Effects of hypoxia on estuarine benthos: the lower Rappahannock River (Chesapeake Bay), a case study

Llansó, Roberto J.

doi:10.1016/s0272-7714(05)80027-7

Cited by 103 publications

(56 citation statements)

References 31 publications

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“…Parameters organisms is similar to what occurs in Chesapeake Bay under stressors such as hypoxia (Llansó, 1992;Long and Seitz, 2009). The lower density and shift in community structure did not have a significant effect on juvenile blue crab feeding.…”

Section: Modelsupporting

confidence: 60%

Effects of anthropogenic shoreline hardening and invasion by Phragmites australis on habitat quality for juvenile blue crabs (Callinectes sapidus)

Long

Grow

Majoris

et al. 2011

Journal of Experimental Marine Biology and Ecology

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Section: Modelsupporting

confidence: 60%

Effects of anthropogenic shoreline hardening and invasion by Phragmites australis on habitat quality for juvenile blue crabs (Callinectes sapidus)

Long

Grow

Majoris

et al. 2011

Journal of Experimental Marine Biology and Ecology

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“…Although annual recovery of macrofauna is common to systems prone to recurring seasonal hypoxia (Diaz and Rosenberg, 1995;Levin et al, 2009), such rapid recolonization was effectively inhibited in the Haverö basin since 1900 AD, possibly owing to increased porewater H 2 S concentration (Diaz and Rosenberg, 1995). A critical threshold for defaunation in areas experiencing seasonal hypoxia is often around 0.7 mg L −1 (Llansó, 1992;Diaz and Rosenberg, 1995), pointing to severe nearbottom water oxygen depletion at the study site already at 1900 AD.…”

Section: Progressive Intensification Of Hypoxia During the Modern Warmentioning

confidence: 93%

A 1500-year multiproxy record of coastal hypoxia from the northern Baltic Sea indicates unprecedented deoxygenation over the 20th century

et al. 2018

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Abstract. The anthropogenically forced expansion of coastal hypoxia is a major environmental problem affecting coastal ecosystems and biogeochemical cycles throughout the world. The Baltic Sea is a semi-enclosed shelf sea whose central deep basins have been highly prone to deoxygenation during its Holocene history, as shown previously by numerous paleoenvironmental studies. However, long-term data on past fluctuations in the intensity of hypoxia in the coastal zone of the Baltic Sea are largely lacking, despite the significant role of these areas in retaining nutrients derived from the catchment. Here we present a 1500-year multiproxy record of near-bottom water redox changes from the coastal zone of the northern Baltic Sea, encompassing the climatic phases of the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA), and the Modern Warm Period (MoWP). Our reconstruction shows that although multicentennial climate variability has modulated the depositional conditions and delivery of organic matter (OM) to the basin the modern aggravation of coastal hypoxia is unprecedented and, in addition to gradual changes in the basin configuration, it must have been forced by excess human-induced nutrient loading. Alongside the anthropogenic nutrient input, the progressive deoxygenation since the beginning of the 1900s was fueled by the combined effects of gradual shoaling of the basin and warming climate, which amplified sediment focusing and increased the vulnerability to hypoxia. Importantly, the eutrophication of coastal waters in our study area began decades earlier than previously thought, leading to a marked aggravation of hypoxia in the 1950s. We find no evidence of similar anthropogenic forcing during the MCA. These results have implications for the assessment of reference conditions for coastal water quality. Furthermore, this study highlights the need for combined use of sedimentological, ichnological, and geochemical proxies in order to robustly reconstruct subtle redox shifts especially in dynamic, non-euxinic coastal settings with strong seasonal contrasts in the bottom water quality.

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“…On the other hand, subsurface deposit-feeders have been found to be related to TOC levels (Gaston 1987, Maurer et al 1994 or to sediments with more refractory material (Flach & Heip 1996). The shallower distribution of infauna and the higher dominance of tube-building, surface deposit-feeders characterize higher-quality sediments (Dauwe et al 1998), low oxygen settings (Wheatcroft 1989, Díaz & Rosenberg 1995, Levin et al 1997b, and hypoxic periods in estuarine environments (Llansó 1992). Our results reveal a key role of the quality of surface organic matter in addition to oxygen availability in dermining the composition of macrofauna feeding guilds with subsurface-feeding fauna preferentially inhabiting sediments with high TOC of low organic quality, and interface-feeding fauna dominating in sediments with highquality organic matter.…”

Section: Environmental Settingmentioning

confidence: 99%

“…Nevertheless, the interface-feeder/surface-defecator Paraprionospio pinnata still dominated the recolonization of the sediments. This species has been reported to be tolerant of severe hypoxia in estuarine environments (Llansó 1992), and colonizes shallow, usually normoxic bottoms after aperiodic hypoxia and sulphide buildup within the sediments (Harper et al 1991). Off Concepción, P. pinnata appears to be the macrofaunal species best adapted enzymatically to cope with hypoxia (R. González & R. Quiñones unpubl.…”

Section: Changes Induced By El Niñomentioning

confidence: 99%

Effects of dissolved oxygen and fresh organic matter on the bioturbation potential of macrofauna in sublittoral sediments off Central Chile during the 1997/1998 El Niño

Gutiérrez¹,

Gallardo²,

Mayor³

et al. 2000

Mar. Ecol. Prog. Ser.

112

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A study off Concepción, central Chile, during the 1997/1998 El Niño (EN) revealed that the concentration of dissolved oxygen and the organic content and quality of the sediment control the vertical distribution of macrofauna in the sediment and bioturbation potential. The study area, characterized by organic-rich, silty sediments, lies within the most intense upwelling center off the coast of Chile, and is subject to the seasonal influx of hypoxic subsurface waters. Five stations (28 to 120 m depth) were sampled seasonally. The vertical distribution and integrated biomass and abundance of macrofauna (> 0.5 mm) were determined, as well as the dissolved oxygen content of the bottom water (BWDO) and sediment parameters such as total organic carbon (TOC), the C/N ratio, sulphide content, chl a content, and the thickness of the oxidized zone. Chl a proved to be a good indicator of fresh (highquality) organic matter. Major components contributing to variation in the macrofauna feeding guilds, bioturbation categories, and their vertical position in the sediment were: (1) the relative bioturbation potential (contribution of bioturbating taxa to the assemblage) and (2) the vertical distribution and ratio of surface-to subsurface deposit-feeders. Higher levels of BWDO and a lower quality of organic matter at the sediment surface tended to provide better conditions for potentially strong bioturbators, while lower BWDO levels and higher-quality organic matter were accompanied by the dominance of tube-dwelling, surface-defecating (and hence weakly bioturbating) species. Higher TOC levels and lower-quality organic matter at the surface resulted in deeper vertical distributions of animals and a higher relative abundance of subsurface deposit-feeders. During the study period, BWDO levels increased, while the total organic carbon and the quality of organic matter decreased. These conditions encouraged the vertical penetration of macrofauna into the sediment column and the relatively larger contribution of stronger bioturbators to the assemblage. The most drastic changes in faunal lifestyles and vertical distribution during the 1997/1998 EN were observed within the Bay of Concepción, an area usually characterized by sulphidic sediments under the conditions of severe seasonal hypoxia or anoxia obtaining during 'normal' (i.e. non-EN) years; and in the deepest shelf site, which usually experiences permanent hypoxia because of the influence of the 'oxygen minimum zone'.

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Effects of hypoxia on estuarine benthos: the lower Rappahannock River (Chesapeake Bay), a case study

Cited by 103 publications

References 31 publications

Effects of anthropogenic shoreline hardening and invasion by Phragmites australis on habitat quality for juvenile blue crabs (Callinectes sapidus)

Effects of anthropogenic shoreline hardening and invasion by Phragmites australis on habitat quality for juvenile blue crabs (Callinectes sapidus)

A 1500-year multiproxy record of coastal hypoxia from the northern Baltic Sea indicates unprecedented deoxygenation over the 20th century

Effects of dissolved oxygen and fresh organic matter on the bioturbation potential of macrofauna in sublittoral sediments off Central Chile during the 1997/1998 El Niño

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