Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies
Abstract
1. Introduction
2. Materials and Methods
2.1. Calculation of the Insulation Properties
- Variant 1: Façade insulation
- Variant 1.1: Façade insulation without vapour barrier
- Variant 1.2: Façade insulation without rear ventilation
- Variant 2: Wooden stud frame
2.2. Expert Interviews
3. Results
3.1. Simulation Results for Seagrass Insulation Assemblies
- Results Variant 1
- Results Variant 1.1
- Results Variant 1.2
- Results Variant 2
3.2. Results from the Expert Interviews
3.2.1. Special Features on the Response Rate
3.2.2. Experience and Key Figures of the Seagrass Industry
- Collection process
- Treatment process
- Quantity of material required
- Areas of application
- Botanical and Ecological Findings
- Beach Wrack
3.2.3. Challenges of the Use of Seagrass
- Time Expenditure
- Economic efficiency
- Ecological Liabilities from Seagrass Use
- Question of the Suitability of Seagrass on Tropical Islands
- Regulatory and Business Hurdles
- General Reasons for low Market Share and Attention
3.2.4. Opportunities Through Seagrass Insulation
- Seagrass Properties
- Ecological Advantages
- Ideas of Dissemination and Use
- Positive Influence in Tourism
4. Discussion
4.1. Recommended Structure
- Family Cymodoceaceae
- ○
- Cymodocea serrulata: One of the dominant species in Palk Bay and the Gulf of Mannar, it thrives in shallow, sandy substrates and is known for its high resilience to environmental stressors.
- ○
- Cymodocea rotundata: Frequently coexisting with C. serrulata, this species is important for stabilizing sediment and providing habitat for marine fauna.
- ○
- Halodule uninervis: A widespread species found in Chilika Lake, Gulf of Mannar, and the Andaman Islands, it plays a crucial role in nutrient cycling and primary production.
- ○
- Halodule pinifolia: Found in the Lakshadweep Islands and shallow coastal areas, this species is highly adapted to varying salinity levels.
- Family Hydrocharitaceae
- ○
- Halophila ovalis: One of the most widely distributed seagrasses in India, occurring in both intertidal and subtidal regions along the east and west coasts. It has high growth rates and colonization potential, making it a key species for seagrass restoration efforts.
- ○
- Halophila beccarii: A vulnerable species found in mangrove-associated ecosystems on both coasts, it thrives in low-salinity, muddy habitats and is highly sensitive to anthropogenic pressures.
- ○
- Enhalus acoroides: The largest seagrass species in India, primarily found in the Andaman and Nicobar Islands, it is important for providing habitat for dugongs and sea turtles.
4.2. Lack of Presence and Acceptance
4.3. Practical and Ecological Considerations for Seagrass Insulation Implementation
4.4. Possible Use of Seagrass Insulation
4.5. Seagrass Management and Sustainable Supply Chains as Ocean Conservation Opportunity
5. Conclusions and Outlook
- Improving public perception and awareness of seagrass as a valuable building material through educational campaigns, industry outreach, and integration into construction guidelines.
- Expanding the study scope to other tropical regions, conducting a systematic stakeholder consultation process, and refining the research methodology for higher significance and applicability.
- Investigating the physical performance of seagrass insulation by analysing its thermal conductivity, moisture regulation, fire resistance, and long-term durability in tropical climates. Developing a dynamic moisture protection model to assess insulation behaviour under varying climatic conditions.
- Assessing local seagrass availability by conducting ecological impact studies and collaborating with policymakers to determine sustainable harvesting guidelines.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
Abbreviations
B | Biology sector |
DAD | External insulation of the roof |
DI | Internal insulation of the ceiling or the roof |
DZ | Inter-rafter insulation of the roof or the upper storey ceiling |
EPS | Expanded polystyrene |
GT | Gigatons |
H | Tourism sector Seychelles |
MT | Megatons |
MDPI | Multidisciplinary Digital Publishing Institute |
PU | Polyurethane |
S | Seagrass insulation sector |
SBS | Seychelles Bureau of Standards |
SPA | Seychelles Planning Authority |
U | Construction company sector |
UNEP | United Nations Environment Programme |
WAB | External insulation of the wall behind the cladding |
WH | Insulation of double walls for core insulation |
WI | Internal wall insulation |
WTR | Insulation of partition walls |
WZ | External insulation behind the sealing |
XPS | Extruded polystyrene |
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Material | Bulk Density ρ [kg/m³] | Thermal Conductivity λ [W/(m·K)] | Specific Heat Capacity c [J/(kg·K)] | Fire Class | Vapour Diffusion Factor μ |
---|---|---|---|---|---|
Zostera marina (Seagrass) | 65–75 | 0.039–0.046 | 2500 | B2 (normal combustibility) | 1–2 |
Cellulose | 25–90 | 0.040–0.045 | 1500 | B1, B2 | 1–2 |
Flax | 20–40 | 0.040–0.050 | 1400 | B2 (normal combustibility) | 1–2 |
Hemp | 20–40 | 0.040–0.080 | 1700 | B2 (normal combustibility) | 1–2 |
Sheep’s wool | 20–80 | 0.040–0.045 | 1000 | B2 (normal combustibility) | 1–2 |
Rock wool | 25–220 | 0.035–0.050 | 840 | A1, A2 (non-combustible) | 1–2 |
Foam glass | 105–165 | 0.040–0.055 | 840 | A1, A2 (non-combustible) | ∞ |
Expanded Polystyrene (EPS) | 15–40 | 0.032–0.038 | 1300 | E (sometimes D) | 20–100 |
Glass wool (fiberglass) | 12–48 | 0.032–0.034 | 840 | A1 (non-combustible) | 1 |
Rigid PU foam | 30–45 | 0.022–0.028 | 1400 | E/B3 | 30–100 |
Sector | Expert Selection Criteria | Sources/ Method | Inclusion Criteria | Exclusion Criteria |
---|---|---|---|---|
Tourism | Large luxury hotels with air-conditioned rooms; likely to employ technical staff and afford alternative materials | Filtered search on https://www.agoda.com | 4–5 star hotels, presence of air-conditioned rooms, assumed access to engineering/technical staff | Small hotels, guesthouses, focus on sustainability (to avoid bias) |
Seagrass Insulation | Manufacturers, suppliers, and project-experienced experts in seagrass insulation; one research institution | Based on literature review; direct contacts | Active involvement in seagrass insulation production, supply, or project supervision | Lack of direct connection to seagrass insulation |
Biology | Frequently cited authors; members and directors of tropical research centres; biologists in the Seychelles | Derived from literature review and institutional affiliations | Frequent citation in literature, institutional role in tropical biology, geographic relevance (Seychelles) | Authors with marginal relevance or outside the tropical biology field |
Construction | Construction companies active in building (excluding renovation-only firms) | Derived from literature review and institutional affiliations | Listed under “Construction” on SeyBusiness.com, involved in general construction projects | Companies focused solely on renovation work |
Variant | Absolute Thermal Resistance Rt [m2·K/W] | U-Value [W/(m2·K)] | Heat Storage Capacity of Entire Building Component [kJ/(m2·K)] |
---|---|---|---|
Variant 1 | 7.102 | 0.141 | 378 |
Variant 1.1 | 7.100 | 0.141 | 378 |
Variant 1.2 | 7.115 | 0.141 | 400 |
Variant 2 | 6.073 | 0.165 | 124 |
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Rothstein, B.; Heiderich, L.; Bühler, M.; Bhati, L.K. Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies. Sustainability 2025, 17, 4160. https://doi.org/10.3390/su17094160
Rothstein B, Heiderich L, Bühler M, Bhati LK. Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies. Sustainability. 2025; 17(9):4160. https://doi.org/10.3390/su17094160
Chicago/Turabian StyleRothstein, Benno, Lena Heiderich, Michael Bühler, and Lalit Kishor Bhati. 2025. "Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies" Sustainability 17, no. 9: 4160. https://doi.org/10.3390/su17094160
APA StyleRothstein, B., Heiderich, L., Bühler, M., & Bhati, L. K. (2025). Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies. Sustainability, 17(9), 4160. https://doi.org/10.3390/su17094160