Decreasing carbonate load of seagrass leaves with increasing latitude

• Published in: Aquatic Botany
• Main Authors: Mazarrasa, Inés, Marbà, Núria, Krause-Jensen, D., Kennedy, Hilary, Santos, Rui, Lovelock, Catherine E., Duarte, Carlos M.
• Other Authors: Biological and Environmental Sciences and Engineering (BESE) Division, Marine Science Program, Red Sea Research Center (RSRC), Global Change Research Group. IMEDEA (CSIC-UIB) Institut Mediterrani d'Estudis Avançats, C/ Miguel Marqués 21, 07190, Esporles (Mallorca), Spain, Environmental Hydraulics Institute “IH Cantabria”, Universidad de Cantabria, Parque Científico y Tecnológico de Cantabria, 39011, Santander, Spain, Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark, Arctic Research Centre, Aarhus University, Ny Munkegade 114, bldg. 1540, 8000, Aarhus, Denmark, School of Ocean Sciences, Bangor University, Askew Street, Menai Bridge, LL59 5AB, United Kingdom, Marine Plant Ecology Research Group, CCMAR – Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal, School of Biological Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier BV 2019
• Subjects: Seagrass; Epiphytes; Carbonate saturation state; Latitude; Greenland
• Online Access: http://hdl.handle.net/10754/656772; https://doi.org/10.1016/j.aquabot.2019.103147

Seagrass meadows play a significant role in the formation of carbonate sediments, serving as a substrate for carbonate-producing epiphyte communities. The magnitude of the epiphyte load depends on plant structural and physiological parameters, related to the time available for epiphyte colonization. Yet, the carbonate accumulation is likely to also depend on the carbonate saturation state of seawater (Ω) that tends to decrease as latitude increases due to decreasing temperature and salinity. A decrease in carbonate accumulation with increasing latitude has already been demonstrated for other carbonate producing communities. The aim of this study was to assess whether there was any correlation between latitude and the epiphyte carbonate load and net carbonate production rate on seagrass leaves. Shoots from 8 different meadows of the Zostera genus distributed across a broad latitudinal range (27 °S to up to 64 °N) were sampled along with measurements of temperature and Ω. The Ω within meadows significantly decreased as latitude increased and temperature decreased. The mean carbonate content and load on seagrass leaves ranged from 17% DW to 36% DW and 0.4–2.3 mg CO3 cm−2, respectively, and the associated mean carbonate net production rate varied from 0.007 to 0.9 mg CO3 cm−2 d-1. Mean carbonate load and net production rates decreased from subtropical and tropical, warmer regions towards subpolar latitudes, consistent with the decrease in Ω. These results point to a latitudinal variation in the contribution of seagrass to the accumulation of carbonates in their sediments which affect important processes occurring in seagrass meadows, such as nutrient cycling, carbon sequestration and sediment accretion. I.M. was supported by a Pre-Doctoral fellowship by the Government of the Balearic Islands, D.K.-J. was supported by the COCOA project under the BONUS program funded by the EU 7th framework program and the Danish Research Council. The study is also a contribution to the Greenland Ecosystem Monitoring programme ...