Distribution and controlling mechanisms of primary production on the Louisiana–Texas continental shelf

Chen, Xiaogang; Lohrenz, Steven E.; Wiesenburg, Denis A.

doi:10.1016/s0924-7963(00)00014-2

Cited by 66 publications

(57 citation statements)

References 27 publications

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“…Riverine nutrient loads support high phytoplankton productivity in the winter and early spring when discharge from Southwest Pass and the Atchafalaya River is highest (Rabalais et al 2002). Westerly currents create a band of high coastal productivity extending from mid-salinity waters near the Mississippi River westward along the inner shelf (Chen et al 2000;Walker and Rabalais 2006) except during cold fronts and in the late summer when currents change to a more east and southeast direction (Walker and Rabalais 2006). Water-column integrated productivity in the study area ranges from , 0.5 g C m 22 d 21 to .…”

Section: Methodsmentioning

confidence: 99%

“…Water-column integrated productivity in the study area ranges from , 0.5 g C m 22 d 21 to . 2 g C m 22 d 21 and generally decreases in a seaward direction (Chen et al 2000). The contribution of phytoplankton to the inner shelf from midshelf waters and the continental margin is likely to be low due to the wide seaward extent of the Louisiana shelf (up to 200 km) and the relative paucity of nutrients in the open gulf and upwelling slope waters (Chen et al 2000;Dagg and Breed 2003).…”

Section: Methodsmentioning

confidence: 99%

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Spatial variation in basal resources supporting benthic food webs revealed for the inner continental shelf

Grippo

Fleeger

Dubois

et al. 2011

Limnology & Oceanography

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We used stable isotopes to examine the relative importance of phytodetritus and microphytobenthos (MPB) in supporting benthic food webs on the Louisiana continental shelf. Primary producers and macroinfauna were collected from Ship Shoal (SS), a submerged, sandy, barrier island where sediment-associated algae are primarily MPB and from silty, off-shoal areas where sediment-associated algae are primarily phytodetritus or a mixture of the two resources. Macroinfauna, as individual taxa and trophic guilds, were significantly more enriched in 13 C on SS indicating greater dependence on MPB, which is enriched in 13 C compared to phytoplankton. Using d 13 C in a two-source mixing model, the estimated MPB dietary contribution for SS macroinfauna averaged across trophic guilds, ranged from 53.4% to 83.0%, depending on the mixing-model end-members used, and 5 of 14 taxa had lower 95% confidence intervals (CI) . 20%, indicating that MPB was a primary resource for most SS macroinfauna. Off-shoal, the dietary contribution of MPB ranged from14.5% to 47.7% and most taxa had a lower CI near 0%. Settled phytoplankton are the primary microalgal food source in muddy sediments, but the importance of MPB increases in more sandy sediments where MPB are the predominant microalgal resource. Sandy shoals play a unique food-web role in deltaic shelf systems and support benthic food webs on the continental shelf.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Spatial variation in basal resources supporting benthic food webs revealed for the inner continental shelf

Grippo

Fleeger

Dubois

et al. 2011

Limnology & Oceanography

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“…Models were prepared for 4 seasons: July-August (summer); September-October (fall); February-March (winter); and April-May (spring). Since the summer model used data from an extraordinarily productive period, and probably unusually so (see Chen et al 2000 -data from Atchafalaya plume), an alternative summer model (low summer) was prepared by halving summer data for net primary production in P 2 but keeping all other data the same. Data from 3 mo seasons over multiple years were combined into single-season descriptions.…”

Section: Methods and Model Approachmentioning

confidence: 99%

“…Flow is typically highest during the spring freshet and lowest during late-summer river flow, but pulses of freshwater can occur anytime and alter the flow (Chen et al 1997, Hitchcock et al 1997. During the winter, along-shelf currents tend to flow downcoast (to the west), while the associated onshore Ekman transport keeps the buoyant plume close to shore (Li et al 1997, Chen et al 2000. During the summer, plume water usually moves westward, but strong downcoast flow is less frequent and the plume frequently pools, moves offshore, or even flows eastward.…”

Section: Net Autotrophy and Net Heterotrophymentioning

confidence: 99%

“…Such conditions might also occur during late summer; although temperature and irradiance favor high productivity, river flow and nitrogen loading are usually at their minima. Primary production rates used to formulate the winter model may themselves be unusually low, in which case winter may normally be at least periodically net autotrophic (Chen et al 2000). Results from other models represent the more usual intermediate and higher river flow and longer daylengths favorable to high primary productivity.…”

Section: Net Autotrophy and Net Heterotrophymentioning

confidence: 99%

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Sedimentation, carbon export and food web structure in the Mississippi River plume described by inverse analysis

Breed

Jackson²,

Richardson³

2004

Mar. Ecol. Prog. Ser.

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Pulsed, cross‐shelf export of terrigenous dissolved organic carbon to the Gulf of Mexico

2014

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The export of terrigenous dissolved organic carbon (tDOC) and other river-borne material across the continental shelf boundary has important ramifications for biological productivity and the cycling of continentally derived bioelements in the ocean. Recent studies revealed the 275-295 nm spectral slope coefficient of chromophoric dissolved organic matter (CDOM), S 275-295 , is a reliable tracer for terrigenous dissolved organic carbon (tDOC) in river-influenced ocean margins. Here an empirical algorithm for the accurate retrieval of S 275-295 from ocean color was developed and validated using in situ optical properties collected seasonally in the northern Gulf of Mexico. This study also demonstrated S 275-295 is a robust proxy for tDOC concentration in this environment, thereby providing a means to derive surface tDOC concentrations on synoptic scales and in quasi-real time using remote sensing. The resulting tDOC-algorithm was implemented using Aqua-MODIS in a retrospective analysis of surface tDOC concentrations over the northern Gulf of Mexico between July 2002 and June 2013. Large pulses of tDOC were observed in continentalslope surface waters off the Mississippi River delta, indicating cross-shelf export of tDOC was sporadic and exhibited considerable interannual variability. Favorable winds following an anomalously high discharge from the Mississippi-Atchafalaya river system always coincided with a major export event, and in general, cross-shelf export was enhanced during years of anomalously high discharge. The tDOC-algorithm will find applicability in the assessment of future climate-and human-induced changes in tDOC export, in biogeochemical models of the continental shelf, and in the validation of high-resolution coastal models of buoyancy-driven shelf circulation.

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Distribution and controlling mechanisms of primary production on the Louisiana–Texas continental shelf

Cited by 66 publications

References 27 publications

Spatial variation in basal resources supporting benthic food webs revealed for the inner continental shelf

Spatial variation in basal resources supporting benthic food webs revealed for the inner continental shelf

Sedimentation, carbon export and food web structure in the Mississippi River plume described by inverse analysis

Pulsed, cross‐shelf export of terrigenous dissolved organic carbon to the Gulf of Mexico

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