reach-scale canopy cover on trophic pathways of caddisfly larvae in a Japanese mountain stream. Mar Freshw Res 58:811–817. doi:10.1071/MF07067

Finlay JC, Power ME, Cabana G (1999) Effects of water velocity on algal carbon isotope ratios: Implications for river food web studies. Limnol Oceanogr 44:1198–1203. doi:10.4319/lo.1999.44.5.1198

Finlay JC (2001) Stable-carbon-isotope ratios of river biota: implications for energy flow in lotic food webs. Ecology 82:1052–1064. doi:10.1890/0012-9658(2001)082[1052:SCIROR]2.0.CO;2

Harding JN, Harding JMS, Reynolds JD (2014) Movers and shakers: nutrient subsidies and benthic disturbance predict biofilm biomass and stable isotope signatures in coastal streams. Freshw Biol 59:1361–1377. doi:10.1111/fwb.12351

Ishikawa NF, Doi H, Finlay JC (2012) Global meta-analysis for controlling factors on carbon stable isotope ratios of lotic periphyton. Oecologia 170:541–549. doi:10.1007/s00442-012-2308-x

McCutchan JH, Lewis WM (2001) Seasonal variation in stable isotope ratios of stream algae. Verh Internat Verein Limnol 27:3304–3307. doi:10.1080/03680770.1998.11902437

Pastor A, Riera JL, Peipoch M, Cañas L, Ribot M, Gacia E, Martí E, Sabater F (2014) Temporal variability of nitrogen stable isotopes in primary uptake compartments in four streams differing in human impacts. Environ Sci Technol 48:6612–6619. doi:10.1021/es405493k

8. DATA STRUCTURE

9. DATASET REFERENCES

10. ACCESSIBILITY

This work is licensed under a Creative Commons Attribution 4.0 International License.

11. ACKNOWLEDGMENTS

N.F.I. was a Research Fellow (25-1021) and an Overseas Research Fellow (28-0214) ofthe Japan Society for the Promotion of Science.