Wind exposure and sediment type determine the resilience and response of seagrass meadows to climate change

Abstract Seagrass ecosystems are important contributors to mitigation of climate change, since they are responsible for large carbon sinks. However, there is limited knowledge regarding the importance of variability of carbon storage in various ecosystems. In this study, we estimated carbon storage in several structurally different seagrass meadows along the west coast of Thailand and determined whether degree of exposure, human disturbance, and meadow type influenced carbon storage within these meadows. Carbon content within the living vegetation was on average 3±2.7 Mg ha−1, whilst average storage of carbon in the sediment was 122±35.3 Mg ha−1. Meadow type and disturbance had a significant influence on total carbon storage in the ecosystem, while the degree of exposure of the bay did not show great differences. Uniform meadows had a higher average total carbon storage than mixed meadows (133±36.2 and 110±41.3 Mg ha−1, respectively). Undisturbed meadows had a higher average total carbon storage than disturbed ones (140±36.5 and 103±34.8 Mg ha−1, respectively). The results obtained contribute to our understanding of carbon storage on an ecosystem scale and can provide a baseline for proper management, conservation, and climate change studies in the region.

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Assessment of local genetic structure and connectivity of the common eelgrass Zostera marina for seagrass restoration in northern Europe

Marine Ecology Progress Series ◽

10.3354/meps13658 ◽

2021 ◽

Vol 664 ◽

pp. 103-116

Author(s):

L Martínez-García ◽

B Hansson ◽

J Hollander

Keyword(s):

Climate Change ◽

Genetic Variation ◽

Genetic Structure ◽

Genetic Differentiation ◽

Baltic Sea ◽

Zostera Marina ◽

Anthropogenic Impacts ◽

Ecosystem Functions ◽

Long Distance ◽

Seagrass Meadows

Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these ecosystem functions and services, seagrass meadows are a threatened ecosystem worldwide. In the Baltic Sea, seagrass meadows have declined rapidly, mainly because of eutrophication, anthropogenic activities and climate change. This decline has the potential to erode the genetic variation and genetic structure of the species. In this study, we assessed how genetic variation and genetic differentiation vary among Zostera marina meadows and with a number of environmental characteristics in the county of Scania in southern Sweden. A total of 205 individuals sampled at 12 locations were analysed with 10 polymorphic microsatellite loci. Results showed that in spite of anthropogenic impacts and climate change pressures, locations of Z. marina possessed high genetic variation and weak genetic differentiation, with 3 major genetic clusters. Long-distance dispersal and/or stepping-stone dispersal was found among locations, with higher migration rates within the west coast. Organic matter, salinity and maximum depth appeared to be factors most strongly associated with the genetic structure and morphological variation of Z. marina. These findings contribute significantly in the identification of potential donor sites and the viability of impacted areas to recover from natural recruitment, for the development of effective transplantation measures of Z. marina in the southern Baltic Sea and temperate regions elsewhere.

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Canopy Accumulation: Are Seagrass Meadows a Sink of Microplastics?

Oceans ◽

10.3390/oceans2010010 ◽

2021 ◽

Vol 2 (1) ◽

pp. 162-178

Author(s):

Richard K. F. Unsworth ◽

Alex Higgs ◽

Bettina Walter ◽

Leanne C. Cullen-Unsworth ◽

Isabella Inman ◽

...

Keyword(s):

Current Knowledge ◽

Meta Analysis ◽

Dry Weight ◽

Sediment Type ◽

Published Data ◽

Seagrass Meadows ◽

High Dependency ◽

Abundance And Diversity ◽

The Uk ◽

A Site

A growing body of research is documenting the accumulation of microplastics within marine sediments around the world. The hydrodynamic influences of seagrasses in coastal environments are shown to increase sedimentation of finer particles and as a result there has been speculation that this attribute will lead to seagrass meadows acting as a site of elevated microplastic contamination. To date a range of localised studies have provided conflicting answers to this hypothesis. Seagrass meadows provide multiple ecosystem services including vital support roles for a range of fisheries; therefore, there are considerable human health implications for understanding their role as sinks of microplastics. This research investigated the abundance and diversity of microplastics present in temperate North Atlantic seagrass meadow sediments relative to unvegetated sediments and examined how they correlate with the meadow structure and the sediment type. We also placed this data in the context of the current knowledge of microplastics in seagrass sediments through a global meta-analysis of published data. Eight seagrass meadows and adjacent unvegetated sites around the UK were sampled to test for the abundance of microplastic particles in the sediment. Microplastics were found in 98% of the samples, with fibres making up 91.8% of all microplastics identified. Abundance was recorded to overall be 215 ± 163 microplastic particles (MP) kg−1 Dry Weight (DW) of sediment in seagrass and 221 ± 236 MP kg−1 DW of sediment in unvegetated habitats. There were no significant differences found between the number of MP with respect to vegetation. We report evidence of the almost ubiquitous contamination of seagrass sediments with microplastics both in the UK and globally but find that the contamination reflects a general build-up of microplastics in the wider environment rather than becoming concentrated within seagrass as an enhanced sink. Microplastic build up in sediments is hypothesised to be the result of local hydrodynamics and plastic sources rather than the result of elevated habitat level concentration. Although not of a higher abundance in seagrass, such contamination in seagrass is of cause for concern given the high dependency of many species of fish on these habitat types and the potential for plastics to move up the food chain.

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Growth and reproductive responses of the seagrass Zostera marina to sediment nutrient enrichment

ICES Journal of Marine Science ◽

10.1093/icesjms/fsab031 ◽

2021 ◽

Author(s):

Le-Zheng Qin ◽

Zhaxi Suonan ◽

Seung Hyeon Kim ◽

Kun-Seop Lee

Keyword(s):

Climate Change ◽

Sexual Reproduction ◽

Nutrient Enrichment ◽

Zostera Marina ◽

Vegetative Growth ◽

Anthropogenic Activity ◽

P Availability ◽

Shoot Height ◽

Seagrass Meadows ◽

N Enrichment

Abstract Nutrient loading into coastal sediments is increasing due to anthropogenic activity and climate change. We examined the effects of sediment nutrient enrichment on the growth and reproduction of Zostera marina by adding nitrogen (N) and phosphorus (P) fertilizers into sediments. Areal productivity and shoot density increased by ca. 60% in N and N + P enrichment plots and by ca. 20% in the P enrichment plots. Biomass and shoot height were also higher in the N and N + P enrichment plots than in the P enrichment and control plots. These results suggest that sediment N availability was more important than P availability in stimulating the vegetative growth of Z. marina . The density and morphology of reproductive shoots and seed production increased in only the N enrichment plots. The sediment N enrichment stimulated both the vegetative growth and sexual reproduction, improving the meadow resilience through both sexual and asexual mechanisms. The P enrichment slightly increased only the vegetative growth and might have limited influence on seagrass reproduction. According to these results, the alteration of the sediment nutrient regimes might shift the balance between the vegetative growth and sexual reproduction of Z. marina. These findings may have important implications for the management of seagrass meadows under fluctuations in sediment nutrients caused by anthropogenic activity and climate change.

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Seagrass, bioindicator, light, water quality, Zostera marina, Zostera noltii, Halodule wrightii, monitoring, Chlorophyll fluorescence, stable isotope, nutrients.

10.23889/suthesis.57002 ◽

2020 ◽

Author(s):

◽

Chiara M. Bertelli

Keyword(s):

Climate Change ◽

Water Quality ◽

Marine Environment ◽

Environmental Conditions ◽

Zostera Marina ◽

Environmental Drivers ◽

Zostera Noltii ◽

Halodule Wrightii ◽

Storm Events ◽

Seagrass Meadows

This thesis aims to investigate the effect of environmental drivers on seagrasses by studying shoot-scale and meadow-scale responses, focussing on Zostera marina, Zostera noltii and Halodule wrightii. Seagrasses are plants that have evolved from being terrestrial to living in an entirely marine environment which means they have become highly adapted. The conditions that effect seagrass growth can also be described as drivers as they have the ability to modify seagrass meadows in a variety of ways. These drivers can either be natural environmental factors or anthropogenic processes directly or indirectly affecting the marine environment in which seagrasses are found. These responses environmental conditions allow seagrasses to be used as indicators of the health of our coastal waters with poor water quality causing substantial impacts on seagrasses. Better knowledge of seagrass responses to local environmental conditions will help the identification of stressors which can then be managed. It will also help to comprehend the degree of risk to be expected from the threat of climate change including increased storm events, rises in sea level and sea temperature, and ocean acidification. Mitigating existing or potential impacts that lead to a reduction in water quality will improve the overall health and resilience of the seagrass to future threats from climate change.

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Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers

Mediterranean Marine Science ◽

10.12681/mms.621 ◽

2014 ◽

Vol 15 (2) ◽

pp. 462 ◽

Cited By ~ 41

Author(s):

G. PERGENT ◽

H. BAZAIRI ◽

C. N. BIANCHI ◽

C. F. BOUDOURESQUE ◽

M. C. BUIA ◽

...

Keyword(s):

Climate Change ◽

Industrial Revolution ◽

Net Primary Production ◽

Global Climate ◽

Posidonia Oceanica ◽

Total Carbon ◽

Anthropogenic Pressures ◽

Seagrass Meadows ◽

Mediterranean Countries ◽

The Mediterranean

This synopsis focuses on the effects of climate change on Mediterranean seagrasses, and associated communities, and on the contribution of the main species, Posidonia oceanica, to the mitigation of climate change effects through its role of sequestering carbon dioxide. Whilst the regression of seagrass meadows is well documented, generally linked to anthropogenic pressures, global warming could be a cause of new significant regressions, notably linked to the introduction of exotic species, the rise of Sea-Surface Temperature (SST), and relative sea level. Seagrass communities could also be affected by climate change through the replacement of seagrass species having high structural complexity by species of lower complexity and even by opportunistic introduced species. Although it is currently very difficult to predict the consequences of these alterations and their cascade effects, two main conflicting trends in the functioning of seagrass ecosystems that could occur are acceleration of the herbivore pathway or of the detritivore pathway. The mean net primary production of the dominant species, Posidonia oceanica, is relatively high and can be estimated to range between 92.5 to 144.7 g C m-2 a-1. Around 27% of the total carbon fixed by this species enters the sedimentary pathway leading to formation, over millennia, of highly organic deposits rich in refractory carbon. At the Mediterranean scale, the sequestration rate might reach 1.09 Tg C a-1. The amount of this stored carbon is estimated to range from 71 to 273 kg C m-2, which when considered at the Mediterranean scale would represent 11 to 42% of the CO2 emissions produced by Mediterranean countries since the beginning of the Industrial Revolution. The greatest value of the P. oceanica ecosystem, in the context of mitigation of global climate change, is linked to this vast long-term carbon stock accumulated over the millennia, and therefore, efforts should be focused on preserving the meadows to keep this reservoir intact.

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Ocean Warming and Acidification Modify Top-Down and Bottom-Up Control in A Tropical Seagrass Ecosystem

10.21203/rs.3.rs-133932/v1 ◽

2020 ◽

Author(s):

Vina Listiawati ◽

Haruko Kurihara

Keyword(s):

Climate Change ◽

High Temperature ◽

Sea Urchin ◽

Ocean Warming ◽

Ecosystem Functions ◽

Future Climate Change ◽

Top Down ◽

Thalassia Hemprichii ◽

Seagrass Meadows ◽

Seagrass Community

Abstract Seagrass ecosystems are classified as one of the most productive ecosystems in coastal waters providing numerous of ecological functions, however various anthropogenic stressors including climate change are impacting these vulnerable habitats. Here, we investigated the independent and combined effects of ocean warming and ocean acidification on plant-herbivore interactions in a tropical seagrass community. Direct and indirect effects of high temperature and high pCO2 on the physiology of the tropical seagrass Thalassia hemprichii and sea urchin Tripneustes gratilla were evaluated. Productivity of seagrass was found to synergistically increase under the combination of high temperature and high pCO2, while sea urchin physiology including feeding rate decreased particularly under high temperature. The present study indicated that future climate change will affect the botom-up and top-down balance leading to a shift to a seagrass-dominated ecosystem, which potentially decrease biodiversity as well as ecosystem functions and services of tropical seagrass meadows.

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Dynamic of Posidonia oceanica seagrass meadows in the northwestern Mediterranean: Could climate change be to blame?

Comptes Rendus Biologies ◽

10.1016/j.crvi.2015.04.011 ◽

2015 ◽

Vol 338 (7) ◽

pp. 484-493 ◽

Cited By ~ 15

Author(s):

Gérard Pergent ◽

Christine Pergent-Martini ◽

Aymeric Bein ◽

Marine Dedeken ◽

Pascal Oberti ◽

...

Keyword(s):

Climate Change ◽

Posidonia Oceanica ◽

Seagrass Meadows ◽

Northwestern Mediterranean

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Seagrass and Submerged Aquatic Vegetation (VAS) Habitats off the Coast of Brazil: state of knowledge, conservation and main threats

Brazilian Journal of Oceanography ◽

10.1590/s1679-875920161036064sp2 ◽

2016 ◽

Vol 64 (spe2) ◽

pp. 53-80 ◽

Cited By ~ 21

Author(s):

Margareth S. Copertino ◽

Joel C. Creed ◽

Marianna O. Lanari ◽

Karine Magalhães ◽

Kcrishna Barros ◽

...

Keyword(s):

Climate Change ◽

Large Scale ◽

Submerged Aquatic Vegetation ◽

Aquatic Vegetation ◽

Conservation Status ◽

Current Status ◽

Brazilian Coast ◽

Global Changes ◽

Seagrass Meadows ◽

Ecological Features

Abstract Seagrass meadows are among the most threatened ecosystems on earth, raising concerns about the equilibrium of coastal ecosystems and the sustainability of local fisheries. The present review evaluated the current status of the research on seagrasses and submerged aquatic vegetation (SAV) habitats off the coast of Brazil in terms of plant responses to environmental conditions, changes in distribution and abundance, and the possible role of climate change and variability. Despite an increase in the number of studies, the communication of the results is still relatively limited and is mainly addressed to a national or regional public; thus, South American seagrasses are rarely included or cited in global reviews and models. The scarcity of large-scale and long-term studies allowing the detection of changes in the structure, abundance and composition of seagrass habitats and associated species still hinders the investigation of such communities with respect to the potential effects of climate change. Seagrass meadows and SAV occur all along the Brazilian coast, with species distribution and abundance being strongly influenced by regional oceanography, coastal water masses, river runoff and coastal geomorphology. Based on these geomorphological, hydrological and ecological features, we characterised the distribution of seagrass habitats and abundances within the major coastal compartments. The current conservation status of Brazilian seagrasses and SAV is critical. The unsustainable exploitation and occupation of coastal areas and the multifold anthropogenic footprints left during the last 100 years led to the loss and degradation of shoreline habitats potentially suitable for seagrass occupation. Knowledge of the prevailing patterns and processes governing seagrass structure and functioning along the Brazilian coast is necessary for the global discussion on climate change. Our review is a first and much-needed step toward a more integrated and inclusive approach to understanding the diversity of coastal plant formations along the Southwestern Atlantic coast as well as a regional alert the projected or predicted effects of global changes on the goods and services provided by regional seagrasses and SAV.

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Ecological connectivity of seagrasses with mangroves increases the carbon storage of tropical seagrass meadows of an island ecosystem

10.21203/rs.3.rs-839297/v1 ◽

2021 ◽

Author(s):

Amrit Kumar Mishra ◽

Deepak Apte ◽

Syed Hilal Farooq

Keyword(s):

Climate Change ◽

Carbon Storage ◽

Climate Change Mitigation ◽

Total Carbon ◽

Total Biomass ◽

Thalassia Hemprichii ◽

Sediment Grain Size ◽

Seagrass Meadows ◽

Mitigation And Adaptation ◽

Change Mitigation

Abstract Ecologically connected ecosystems are considered more resilient to climate change mitigation by storing increased amounts of carbon than individual ecosystems. This study quantified the carbon storage capacity of seagrass (Thalassia hemprichii) meadows that are adjacent to mangroves (MG; Rhizophora apiculate) and without mangroves (WMG) at three locations in tropical Andaman and Nicobar Islands (ANI) of India. The sediment organic matter (OM) carbon (Corg) content was 2-fold higher at the MG sites than WMG sites of all three locations within the top 10 cm. The Corg in the total biomass was higher at MG sites than the biomass at WMG sites. The sediment grain size positively influenced the sediment OM and Corg content. The canopy height of T. hemprichii showed a better relationship with sediment OM and Corg at MG sites. In contrast, the shoot density of T. hemprichii showed a better relationship with sediment OM and Corg at WMG sites. The total carbon in 144 ha of T. hemprichii meadows of all three MG sites was 11031± 5223 Mg C, whereas the carbon in 148 ha of WMG sites was 4921±3725 Mg C. These T. hemprichii meadows of ANI store around 40487±19171 ton of CO2 in the MG sites and 18036 ±13672 ton of CO2 at WMG sites. The social cost of these carbon stored in these T. hemprichii meadows is around US$ 34.82 and 1.5 million at the MG and WMG sites, respectively. This study points out the efficiency of seagrass ecosystems of ANI as carbon sinks and the potential of these connected seascapes in increasing the efficiency of seagrass carbon storage. Therefore, this connectivity approach should be further explored to include these connected ecosystems of India as a nature-based solution for climate change mitigation and adaptation plans.

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