Increasing nutrient inputs over the last 500 years in an Italian low-impacted seagrass meadow.

Posidonia oceanica is a seagrass endemic to the Mediterranean and it has been widely used as a bioindicator. We studied the layers of a 500-year-old matte using a multiproxy approach (δ13C, δ15N, 14C and C and N concentrations in seagrass debris) in order to evaluate the potential of P. oceanica as a long-term environmental indicator of N pollution and CO2 emissions. From 1581 to 1800, accumulation rate was ca. 0.35 cm year-1, while in the last 100 years it has amounted to ca. 0.51 cm year-1. We observed increasing δ15N values with height in the vertical matte profile, indicating an increase in anthropogenic organic N inputs over time. In contrast, no clear trend in the δ13C values was observed. This study reconstructs the long-term impact of human activities on a seagrass meadow located off the Italian coast, yielding long-term background information that can help managers to implement efficient plans.

Radiocarbon dating of ivory: Potentialities and limitations in forensics.

The determination of the age of elephant ivory is a crucial aspect in the fight against illegal ivory trade which is still a relevant problem having triggered the decline of elephant populations due to poaching in different areas of the globe. Indeed, the absolute dating of the ivory allows, in forensics practice, to establish whether a determined sample or object was obtained and imported illegally, violating the international trade ban. In this frame the use radiocarbon dating has surely a great potential and is widely used. In this paper we review the potential of the method in this field, highlighting its advantages and drawbacks. In particular we show, through the discussion of real cases, how it is possible to improve the achievable chronological resolution by refining the obtained ages trough the proper use of available information and considerations.

Persistence of pristine deep-sea coral gardens in the Mediterranean Sea (SW Sardinia).

Leiopathes glaberrima is a tall arborescent black coral species structuring important facies of the deep-sea rocky bottoms of the Mediterranean Sea that are severely stifled by fishing activities. At present, however, no morphological in vivo description, ecological characterization, age dating and evaluation of the possible conservation actions have ever been made for any population of this species in the basin. A dense coral population was reported during two Remotely Operated Vehicle (ROV) surveys conducted on a rocky bank off the SW coasts of Sardinia (Western Mediterranean Sea). L. glaberrima forms up to 2 m-tall colonies with a maximal observed basal diameter of nearly 7 cm. The radiocarbon dating carried out on a colony from this site with a 4 cm basal diameter revealed an approximately age of 2000 years. Considering the size-frequency distribution of the colonies in the area it is possible to hypothesize the existence of other millennial specimens occupying a supposedly very stable ecosystem. The persistence of this ecosystem is likely guaranteed by the heterogeneous rocky substrate hosting the black coral population that represents a physical barrier against the mechanical impacts acted on the surrounding muddy areas, heavily exploited as trawling fishing grounds. This favorable condition, together with the existence of a nursery area for catsharks within the coral ramifications and the occurrence of a meadow of the now rare soft bottom alcyonacean Isidella elongata in small surviving muddy enclaves, indicates that this ecosystem have to be considered a pristine Mediterranean deep-sea coral sanctuary that would deserve special protection.