scholarly journals Spatial distribution of suspended solids during short-term high river discharge in the Bay of Koper, northern Adriatic Sea

2018 ◽  
Vol 19 (1) ◽  
pp. 36 ◽  
Author(s):  
ROK SOCZKA MANDAC ◽  
DUŠAN ŽAGAR
Keyword(s):  
Spatial Distribution ◽  
River Discharge ◽  
Suspended Solids ◽  
Adriatic Sea ◽  
Anthropogenic Influences ◽  
Short Term ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
River Flooding ◽  
The Impact

The Bay of Koper (BoK) located in the Gulf of Trieste (northern Adriatic Sea) is subject to a variety of anthropogenic influences; pollutants from inland are transported to the sea by the local rivers. The impact of high river discharge on suspended solids distribution was assessed by analysing results of an extensive measurement campaign conducted during two episodes of river flooding. The spatial analysis demonstrated the area influenced by fresh water and the distribution of inorganic suspended solids (ISS). The results were then used to calibrate the PCFLOW3D model and to simulate two episodes. A correlation was identified between the measurements and short-term simulations found in the central part of the bay. The results confirm the methods and the model used in this study to be appropriate for studying complex suspended solids processes in coastal areas.

scholarly journals Short-term post-mortality scavenging and longer term recovery after anoxia in the northern Adriatic Sea

2013 ◽  
Vol 10 (11) ◽  
pp. 7647-7659 ◽  
Author(s):  
M. Blasnig ◽  
B. Riedel ◽  
L. Schiemer ◽  
M. Zuschin ◽  
M. Stachowitsch
Keyword(s):  
Adriatic Sea ◽  
Time Lapse ◽  
Hermit Crabs ◽  
Small Scale ◽  
Short Term ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Hexaplex Trunculus ◽  
Distinct Sequence ◽  
And Function

Abstract. The northern Adriatic Sea is one of nearly 500 areas worldwide suffering widespread mortalities due to anoxia. The present study documents post-anoxia macrofauna dynamics after experimentally inducing small-scale anoxia in 24 m depth (2 plots, each 50 cm × 50 cm). Time-lapse camera deployments examined short-term scavenging of the moribund and dead organisms (multi-species clumps consisting of sponges and ascidians) over two 3-day periods (August 2009: 71.5 h, September 2009: 67.5 h). Longer term recovery (days to 2 yr) in the same two plots was examined with an independent photo series. Scavengers arrived quickly and in a distinct sequence: demersal (Gobius niger, Serranus hepatus) and benthopelagic fishes (Diplodus vulgaris, Pagellus erythrinus), followed by hermit crabs (Paguristes eremita, showing a clear day/night rhythm in presence) and gastropods (Hexaplex trunculus). This sequence is attributed to the relative speeds and densities of the organisms. The sessile fauna was largely removed or consumed within seven (August plot) and 13 (September plot) days after anoxia, confirming our first hypothesis that decaying organisms are quickly utilised. The scavengers remained in dense aggregations (e.g. up to 33 P. eremita individuals at one time) as long as dead organisms were available. No recovery of sessile macroepibenthos macroepibenthos occurred in the experimental plots one and two years after anoxia, undermining our second hypothesis that small denuded areas are more rapidly recolonised. This study underlines the sensitivity of this soft-bottom community and supports calls for reducing additional anthropogenic disturbances such as fishing practices that further impede recolonisation and threaten benthic community structure and function over the long term.

Reconstructing the baseline population structure of the exploited bivalve Arca noae in the Northern Adriatic Sea

2021 ◽  
Author(s):  
Saskia Macharia ◽  
Rafał Nawrot ◽  
Michaela Berensmeier ◽  
Ivo Gallmetzer ◽  
Alexandra Haselmair ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Size Structure ◽  
Anthropogenic Impacts ◽  
Natural State ◽  
Published Data ◽  
Northern Adriatic Sea ◽  
Important Species ◽  
Northern Adriatic ◽  
Shell Bed ◽  
The Impact

<p>The Northern Adriatic Sea is one of the most impacted ecosystems worldwide with a long history of anthropogenic impacts, ranging from overfishing and bottom trawling to eutrophication, deoxygenation and pollution. The impact of these multiple pressures on populations of economically important species is often difficult to evaluate due to paucity of long-term monitoring data. The edible bivalve Noah’s Ark shell (<em>Arca noae </em>L.) was intensively harvested in the eastern Adriatic Sea until 1949-1950 when it suffered a catastrophic population collapse due to unknown agents. The assessment of its subsequent recovery is hindered by the lack of data on the population size structure prior to that event. To reconstruct the natural baseline state of populations of <em>A. noae</em> before the onset of extensive harvesting, we studied fossil assemblages from two 1.5-m-long sediment cores collected in the southern Gulf of Trieste (off Piran, Slovenia), both recording the last ~9,500 years.</p><p>The abundance and shell length of <em>A. noae</em> remained low in the lower part of the cores but increased strongly within the oyster-<em>Arca</em> shell bed corresponding to maximum flooding and early highstand sea-level phases (6,500-1,000 years ago). In contrasts, the top 8 cm of the core (the late highstand phase), marked by high concentration of pollutants and organic enrichment, contained only few and small (< 10 mm) <em>A. noae</em> shells. Moreover, no living individuals were found in grab samples taken from the two stations suggesting that the dense populations of <em>A. noae, </em><span>persisting </span><span>there</span> <span>for</span><span> several thousand years, </span>were locally extirpated in the 20<sup>th</sup> century. To evaluate population recovery in other parts of the NE Adriatic, we compared the size distribution of<em> </em>fossil<em> </em><em>A. noae</em> from the shell bed interval to the previously published data on living populations of this species sampled<em> </em>along Istrian peninsula between 1966 and 1978. Both fossil and extant populations were characterized by similar <span>median </span><span>size, </span><span>modal size </span><span>class and</span><span> proportion of </span><span>specimens > 50 mm </span><span>(minimal legal landing size). </span><span>These results suggest that within few </span><span>decades</span><span> after the </span><span>1949-1950 </span><span>mass mortality event </span><span>the size structure of populations </span><span>of</span> <span><em>A. noae</em></span> <span>have largely returned to their earlier, natural state.</span><span> The recovery was </span><span>spatially variable, however, as attested by</span><span> the decline of</span> <span><em>A. noae</em></span> <span>populations </span><span>due to loss of </span><span>suitable shell-bed habitat</span><span>s</span><span> in</span><span> the two </span><span>studied</span><span> station</span><span>s</span><span> off Piran.</span></p>

scholarly journals CellTracker Green labelling vs. Rose Bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes

2013 ◽  
Vol 10 (2) ◽  
pp. 2857-2887 ◽  
Author(s):  
M. Grego ◽  
M. Stachowitsch ◽  
M. De Troch ◽  
B. Riedel
Keyword(s):  
Rose Bengal ◽  
Adriatic Sea ◽  
Staining Method ◽  
Tipping Points ◽  
Sediment Layer ◽  
Short Term ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Harpacticoid Copepods ◽  
Sediment Layers

Abstract. Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week) in the Northern Adriatic Sea, Mediterranean, and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG) – new labelling approach for meiofauna – with the traditional Rose Bengal (RB) staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. Surprisingly, RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more fine-scaled (days, hours, tipping points) studies, especially on hypoxia and anoxia where it is necessary to resolve the course of events, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

scholarly journals Short-term post-mortality predation and scavenging and longer-term recovery after anoxia in the northern Adriatic Sea

2013 ◽  
Vol 10 (3) ◽  
pp. 4367-4401 ◽  
Author(s):  
M. Blasnig ◽  
B. Riedel ◽  
M. Zuschin ◽  
L. Schiemer ◽  
M. Stachowitsch
Keyword(s):  
Adriatic Sea ◽  
Late Summer ◽  
Time Lapse ◽  
Hermit Crabs ◽  
Small Scale ◽  
Commercial Fishing ◽  
Short Term ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
And Function

Abstract. In the Mediterranean, the northern Adriatic Sea shows most features known to promote late-summer hypoxia and anoxia. These features, along with anthropogenic eutrophication and marine snow events, have led to repeated benthic mortalities here. The present study was designed to document the post-anoxia macrofauna dynamics. We deployed an underwater instrument to induce small-scale anoxia in situ (total area 0.5 m2). Two time-lapse camera deployments examined short-term scavenging of the moribund and dead organisms (multi-species clumps consisting of sponges and ascidians) over a 3-day period (August 2008: 71.5 h, September 2008: 67.5 h). Longer-term recovery (2 yr) in the same two plots was examined with an independent photo-series. Predators and scavengers arrived in a distinct sequence. The first to arrive were demersal (Gobius niger, Serranus hepatus) and benthopelagic fishes (Diplodus vulgaris, Pagellus erythrinus), followed by hermit crabs (Paguristes eremita, showing a clear day/night rhythm in presence) and gastropods (Hexaplex trunculus). This sequence of arrival is attributed to the relative speeds of the organisms and their densities. The scavengers remained in dense aggregations (e.g. up to 33 P. eremita individuals at one time) as long as the dead organisms were available. The whole sessile fauna was largely removed or consumed within 7 (August plot) and 13 (September plot) days after anoxia. No macroepibenthic recovery took place in the experimental plots one and two years after anoxia. This study underlines the sensitivity of this soft-bottom community and supports calls for reducing additional anthropogenic disturbances such as damaging commercial fishing practices that impede recolonization and threaten benthic community structure and function over the long-term.

Modeling the Environmental Dynamics of the Northern Adriatic Sea with an explicit benthic-pelagic coupling.

2021 ◽  
Author(s):  
Marco Zavatarelli ◽  
Isabella Scroccaro ◽  
Tomas Lovato
Keyword(s):  
General Circulation ◽  
Adriatic Sea ◽  
Circulation Model ◽  
Open Boundary ◽  
Biogeochemical Model ◽  
Northern Adriatic Sea ◽  
Po River ◽  
Northern Adriatic ◽  
Benthic Pelagic Coupling ◽  
The Impact

<p>In the framework of the European Project H2020 "ODYSSEA" (Operating a network of integrated observatory systems in the Mediterranean SEA, http://odysseaplatform.eu/) a forecasting modeling system of the coupled physical and biogeochemical conditions of the Northern Adriatic Sea is under development.</p><p>The modeling system consists of the on-line coupling of the European general circulation model - NEMO (Nucleus for European Modeling of the Ocean, https://www.nemo-ocean.eu/), with the marine biogeochemical model - BFM (Biogeochemical Flux Model, bfm-community.eu/).<br>The biogeochemical component of the model includes the simulation of the biogeochemical processes of both water column and sediments and their coupling. The model is run for the first time in the Northern Adriatic Sea with an explicit benthic-pelagic coupling.</p><p>The horizontal spatial discretization is defined by a rectangular grid of 315 × 278 cells, having a horizontal resolution of about 800 m. The vertical resolution is defined at 2 m, with 48 z-levels regularly spaced. Currently the atmospheric forcing are the ECMWF 6hr analysis atmospheric fields. The river supplies of fresh water and nutrient salts consider the daily runoff of the Po river, while the other rivers within the study area are included as climatological values. The open boundary conditions of the modeling system come from the Copernicus Marine Environment Monitoring Service (CMEMS, http://marine.copernicus.eu/).</p><p>In this work, the hindcast simulations encompassing the period 2000 – 2009 are validated against available observations from in situ and satellite platforms for sea surface temperature, chlorophyll-a and dissolved inorganic nutrients and, in order to evaluate the impact of a resolved benthic biogeochemical dynamics,  compared against simulations results obtained utilising a simple benthic closure parameterisation.</p>

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