1
|
Zepernick BN, Chase EE, Denison ER, Gilbert NE, Truchon AR, Frenken T, Cody WR, Martin RM, Chaffin JD, Bullerjahn GS, McKay RML, Wilhelm SW. Declines in ice cover are accompanied by light limitation responses and community change in freshwater diatoms. ISME J 2024; 18:wrad015. [PMID: 38366077 PMCID: PMC10939406 DOI: 10.1093/ismejo/wrad015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 02/18/2024]
Abstract
The rediscovery of diatom blooms embedded within and beneath the Lake Erie ice cover (2007-2012) ignited interest in psychrophilic adaptations and winter limnology. Subsequent studies determined the vital role ice plays in winter diatom ecophysiology as diatoms partition to the underside of ice, thereby fixing their location within the photic zone. Yet, climate change has led to widespread ice decline across the Great Lakes, with Lake Erie presenting a nearly "ice-free" state in several recent winters. It has been hypothesized that the resultant turbid, isothermal water column induces light limitation amongst winter diatoms and thus serves as a competitive disadvantage. To investigate this hypothesis, we conducted a physiochemical and metatranscriptomic survey that spanned spatial, temporal, and climatic gradients of the winter Lake Erie water column (2019-2020). Our results suggest that ice-free conditions decreased planktonic diatom bloom magnitude and altered diatom community composition. Diatoms increased their expression of various photosynthetic genes and iron transporters, which suggests that the diatoms are attempting to increase their quantity of photosystems and light-harvesting components (a well-defined indicator of light limitation). We identified two gene families which serve to increase diatom fitness in the turbid ice-free water column: proton-pumping rhodopsins (a potential second means of light-driven energy acquisition) and fasciclins (a means to "raft" together to increase buoyancy and co-locate to the surface to optimize light acquisition). With large-scale climatic changes already underway, our observations provide insight into how diatoms respond to the dynamic ice conditions of today and shed light on how they will fare in a climatically altered tomorrow.
Collapse
Affiliation(s)
- Brittany N Zepernick
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| | - Emily E Chase
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| | - Elizabeth R Denison
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| | - Naomi E Gilbert
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
- Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - Alexander R Truchon
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| | - Thijs Frenken
- HAS University of Applied Sciences, 5223 DE ‘s-Hertogenbosch, The Netherlands
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, N9C 1A2, Canada
| | - William R Cody
- Aquatic Taxonomy Specialists, Malinta, OH 43535, United States
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| | - Justin D Chaffin
- Stone Laboratory and Ohio Sea Grant, The Ohio State University, Put-In-Bay, OH 43456, United States
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, United States
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, N9C 1A2, Canada
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, United States
| |
Collapse
|
2
|
Wieczynski DJ, Yoshimura KM, Denison ER, Geisen S, DeBruyn JM, Shaw AJ, Weston DJ, Pelletier DA, Wilhelm SW, Gibert JP. Viral infections likely mediate microbial controls on ecosystem responses to global warming. FEMS Microbiol Ecol 2023; 99:7057867. [PMID: 36828391 DOI: 10.1093/femsec/fiad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/05/2022] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Climate change is affecting how energy and matter flow through ecosystems, thereby altering global carbon and nutrient cycles. Microorganisms play a fundamental role in carbon and nutrient cycling and are thus an integral link between ecosystems and climate. Here, we highlight a major black box hindering our ability to anticipate ecosystem climate responses: viral infections within complex microbial food webs. We show how understanding and predicting ecosystem responses to warming could be challenging-if not impossible-without accounting for the direct and indirect effects of viral infections on different microbes (bacteria, archaea, fungi, protists) that together perform diverse ecosystem functions. Importantly, understanding how rising temperatures associated with climate change influence viruses and virus-host dynamics is crucial to this task, yet is severely understudied. In this perspective, we (i) synthesize existing knowledge about virus-microbe-temperature interactions and (ii) identify important gaps to guide future investigations regarding how climate change might alter microbial food web effects on ecosystem functioning. To provide real-world context, we consider how these processes may operate in peatlands-globally significant carbon sinks that are threatened by climate change. We stress that understanding how warming affects biogeochemical cycles in any ecosystem hinges on disentangling complex interactions and temperature responses within microbial food webs.
Collapse
Affiliation(s)
| | - Kristin M Yoshimura
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Elizabeth R Denison
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Stefan Geisen
- Netherlands Institute of Ecology, 6708 PB Wageningen, Netherlands
| | - Jennifer M DeBruyn
- Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, United States
| | - A Jonathan Shaw
- Department of Biology, Duke University, Durham, NC, 27708, United States
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, United States
| | - Jean P Gibert
- Department of Biology, Duke University, Durham, NC, 27708, United States
| |
Collapse
|
3
|
Denison ER, Rhodes RG, McLellan WA, Pabst DA, Erwin PM. Host phylogeny and life history stage shape the gut microbiome in dwarf (Kogia sima) and pygmy (Kogia breviceps) sperm whales. Sci Rep 2020; 10:15162. [PMID: 32938948 PMCID: PMC7495435 DOI: 10.1038/s41598-020-72032-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/20/2020] [Indexed: 01/05/2023] Open
Abstract
Gut microbiomes perform crucial roles in host health and development, but few studies have explored cetacean microbiomes especially deep divers. We characterized the gut microbiomes of stranded dwarf (Kogia sima) and pygmy (K. breviceps) sperm whales to examine the effects of phylogeny and life stage on microbiome composition and diversity. 16S rRNA gene sequence analysis revealed diverse gut communities (averaging 674 OTUs) dominated by a few symbiont taxa (25 OTUs accounted for 64% of total relative abundance). Both phylogeny and life stage shaped community composition and diversity, with species-specific microbiome differences present early in life. Further analysis showed evidence of microbiome convergence with host maturity, albeit through different processes: symbiont 'accumulation' in K. sima and 'winnowing' in K. breviceps, indicating different methods of community assembly during host development. Furthermore, culture-based analyses yielded 116 pure cultures matching 25 OTUs, including one isolate positive for chitin utilization. Our findings indicate that kogiid gut microbiomes are highly diverse and species-specific, undergo significant shifts with host development, and can be cultivated on specialized media under anaerobic conditions. These results enhance our understanding of the kogiid gut microbiome and may provide useful information for symbiont assessment in host health.
Collapse
Affiliation(s)
- Elizabeth R Denison
- Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28409, USA
| | - Ryan G Rhodes
- Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28409, USA
| | - William A McLellan
- Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28409, USA
| | - D Ann Pabst
- Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28409, USA
| | - Patrick M Erwin
- Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, 28409, USA.
| |
Collapse
|