Seasonal Growth Dynamics of Posidonia oceanica in a Pristine Mediterranean Gulf

Mutlu, Erhan; Olguner, Cansu; Gökoğlu, Mehmet; Özvarol, Yaşar

doi:10.1007/s12601-022-00078-8

Cited by 14 publications

(44 citation statements)

References 63 publications

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“…Temperature is widely known to be one of the main ecological factors that determines seagrass performance, survival and distribution limits. Temperatures close to the threshold of 30°C have been shown to negatively affect seedlings development, leaf formation rates and leaf biomass as well as to increase the vulnerability of newly germinated seedlings to extreme events (Olsen et al, 2012;Guerrero-Meseguer et al, 2017;Mutlu et al, 2022). High water temperatures significantly affect the photosynthetic rate of seagrass, decreasing oxygen production (Rasmusson et al, 2020), PSII performance and growth rates (Ontoria et al, 2019), while increasing leaf necrosis and mortality events (Collier and Waycott, 2014;Pazzaglia et al, 2022b).…”

Section: Discussionmentioning

confidence: 99%

The ontogeny-specific thermal sensitivity of the seagrass Posidonia oceanica

Rinaldi

Martinez²,

Badalamenti

et al. 2023

Front. Mar. Sci.

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IntroductionThe rapid increase in sea-water temperatures and frequency of extreme thermal events have amplified the risk of functional extinction of Mediterranean species such as the endemic long-lived seagrass Posidonia oceanica. Because of the valuable ecological functions and ecosystem services the species provides, understanding the life-stage specific thermal vulnerability is crucial to accurately predict the consequences of current and future global climate change and to protect and conserve existing meadows.MethodsTo this end, here we report a study on the ontogeny-specific thermal sensitivity of important physiological functions (i.e. respiration and net production) of three different early life history stages of P. oceanica, namely seed, seedling (4-month-old individuals) and 16-month-old plantlet by measuring thermal performance curves (eleven temperatures treatments between 15-36°C with n=8).ResultsAll three stages examined showed photosynthetic activity during light exposure with similar optimal temperatures for both net and gross production. Gross photosynthesis increased with rising temperature up to 28-30°C, subsequently declining at higher temperatures until complete inhibition at 36°C. The metabolic response of seeds was found to be temperature-dependent up to 26°C, while respiration of seedlings and plantlets was almost stable up to 28-30°C, but increased markedly at higher temperatures, resulting in a negative whole-plant C balance at temperatures above 32°C. Overall, our results show that seedlings and plantlets tolerate a wider temperature range (15 - 32°C) than seeds, which experience metabolic and physiological dysfunction from 26-28°C onwards.DiscussionThese findings suggest that the impact of warming on recruitment in P. oceanica meadows may vary depending on the timing of marine heatwaves (i.e. mid-spring to mid-autumn) and provide useful knowledge to inform restoration programs using early life stages of the species. In conclusion, the study of physiological responses during the early life stages of species is key to identify life history stages that are particularly vulnerable to climate change, which is vital knowledge for ecosystem management and conservation.

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Section: Discussionmentioning

confidence: 99%

The ontogeny-specific thermal sensitivity of the seagrass Posidonia oceanica

Rinaldi

Martinez²,

Badalamenti

et al. 2023

Front. Mar. Sci.

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“…The mortality occurred due to the highest annual salinity in late summer. A transition depth in space and month in time was assessed as 15 m and as August for variation of the biometrics, respectively" (Mutlu et al, 2022a). ii) "Of C. nodosa, excluding the number of leaves per shoot and internodal distance, the grass densities and plant traits showed regional (four bays) and depth (5-20 m) differences; higher in Kekova and Kaş Bays, both on sit on the rim current, compared to Finike and Antalya Bays were virtually devoid of the grass and rim current (Fig.…”

Section: Introductionmentioning

confidence: 99%

Density-depended Acoustical Identification of Two Common Seaweeds (Posidonia Oceanica and Cymodocea Nodosa) in the Mediterranean Sea

Mutlu

Olguner²

2023

Thalassas

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The non-destructive samplings are very important in not damaging seagrasses and seaweed under protection, at the eld studies. The grasses are prominent in the assessment of the ecological status of the marine environments. One of the effective non-destructive samplings was the acoustical methods which need a low level of the sea and atmospheric conditions as compared to the other remote sensing system. Like the others, acoustic data alone are inherently ambiguous concerning the identities of the scatterers and need sea-truthing at the eld studies. Considering the requirements above and the advantages of the acoustical methods, an acoustical in situ study was conducted to discriminate two dominant seagrasses along the western Turkish Mediterranean coast in August (in the year 2012) when biometrics of both species was at maxima. Four different regions were involved in the study during data collection using a split beam echosounder operated at 206 kHz since each region had different strengths of their biometrics re ecting regional variations of the acoustical measurements. For discrimination, a statistical approach based on the acoustical parameters and their statistics was enriched and validated with multivariate analyses (Silhouette, k-means, PCA and CAP analyses). Posidonia oceanica was correlated with mean, median, SD and maximum value of Sa, whereas Cymodocea nodosa was characterized by hardness and roughness of leaf echo, followed by skewness and kurtosis of Sa. The acoustics of C. nodosa were related to regional differences, but P. oceanica was related to the depthwise difference. Both species had highly different densities (g/cm 3 ), followed by biomass. The present study will interactively help acoustical studies to be more common and comprehensible and the other previous studies published did as well.Recently, in/ex situ acoustical studies have increased to relate the biometrics to the Elementary Distance Sampling Unit (EDSU, Simmonds and

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“…Besides microscopic algae and photosynthetic bacteria, most of marine macrophytes reveal status of the marine ecosystem health and ecological level. Some of them are indicators of pollution whereas some are indicators of the pristine environment [4,5]. There are a lot of further importance and contributions of them to the marine system.…”

Section: Introductionmentioning

confidence: 99%

“…There are a lot of further importance and contributions of them to the marine system. Unlike the algae, the seagrasses are associated with the sediments (benthic system) by their below-ground parts (rhizomes, and roots) [6] and pelagic system by their above-ground parts (sheaths, and leaves) [5].…”

Section: Introductionmentioning

confidence: 99%

“…Like other seagrass (angiosperms), Posidonia oceanica (the Mediterranean meadow) is a prominent component in the zonal classification in the Mediterranean Sea, and classifies the border between the Infralittoral and the Circalittoral of the benthic environment [1,3,5,17,18]. Therefore, it is positioned as a coastal engineer and interior architect in the coastal environment with their following functions [19,20].…”

Section: Introductionmentioning

confidence: 99%

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A Package of Script Codes, POSIBIOM for Vegetation Acoustics;<em> POSIdonia</em> BIOMass

Mutlu¹

2023

Preprint

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Macrophytes and seagrasses play a crucial role with a variety of the functions in the marine ecosystem and respond synchronized-promptly to the changing climate, followed by ecological status. Monitoring of the seagrasses was one of the paramount topics at the marine environment. One of the fast monitoring techniques is the vegetation acoustics with the advantages compared to the other remote sensing techniques. The acoustic method alone is ambitious to sea-truth identities of the backscatterers at the sea. Therefore, a package of computer programs was developed to identify, estimate leaf biometrics (leaf length and biomass) of one of the common seagrasses, Posidonia oceanica. Some troubleshooting in the acoustical data were fixed and then solved to reach the estimates regarding to the matters encountered for the vegetation as well as fisheries and plankton acoustics. One of the trouble was the “Lost” bottom which occurred during the data collection and post-processing due to occurrence of the acoustical noises, reverberations, interferences and intense scatterers suchlike fish schools. Another problem to remove was the occurrence as studying the near-bottom echoes belonging to submerged vegetations such as seagrasses, followed by spurious echoes. Last one was recognition of the seagrass to estimate leaf length and biomass calibrating the sheaths/vertical rhizome of the seagrass and establishing relationships between acoustical units and biometrics, respectively. As a consequence, an autonomous package of the code written in language MatLab was developed to perform all processes, and the name of the package was abbreviated as POSIBIOM, POSIdonia BIOMass. This study presented the algorithms, methodology, acoustics-biometrics relation, and mapping of the biometrics for the first time, and discussed advantages and disadvantages of the package compared to the software purposed for the bottom types, habitat and vegetation acoustic. The future studies were recommended to improve the package.

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Seasonal Growth Dynamics of Posidonia oceanica in a Pristine Mediterranean Gulf

Cited by 14 publications

References 63 publications

The ontogeny-specific thermal sensitivity of the seagrass Posidonia oceanica

The ontogeny-specific thermal sensitivity of the seagrass Posidonia oceanica

Density-depended Acoustical Identification of Two Common Seaweeds (Posidonia Oceanica and Cymodocea Nodosa) in the Mediterranean Sea

A Package of Script Codes, POSIBIOM for Vegetation Acoustics;<em> POSIdonia</em> BIOMass

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