Tracing the effects of eutrophication on molluscan communities in sediment cores: outbreaks of an opportunistic species coincide with reduced bioturbation and high frequency of hypoxia in the Adriatic Sea

AbstractEstimating the effects and timing of anthropogenic impacts on the composition of macrobenthic communities is challenging, because early twentieth-century surveys are sparse and the corresponding intervals in sedimentary sequences are mixed by bioturbation. Here, to assess the effects of eutrophication on macrobenthic communities in the northern Adriatic Sea, we account for mixing with dating of the bivalve Corbula gibba at two stations with high accumulation (Po prodelta) and one station with moderate accumulation (Isonzo prodelta). We find that, first, pervasively bioturbated muds typical of highstand conditions deposited in the early twentieth century were replaced by muds with relicts of flood layers and high content of total organic carbon (TOC) deposited in the late twentieth century at the Po prodelta. The twentieth century shelly muds at the Isonzo prodelta are amalgamated but also show an upward increase in TOC. Second, dating of C. gibba shells shows that the shift from the early to the late twentieth century is characterized by a decrease in stratigraphic disorder and by an increase in temporal resolution of assemblages from ~25–50 years to ~10–20 years in both regions. This shift reflects a decline in the depth of the fully mixed layer from more than 20 cm to a few centimeters. Third, the increase in abundance of the opportunistic species C. gibba and the loss of formerly abundant, hypoxia-sensitive species coincided with the decline in bioturbation, higher preservation of organic matter, and higher frequency of seasonal hypoxia in both regions. This depositional and ecosystem regime shift occurred in ca. a.d. 1950. Therefore, the effects of enhanced food supply on macrobenthic communities were overwhelmed by oxygen depletion, even when hypoxic conditions were limited to few weeks per year in the northern Adriatic Sea. Preservation of trends in molluscan abundance and flood events in cores was enhanced by higher frequency of hypoxia that reduced bioturbation in the late twentieth century.

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

10.5194/egusphere-egu21-7694 ◽

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

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&#8217;s Ark shell (Arca noae 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 A. noae 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.The abundance and shell length of A. noae remained low in the lower part of the cores but increased strongly within the oyster-Arca 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) A. noae shells. Moreover, no living individuals were found in grab samples taken from the two stations suggesting that the dense populations of A. noae, persisting there for several thousand years, were locally extirpated in the 20th century. To evaluate population recovery in other parts of the NE Adriatic, we compared the size distribution of fossil A. noae from the shell bed interval to the previously published data on living populations of this species sampled along Istrian peninsula between 1966 and 1978. Both fossil and extant populations were characterized by similar median size, modal size class and proportion of specimens > 50 mm (minimal legal landing size). These results suggest that within few decades after the 1949-1950 mass mortality event the size structure of populations of A. noae have largely returned to their earlier, natural state. The recovery was spatially variable, however, as attested by the decline of A. noae populations due to loss of suitable shell-bed habitats in the two studied stations off Piran.

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V.M. SHUKSHIN AND “NEW PEASANT POETS”: SURVIVED CHILDREN OF NOT SURVIVED FATHERS

Siberian philological forum ◽

10.25146/2587-7844-2020-10-2-38 ◽

2020 ◽

Vol 10 (2) ◽

pp. 4-15

Author(s):

A.A. Shorokhov ◽

Keyword(s):

Twentieth Century ◽

World Literature ◽

Cultural Phenomenon ◽

Early Twentieth Century ◽

History Of ◽

Late Twentieth ◽

Points Of View ◽

Definition Of ◽

Late Twentieth Century

The article combines two significant historical and literary phenomena. The first is a group of Russian poets and prose writers of the early twentieth century, known under the general name “new peasant poets”. The second is a group of Russian writers of the late twentieth century, whose work has received a steady definition of “village prose”. V.M. Shukshin’s works are also referred to this cultural phenomenon. The article attempts to get away from simplifying definitions of “urban romance”, “village prose”, and to establish the civilizational continuity of Shukshin’s work with “new peasant poets” of the early twentieth century. The author also tries to consider the phenomenon of the group of “new peasant poets” from the cultural, philosophical and historical-biographical points of view – In the unity of their work, fate and dramatic changes in the history of Russia. The article uses theoretical works on Russian and world literature and history by M.M. Bakhtin, V.V. Kozhinova, I.R. Shafarevich, G.I. Shmeleva, P.F. Alyoshkina, S.Yu. and S.S. Kunyaevs, recent publications on Shukshin’s works by V.I. Belov, A.D. Zabolotsky, and A.N. Varlamov.

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Marine Seagrasses Transplantation in Confined and Coastal Adriatic Environments: Methods and Results

Water ◽

10.3390/w13162289 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2289

Author(s):

Daniele Curiel ◽

Sandra Kraljević Pavelić ◽

Agata Kovačev ◽

Chiara Miotti ◽

Andrea Rismondo

Keyword(s):

Twentieth Century ◽

Zostera Marina ◽

Adriatic Sea ◽

Posidonia Oceanica ◽

Cymodocea Nodosa ◽

Anthropogenic Pressures ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

The North ◽

Over Time

The anthropogenic pressures of the twentieth century have seriously endangered the Mediterranean coastal zone; as a consequence, marine seagrass habitats have strongly retreated, mostly those of Posidonia oceanica. For this reason, over time, restoration programs have been put in place through transplantation activities, with different success. These actions have also been conducted with other Mediterranean marine seagrasses. The results of numerous transplanting operations conducted in the Northern Adriatic Sea and lagoons with Cymodocea nodosa, Zostera marina and Z. noltei and in the Central and Southern Adriatic Sea with P. oceanica (only within the project Interreg SASPAS), are herein presented and compared, taking also into account the presence of extensive meadows of C. nodosa, Z. marina and Z. noltei, along the North Adriatic coasts and lagoons.

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Dissenting Traditions and Missionary Imaginations

10.1093/oso/9780198702252.003.0012 ◽

2018 ◽

Author(s):

Justin D. Livingstone

Keyword(s):

Twentieth Century ◽

Case Studies ◽

Literary Culture ◽

Early Twentieth Century ◽

Late Twentieth ◽

Twentieth Century Europe ◽

Directing Attention ◽

Independence Movements ◽

Late Twentieth Century

This chapter follows the long arc of the ‘missionary novel’, from the exhortation and promotion emanating from a missionary culture embraced by a Protestant Christendom to a dissenting literary culture under siege from imperial servants, secularists, and postcolonial independence movements. It notes that the African missionary novel in particular provides fertile material for the investigation of Dissenting Protestantism as it engaged with the twentieth century. Many ‘humanitarian’ novels disseminated knowledge about mission fields and ‘new’ peoples, and so were part of (and criticized for) the globalizing imagination of early twentieth-century Europe and the spread of the professions. Case studies include Elsie Milligan, Arthur E. Southon, Ambrose Haynes, Marion Percy Williams, Arthur Chirgwin, Harry H. Johnston, and Joyce Cary, among others. The chapter extends the debate on mission and empire by directing attention to issues of postcolonial reception, disclosing the ways in which the so-called ‘dissidence of Dissent’ was both challenged and appropriated by anti-colonial authors in the mid to late twentieth century.

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‘The dense, murky water of the past’: Swamps, Nostalgia and Settlement Myth in Meir Shalev’s The Blue Mountain

Hydrofictions ◽

10.3366/edinburgh/9781474443807.003.0003 ◽

2020 ◽

pp. 69-107

Author(s):

Hannah Boast

Keyword(s):

Twentieth Century ◽

The State ◽

Realist Novel ◽

The Past ◽

Blue Mountain ◽

Early Twentieth Century ◽

Late Twentieth ◽

State Of Israel ◽

Late Twentieth Century ◽

National Mythology

This chapter examines the changing meanings of swamp drainage in Israel’s national mythology. Swamp drainage was undertaken in the early twentieth century by the Jewish National Fund and again after the establishment of the State of Israel. Once seen as a triumph of Zionist ingenuity, draining swamps was redefined in the late twentieth century as an emblem of Zionism’s environmental hubris. This chapter assesses this history through Meir Shalev’s magical realist novel The Blue Mountain (1988), situating Shalev’s text in its contemporary contexts of environmentalism and post-Zionism.

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Rare records of the false killer whales (Pseudorca crassidens) in the Adriatic Sea

Natura Croatica ◽

10.20302/nc.2021.30.18 ◽

2021 ◽

Vol 30 (1) ◽

pp. 263-268

Author(s):

Draško Holcer ◽

◽

Jure Miočić-Stošić ◽

Tihana Vučur Blazinić ◽

◽

...

Keyword(s):

Twentieth Century ◽

Mediterranean Sea ◽

Species Identification ◽

Citizen Science ◽

Adriatic Sea ◽

Marine Species ◽

Killer Whales ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

Pseudorca Crassidens

In spring 2021, four unusual encounters with a group of false killer whales were recorded in Kvarner Bay, Northern Adriatic Sea. A minimum of five individuals, including a calf, were observed and two photos were taken corroborating species identification. These are the first reported sightings of the species in the Adriatic Sea since the mid-twentieth century. In addition, another encounter was revealed that occurred at the end of the 2000s in the same location and should be added to the list of historic observations. These reports were obtained by chance and show the importance of citizen science in obtaining data on rare marine species. The information gathered goes towards a better understanding of the distribution of the species in the Mediterranean Sea.

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Media, Messages, and Emotions

10.5406/illinois/9780252038051.003.0010 ◽

2017 ◽

Author(s):

Brenton J. Malin

Keyword(s):

Twentieth Century ◽

Mass Media ◽

First Century ◽

Media Criticism ◽

Media Messages ◽

Early Twentieth Century ◽

American Media ◽

Late Twentieth ◽

Twenty First Century ◽

Late Twentieth Century

This chapter considers links between media and emotion in a modern American context. It traces certain understandings of emotion in order to tell a story about how American media critics have wrestled with questions of the affective life. The chapter shows some thinking about emotion and media that preceded the explosion of mass media and mass media criticism in the early twentieth century, before laying out some key popular and academic understandings of media from the early twentieth century. From here, the chapter turns to late-twentieth-century modifications and extensions of these ideas and then discusses their continued relevance at the dawn of the twenty-first century.

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Cross-scale connectivity of macrobenthic communities in a patchy network of habitats: The Mesophotic Biogenic Habitats of the Northern Adriatic Sea

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2020.106978 ◽

2020 ◽

Vol 245 ◽

pp. 106978

Author(s):

Vinko Bandelj ◽

Cosimo Solidoro ◽

Célia Laurent ◽

Stefano Querin ◽

Sara Kaleb ◽

...

Keyword(s):

Adriatic Sea ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

Macrobenthic Communities

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Molluscan benthic communities at Brijuni Islands (northern Adriatic Sea) shaped by Holocene sea-level rise and recent human eutrophication and pollution

The Holocene ◽

10.1177/0959683618788651 ◽

2018 ◽

Vol 28 (11) ◽

pp. 1801-1817 ◽

Cited By ~ 3

Author(s):

Sara-Maria Schnedl ◽

Alexandra Haselmair ◽

Ivo Gallmetzer ◽

Anna-Katharina Mautner ◽

Adam Tomašových ◽

...

Keyword(s):

Sea Level ◽

Adriatic Sea ◽

Environmental Changes ◽

Anthropogenic Impacts ◽

Benthic Communities ◽

Marine Species ◽

Benthic Assemblages ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

The Impact

The effects of and the interplay between natural and anthropogenic influences on the composition of benthic communities over long time spans are poorly understood. Based on a 160-cm-long sediment core collected at 44 m water depth in the NE Adriatic Sea (Brijuni Islands, Croatia), we document changes in molluscan communities since the Holocene transgression ~11,000 years ago and assess how they were shaped by environmental changes. We find that (1) a transgressive lag deposit with a mixture of terrestrial and marine species contains abundant seagrass-associated gastropods and epifaunal suspension-feeding bivalves, (2) the maximum-flooding phase captures the establishment of epifaunal bivalve-dominated biostromes in the photic zone, and (3) the highstand phase is characterized by increasing infaunal suspension feeders and declining seagrass-dwellers in bryozoan-molluscan muddy sands. Changes in the community composition between the transgressive and the highstand phase can be explained by rising sea level, reduced light penetration, and increase in turbidity, as documented by the gradual up-core shift from coarse molluscan skeletal gravel with seagrass-associated molluscs to bryozoan sandy muds. In the uppermost 20 cm (median age <200 years), however, epifaunal and grazing species decline and deposit-feeding and chemosymbiotic species increase in abundance. These changes concur with rising concentrations of nitrogen and organic pollutants due to the impact of eutrophication, pollution, and trawling in the 20th century. The late highstand benthic assemblages with abundant bryozoans, high molluscan diversity, and abundance of soft-bottom epi- and infaunal filter feeders and herbivores represent the circalittoral baseline community largely unaffected by anthropogenic impacts.

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Trends of Nitrogen and Phosphorus in Surface Sediments of the Lagoons of the Northern Adriatic Sea as a Study Case

Water ◽

10.3390/w13202914 ◽

2021 ◽

Vol 13 (20) ◽

pp. 2914

Author(s):

Adriano Sfriso ◽

Alessandro Buosi ◽

Yari Tomio ◽

Abdul-Salam Juhmani ◽

Michele Mistri ◽

...

Keyword(s):

Surface Sediments ◽

Adriatic Sea ◽

Organic Phosphorus ◽

Anthropogenic Impacts ◽

Venice Lagoon ◽

Nutrient Concentrations ◽

Nitrogen And Phosphorus ◽

Northern Adriatic Sea ◽

Northern Adriatic ◽

Po Delta

The analysis of nutrient concentrations in surface sediments is a reliable tool for assessing the trophic status of a water body. Nitrogen and phosphorus concentrations are strongly related to the sediment characteristics but are mainly driven by anthropogenic impacts. The results of the determination of total nitrogen and total inorganic and organic phosphorus in surface sediments of the lagoons and ponds of the northwestern Adriatic Sea (Marano-Grado, Venice, Po Delta, Comacchio Valleys, Pialassa della Baiona) show the merit of this approach. Indeed, when previous data are available, the ratio between the actual and background values can provide useful information on the trophic changes that have occurred in the most recent times, and the results can also explain the conditions present in less studied environments. In this context, numerous studies performed in the Venice lagoon since the second half of the 20th century during different environmental scenarios provide mean concentration ranges and propose the main causes of changes. The results of single datasets available for the other lagoons fall into scenarios that occurred in the Venice lagoon. At present, the most eutrophic basins are Pialassa della Baiona, the Po Delta lagoons and ponds and the Comacchio valleys due to industrial effluents, fish farming and clam harvesting, respectively, whereas the Venice lagoon is now experiencing environmental recovery.

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