Anthropogenic disturbance and spatial heterogeneity of macrobenthic invertebrate assemblages in coastal lagoons: the study case of Pialassa Baiona (northern Adriatic Sea)

Abstract

The distribution patterns of macrobenthic invertebrate assemblages at different spatial scales and in relation to natural and anthropogenic disturbance gradients were investigated in the Pialassa Baiona, a eutrophic and polluted brackish coastal lagoon located along the Italian coast of the northern Adriatic Sea. This coastal lagoon shows a complex physiography with several shallow water ponds and channels separated by discontinuous artificial embankments. Environmental variables and macrobenthic invertebrate assemblages showed higher heterogeneity at small spatial scale (i.e. within channels and ponds). Distinction between channels and ponds is only weakly supported by the distribution patterns of macrobenthic assemblages. Depth was the major factor in structuring benthic communities within ponds, while species distributions along the channels were strongly correlated with the anthropogenic disturbance gradient. Anthropogenic disturbance mainly affected species richness, which was inversely correlated with the organic carbon contents in the sediments and the water surface temperature, which is affected by the input of cooling water from two thermal power plants. Some opportunistic species, like the polychaetes Streblospio shrubsolii and Capitella capitata, were more abundant in the southern polluted areas. In particular, the abundance of S. shrubsolii significantly increased with organic carbon contents in the sediments and water surface temperature, while C. capitata was more abundant in the warmed sites and close to sewages. Conversely, the abundance of the amphipod Corophium insidiosum was inversely related to organic carbon contents.

Polycyclic Aromatic Hydrocarbons, Polychlorinated Biphenyls and Trace Metals in Sediments from a Coastal Lagoon (Northern Adriatic, Italy)

“…and Gracilaria sp.) followed by dystrophic crises have been frequently observed during the summer, especially in the southern area (Ponti et al 2005). At present, the lagoon is exploited for recreational fishing, Manila clam (Ruditapes philippinarum) harvesting, regulated hunting, leisure and cultural activities such as canoeing, guided walking tours and bird watching.…”

“…Examples of industrial facilities located in the vicinity of the lagoon include two thermoelectric power plants and various chemical plants, all located in the southern side of the lagoon. Nowadays, there is an increasing concern that the proximity of anthropogenic activities taking place near the lagoon could result in undue pressure on this coastal ecosystem (Donnini et al 2007;Ponti et al 2010).…”

Macroinfauna Dynamics and Sediment Parameters of a Subtropical Estuarine Lake—Coombabah Lake (Southern Moreton Bay, Australia)

“…In addition to stimulating microbial metabolism, sediment oxygen demand and nutrient regeneration (Ferguson, Eyre, and Gay, 2003;Slomp et al, 1993), sedimentary organic matter is a major food source for benthic infauna (Cheng and Chang, 1999;Spilmont et al, 2009) despite its often refractory nature (Cheng, 1995). Variations in the delivery and bioavailability of organic matter and regenerated nutrients, therefore, might influence benthic infauna population dynamics (Cheng and Chang, 1999;Ponti, Casselli, and Abbiati, 2010;Sánchez-Moyano, García-Asencio, and García-Gómez, 2010). During this study, increases in the combined macroinfauna density were observed to significantly correlate (r ¼ 0.755, p¼ 0.001, n¼ 16) with increased sediment organic matter content (food supply) within the surface sediments of Coombabah Lake, indicating that sediment column organic matter content was a factor influencing the combined macrofauna population dynamics of Coombabah Lake on a relatively small spatial scale (e.g.,~500 m).…”

Biodiversity and Conservation of Coastal Lagoons

“…These ecosystems are very heterogeneous in physiography and hydrology (Ponti et al, 2011), due to the varying balance of water, salt, nutrients, particulate organic and inorganic matter (Orfanidis et al, 2008). They can receive freshwater from streams and brooks, runoff or groundwater, as well as seawater by the action of tides or waves.…”

“…Increasing of tourism pressure and the use of these ecosystems for different human activities such as aquaculture or fisheries has induced internal perturbations such as pollution or removal of indigenous species (Aliaume et al, 2007). In coastal lagoons, species distribution is affected by heterogeneity of the environmental variable, such as water depth, hydrodynamic conditions, sediment characteristics, as well as by sources of anthropogenic disturbance that could interact with natural heterogeneity affecting patterns of species distribution, species diversity and ecosystem functioning (Ponti et al, 2011). Sometimes it is difficult to distinguish between natural heterogeneity and human disturbance.…”