Search

This paper presents a detailed geological and geomorphological analysis of the so‐called givoni (low‐relief, mainly gravelly landforms subparallel to the coastline) associated with the MIS 5 terrace in the northern Gulf of Taranto (southern Italy). These landforms can be interpreted as former beach ridges, swash/drift‐aligned spits, or swash/drift‐aligned barriers (BSBs); thus, givoni are palaeoshoreline indicators. In the study area, recognizing the classic landforms associated with marine terraces, that is, surfaces and scarps, is difficult, as the givoni are often associated and variably combined with surfaces and scarps. Thus, we reconstruct the formation and evolution processes of the MIS 5 marine terrace, including the formation of surfaces, scarps, and BSBs (and the resulting composite landforms), in an overall evolutionary framework based on eustatic oscillations. Then, we reconstruct a complete set of situations in which BSBs form on loose or semiconsolidated substrates in response to eustatic oscillations: (a) BSBs can form during a highstand of a warm stage on previously consolidated sediment; (b) BSBs may represent coastlines formed during sea‐level standstills in the context of a general regressive phase following the highstand peak that created a relict sea cliff; (c) BSBs may represent coastlines formed during a new relative highstand in a warm substage on previously unconsolidated deposits formed during the same stage; and (d) BSBs may be formed by a process similar to that of the previous case, except that the sea level stopped rising against a pre‐existing BSB. [ABSTRACT FROM AUTHOR]

The population dynamics and gametogenesis of the non-indigenous polychaete species Branchiomma luctuosum Grube, 1869 (Annelida, Sabellidae) has been investigated at three sites in the Taranto Seas (Ionian Sea, Mediterranean Sea). The species, probably introduced from the Red Sea, has been reported in the Mediterranean Sea since 1983. The species is hermaphrodite, and the reproductive season is between June and October when the largest mean size of oocytes was recorded together with the presence of mature spermatozoa. Small oocytes are present in specimens reaching about 20-25 mm in length. Therefore oogenesis seems to begin early during the first year of life, but the first reproduction can occur when the worms attain a larger size and are at least 6 months of age. Although most of the individuals reproduce seasonally within a discrete period, some individuals can reproduce in different periods during the year, the oogenesis of individuals not being synchronous. A life span of at least 2 years is highlighted, with a faster growth rate during the first months (about 20 mm per month) decreasing to about 10 mm from the 3rd to the 8th months and slowing down again after the worm reaches 100 mm in size. Some differences in growth performance are discussed, enhanced by comparing the sites located at greater depth (5-7 m) and those located at 0.5 m depth, together with the possible interactions of this alien species with the autochthonous sabellid Sabella spallanzanii. [ABSTRACT FROM AUTHOR]