Kelps and Environmental Changes in Kongsfjorden: Stress Perception and Responses

Bischof, Kai; Buschbaum, Christian; Fredriksen, Stein; Gordillo, Francisco J. L.; Heinrich, S.; Jiménez, Carlos; Molis, Markus; Roleda, Michael Y.; Schwanitz, Max; Wiencke, Christian

doi:10.1007/978-3-319-46425-1_10

Cited by 15 publications

(15 citation statements)

References 212 publications

(299 reference statements)

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“…Comparable studies took place in the Svalbard Archipelago and most at greater depths. Fjord environments in Svalbard differ considerably from those of Arctic inner shelves, with less variable salinity, higher mean temperatures, and shorter periods of ice cover which results in higher annual photon flux (Table 5; Svendsen et al, 2002;Carmack and Wassmann, 2006;Cottier et al, 2010;Bischof et al, 2019). The biogeographical history of these fjords is also different.…”

Section: Recruitment Patternsmentioning

confidence: 99%

Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

Bonsell¹,

Dunton²

2021

Front. Mar. Sci.

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We examined the patterns of propagule recruitment to assess the timescale and trajectory of succession and the possible roles of physical factors in controlling benthic community structure in a shallow High Arctic kelp bed in the Beaufort Sea, Alaska. Spatial differences in established epilithic assemblages were evaluated against static habitat attributes (depth, distance from river inputs) and environmental factors (temperature, salinity, current speed, underwater light) collected continuously over 2–6 years. Our measurements revealed that bottom waters remained below freezing (mean winter temperatures ∼−1.8°C) and saline (33–36) with negligible light levels for 8–9 months. In contrast, the summer open water period was characterized by variable salinities (22–36), higher temperatures (up to 8–9°C) and measurable irradiance (1–8 mol photons m–2 day–1). An inshore, near-river site experienced strong, acute, springtime drops in salinity to nearly 0 in some years. The epilithic community was dominated by foliose red algae (47–79%), prostrate kelps (2–19%), and crustose coralline algae (0–19%). Strong spatial distinctions among sites included a positive correlation between cover by crustose coralline algae and distance to river inputs, but we found no significant relationships between multi-year means of physical factors and functional groups. Low rates of colonization and the very slow growth rates of recruits are the main factors that contribute to prolonged community development, which augments the influence of low-frequency physical events over local community structure. Mortality during early succession largely determines crustose coralline algal and invertebrate prevalence in the established community, while kelp seem to be recruitment-limited. On scales > 1 m, community structure varies with bathymetry and exposure to freshwater intrusion, which regulate frequency of primary and physiological disturbance. Colonization rates (means of 3.3–69.9 ind. 100 cm–1 year–1 site–1) were much lower than studies in other Arctic kelp habitats, and likely reflect the nature of a truly High Arctic environment. Our results suggest that community development in the nearshore Beaufort Sea occurs over decades, and is affected by combinations of recruitment limitation, primary disturbance, and abiotic stressors. While seasonality exerts strong influence on Arctic systems, static habitat characteristics largely determine benthic ecosystem structure by integrating seasonal and interannual variability over timescales longer than most ecological studies.

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Section: Recruitment Patternsmentioning

confidence: 99%

Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

Bonsell¹,

Dunton²

2021

Front. Mar. Sci.

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“…In contrast, increased terpene biosynthesis in H × S, as indicated by expression of transcripts coding for hydroxymethylglutaryl-CoA synthase, might indicate defense reactions or increased antioxidant capacity (Fisch et al, 2003;de Oliveira et al, 2017). As protein-serine/threonine kinases are involved in stress-related signaling cascades (Graves et al, 1995;Bischof et al, 2019), the increased expression of related genes in H × S indicates a stronger response to heat stress than in S × H. The increased expression of other KEGG genes in H × S points toward measures of metabolic maintenance. NADH:ubiquinone reductase is involved in cyclic electron transport in photosystem I (Shikanai and Aro, 2016;Zhao et al, 2018), while the expression of RRP5 indicates increased ribosome biogenesis (Missbach et al, 2013).…”

Section: Differential Gene Expression Between the Reciprocal Crossesmentioning

confidence: 99%

Increased Heat Resilience of Intraspecific Outbred Compared to Inbred Lineages in the Kelp Laminaria digitata: Physiology and Transcriptomics

et al. 2022

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Marine forests and kelps as their foundation species are threatened by ocean warming especially at the warm distributional edges. Previously identified genetic divergence and ecotypic differentiation within kelp species may allow to produce more resilient lineages by intraspecific outbreeding among populations. In a mechanistic investigation of heat stress, heterosis (hybrid vigour), and underlying gene expression patterns, we assessed the thermal performance of inbred (selfings) and outbred (reciprocal crosses) sporophytes of the N-Atlantic kelp Laminaria digitata among clonal isolates from two divergent populations; one from the temperate North Sea (Helgoland) and one from the Arctic (Spitsbergen). First, we investigated the upper thermal tolerance of microscopic sporophytes in a 14-day experiment applying sublethal to lethal 20–23°C. The upper survival temperature of microscopic sporophytes was lower for the inbred Arctic selfing (21°C) than for the temperate selfing and the reciprocal crosses (22°C). Only in the temperate selfing, 4.5% of sporophytes survived 23°C. We then subjected 4–7 cm long sporophytes to a control temperature (10°C), moderate (19°C) and sublethal to lethal heat stress (20.5°C) for 18 days to assess gene expression in addition to physiological parameters. Growth and optimum quantum yield decreased similarly in the reciprocal crosses and the temperate selfing at 19 and 20.5°C, while inbred Arctic sporophytes died within seven days at both 19 and 20.5°C. In response to 20.5°C, 252 genes were constitutively regulated across all surviving lineages, which we use to describe metabolic regulation patterns in response to heat stress in kelp. At sublethal 20.5°C, ca. 150 genes were differentially expressed by either crossed lineage in comparison to the temperate selfing, indicating that they maintained a growth response similar to the temperate selfing with differential metabolic regulation during sublethal heat stress. Subtle differences in physiology and the differential expression of nine genes between the reciprocal crosses at 20.5°C indicate that female and male gametophytes may contribute differently to offspring traits. We consider potential inbreeding depression in the Spitsbergen selfing and quantify the better performance of both crosses using heterosis-related parameters. We discuss the potential and risks of outbreeding to produce more resilient crops for mariculture and marine forest restoration.

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“…The investigation of organic carbon metabolism throughout the year could also help to study the final carbon balance of S. latissima. Moreover, Saccharina latissima, as a season responder, grows mostly during a brief period in early spring, when light and temperature increase, and nutrients are not yet depleted by phytoplankton blooms (Bischof et al, 2019). Therefore, the survival of sporophytes under warming conditions would be much clearer if the sporophytes were subjected to a light recovery after the dark incubation.…”

Section: Ecological Implicationmentioning

confidence: 99%

“…Kelps are perennial macroalgae with high economic and ecological significance. They are important primary producers and provide food and shelter for numerous organisms in the marine ecosystem (Bischof et al, 2019). Kelps show a broad geographical distribution from cold-temperate to Arctic coastlines.…”

Section: Introductionmentioning

confidence: 99%

Transcriptomic Responses to Darkness and the Survival Strategy of the Kelp Saccharina latissima in the Early Polar Night

Scheschonk

Heinrich³

et al. 2020

Front. Mar. Sci.

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Kelps in the Arctic region are facing challenging natural conditions. They experience over 120 days of darkness during the polar night surviving on storage compounds without conducting photosynthesis. Furthermore, the Arctic is experiencing continuous warming as a consequence of climate change. Such temperature increase may enhance the metabolic activity of kelps, using up storage compounds faster. As the survival strategy of kelps during darkness in the warming Arctic is poorly understood, we studied the physiological and transcriptomic responses of Saccharina latissima, one of the most common kelp species in the Arctic, after a 2-week dark exposure at two temperatures (0 and 4°C) versus the same temperatures under low light conditions. Growth rates were decreased in darkness but remained stable at two temperatures. Pigments had higher values in darkness and at 4°C. Darkness had a greater impact on the transcriptomic performance of S. latissima than increased temperature according to the high numbers of differentially expressed genes between dark and light treatments. Darkness generally repressed the expression of genes coding for glycolysis and metabolite biosynthesis, as well as some energy-demanding processes, such as synthesis of photosynthetic components and transporters. Moreover, increased temperature enhanced these repressions, while the expression of some genes encoding components of the lipid and laminaran catabolism, glyoxylate cycle and signaling were enhanced in darkness. Our study helps to understand the survival strategy of kelp in the early polar night and its potential resilience to the warming Arctic.

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Kelps and Environmental Changes in Kongsfjorden: Stress Perception and Responses

Cited by 15 publications

References 212 publications

Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

Increased Heat Resilience of Intraspecific Outbred Compared to Inbred Lineages in the Kelp Laminaria digitata: Physiology and Transcriptomics

Transcriptomic Responses to Darkness and the Survival Strategy of the Kelp Saccharina latissima in the Early Polar Night

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