RT journal article
T1 High contribution of an invasive macroalgae species to beach wrack CO2 emissions
A1 Franco Rodil, Iván
A1 Pérez Rodríguez, Valle
A1 Bernal-Ibáñez, Alejandro
A1 Pardiello, Mauro
A1 Soccio, Federica
A1 Gestoso García, Ignacio José
A2 Biología
AB Accumulations of macroalgal wrack are important for adequate functioning of the beach ecosystem. However,the sudden beaching of seaweed masses smothers the coastline and forms decomposing piles on the shore,harming tourism-based economies, but also affecting the beach ecosystem metabolism. The decomposition ofsudden pulses of wrack can modify the biogeochemistry of beach sands and increase greenhouse gas (GHG)emissions. The presence of invasive species in the wrack deposits can superimpose harmful effects on the beachfunctioning. We quantified the wrack biomass of Rugulopteryx okamurae, an invasive species of extreme impact,on five sandy beaches from the Atlantic coast of the Strait of Gibraltar (Spain), and we tested the effects on in siturespiratory CO2 fluxes using an infrared gas analyser. All the beaches showed massive accumulations of Rugulopteryx wrack deposits. However, the biomass changed significantly between beaches, ranging (mean ± SE)from 968.3 ± 287.7 kg m− 1 to 9210 ± 1279.4 kg m− 1 of wet weight. Wrack supported high respiration rates,with CO2 fluxes averaging (±SE) 19.15 ± 5.5 μmol CO2 m− 2 s− 1 across beaches, reaching astounding maximumpeaks of 291 μmol CO2 m− 2 s− 1. The within-beach variability was related to the distance of the wrack depositsfrom the shoreline, as the average metabolic rates tended to increase significantly from the swash to the drift line.Thicker wrack and a more degraded algae stage showed significantly higher CO2 fluxes. We estimated that theannual CO2 flux of R. okamurae in our study area ranged between 0.39 (±0.01) and 23.30 (±11.33) kg C m− 2y− 1. We suggest that massive amounts of beach wrack can become a globally significant contributor to GHGemissions that can offset any potential carbon-sink capacity of macroalgal forests. However, the piles of wracklocated several meters above the drift line showed non-measurable CO2 efflux. Transferring beach wrack fromswash to drier upper-beach areas, a common practice in many coastal regions suffering from massive wrackaccumulations, might help reduce GHG emissions while removing the wrack stockpiles from the intertidal.However, this practice is not necessarily suitable for all beaches and can create ecological and conservationproblems in the dune system. There is an urgent need to implement practical and sustainable managementpractices for massive wrack deposits capable of presenting various solutions to achieve a balance betweenconservation and recreation actions, answering the consequences of a problem that links both, environmentaland economic issues.
PB Elsevier
SN 1095-8630
YR 2024
FD 2024
LK http://hdl.handle.net/10498/35311
UL http://hdl.handle.net/10498/35311
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 15-nov-2026