Bed structure (frond bleaching, density and biomass) of the red alga Gelidium corneum under different irradiance levels

Quintano, E.; Díez, I.; Muguerza, N.; Figueroa, Félix L.; Gorostiaga, J.M.

doi:10.1016/j.seares.2017.02.008

Cited by 16 publications

(13 citation statements)

References 54 publications

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“…In this regard, Quintano et al. () found that G. corneum plants living in shallow waters of our study area exhibited major bleaching that might weaken macroalgae thalli, making them more susceptible to frond breakage. Likewise, grazing pressure could also be an important underlying factor controlling thallus size in macroalgae (Viejo & Aberg, ).…”

Section: Discussionmentioning

confidence: 63%

“…Despite the fact that seaweeds are able to resist hydrodynamic forces by changing shape and reducing projected area (Martone et al, 2012), when some fluid forces are exceeded breakage and dislodgement might not be avoided (Hurd, 2000;Martone et al, 2012). In this regard, Quintano et al (2017) found that G. corneum plants living in shallow waters of our study area exhibited major bleaching that might weaken macroalgae thalli, making them more susceptible to frond breakage. Likewise, grazing pressure could also be an important underlying factor controlling thallus size in macroalgae (Viejo & Aberg, 2003).…”

Section: Discussionmentioning

confidence: 63%

“…Likewise, in pristine coastal stretches in this last region, the declining populations of the canopy‐forming species Gelidium corneum (Hudson) J.V. Lamouroux exhibit partial frond bleaching and an unusual branch breakdown pattern (Díez et al., ; Quintano, Díez, Muguerza, Figueroa, & Gorostiaga, ). Previous studies (e.g., Quintano, Ganzedo, Díez, Figueroa, & Gorostiaga, ) suggest that high ambient levels of irradiance may be imposing stressful environmental conditions for these populations of G. corneum .…”

Section: Introductionmentioning

confidence: 99%

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Depth influence on biochemical performance and thallus size of the red alga Gelidium corneum

et al. 2018

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Recent declines in the foundation species Gelidium corneum (Hudson) J.V. Lamouroux in pristine coastal stretches of the Southeastern Bay of Biscay have been documented in which individuals showed a high bleaching incidence. Among the potential factorsthat may be responsible for these changes in G. corneum abundance, it has been suggested that high levels of irradiance may be imposing stressful environmental conditions for shallow populations. Given that light is reduced exponentially as depth increases, in this investigation we examined the influence of depth on the stress of G. corneum by comparing the performance of several biochemical parameters and thallus size in plants collected at three different depths. The results revealed that plants growing in shallow waters showed lower antioxidant activity, lower concentrations of photosynthetic pigments (Chl‐a, total carotenoids, phycoerythrin), lower internal nitrogen levels (higher C:N ratio) and shorter thallus lengths than those living in deeper waters. Some of these results may be an expression of photoacclimation, but the low antioxidant activity and total carotenoid concentration detected in plants living in shallow waters suggest that the photoprotective mechanisms of G. corneum may have failed to offset photodamage. If so, our findings support previous studies that suggest that recent changes in solar radiation are partially responsible for G. corneum declines. Nevertheless, given that the metabolic performance of macroalgae is determined by the inter‐play of irradiance with other factors, including temperature and nutrient availability, further research is needed to reach a better understanding of the factors causing stress in G. corneum.

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

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Depth influence on biochemical performance and thallus size of the red alga Gelidium corneum

et al. 2018

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“…The poor quality of storm-tossed seaweeds, highly contaminated with sand and other seaweeds, and the large fluctuations in yearly landings posed a serious problem to the industry that required a steady input of high-quality raw material. Quintano et al (2017) suggested that light and nutrient availability and wave energy may be involved in the reduction of G. corneum beds in Euskadi. These factors explain why the industry started importing the better quality (and lower priced) Moroccan Gelidium , which were hand-picked by divers.…”

Section: Discussionmentioning

confidence: 99%

Global shortage of technical agars: back to basics (resource management)

Santos

Melo

2018

J Appl Phycol

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Bacteriological and technical agars are in short supply with potential consequences for research, public health, and clinical labs around the world. To diagnose bottlenecks and sustainability problems that may be putting the industry at risk, we analyzed the available time series for the global landings of Gelidium, the most important raw materials for the industry. Data on the harvest of Gelidium spp. have been reported since1912, when Japan was the only producer. After World War II the diversification of harvested species and producing countries resulted in a strong increase in global landings. Maximum harvest yields of almost 60,000 t year−1 in the 1960s were sustained until the 1980s, after which landings decreased continuously to the present. In the 2010s, a reduction in the global production to about 25,000 t year−1 was observed, which was lower than the yields of the 1950s. Landings by important producers such as Japan, Korea, Spain, and Portugal have collapsed. This is the ultimate cause of the present shortage of bacteriological and technical agars. However, an important factor at play is the concentration of the global landings of Gelidium in Morocco, as its relative contribution increased from 23% in the 1960s to the present 82%. Two specific bottlenecks were identified: restrictive export quotas of unprocessed Gelidium in favor of the national agar industry and resource management regulations that were apparently not enforced resulting in over-harvesting and resource decline. The global industry may well be dependent on resource management basics. Simple harvest statistics must be gathered such as the harvest effort and the variation of harvest yields along the harvest season. We discuss how this information is fundamental to manage the resource. The available harvest statistics are generally poor and limited and vary significantly among different sources of data. Probable confusions between dry and wet weight reporting and poor discrimination of the species harvested need to be resolved.

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“…Bleached, degenerated conditions of Ulva spp. predominate during summer periods (as a response to increased irradiance, temperature and desiccation: [ 32 , 33 ]) when there is a more persistent freshwater pool state ( figure 1 ). This suggests a degree of variability in macroalgal resources available to stromatolite-inhabiting metazoans.…”

Section: Introductionmentioning

confidence: 99%

Grazer responses to variable macroalgal resource conditions facilitate habitat structuring

et al. 2018

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Consumer responses to altered resource conditions can vary depending on dietary preference, resource characteristics and secondary resource features such as shelter. These can have cascading effects, especially if the consumed resource impacts on overall ecological functioning. In this study, we assessed the dietary composition of grazer communities following seasonal changes in the characteristics of their staple food-source (macroalgae). This was conducted in the living stromatolite pools growing along the coast of South Africa. Stable isotope mixing models suggested that following macroalgal bleaching in summer, metazoan consumers shifted their diet from predominantly macroalgae to a generalist composition. This has important implications for the integrity of the stromatolite matrix and its layered deposition. Where previously in winter stromatolite microalgae comprised a minor component of metazoan consumer diets, in summer, following a change in the resource conditions of macroalgae, microalgae featured more prominently in grazer diets. This seasonal grazing pressure on stromatolite-related resources probably promotes the pattern of annual layering observed in the stromatolite accretion. It also demonstrates a mechanism whereby grazer dietary shifts following a change in their preferred food resource can affect the ecosystem structure of their environment, specifically the stromatolite layering process which responds to microalgal growth or grazing conditions.

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Bed structure (frond bleaching, density and biomass) of the red alga Gelidium corneum under different irradiance levels

Cited by 16 publications

References 54 publications

Depth influence on biochemical performance and thallus size of the red alga Gelidium corneum

Depth influence on biochemical performance and thallus size of the red alga Gelidium corneum

Global shortage of technical agars: back to basics (resource management)

Grazer responses to variable macroalgal resource conditions facilitate habitat structuring

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