Managing nitrogen inputs into seagrass meadows near a coastal city: Flow-on from research to environmental improvement plans

Nayar, Sasi; Collings, Greg; Pfennig, P.; Royal, Meredith J.

doi:10.1016/j.marpolbul.2012.03.005

Cited by 14 publications

(12 citation statements)

References 28 publications

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“…Seagrasses are in decline; with 29% of known seagrass areal extent being lost since 1879 [12,13]. The situation is similar in metropolitan coastal waters of South Australia [14], a region that experienced a loss of 85 ha yr −1 on average until the early 2010s [15,16], with a slow come back in the last decade, highlighting the need for more accurate mapping of seagrasses [17][18][19] in the area.…”

Section: Introductionmentioning

confidence: 99%

Spectral Deconvolution for Dimension Reduction and Differentiation of Seagrasses: Case Study of Gulf St. Vincent, South Australia

et al. 2019

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Seagrasses are a vulnerable and declining coastal habitat, which provide shelter and substrate for aquatic microbiota, invertebrates, and fishes. More accurate mapping of seagrasses is imperative for their sustainability but is hindered by the lack of data on reflectance spectra representing the optical signatures of individual species. Objectives of this study are: (1) To determine distinct characteristics of spectral profiles for sand versus three temperate seagrasses (Posidonia, Amphibolis, and Heterozostera); (2) to evaluate the most efficient derivative analysis method of spectral reflectance profiles for determining benthic types; and to assess the influences of (3) site location and (4) the water column on spectral responses. Results show that 566:689 and 566:600 bandwidth ratios are useful in separating seagrasses from sand and from detritus and algae, respectively; first-derivative reflectance spectra generally is the most efficient method, especially with deconvolution analyses further helping to reveal and isolate 11 key wavelength dimensions; and differences between sites and water column composition, which can include suspended particulate matter, both have no effect on endmembers. These findings helped develop a spectral reflectance library that can be used as an endmember reference for remote sensing, thereby providing continued monitoring, assessment, and management of seagrasses.

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Section: Introductionmentioning

confidence: 99%

Spectral Deconvolution for Dimension Reduction and Differentiation of Seagrasses: Case Study of Gulf St. Vincent, South Australia

et al. 2019

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“…Atypical of the seagrasses in the current study, excessive nitrogen loading globally has been reported to have detrimental effects on seagrass-dominated estuaries by inhibiting seagrass growth and survival through the stimulation of phytoplankton, epiphytic algae and benthic microalgal growth 11 – 13 . Eutrophication is also considered to be a major cause of the loss of seagrass in Australia 14 – 16 . Eutrophication not only has an indirect effect by stimulating algal overgrowth and consequently reducing available light, but for some species a direct physiological effect 8 , 13 , 17 .…”

Section: Introductionmentioning

confidence: 99%

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Nayar

Loo

Tanner

et al. 2018

Sci Rep

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The dominant seagrass in Port Phillip Bay (PPB), Australia, Zostera nigricaulis, declined between 2000 and 2011, coinciding with the ‘Millennium drought’ that ended in 2009. These seagrasses are nitrogen-limited, underpinning the need to develop nitrogen budgets for better ecosystem management. Environmentally realistic measurements of specific uptake rates and resource allocation were undertaken to develop nitrogen budgets and test the hypothesis that the above-ground and below-ground compartments are able to re-mobilise ammonium and nitrate through uptake, translocation and assimilation to adapt to varying levels of nitrogen in the ecosystem. Uptake of 15N labelled ammonium and nitrate by above- and below-ground seagrass biomass, epiphytes and phytoplankton was quantified in chambers in situ. Preferential uptake of ammonium over nitrate was observed, where the uptake rate for nitrate was about one sixth of that for ammonium. Epiphytes and phytoplankton also registered an increased affinity for ammonium over nitrate. Translocation experiments demonstrated the uptake by both the above-ground and below-ground biomass, respectively from the water column and pore water, and subsequent translocation to the opposite compartment. Acropetal translocation (below- to above-ground biomass) was more prevalent than basipetal translocation. This is a unique outcome given basipetal translocation has been widely reported for Zostera by other researchers.

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“…For restoration to be successful, restored seagrass patches should persist and recover similar ecosystem function, such as the recovery of fauna due to the provision of habitat, to that of a natural undisturbed seagrass meadow (Fonseca et al 1998). Wear et al (2010) developed a novel seagrass restoration technique, using biodegradable hessian (burlap) bags to stabilize the sediment and facilitate the natural recruitment of Amphibolis antarctica seedlings, with the overall intention of re-establishing an extensive continuous seagrass meadow, which was present in the area prior to substantial seagrass loss 5 (> 5,200 ha) (Neverauskas 1987;Nayar et al 2012). This technique has allowed A.…”

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Habitat restoration: Early signs and extent of faunal recovery relative to seagrass recovery

McSkimming

Connell

Russell

et al. 2016

Estuarine, Coastal and Shelf Science

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The overall intent of restoration is often not only to restore the habitat per se, but to restore the ecosystem services it supplies, and particularly to encourage the return of fauna. Seagrass meadows act as habitat for some of the most diverse and abundant animal life, and as the global loss of seagrass continues, managers have sought to restore lost meadows. We tested how quickly the epifaunal richness, abundances and community composition of experimental restoration plots recovered to that in an adjacent natural seagrass meadow relative to the recovery of seagrass per se. Seagrass structure in the restoration plots took three years to become similar to a nearby natural meadow. The recovery of epifaunal richness and total abundance, however, occurred within one year. These results suggest that although recovering habitats may not be structurally similar to undisturbed habitats, they can support similar richness and abundances of epifauna, and thus have greater economic and social value than otherwise might have been expected. Nevertheless, whilst epifaunal richness and total abundance recovered prior to the recovery of seagrass structure, full recovery of seagrass was required before the composition and relative abundances of the epifaunal community matched that of the natural seagrass meadow.

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Managing nitrogen inputs into seagrass meadows near a coastal city: Flow-on from research to environmental improvement plans

Cited by 14 publications

References 28 publications

Spectral Deconvolution for Dimension Reduction and Differentiation of Seagrasses: Case Study of Gulf St. Vincent, South Australia

Spectral Deconvolution for Dimension Reduction and Differentiation of Seagrasses: Case Study of Gulf St. Vincent, South Australia

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Habitat restoration: Early signs and extent of faunal recovery relative to seagrass recovery

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