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Abstract Temperature increases due to climate change have affected the distribution and severity of diseases in natural systems, causing outbreaks that can destroy host populations. Host identity, diversity, and the associated microbiome can affect host responses to both infection and temperature, but little is known about how they could function as important mediators of disease in altered thermal environments. We conducted an 8‐week warming experiment to test the independent and interactive effects of warming, host genotypic identity, and host genotypic diversity on the prevalence and intensity of infections of seagrass (Zostera marina) by the wasting disease parasite (Labyrinthula zosterae). At elevated temperatures, we found that genotypically diverse host assemblages had reduced infection intensity, but not reduced prevalence, relative to less diverse assemblages. This dilution effect on parasite intensity was the result of both host composition effects as well as emergent properties of biodiversity. In contrast with the benefits of genotypic diversity under warming, diversity actually increased parasite intensity slightly in ambient temperatures. We found mixed support for the hypothesis that a growth–defense trade‐off contributed to elevated disease intensity under warming. Changes in the abundance (but not composition) of a few taxa in the host microbiome were correlated with genotype‐specific responses to wasting disease infections under warming, consistent with the emerging evidence linking changes in the host microbiome to the outcome of host–parasite interactions. This work emphasizes the context dependence of biodiversity–disease relationships and highlights the potential importance of interactions among biodiversity loss, climate change, and disease outbreaks in a key foundation species.
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This content will become publicly available on November 20, 2026
Spatio-temporal patterns of Perkinsus marinus infections are driven by a changing environment in the Chesapeake Bay
Shellfish fisheries and aquaculture within the Chesapeake Bay (hereafter 'the Bay') and its tributaries have been historically impacted by disease and climate events. Climate-driven shifts in temperature and salinity can alter host-parasite dynamics, influencing outbreaks. Here, we explore the relationship between temperature, salinity and parasite distribution and abundance in the eastern oysterCrassostrea virginica-Perkinsus marinussystem. We use long-term (30 yr) environmental data andP. marinussurveys in the Bay to identify (1) how climate affectsP. marinusprevalence and intensity, (2) seasonal and climate-driven infection patterns, and (3) regional environmental influences on disease. We found significant relationships betweenP. marinusinfection intensity, prevalence, increasing temperature and decreasing salinity. Our results indicated that there is an overall decreased abundance ofP. marinusprevalence and intensity throughout the Bay driven by decreases in salinity over time, most prominently from 2003-2020. However, these temporal trends in prevalence and intensity vary largely by region, with some regions still experiencing high disease burden. Examining monthly environmental parameters reinforced the dominant role of salinity in driving disease patterns. Salinity had significant relationships with prevalence and intensity year-round, with the largest effects in late spring/early summer. Monthly temperatures had fewer significant relationships to prevalence and intensity, but the largest significant effects were seen in late winter/early spring. Notably, this study is the first to document that winter salinity influences fall parasite prevalence, sometimes exerting a greater effect than temperature. Continued and expanded monitoring of marine disease is crucial to understand how the changing climate is impacting disease.
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- Award ID(s):
- 2222310
- PAR ID:
- 10648671
- Publisher / Repository:
- Diseases of Aquatic Organisms
- Date Published:
- Journal Name:
- Diseases of Aquatic Organisms
- Volume:
- 164
- ISSN:
- 0177-5103
- Page Range / eLocation ID:
- 111 to 127
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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