Seasonal changes in fatty acid composition of estuarine intertidal biofilm: Implications for western sandpiper migration

Schnurr, Peter J.; Drever, Mark C.; Kling, Hedy; Elner, Robert W.; Arts, Michael T.

doi:10.1016/j.ecss.2019.04.047

Cited by 24 publications

(42 citation statements)

References 82 publications

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“…We demonstrate that intertidal mudflat biofilm in the Fraser River estuary, especially in spring when these communities are dominated by diatoms, is a rich source of lipid and essential fatty acids. These riches of energy and nutrients occur around the same time that Western Sandpipers and other shorebirds make their annual northward migration through the area in large congregations (Drever et al, 2014;Schnurr et al, 2019). These seasonal changes in fatty acid content may result from three (non-mutually exclusive) processes: (i) changes in the proportion of diatom biomass within the biofilm which results in more fatty acids; (ii) physiological changes within diatoms already present on the mudflats, resulting in an increase in per cell total lipid and individual fatty acid content, and (iii) seasonal species turnover within the biofilm community.…”

Section: Discussionmentioning

confidence: 99%

“…Elevated areas have longer times (i.e., several hours per tidal period) when the mudflat is exposed to ambient air conditions. These conditions likely allow algal cells to photosynthesize at higher rates since they are exposed to higher photon flux densities, warmer springtime temperatures (Schnurr et al, 2019), and higher rates of gas exchange (i.e., CO 2 into the cells and O 2 out of the biofilms). The sites closer to shore would have longer exposure times (to ambient air conditions) and may experience less shear stress associated with tidal and wave energy (Underwood and Paterson, 1993).…”

Section: Spatial Variabilitymentioning

confidence: 99%

“…Although many consumers require, to various degrees, specific fatty acids, our focus is on the Western Sandpiper (Calidris mauri). Western Sandpipers extensively graze estuarine intertidal mudflat biofilm (Elner et al, 2005;Kuwae et al, 2008), which serves as a primary source of fatty acids to meet their energetic and physiological demands, particularly during their northward breeding migration each spring (Schnurr et al, 2019). Fats are a preferred migratory fuel because they represent a compact and energy-dense resource compared to carbohydrates and proteins (Guglielmo, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Estuarine biofilm communities are dominated by diatoms (Underwood and Paterson, 1993), which can rapidly accumulate fatty acids under specific environmental conditions and growth phases (Schnurr et al, 2019). Under ideal growth conditions diatoms grow and reproduce maximally, causing them to rapidly produce membrane lipids (required for cell division), which consist mostly of phospholipids containing relatively higher proportions of PUFA.…”

Section: Introductionmentioning

confidence: 99%

“…If migrating birds are broadly synchronizing the timing of their northward migration with the peak availability of fatty acids in estuarine biofilm, then seasonal changes in total lipid and fatty acid content should mirror the differences in shorebird use between spring and summer. Given that the realized fatty acid content of estuarine mudflat biofilms is likely a result of complex interactions among a variety of environmental conditions (Schnurr et al, 2019), our aim was to understand how spatial and temporal environmental conditions affect biofilm organic and fatty acid content during these two seasons. Specifically, we investigated how biofilm organic and fatty acid content in biofilms were affected by spatial variables such as mudflat elevation (and how that affects mudflat exposure time), proximity to shore, proximity to the outlet of the Fraser River, and by time-varying factors, including salinity, temperature, nutrient concentrations, and light conditions.…”

Section: Introductionmentioning

confidence: 99%

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Peak Abundance of Fatty Acids From Intertidal Biofilm in Relation to the Breeding Migration of Shorebirds

et al. 2020

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Intertidal biofilm is a thin layer of microbes and meiofauna enmeshed in an extracellular polymeric matrix within and on top of mudflat sediment. This medium provides a dynamic resource for a variety of consumers in estuarine habitats, and is rich in essential fatty acids that birds require for long-distance migration. We measured seasonal changes in biofilm fatty acid content from spring to summer on the Fraser River Estuary, one of the richest and most important ecosystems for migrant and wintering waterbirds in Canada. Fatty acid content in biofilm showed a strong seasonal pattern with a peak in the spring that is associated with the northward migration of Western Sandpipers (Calidris mauri) to their breeding grounds. This peak is linked to the abundance and physiological state, and hence nutritional condition, of epipelic diatoms, which, in turn, depend on a combination of mudflat topography, salinity, temperature, and nutrients that can fluctuate widely with the freshwater inputs from the Fraser River. Specifically, areas with higher elevation (i.e., ∼1 m) had longer periods of exposure to ambient conditions (i.e., light, warm temperatures, gas exchange into/out of biofilms) that facilitated more biofilm growth and higher fatty acid content. Moreover, springtime changes in water chemistry (i.e., salinity/osmotic stresses and nutrients) and temperature facilitated the production of higher overall total lipid/fatty acid contents in the mudflat biofilms compared to summer. Effective conservation of migrating shorebirds depends on the protection of underlying processes at important stopover sites that promote biofilm communities to escalate their production of lipids, including essential fatty acids, during key times of the year.

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Section: Discussionmentioning

confidence: 99%

Section: Spatial Variabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Peak Abundance of Fatty Acids From Intertidal Biofilm in Relation to the Breeding Migration of Shorebirds

et al. 2020

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Seven ecological and technical attributes for biofilm‐based recovery of shorebird populations in intertidal flat ecosystems

Kuwae

Elner

Amano

et al. 2021

Ecol Sol and Evidence

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1. Soft-bottomed intertidal flats are essential foraging areas for shorebirds but are severely impacted by threats such as coastal development and climate change.Notwithstanding the urgency for humanintervention (conservation, restoration and creation) of tidal flats, few ecologically based technical guidelines exist for the artificial (clearly intended human intervention) intertidal flats, and none explicitly consider the unique properties of intertidal biofilm as a critical food source for small-bodied shorebirds.2. We propose that effective human intervention in intertidal flat ecosystems can be developed through mirroring the needs of small-bodied shorebirds. Scientific evidence from intertidal flat recovery projects in Japan is summarized, and foraging requirements of shorebirds are reviewed with a focus on intertidal biofilm as a critical food source.3. These findings are used to propose the primary goal of intervention, that is maximizing total energy intake for population recovery of small-bodied shorebirds through biofilm. Three sub-goals are presented for creating environmental conditions in which (1) a broad spectrum of food sources is available, but particularly intertidal biofilm; (2) maximizing energy intake rate per individual; and (3) maximizing foraging activity. We then describe seven key ecologically based technical attributes for artificial intertidal flats that promote use by small-bodied shorebirds: depositional environment, complex shoreline, gentle slope, gradient of grain sizes from muddy to sandy, maximum water depth at the lowest tide 5 cm or less, freshwater inflow and unobstructed sight-lines. 4. Critical questions remain for effective intervention in intertidal flat ecosystems, including food web dynamics, variation in the quality and quantity of food sources, especially biofilm, optimal sedimentary environment systems (interaction between grain size, bed slope and elevation), monitoring involving comparisons with appropriate benchmark (control) habitats, quantifying foraging behaviour and the synergy and trade-offs among ecosystem services.

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Diatom Biofilms: Ecosystem Engineering and Niche Construction

Paterson

Hope

2021

Diatom Gliding Motility

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Seasonal changes in fatty acid composition of estuarine intertidal biofilm: Implications for western sandpiper migration

Cited by 24 publications

References 82 publications

Peak Abundance of Fatty Acids From Intertidal Biofilm in Relation to the Breeding Migration of Shorebirds

Peak Abundance of Fatty Acids From Intertidal Biofilm in Relation to the Breeding Migration of Shorebirds

Seven ecological and technical attributes for biofilm‐based recovery of shorebird populations in intertidal flat ecosystems

Diatom Biofilms: Ecosystem Engineering and Niche Construction

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