Biomass and productivity of seagrasses in Africa

Githaiga, Michael N.; Gilpin, Linda; Kairo, James Gitundu; Huxham, Mark

doi:10.1515/bot-2015-0075

Cited by 22 publications

(18 citation statements)

References 36 publications

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“…Fig. 4 is based on the maximum values of three resistance proxies and three recovery measures found in the literature for each genera, normalized against the maximum overall Table S5); B) Rhizome diameter (Duarte, 1991a); C) Shoot weight (Brouns and Heijs, 1986;Duarte, 1991a;Edgar and Robertson, 1992;Ramírez-García et al, 1998); D) Total biomass (Duarte and Chiscano, 1999;Githaiga et al, 2016;Menéndez, 2002;Paling and McComb, 2000); E) Seed density (Kim et al, 2015;Orth et al, 2006b); F) Rhizome extension rate (Duarte, 1991a;Marba and Duarte, 1998;Wortmann et al, 1998); G) Leaf turnover rate (Duarte, 1991a;Vonk et al, 2015); H) Above: below ground biomass ratio (Duarte and Chiscano, 1999;Githaiga et al, 2016). Genera are classified as persistent, colonizing and/or opportunistic as per Kilminster et al (2015).…”

Section: Resistance Recovery and Seagrass Life History Strategymentioning

confidence: 99%

Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance

O’Brien

Waycott

Maxwell

et al. 2018

Marine Pollution Bulletin

120

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Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of 12 seagrass genera. We document four classic trajectories of degradation and recovery for seagrass ecosystems, illustrated with examples from around the world. Recovery can be rapid once conditions improve, but seagrass absence at landscape scales may persist for many decades, perpetuated by feedbacks and/or lack of seed or plant propagules to initiate recovery. It can be difficult to distinguish between slow recovery, recalcitrant degradation, and the need for a window of opportunity to trigger recovery. We propose a framework synthesizing how the spatial and temporal scales of both disturbance and seagrass response affect ecosystem trajectory and hence resilience.

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Section: Resistance Recovery and Seagrass Life History Strategymentioning

confidence: 99%

Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance

O’Brien

Waycott

Maxwell

et al. 2018

Marine Pollution Bulletin

120

View full text Add to dashboard Cite

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“…Seagrass beds mixed with macroalgae cover both the creeks and the bay up to the seaward mouth (Githaiga et al, 2016). Thalassodendron ciliatum, Cymodocea serrulata, C. rotundata and Enhalus acoroides are among the most abundant seagrass species, while Sargassum binderi, Dictyota cervicornis, and Turbinaria conoides are among the most abundant brown and Gracilaria corticata and Hypnea cornuta among the most abundant red macroalgae.…”

Section: Study Area and Sample Collectionmentioning

confidence: 99%

Small-scale variability in geomorphological settings influences mangrove-derived organic matter export in a tropical bay

et al. 2017

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Abstract. Organic matter (OM) exchanges between adjacent habitats affect the dynamics and functioning of coastal systems, as well as the role of the different primary producers as energy and nutrient sources in food webs. Elemental (C, N, C : N) and isotope (δ 13 C) signatures and fatty acid (FA) profiles were used to assess the influence of geomorphological setting in two climatic seasons on the export and fate of mangrove OM across a tidally influenced tropical area, Gazi Bay (Kenya). The main results indicate that tidal transport, along with riverine runoff, plays a significant role in the distribution of mangrove organic matter. In particular, a marked spatial variability in the export of organic matter from mangroves to adjacent habitats was due to the different settings of the creeks flowing into the bay. Kinondo Creek acted as a mangrove retention site, where export of mangrove material was limited to the contiguous intertidal area, while Kidogoweni Creek acted as a "flow-through" system, from which mangrove material spreads into the bay, especially in the rainy season. This pattern was evident from the isotopic signature of primary producers, which were more 13 C-depleted in the Kinondo Creek and nearby, due to the lower dilution of the dissolved inorganic carbon (DIC) pool, typically depleted as an effect of intense mangrove mineralisation. Despite the trapping efficiency of the seagrass canopy, suspended particulate OM showed the important contribution of mangroves across the whole bay, up to the coral reef, as an effect of the strong ebb tide. Overall, mixing model outcomes indicated a widespread mixed contribution of both allochthonous and autochthonous OM sources across Gazi Bay. Moreover, FAs indicated a notable contribution of brown macroalgae and bacteria in both sediment and suspended pools. These results suggest that ecological connectivity in Gazi Bay is strongly influenced by geomorphological setting, which may have far-reaching consequences for the functioning of the whole ecosystem and the local food webs.

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“…Compared to other blue carbon sinks, there is less research focusing on seagrass carbon dynamics, leading to uncertainties in the seagrass habitat extent and contribution to the blue carbon budget. In the African coastline for example, there is still a huge paucity of information regarding seagrass habitat extent, quantitative carbon estimates, and habitat influence despite the extensive meadows (Githaiga et al, 2016(Githaiga et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

Variation in Seagrass Carbon Stocks Between Tropical Estuarine and Marine Mangrove-Fringed Creeks

et al. 2020

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Seagrass and associated blue carbon ecosystems are important carbon sinks, and hence understanding their spatial and temporal variability is vital in appreciating their potential roles in climate change mitigation and adaptation. The Indo-Pacific region has the highest seagrass biodiversity, yet little focus has been made to compare seagrass habitat extent and carbon dynamics with their temperate counterparts. The present study assessed habitat characteristics and seagrass species distribution, diversity, and carbon storage in Eastern (marine) and Western (estuarine) mangrove-fringed creeks of Gazi Bay, Kenya. Data on species composition, canopy cover, biomass, and sediment organic carbon were collected in 80 plots of 0.25 × 0.25 m laid along transects established perpendicular to the waterline. Five species formation, viz., Thalassia hemprichii, Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, and Thalassidendron ciliatum, were encountered as either single or mixed stands. There was a significant difference in total seagrass biomass between creeks (p < 0.01), with the Eastern creek recording a mean of 10.2 ± 0.6 Mg C ha −1 while the Western creek recording 4.3 ± 0.3 Mg C ha −1. In addition, sediment carbon to 1-m depth varied significantly (p < 0.01) between species in the two creeks and ranged from 98 to 302 Mg C ha −1 , with the Eastern and Western creeks recording means of 258 ± 90 and 107 ± 21 Mg C ha −1 , respectively. The total carbon stock from 50 ha of seagrasses in the Eastern creek was 13,420 Mg C, whereas in the 70 ha of the Western creek it was 7,769 Mg C. The study shows that seagrass community attributes such as species composition and productivity can vary dramatically over a small spatial extent due to differences in biophysical conditions and caution estimations of site-specific carbon stocks using generalized global values.

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Biomass and productivity of seagrasses in Africa

Cited by 22 publications

References 36 publications

Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance

Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance

Small-scale variability in geomorphological settings influences mangrove-derived organic matter export in a tropical bay

Variation in Seagrass Carbon Stocks Between Tropical Estuarine and Marine Mangrove-Fringed Creeks

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