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Graf L, Shin Y, Yang JH, Hwang IK, Yoon HS. Transcriptome analysis reveals the spatial and temporal differentiation of gene expression in the sporophyte of Undaria pinnatifida. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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2
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Dobkowski KA, Crofts SB. Scaling and Structural Properties of Juvenile Bull Kelp ( Nereocystis luetkeana). Integr Org Biol 2021; 3:obab022. [PMID: 34409261 PMCID: PMC8363980 DOI: 10.1093/iob/obab022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 06/20/2021] [Accepted: 07/05/2021] [Indexed: 11/14/2022] Open
Abstract
Bull kelp (Nereocystis luetkeana), the only canopy-forming kelp in the Salish Sea, provides primary production in the nearshore subtidal environment and serves as an important habitat for economically and ecologically important species. An annual species, each year juvenile bull kelp sporophytes must grow from the hydrodynamically more benign benthos to the water column, where they experience substantial drag at the surface. Because of the differences in morphology and ecology across life stages, and the fact that previous work has focused mainly on adult bull kelp, we tested whether morphology and structural properties change with stipe length, investigating scaling of both juvenile (stipe length < 40 cm) and mature (stipe length > 40 cm) kelp, and testing how juvenile stipes fail. Juvenile bull kelp grow proportionally (isometric growth) when young, but lengthen more quickly than would be predicted by bulb size (negative allometry) at maturity. Based on our data, the predicted breakpoint between isometric and allometric growth occurred at about 33 cm, likely approximately one to two weeks of growth. Cross-sectional area of the stipe, force to failure, work to failure, and stiffness (Young's modulus) all grow more slowly than would be predicted based on length, while maximum stress and toughness increase more quickly than predicted. There is no change in extensibility over the size range we tested, suggesting that this material property does not change with stipe length. The differences in biomechanics between juvenile and adult kelp are likely a response to the varied hydrodynamic environments experienced during the annual life cycle, which highlights the importance of studying organisms across life stages.
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Affiliation(s)
- Katie A Dobkowski
- Department of Biology, Bates College, 44 Campus Ave, Lewiston, ME 04240, USA
| | - Stephanie B Crofts
- Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, USA
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Demes KW, Starko S, Harley CDG. Multiple stressors drive convergent evolution of performance properties in marine macrophytes. THE NEW PHYTOLOGIST 2021; 229:2311-2323. [PMID: 33037641 DOI: 10.1111/nph.16994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Extreme environments have driven the evolution of some of the most inspiring adaptations in nature. In the intertidal zone of wave-swept shores, organisms face physical forces comparable to hurricanes and must further endure thermal and desiccation stress during low tides, compromising their physiological and biomechanical performance. We examine how these multiple stressors have influenced the evolution of tissue properties during desiccation using eight phylogenetically independent pairs of intertidal and subtidal macrophytes. Intertidal species generally lost water more slowly than their subtidal counterparts, presumably as an adaption to regular emersion. Under partial desiccation, breaking force, strength, and extensibility of intertidal species generally exceeded those of subtidal species, although important differences existed among phylogenetic pairs. This was often true even when subtidal relatives resisted greater forces or were more extensible under full hydration. The interacting effects of mechanical forces and desiccation during low tide are likely a major selective agent in determining macrophyte performance and fitness. Overall, we found that lineages that have independently evolved to occupy the wave-swept intertidal have converged on performance metrics that are likely to be adaptive to the interacting stressors associated with their extreme niches.
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Affiliation(s)
- Kyle W Demes
- Department of Institutional Strategic Awards, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Samuel Starko
- Department of Biology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Biology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Christopher D G Harley
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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4
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Supratya VP, Coleman LJM, Martone PT. Elevated Temperature Affects Phenotypic Plasticity in the Bull Kelp (Nereocystis luetkeana, Phaeophyceae). JOURNAL OF PHYCOLOGY 2020; 56:1534-1541. [PMID: 32666523 DOI: 10.1111/jpy.13049] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
The sensitivity of kelps to elevated temperatures has been linked to recent declines in some kelp populations, with cascading impacts on marine communities. However, it remains unclear how thermal stress affects the ability of kelps to respond to other environmental factors, which could influence their vulnerability to climate change. We investigated the effect of thermal stress on the ability of the bull kelp Nereocystis luetkeana to acclimate to its surrounding hydrodynamic environment through tension-regulated plasticity in blade morphology. We first determined optimal and stressful temperatures for N. luetkeana by measuring growth over nine temperatures from 5°C to 22°C. We then exposed N. luetkeana blades to a factorial combination of temperature (13°C and 20°C) and tension (0.5 N and 2.0 N) simulating different flow conditions, and measured changes in blade length and width after 7 days. The temperature at which N. luetkeana exhibited maximum growth was estimated to be ~11.9°C, though growth was high over a relatively wide temperature range. When thermally stressed, N. luetkeana maintained morphological responses to simulated high flow, but were inhibited from acclimating to low flow, indicated by an inability of blades to widen. Our results suggest that N. luetkeana in sheltered habitats may be particularly vulnerable to climate warming, where an inability to adjust blade morphology to local hydrodynamic conditions could drive declines at sublethal levels of warming. As ecologically important foundation species, declines in sheltered kelp populations could result in major biodiversity loss and disrupt ecosystem function.
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Affiliation(s)
- Varoon P Supratya
- Department of Botany and Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T1Z4, Canada
| | - Liam J M Coleman
- Department of Botany and Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T1Z4, Canada
| | - Patrick T Martone
- Department of Botany and Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, V6T1Z4, Canada
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Coleman LJM, Martone PT. Morphological plasticity in the kelp Nereocystis luetkeana (Phaeophyceae) is sensitive to the magnitude, direction, and location of mechanical loading. JOURNAL OF PHYCOLOGY 2020; 56:1414-1427. [PMID: 32602559 DOI: 10.1111/jpy.13043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Nereocystis luetkeana is a canopy-forming kelp that exhibits morphological plasticity across hydrodynamic gradients, producing broad, undulate blades in slow flow and narrow, flattened blades in fast flow, enabling thalli to reduce drag while optimizing photosynthesis. While the functional significance of this phenomenon has been well studied, the developmental and physiological mechanisms that facilitate the plasticity remain poorly understood. In this study, we conducted three experiments to characterize how the (1) magnitude, (2) direction, and (3) location of plasticity-inducing mechanical stimuli affect the morphology of Nereocystis blades. We found that applying a gradient of tensile force caused blades to grow progressively longer, narrower, less ruffled, and heavier in a linear fashion, suggesting that Nereocystis is equally well adapted for all conditions within its hydrodynamic niche. We also found that applying tension transversely across blades caused the growth response to rotate 90°, indicating that there is no substantial separation between the sites of stimulus perception and response and suggesting that a long-distance signaling mechanism, such as a hormone, is unlikely to mediate this phenomenon. Meristoderm cells showed morphological changes that paralleled those of their respective blades in this experiment, implying that tissue-level morphology is influenced by cell growth. Finally, we found that plasticity was only induced when tension was applied directly to the growing tissue, reinforcing that long-distance signaling is probably not involved and possibly indicating that the mechanism on display generally requires an intercalary meristem to facilitate mechanoperception.
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Affiliation(s)
- Liam J M Coleman
- Department of Botany & Biodiversity Research Centre, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Patrick T Martone
- Department of Botany & Biodiversity Research Centre, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, V6T 1Z4, Canada
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Starko S, Demes KW, Neufeld CJ, Martone PT. Convergent evolution of niche structure in Northeast Pacific kelp forests. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13621] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Samuel Starko
- Department of Botany & Biodiversity Research Centre University of British Columbia Vancouver BC Canada
- Department of Biology University of Victoria Victoria BC Canada
- Bamfield Marine Sciences Centre Bamfield BC Canada
| | - Kyle W. Demes
- Institutional Strategic Awards Simon Fraser University Burnaby BC Canada
| | | | - Patrick T. Martone
- Department of Botany & Biodiversity Research Centre University of British Columbia Vancouver BC Canada
- Bamfield Marine Sciences Centre Bamfield BC Canada
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7
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Starko S, Soto Gomez M, Darby H, Demes KW, Kawai H, Yotsukura N, Lindstrom SC, Keeling PJ, Graham SW, Martone PT. A comprehensive kelp phylogeny sheds light on the evolution of an ecosystem. Mol Phylogenet Evol 2019; 136:138-150. [PMID: 30980936 DOI: 10.1016/j.ympev.2019.04.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/24/2022]
Abstract
Reconstructing phylogenetic topologies and divergence times is essential for inferring the timing of radiations, the appearance of adaptations, and the historical biogeography of key lineages. In temperate marine ecosystems, kelps (Laminariales) drive productivity and form essential habitat but an incomplete understanding of their phylogeny has limited our ability to infer their evolutionary origins and the spatial and temporal patterns of their diversification. Here, we reconstruct the diversification of habitat-forming kelps using a global genus-level phylogeny inferred primarily from organellar genome datasets, and investigate the timing of kelp radiation. We resolve several important phylogenetic features, including relationships among the morphologically simple kelp families and the broader radiation of complex kelps, demonstrating that the initial radiation of the latter resulted from an increase in speciation rate around the Eocene-Oligocene boundary. This burst in speciation rate is consistent with a possible role of recent climatic cooling in triggering the kelp radiation and pre-dates the origin of benthic-foraging carnivores. Historical biogeographical reconstructions point to a northeast Pacific origin of complex kelps, with subsequent colonization of new habitats likely playing an important role in driving their ecological diversification. We infer that complex morphologies associated with modern kelp forests (e.g. branching, pneumatocysts) evolved several times over the past 15-20 MY, highlighting the importance of morphological convergence in establishing modern upright kelp forests. Our phylogenomic findings provide new insights into the geographical and ecological proliferation of kelps and provide a timeline along which feedbacks between kelps and their food-webs could have shaped the structure of temperate ecosystems.
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Affiliation(s)
- Samuel Starko
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada; Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield V0R 1B0, Canada; Hakai Institute, Heriot Bay, Quadra Island, Canada.
| | - Marybel Soto Gomez
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Hayley Darby
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Kyle W Demes
- Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Hiroshi Kawai
- Department of Biology, Kobe University, Rokkodaicho 657-8501, Japan
| | - Norishige Yotsukura
- Field Science Center for Northern Biosphere, Hokkaido University, Sapporo 060-0809, Japan
| | - Sandra C Lindstrom
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Patrick J Keeling
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada; Department of Zoology, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Sean W Graham
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada
| | - Patrick T Martone
- Department of Botany & Biodiversity Research Centre, The University of British Columbia, 6270 University Blvd., Vancouver V6T 1Z4, Canada; Bamfield Marine Sciences Centre, 100 Pachena Rd., Bamfield V0R 1B0, Canada; Hakai Institute, Heriot Bay, Quadra Island, Canada
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Starko S, Bailey LA, Creviston E, James KA, Warren A, Brophy MK, Danasel A, Fass MP, Townsend JA, Neufeld CJ. Environmental heterogeneity mediates scale-dependent declines in kelp diversity on intertidal rocky shores. PLoS One 2019; 14:e0213191. [PMID: 30913219 PMCID: PMC6435185 DOI: 10.1371/journal.pone.0213191] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/16/2019] [Indexed: 11/18/2022] Open
Abstract
Biodiversity loss is driven by interacting factors operating at different spatial scales. Yet, there remains uncertainty as to how fine-scale environmental conditions mediate biological responses to broad-scale stressors. We surveyed intertidal rocky shore kelp beds situated across a local gradient of wave action and evaluated changes in kelp diversity and abundance after more than two decades of broad scale stressors, most notably the 2013-2016 heat wave. Across all sites, species were less abundant on average in 2017 and 2018 than during 1993-1995 but changes in kelp diversity were dependent on wave exposure, with wave exposed habitats remaining stable and wave sheltered habitats experiencing near complete losses of kelp diversity. In this way, wave exposed sites have acted as refugia, maintaining regional kelp diversity despite widespread local declines. Fucoids, seagrasses and two stress-tolerant kelp species (Saccharina sessilis, Egregia menziesii) did not decline as observed in other kelps, and the invasive species Sargassum muticum increased significantly at wave sheltered sites. Long-term monitoring data from a centrally-located moderate site suggest that kelp communities were negatively impacted by the recent heatwave which may have driven observed losses throughout the region. Wave-sheltered shores, which saw the largest declines, are a very common habitat type in the Northeast Pacific and may be especially sensitive to losses in kelp diversity and abundance, with potential consequences for coastal productivity. Our findings highlight the importance of fine-scale environmental heterogeneity in mediating biological responses and demonstrate how incorporating differences between habitat patches can be essential to capturing scale-dependent biodiversity loss across the landscape.
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Affiliation(s)
- Samuel Starko
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Lauren A. Bailey
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Elandra Creviston
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Katelyn A. James
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Alison Warren
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Megan K. Brophy
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
| | - Andreea Danasel
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Megan P. Fass
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - James A. Townsend
- Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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Ruesink JL, Stachowicz JJ, Reynolds PL, Boström C, Cusson M, Douglass J, Eklöf J, Engelen AH, Hori M, Hovel K, Iken K, Moksnes PO, Nakaoka M, O'Connor MI, Olsen JL, Sotka EE, Whalen MA, Duffy JE. Form-function relationships in a marine foundation species depend on scale: a shoot to global perspective from a distributed ecological experiment. OIKOS 2017. [DOI: 10.1111/oik.04270] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - Pamela L. Reynolds
- Dept of Evolution and Ecology; Univ. of California; Davis CA USA
- Virginia Inst. of Marine Science, Gloucester Point; VA USA
| | - Christoffer Boström
- Environmental and Marine Biology, Faculty of Science and Engineering, Åbo Akademi Univ.; Åbo Finland
| | - Mathieu Cusson
- Dépt des sciences fondamentales; Univ. du Québec à Chicoutimi; Chicoutimi QC Canada
| | | | - Johan Eklöf
- Dept of Ecology, Environment and Plant Sciences; Stockholm Univ.; Stockholm Sweden
| | - Aschwin H. Engelen
- Centro de Ciencias do Mar do Algarve (CCMAR), Univ. of Algarve; Faro Portugal
| | - Masakazu Hori
- Inst. of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency; Hiroshima Japan
| | - Kevin Hovel
- Dept of Biology; San Diego State Univ.; San Diego CA USA
| | - Katrin Iken
- College of Fisheries and Ocean Sciences, Univ. of Alaska Fairbanks; AK USA
| | | | - Masahiro Nakaoka
- Akkeshi Marine Station, Field Sciences Center of Northern Biosphere, Hokkaido Univ.; Aikappu, Akkeshi Hokkaido Japan
| | - Mary I. O'Connor
- Dept of Zoology and Biodiversity Research Centre; Univ. of British Columbia; Vancouver BC Canada
| | - Jeanine L. Olsen
- Groningen Inst. for Evolutionary Life Sciences, Univ. of Groningen; Groningen the Netherlands
| | - Erik E. Sotka
- Grice Marine Laboratory, College of Charleston; Charleston SC USA
| | | | - J. Emmett Duffy
- Virginia Inst. of Marine Science, Gloucester Point; VA USA
- Tennenbaum Marine Observatories Network, Smithsonian Inst.; Washington D.C. USA
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