Capturing of organic carbon and nitrogen in eelgrass sediments of southern Scandinavia

Authors

Carmen Leiva-Dueñas
Anna Elizabeth Løvgren Graversen
Gary T. Banta
Marianne Holmer
Pere Masque, Edith Cowan UniversityFollow
Peter Anton Upadhyay Stæhr
Dorte Krause-Jensen

Document Type

Journal Article

Publication Title

Limnology and Oceanography

Volume

68

Issue

3

First Page

631

Last Page

648

Publisher

Wiley

School

School of Science / Centre for Marine Ecosystems Research

RAS ID

56470

Funders

Australian Research Council. Grant Number: LIEF Project / Velux Fonden. Grant Number: “Blå Skove-Havets skove som kulstofdræn”

Grant Number

ARC Number: LE170100219

Grant Link

http://purl.org/au-research/grants/arc/LE170100219

Comments

Leiva‐Dueñas, C., Graversen, A. E. L., Banta, G. T., Holmer, M., Masque, P., Stæhr, P. A. U., & Krause‐Jensen, D. (2023). Capturing of organic carbon and nitrogen in eelgrass sediments of southern Scandinavia. Limnology and Oceanography, 68(3), 631-648.

https://doi.org/10.1002/lno.12299

Abstract

The ability of seagrass meadows to filter nutrients and capture and store CO₂ and nutrients in the form of organic carbon (OC) and nitrogen (N) in their sediments may help to mitigate local eutrophication as well as climate change via meadow restoration and protection. This study assesses OC and N sediment stocks (top 50 cm) and sequestration rates within Danish eelgrass meadows. At four locations, eelgrass-vegetated and nearby unvegetated plots were studied in protected and exposed areas. The average OC and N sediment 50 cm stocks were 2.6 ± 0.3 kg OC m ^{− 2} and 0.23 ± 0.01 kg N m ^{− 2}, including vegetated and unvegetated plots. In general, OC and N stocks did not differ significantly between eelgrass meadows and unvegetated sediments. Lack of accumulation of excess ²¹⁰Pb suggested sediment erosion or low rates of sediment accumulation at most sites. OC accumulation rates ranged from 6 to 134 g m ^{− 2} yr ^{− 1} and N from 0.7 to 14 g m ^{− 2} yr ^{− 1}. Generalized additive models showed that ≥ 80 % of the variation in sediment OC and N stocks was explained by sediment grain size, organic matter source, and hydrodynamic exposure. Long cores, dated with ²¹⁰Pb, showed declining OC and N densities toward present time, suggesting long-term declines in eelgrass OC and N pools. Estimates of potential nation-wide OC and N accumulation in eelgrass sediments show that they could annually capture up to 0.7 % ± 0.5 % of CO₂ emissions and 6.9 % ± 5.2 % of the total terrestrial N load.

DOI

10.1002/lno.12299

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License