Long term eutrophication effects on macrofaunal communities in northern Adriatic Sea

Crema, Roberto; Castelli, Alberto; Prevedelli, Daniela

doi:10.1016/0025-326x(91)90405-h

Cited by 69 publications

(58 citation statements)

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“…The pioneer species, which are dominant within particular assemblages during the early recovery period (stagnation), are usually not typical of the community in consideration (Leppäkoski 1971). However, C. gibba with significantly low abundance was permanently present throughout the investigated area; Vatova (1949) and Crema et al (1991) pointed out that C. gibba is a typical species and highly abundant lamellibranch of the transition zone between detritic and muddy bottoms. Together with Atrina pectinata (L., 1767) and T. ovata, C. gibba is described as an accompanied species for Schizaster chiajei-community margined with Turritella zoocenosis (Vatova 1949;Zavodnik et al 1994).…”

Section: Discussionmentioning

confidence: 97%

“…This area is under pressure from eutrophication and, combined with marine mucilage events (the accumulation of dissolved organic matter), this can result in oxygen depletion (Justić et al 1993;Degobbis et al 1999) and, consequently, benthic mortalities (Stachowitsch et al 1991;Ott 1992). Mucilage events and benthic mortalities in this area have occurred periodically for centuries (Crema et al 1991) but, after 1969, (Piccinetti & Manfrin 1969) have become more frequent and more widespread than ever before (Voltolina 1973;Federa et al 1976;Stachowitsch 1984;Faganeli et al 1985;Riedel et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Response to oxygen deficiency (depletion): Bivalve assemblages as an indicator of ecosystem instability in the northern Adriatic Sea

2011

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Benthic communities represent a powerful tool for the detection of natural and anthropogenic disturbances, as well as for the assessment of marine ecosystem stability. This paper shows that bivalve assemblages could serve as excellent indicators of disturbance and ecosystem instability. The goal of this study was to compare two sets of data in order to determine the differences between two different periods belonging to bivalve assemblage in the muddy detritic bottom of the northern Adriatic Sea in the post-anoxic period during December 1989December , 1990December , 1991 and quite a while later, during 2003, 2004 and 2005. Abundances of some indicator species such as Corbula gibba, Modiolarca subpicta and Timoclea ovata were detected during the post-anoxic period. Recruitment in the quality of bivalve assemblages was proved by the ecologic and biotic indexes during 2003, 2004 and 2005, during a period of relatively stable ecological conditions. Fluctuation in bivalve diversity due to the ecological quality of the marine ecosystem in the eastern part of the northern Adriatic Sea is also discussed.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Response to oxygen deficiency (depletion): Bivalve assemblages as an indicator of ecosystem instability in the northern Adriatic Sea

2011

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“…Paleoindicators in sediment cores from the vicinity of the Po River delta plume indicate a gradual increase in eutrophication at the end of the 19th century, which accelerated after 1930. Prior to the 19th century there are aperiodic accounts of massive phytoplankton blooms that likely led to oxygen depletion (Crema et al, 1991). Seasonal hypoxia began in 1960 and became more intense and prolonged in 1980 (Barmawidjaja et al, 1995).…”

Section: Northern Adriatic Seamentioning

confidence: 99%

Dynamics and distribution of natural and human-caused hypoxia

et al. 2010

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Abstract. Water masses can become undersaturated with oxygen when natural processes alone or in combination with anthropogenic processes produce enough organic carbon that is aerobically decomposed faster than the rate of oxygen reaeration. The dominant natural processes usually involved are photosynthetic carbon production and microbial respiration. The re-supply rate is indirectly related to its isolation from the surface layer. Hypoxic water masses (<2 mg L −1 , or approximately 30% saturation) can form, therefore, under "natural" conditions, and are more likely to occur in marine systems when the water residence time is extended, water exchange and ventilation are minimal, stratification occurs, and where carbon production and export to the bottom layer are relatively high. Hypoxia has occurred through geological time and naturally occurs in oxygen minimum zones, deep basins, eastern boundary upwelling systems, and fjords.Hypoxia development and continuation in many areas of the world's coastal ocean is accelerated by human activities, especially where nutrient loading increased in the Anthropocene. This higher loading set in motion a cascading set of events related to eutrophication. The formation of hypoxic areas has been exacerbated by any combination of interactions that increase primary production and accumulation of organic carbon leading to increased respiratory demand for oxygen below a seasonal or permanent pycnocline. Nutrient loading is likely to increase further as population growth and resource intensification rises, especially with increased Correspondence to: N. N. Rabalais (nrabalais@lumcon.edu) dependency on crops using fertilizers, burning of fossil fuels, urbanization, and waste water generation. It is likely that the occurrence and persistence of hypoxia will be even more widespread and have more impacts than presently observed.Global climate change will further complicate the causative factors in both natural and human-caused hypoxia. The likelihood of strengthened stratification alone, from increased surface water temperature as the global climate warms, is sufficient to worsen hypoxia where it currently exists and facilitate its formation in additional waters. Increased precipitation that increases freshwater discharge and flux of nutrients will result in increased primary production in the receiving waters up to a point. The interplay of increased nutrients and stratification where they occur will aggravate and accelerate hypoxia. Changes in wind fields may expand oxygen minimum zones onto more continental shelf areas. On the other hand, not all regions will experience increased precipitation, some oceanic water temperatures may decrease as currents shift, and frequency and severity of tropical storms may increase and temporarily disrupt hypoxia more often.The consequences of global warming and climate change are effectively uncontrollable at least in the near term. On the other hand, the consequences of eutrophication-induced hypoxia can be reversed if long-term, broad-scale, and per...

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“…In the Northern Adriatic, seasonal oxygen depletions, often associated with massive marine snow events, have also been noted periodically for centuries (Crema et al, 1991). In the second half of the 20th century their frequency and sever-ity, however, have markedly increased due to high anthropogenic input of nutrients (Druon et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach

et al. 2013

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Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean). Nematodes were found as the most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia) or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples.

The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding ¹³C pre-labelled diatoms to sediment cores in order to test (1) if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2) whether initial (normoxia) feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect) but also of primary producers (indirect effect), with important implications for the recovery phase

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Long term eutrophication effects on macrofaunal communities in northern Adriatic Sea

Cited by 69 publications

References 10 publications

Response to oxygen deficiency (depletion): Bivalve assemblages as an indicator of ecosystem instability in the northern Adriatic Sea

Response to oxygen deficiency (depletion): Bivalve assemblages as an indicator of ecosystem instability in the northern Adriatic Sea

Dynamics and distribution of natural and human-caused hypoxia

Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach

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