Journal article
Green gravel as a vector of dispersal for kelp restoration
Frontiers in Marine Science, Vol.9, 910417
12/09/2022
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Abstract
Kelp forests are experiencing substantial declines due to climate change, particularly ocean warming and marine heatwaves, and active interventions are necessary to halt this decline. A new restoration approach termed “green gravel” has shown promise as a tool to combat kelp forest loss. In this approach, substrata (i.e. small gravel) are seeded with kelp propagules, reared in controlled conditions in the laboratory before out-planting to degraded reefs. Here, we tested the feasibility of cultivating Australia’s dominant kelp, Ecklonia radiata on green gravel with the aim of optimising the seeding conditions for E.radiata. We seeded substrata (i.e. gravel), that had different surface texture and size, with E. radiata gametophytes at two average seeding densities: high density of ~230 fragments mL-1 and low density of ~115 fragments mL-1. The tested substrata were small basalt, large basalt, crushed laterite and limestone. Gametophytes successfully adhered to all four tested substrata, however, gametophytes that adhered to the limestone gravel (the natural reef type off Western Australia) suffered extreme tissue bleaching likely due to dissolution and decrease in seawater pH. Gametophytes that adhered to the three other test substrata were healthy, fertilised following seeding and microscopic sporophytes were observed attaching to the gravel. Substrata and seeding density did not affect sporophyte growth (i.e. length) at the time of transferring into aquarium tanks (after three months of rearing in incubators) but over time substrata showed a significant effect on maximum lengths. After 12 months in aquarium tanks, sporophytes on both small and large basalt gravel were significantly larger than those on the crushed laterite. Gametophytes were also found to not only survive on the gravel itself but also detach from the gravel, settle successfully, fertilise and develop into healthy sporophytes ex situ on the surrounding substratum through lateral transfer. Substrata had a significant effect on density of detached gametophytes with rougher and larger gravel showing higher densities of detachment. Our results show the potential for green gravel to be a vector of dispersal for restoration in Western Australia where natural recovery of kelp forests has failed.
Details
- Title
- Green gravel as a vector of dispersal for kelp restoration
- Creators
- Nahlah A. Alsuwaiyan - University of Western AustraliaKaren Filbee-Dexter - Institute of Marine Research, His, NorwaySofie Vranken - University of Western Australia (UWA) Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, Crawley, WA, AustraliaCelina Burkholz - University of Western Australia (UWA) Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, Crawley, WA, AustraliaMarion Cambridge - University of Western Australia (UWA) Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, Crawley, WA, AustraliaMelinda A. Coleman - Southern Cross UniversityThomas Wernberg - Roskilde University
- Publication Details
- Frontiers in Marine Science, Vol.9, 910417
- Publisher
- Frontiers Media S.A
- Grant note
- This work was funded through the Australian Research Council grants DP160100114 (TW, MAC), DP190100058 (TW, MAC, KFD), LP1931001500 (TW, MAC, KF-D) and DE1901006192 (KFD). NAA was supported by a postgraduate scholarship from Qassim University, Kingdom of Saudi Arabia. CB was supported by a Forrest Research Foundation scholarship and Australian Government Research Training Program scholarship
- Identifiers
- 991013051707902368
- Copyright
- © 2022 Alsuwaiyan, Filbee-Dexter, Vranken, Burkholz, Cambridge, Coleman and Wernberg. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
- Academic Unit
- Faculty of Science and Engineering
- Language
- English
- Resource Type
- Journal article