Dragana Drakulović

Distribution of phytoplankton community in Kotor Bay (south-eastern Adriatic Sea)

The goal of this paper was to explain variability of phytoplankton in a shallow coastal area in relation to physico-chemical parameters. Temporal variability and composition of phytoplankton were investigated in the Kotor Bay, a small bay located in the south-eastern part of the Adriatic Sea. Samplings were performed weekly from February 2008 to January 2009 at one station in the inner part of the Kotor Bay, at five depths (0 m, 2 m, 5 m, 10 m, 15 m). Phosphates, nitrites and nitrates ranged from values under the level of detection to the maximum values of 1.54, 1.53 and 23.91 µmol l−1, respectively. The phytoplankton biomass — represented by chlorophyll a concentration — ranged from 0.12 to 6.78 mg m−3, reaching a maximum in summer. Diatoms were present throughout the whole sampling period, reaching the highest abundance in March (3.42×105 cells l−1at surface). The peak of dinoflagellates in July (2.2×106 cells l−1 at surface) was due to a single species, Prorocentrum micans. The toxic dinoflagellate Dinophysis fortii occurred at a concentration of 2140 cells l−1 in May. The present results of phytoplankton assemblages and distribution provide valuable information for this part of the south-eastern Adriatic Sea where data is currently absent.

Phytoplankton diversity in Adriatic ports: Lessons from the port baseline survey for the management of harmful algal species

An inventory of phytoplankton diversity in 12 Adriatic ports was performed with the port baseline survey. Particular emphasis was put on the detection of harmful aquatic organisms and pathogens (HAOP) because of their negative impact on ecosystem, human health, and the economy. Phytoplanktonic HAOP are identified as species, either native or non-indigenous (NIS), which can trigger harmful algal blooms (HAB). A list of 691 taxa was prepared, and among them 52 were classified as HAB and five as NIS. Records of toxigenic NIS (Pseudo-nitzschia multistriata, Ostreopsis species including O. cf. ovata) indicate that the intrusion of non-native invasive phytoplankton species has already occurred in some Adriatic ports. The seasonal occurrence and abundance of HAOP offers a solid baseline for a monitoring design in ports in order to prevent ballast water uptake and possible expansion of HAOP outside their native region.

Phytoplankton Community and Trophic State in Boka Kotorska Bay

Compiling the available data collected over many years of research of Boka Kotorska Bay showed variability in terms of dynamics and abundance of phytoplankton organisms. The Boka Kotorska Bay is a relatively large (87 km2), semi-enclosed bay, located in the south-eastern part of the Adriatic Sea. In addition to human impact, significant inflow of freshwater from numerous karstic streams and submarine springs contributes to the unique ecological characteristics of the Bay, particularly in its inner part (the Kotor Bay). Based on the data presented for the Boka Kotorska Bay (the Kotor Bay) phytoplankton abundance reaches up to 107 cells/l. Diatoms are the phytoplankton group present throughout the year. In some researches conducted in the Boka Kotorska Bay diatoms abundance reaching up to 107 cells/l was recorded. Dominant species are typical of areas with higher eutrophication that prefer nutrient rich areas and are very good indicators of ecosystem conditions. Dinoflagellates are the second important group of microplankton, frequently found in the aquatorium of the Boka Kotorska Bay. Dinoflagellates are generally less represented than diatoms, both quantitatively and qualitatively.

Status of faecal pollution in ports: A basin-wide investigation in the Adriatic Sea

Ports are subject to a variety of anthropogenic impacts, and there is mounting evidence of faecal contamination through several routes. Yet, little is known about pollution in ports by faecal indicator bacteria (FIB). FIB spatio-temporal dynamics were assessed in 12 ports of the Adriatic Sea, a semi-enclosed basin under strong anthropogenic pressure, and their relationships with environmental variables were explored to gain insight into pollution sources. FIB were abundant in ports, often more so than in adjacent areas; their abundance patterns were related to salinity, oxygen, and nutrient levels. In addition, a molecular method, quantitative (q)PCR, was used to quantify FIB. qPCR enabled faster FIB determination and water quality monitoring that culture-based methods. These data provide robust baseline evidence of faecal contamination in ports and can be used to improve the management of routine port activities (dredging and ballast water exchange), having potential to spread pathogens in the sea.

Strategy of port baseline surveys (PBS) in the Adriatic Sea

Port baseline surveys (PBS) provide species inventories in and around ports, with a focus on non-indigenous species that may have been introduced by vessels, primarily via ballast water. PBS are an essential tool to support effective management strategies for non-indigenous as well as native harmful aquatic organisms and pathogens (HAOP). This paper describes the methodology of PBS that were conducted in 12 Adriatic ports. The PBS employed existing protocols that were adapted to meet the characteristics of the Adriatic sites. Their results are reported in several papers included in this special issue, each of which is devoted to a specific community. An overview of existing surveys protocols - which provide valuable support to decision-making and to design effective monitoring of non-indigenous species - is also supplied.

Detecting the occurrence of indigenous and non-indigenous megafauna through fishermen knowledge: A complementary tool to coastal and port surveys

Marine bioinvasions and other rapid biodiversity changes require today integrating existing monitoring tools with other complementary detection strategies to provide a more efficient management. Here we explored the efficacy of fishermen observations and traditional port surveys to effectively track the occurrence of both indigenous and non-indigenous megafauna in the Adriatic Sea. This consisted mainly of mobile taxa such as fishes, crustaceans and molluscs. Port surveys using traps and nets within 10 major Adriatic harbours, were compared with the information obtained from 153 interviews with local fishermen. Information gathered by traps and nets varied significantly and generally resulted of limited efficacy in exotic species detection. Interviews allowed tracking the occurrence of new species through time and space, providing complementary knowledge at the low cost. This combined approach improves our capability of being informed on the arrival of species of different origin, providing a more rational, improved basis for environmental management and decision making.

Zooplankton Community in the Boka Kotorska Bay

This study includes a review of recently published results regarding zooplankton in the Boka Kotorska Bay (since 2009), and comparison of these results with earlier investigations. Non-loricate ciliates were the most numerous microzooplankton in spring 2013 (37%). Loricate ciliates (tintinnids) values were low and similar to those recorded in the open Adriatic Sea. However, their diversity was quite high: 20 estuarine–neritic and 26 species typical of the open sea were identified. Copepod nauplii were dominant metazoan microzooplankton component (32%). Seven phylums and 81 mesozooplankton taxa were determined. Copepods were the most dominant group. Among them, Oncaea–cyclopoids and Oithona nana were the dominant copepod taxa at all stations. Heterotrophic dinoflagellate Noctiluca scintillans and cladocera Penilia avirostris were often extremely numerous during warm seasons. Changes in the zooplankton community noted during recent investigations can be linked with the observed climate changes identified in the Adriatic and Mediterranean Sea since the 1990s, which are reflected in: (1) zooplankton high densities in the winter period with a lack of spring peak; (2) domination of small-size cyclopoid copepods and decreasing of contribution of neritic calanoid species; (3) prolongation of high Penilia avirostris abundance in the autumn period; (4) spreading of invasive siphonophorae Muggiaea atlantica in the inner part of the Bay; (5) frequent outbreaks of gelatinous zooplankton; and (6) The first registered bloom of the ctenophore Bolinopsis vitrea in the Mediterranean in spring 2014, having a major impact on the regular planktonic food web system.