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Published byAbigayle Wilkerson Modified over 9 years ago
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>Vertical gradient; >FW overlays SW; >FW flow dominates over tides >greater vertical mixing; >Moderate tidal action >Vertically homogenous; >Vigorous tidal action
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Turner et al. 2006 – Hurricane sediments
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- Pulsed Flood Events – natural disturbances drive high productivity & diversity in river, floodplain and estuary
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Relationship between FW species percentage and tidal influence
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Relationship between species richness and salinity
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Table of TFW vs SM conditions
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Abiotic gradients along a salinity gradient Coupled response between Chlorophyll, DOC and DO along the salinity gradient
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Salinity zonation patterns and the River Continuum Concept
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Odum’s 1984 Dual Gradient Concept Stream orders = marsh dendritic pattern River ≠ Estuary ≠ Marsh
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Dual Gradient Concept: salinity & marsh stream order gradients DOC input to estuary POC input to estuary DOC gradient along marsh stream orders
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Dual Gradient Concept: salinity & marsh stream order gradients POC gradient along marsh stream orders Main sources of organic carbon along marsh stream gradient
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Nekton as carbon sources and movement among subsystems
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Gradients in primary production in estuaries Juvenile menhaden nursery driven by phytoplankton gradients Relationship between salinity – menhaden abundance - chlorophyll signatures (Neuse River: 2 May 1984)
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Relationship between salinity – menhaden abundance - chlorophyll signatures (Neuse River: 15 May 1984) Relationship between salinity – menhaden abundance - chlorophyll signatures (Pamlico River: 16 May 1984)
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Size ranges were nearly similar so fish considered same cohort
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The FW/SW gradient & phytoplankton biomass max were correlated; Generally occurred within 4-6 psu in both rivers and shifted seasonally Neuse River: 4-6 psu @ 60km during early spring freshet & km 60 in summer Pamlico River: 4-6 psu @ 30km during early spring freshet & km 10 in summer
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Spring – high spring flows = high primary production in lower estuary = nursery Summer – low summer flows = high primary production in upper estuary = nursery Creeks have salinity gradients with isolated chlorophyll maxima regardless of location
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O = predominantly open estuary M = moderate/large (>10 ha) closed estuary S = small (< 10 ha) closed estuary Subtropical & warm-temperate: O - near top left M - near the middle S - near lower right ANOSIM = overall difference in community structure in subtropical & warm- temperate; O most discrete. less clear in cold-temperate estuaries (no differences). Cold-temperate: O & M - near top left S – broad spread Harrison & Whitfield 2006 estuary typology/community structure model
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O = species rich; allows access and recruitment form sea. L/M-C = species poor; closed w/limited access and recruitment from sea. S-C = lowest species richness; due to size and limited habitat diversity and isolation from sea. A = open systems B = open & L/M closed systems C = all but L/M closed mainly D = all systems but mainly in S closed systems. Large estuaries – increased habitat heterogeneity & increased diversity Surface area – linked to mouth width & depth, geomorphology & runoff. Mouth conditions & surface area = different fish communities
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