Organic matter and benthic metabolism in euphotic sediments along shallow sub-tropical estuaries, northern New South Wales, Australia

Ferguson, A.; Eyre, Bradley D.

doi:10.3354/ame033137

Cited by 72 publications

(83 citation statements)

References 72 publications

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“…Although algae are typically characterized by high glucose concentration and appeared to be the main source of sediment OC, the uniform carbohydrate composition we observed suggests that the organic matter within sediments was highly degraded. The productivity of MPB was comparable to that of sands studied previously (Middelburg et al 2000) and was at the upper range of productivity observed for muddy, photic, subtidal sediments in the upper reaches of the Brunswick River estuary (Eyre and Ferguson 2005) and sandy sediments in the lower estuary (Ferguson et al 2003). This high productivity is likely reflected in the rapid transfer of fixed carbon to carbohydrates at rates at the upper end of expected ranges.…”

Section: Discussionmentioning

confidence: 58%

“…The average PLFA concentration given assumes a carbon to chlorophyll a ratio (C : Chl a) of 40, which is within the range recorded for the Brunswick River in summer (Ferguson et al 2004). MPB biomass calculated using minimum and maximum values for c (62-71%, Volkman et al 1989) and d (assuming C : Chl a 5 30-60, Ferguson et al 2004) was within , 30% of biomass calculated from average values.…”

Section: Methodsmentioning

confidence: 85%

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Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling

Oakes

Eyre

Middelburg

et al. 2010

Limnology & Oceanography

104

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The composition and production of carbohydrates (mannose, rhamnose, fucose, galactose, glucose, and xylose) and their transfer among sediment compartments (microphytobenthos [MPB], bacteria, and detritus) was investigated through in situ labeling with 13 C-bicarbonate. After 60 h, 13 C was found in all sediment compartments, demonstrating rapid transfer of fixed carbon from autotrophs to heterotrophs. Carbohydrates were a major carbon reservoir, accounting for 30% (day 0) to 15% (day 30) of the 13 C within sediments, and probably played a role in this transfer. Carbohydrate fractions were highly reactive (65-87%), less reactive (7-18%), and nonreactive (6-23%) over the experimental period. The rate of loss of the less reactive fraction (0.01-0.05 d 21 ) was at least an order of magnitude lower than that for the highly reactive fraction (0.8-4.4 d 21 ). Patterns of diagenesis estimated from label uptake and loss matched the carbohydrate composition observed in the sediment (glucose . galactose . rhamnose . fucose . xylose . mannose) and were similar to patterns reported previously. C : N ratios and d 13 C of sediment organic matter indicated an algal origin (MPB and phytoplankton). Although carbon was rapidly processed, loss from sediments was not immediate, and there was evidence of recycling into MPB and bacteria. Rapid transfer of carbon to and from carbohydrates has been found in various environments, including temperate, muddy, and intertidal sediments, and this study demonstrates the important role of carbohydrates in supporting heterotrophic production over extended periods (. 30 d) in subtropical shallow subtidal sands.

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Section: Discussionmentioning

confidence: 58%

Section: Methodsmentioning

confidence: 85%

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling

Oakes

Eyre

Middelburg

et al. 2010

Limnology & Oceanography

104

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“…Ultimately, the magnitude of potential shifts in coral reef sediment GPP / R and G net under global warming scenarios will depend critically on the availability of organic matter (OM) substrate for remineralisation (Ferguson et al, 2003;Rabalais et al, 2009). Carbonate sediment dissolution is strongly controlled by the extent of OM decomposition in the sediments (Andersson, 2015).…”

Section: Introductionmentioning

confidence: 99%

The short-term combined effects of temperature and organic matter enrichment on permeable coral reef carbonate sediment metabolism and dissolution

et al. 2017

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Abstract. Rates of gross primary production (GPP), respiration (R), and net calcification (G net ) in coral reef sediments are expected to change in response to global warming (and the consequent increase in sea surface temperature) and coastal eutrophication (and the subsequent increase in the concentration of organic matter, OM, being filtered by permeable coral reef carbonate sediments). To date, no studies have examined the combined effect of seawater warming and OM enrichment on coral reef carbonate sediment metabolism and dissolution. This study used 22 h in situ benthic chamber incubations to examine the combined effect of temperature (T ) and OM, in the form of coral mucus and phytodetritus, on GPP, R, and G net in the permeable coral reef carbonate sediments of Heron Island lagoon, Australia. Compared to control incubations, both warming (+2.4 • C) and OM increased R and GPP. Under warmed conditions, R (Q 10 = 10.7) was enhanced to a greater extent than GPP (Q 10 = 7.3), resulting in a shift to net heterotrophy and net dissolution. Under both phytodetritus and coral mucus treatments, GPP was enhanced to a greater extent than R, resulting in a net increase in GPP / R and G net . The combined effect of warming and OM enhanced R and GPP, but the net effect on GPP / R and G net was not significantly different from control incubations. These findings show that a shift to net heterotrophy and dissolution due to short-term increases in seawater warming may be countered by a net increase GPP / R and G net due to short-term increases in nutrient release from OM.

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“…Dissolved oxygen concentrations (and saturation values) were measured at the start and finish of the incubations. The method is based on that of Ferguson et al (2003).…”

Section: Discussionmentioning

confidence: 99%

“…higher than those of refractory OM (4 days-0.33 years v. 1-440 years; Stephens et al 1997) and is considered more important in benthic metabolism (Ferguson et al 2003) and invertebrate nutrition (Danovaro et al 1995).…”

Section: Trcmentioning

confidence: 99%

Baseline biogeochemical data from Australia's continental margin links seabed sediments to water column characteristics

Radke

Nicholas

Thompson

et al. 2017

Mar. Freshwater Res.

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Abstract. Surficial marine sediments are an important source of nutrients for productivity and biodiversity, yet the biogeochemistry of these sediments is poorly known in Australia. Seabed samples were collected at .350 locations in Australia's western, northern and eastern continental margins during Federal Government surveys . Parameters analysed included measures of organic matter (OM) source (d 13 C, d 15 N and C : N ratios), concentration (percentage total organic carbon, %TOC, and surface area-normalised TOC, OC : SA) and bioavailability (chlorin indices, total reactive chlorins, total oxygen uptake, total sediment metabolism (TSM), sediment oxygen demand (SOD) and SOD and TSM normalised against TOC). The aim of the present study was to summarise these biogeochemical 'baseline' data and make contextualised inferences about processes that govern the observed concentrations. The OM was primarily from marine sources and the OC : SA broadly reflected water column productivity (based on Moderate Resolution Imaging Spectroradiometer, MODIS). Approximately 40% of sediments were organic poor by global standards, reflecting seawater oligotrophy; ,12% were organic rich due to benthic production, high water column productivity and pockmark formation. OM freshness varied due to pigment degradation in water columns and dilution with refractory OM in reworked sediments. d 15 N values confirmed the importance of N 2 fixation to Timor Sea productivity, and point to recycling of fixed nitrogen within food chains in Western Australia.

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Organic matter and benthic metabolism in euphotic sediments along shallow sub-tropical estuaries, northern New South Wales, Australia

Cited by 72 publications

References 72 publications

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling

The short-term combined effects of temperature and organic matter enrichment on permeable coral reef carbonate sediment metabolism and dissolution

Baseline biogeochemical data from Australia's continental margin links seabed sediments to water column characteristics

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Organic matter and benthic metabolism in euphotic sediments along shallow sub-tropical estuaries, northern New South Wales, Australia

Cited by 72 publications

References 72 publications

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by 13C‐labeling

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by 13C‐labeling

The short-term combined effects of temperature and organic matter enrichment on permeable coral reef carbonate sediment metabolism and dissolution

Baseline biogeochemical data from Australia's continental margin links seabed sediments to water column characteristics

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Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling

Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long‐term retention revealed by ¹³C‐labeling