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Potential of Marine Biota and Bio-waste Materials as Feedstock for Biofuel Production
Published in Gunjan Mukherjee, Sunny Dhiman, Waste Management, 2023
Mostafa M. El-Sheekh, Hassan A.H. Ibrahim, Khouloud M. Barakat, Nayrah A. Shaltout, Waleed M.M. EL Sayed, Reda A.I. Abou-Shanab, Michael J. Sadowsky
Seagrasses belong to the flowering plants from the families Posidoniaceae, Zosteraceae, Hydrocharitaceae, or Cymodoceaceae that developed in fully saline marine environments (Ravikumar et al. 2011). Despite the large numbers of widely diverse marine plants, few studies report their use as the main source for biofuels. Concerning the eutrophication process, enormous plants are deposited on the beaches of many countries each year, negatively affecting tourism (Morand and Briand 1996). Although studies related to ethanol production from seagrass bio-waste are limited, it is easy to calculate that use of marine vegetation for biofuel feedstock would result in a lowering of competition amongst food for biofuels (Marquez et al. 2013). Results from some studies look very promising to make this a reality. Ravikumar et al. (2011) produced the bioethanol from seagrass bio-wastes using commercial yeast, S. cerevisiae and Viola et al. (2008) investigated Zostera marina for the production of fermentative ethanol.
Application
Published in Andrew Braham, Sadie Casillas, Fundamentals of Sustainability in Civil Engineering, 2020
Seagrass, which grows in large meadows in subtidal ecosystems, can also provide an additional line of defense for coastlines by reducing suspended sediment, raising the elevation of the seabed and reducing erosion. Unlike oysters, which filter water through and pull out suspended particles through a feeding process, seagrass collects suspended particles within the grass as waves pass through the meadows, much like mangroves. Also like mangroves, trapped sediment is deposited on the seabed, bound together by the root system, and allows the plant height to continue to grow as the seabed rises. Finally, reducing erosion near the shoreline is a major concern for coastlines which can be addressed using seagrass. Because the grass can dissipate wave energy, erosion is indirectly decreased through the reduction in forces of the waves. The seagrass root system is also believed to increase the shear resistance of soils below the seagrass, stabilizing the sediment.
The Indian Scenario
Published in Ranadhir Mukhopadhyay, Victor J. Loveson, Sridhar D. Iyer, P.K. Sudarsan, Blue Economy of the Indian Ocean, 2020
Ranadhir Mukhopadhyay, Victor J. Loveson, Sridhar D. Iyer, P.K. Sudarsan
Seagrass meadows occur up to 50 m water depth and globally cover 300,000 to 600,000 km2, with up to 4,320,000 km2 (Gattuso, 2006) and the loss is estimated at 7% of their known area per year (www.iucn.org/content/seagrass-habitat-declining-globally). Although seagrass forms only 0.1% of the ocean floor the total carbon burial is 10–18% and storage is as much as 19.9 Pg of organic carbon (1 Pg = petagram is equal to one quadrillion grams, or one trillion kilograms; Fourqurean, 2012). The average carbon burial rate by seagrass is about 138 g C m−2 yr−1 (grams of carbon per m2 per year). Seagrass is affected by coastal eutrophication, increase in seawater temperatures, enhanced sedimentation, and coastal development (Duarte et al., 2011).
Metals in coastal seagrass habitats: A systematic quantitative literature review
Published in Critical Reviews in Environmental Science and Technology, 2023
Heera Lee, Clare Morrison, Nicholas J. C. Doriean, David T. Welsh, William W. Bennett
Seagrasses are marine flowering plants that inhabit shallow estuarine and marine environments (Short et al., 2001, 2007). All seagrasses consist of roots, below-ground stems (rhizomes) and leaves (Hemminga & Duarte, 2000), however, their morphology varies substantially between species (Kuo & Hartog, 2007). For example, Halophila acoroides has very long ribbon-like leaves with inrolled leaf margins, whereas the leaves of H. capricorni are small and oval with hairs on one side (El Shaffai et al., 2016). Seagrass meadows are highly productive and dynamic environments that are ecologically important to coastal marine ecosystems (Unsworth & Cullen, 2010). Seagrass meadows act as nursery habitats and ecological food sources (Du et al., 2020; Heck et al., 1997), mitigate climate change via carbon sequestration (Macreadie et al., 2019), provide coastal protection (Barbier et al., 2011), and improve water quality (de los Santos et al., 2020). Despite their ecological significance, consistent declines in seagrass coverage have been observed since the 1950s (Spalding et al., 2003; Waycott et al., 2009).
Flow field and wake structure characteristics imposed by single seagrass blade surrogates
Published in Journal of Ecohydraulics, 2022
M. Taphorn, R. Villanueva, M. Paul, J. Visscher, T. Schlurmann
Seagrass meadows in coastal environments are known to provide important ecosystem services such as dissipating energy from waves and currents, stabilizing sediments and providing habitats for other marine species (Koch et al. 2006; de Boer 2007; Barbier et al. 2011; Kirkman 2014). Thus, as ecosystem engineers, seagrass meadows play an important ecological role and are considered as soft contributions to coastal protection efforts (Ondiviela et al. 2014; Spalding et al. 2014). The seagrass species Zostera marina occurs in tropic, temperate, cold and polar regions on all continents of the Northern hemisphere and is thus one of the most wide-ranging seagrass species (Kirkman 2014). It is able to live in water depths of up to 50 m as well as in a wide range of temperature and short-term salinity fluctuations. Furthermore, Zostera marina can be found in regions with mean current velocities between 0.03 and 1.8 m/s and maximum wave heights up to 2 m (Koch 2001; Kirkman 2014).
Effect of artificial seagrass on hydrodynamic thresholds for the early establishment of Zostera marina
Published in Journal of Ecohydraulics, 2022
J. Carus, C. Arndt, T. J. Bouma, B. Schröder, M. Paul
The strength of the seagrass-sediment-light (SSL) feedback depends on both the environmental characteristics (e.g., wave and current speed, sediment properties) and the properties of the seagrass meadow (e.g., meadow length and shoot height, canopy density, leaf morphology). For example, the impact of seagrass on hydrodynamics and thus sediment erosion and resuspension is greater under higher input flow velocities (Adams et al. 2016). Higher shoot densities for instance lead to higher reductions in near-bed velocity (Wilkie et al. 2012), wave height (Paul and Amos 2011) and sediment resuspension (Widdows et al. 2008). The seagrass-sediment-light (SSL) feedback is dependent on plant functional traits, like being adapted to hydrodynamically stressful environments (Carus et al. 2016). By investing in belowground biomass, seagrass also improve their anchorage system, and thereby its critical capacity to withstand dislodgement during sediment erosion (Widdows et al. 2008; Infantes et al. 2011).