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Fish, cephalopods and shellfish provide a healthy source of high-quality proteins, essential vitamins, minerals and polyunsaturated fatty acids. The beneficial effects of fish consumption on human health such as protection against coronary heart disease and certain cancer may be offset by fish decomposition and the formation of chemical contaminants such as biogenic amines. There are several toxicological effects of biogenic amines on humans, especially histamine. It is the causative agent of histamine or scombroid fish poisoning which is a significant public health problem. In individuals with diminished histamine detoxification, ingestion of even a low or moderate histamine- or tyramine-containing fish may lead to food intolerance. Biogenic amines such as putrescine, tyramine and cadaverine can potentiate histamine toxicity. Furthermore, dietary polyamine intake should be minimised in some cancer patients. Besides their potential toxicity, biogenic amines are used for the evaluation of hygienic quality ...

Biogenic amines in fish, fish products and shellfish: a review

Pseudo-nitzschia, Nitzschia, and domoic acid: New research since 2011.

. Analysis of 20-year time-series of the vertically averaged salinity and nutrient data in the Southern Adriatic shows that the two parameters are subject to strong decadal variability. In addition, it is documented that nutrient and salinity variations are out of phase. Nutrients in the Ionian and in the Adriatic vary in parallel except that generally the nutrient content in the Adriatic is lower than in the Ionian, a fact that has been attributed to primary producer consumption following the winter convective mixing. As shown earlier, North Ionian Gyre (NIG) changes its circulation sense on a decadal scale due to the Bimodal Oscillating System, i.e. the feedback mechanism between the Adriatic and Ionian. Cyclonic circulation causes a downwelling of the nitracline along the borders of the NIG and a decrease in the nutrient content of the water flowing into the Adriatic across the Otranto Strait, and vice versa. In addition, the highly oligotrophic central area of the Ionian shows annual blooms only during cyclonic NIG circulation. Inversion of the sense of the NIG results in the advection of Modified Atlantic Water or of the Levantine/Eastern Mediterranean waters in the Adriatic. Here, we show that the presence of allochtonous organisms from Atlantic/Western Mediterranean and Eastern Mediterranean/temperate zone in the Adriatic are concurrent with the anticyclonic and cyclonic circulations of the NIG, respectively. On the basis of the results presented, a revision of the theory of Adriatic ingressions formulated in the early 1950s is proposed.

/pdf/on-the-impact-of-the-bimodal-oscillating-system-bios-on-the-hzifz98itg.pdf

On the impact of the Bimodal Oscillating System (BiOS) on the biogeochemistry and biology of the Adriatic and Ionian Seas (Eastern Mediterranean)

The Catalan Sea, located between the eastern Iberian coast and the Balearic Islands, is a representative portion of the western Mediterranean basin and provides a valuable case study for climate change effects on Mediterranean ecosystems. Global warming is reflected regionally by a rise in sea level over the last century, an increase in surface temperature of around 1.1°C in the last 35 yr, a progressive salinisation of intermediate and deep waters and a strengthening of the stratification. A likely scenario of what we can expect in the Mediterranean Sea is a consider- able decrease in rainfall and wind, warmer surface waters and a prolonged stratification period. The effects on Mediterranean ecosystems are evident in: (1) a meridionalisation of the algal, inver- tebrate and vertebrate species, which favours the more thermophilic species over the temperate species; (2) mass mortality events of sessile invertebrates of the coralligenous communities owing to anomalous warm waters during the period when food is scarce; (3) increases in the smallest phytoplankton due to the prolongation of the water stratification period; (4) proliferation of gelati- nous carnivores, including jellyfish, due to the temperature rise and the lack of rainfall; (5) a faster acidification of seawater, compared with the global oceans, accompanied by a decrease in the capacity to absorb atmospheric CO2. In order to anticipate and mitigate these predicted changes, we recommend investing in research and observation, conserving areas that serve as indicators of climate change and reducing other anthropogenic pressures such as habitat destruction, over- fishing or pollution, which may act synergistically to accelerate these changes.

https://www.int-res.com/articles/cr2012/50/c050p001.pdf

Effects of climate change on Mediterranean marine ecosystems: the case of the Catalan Sea

Evaluation of a 45-year data set of primary production (PP), a 30-year data set of phytoplankton biomass, and a 51-year data set of species composition shows an increase of phytoplankton biomass and abundance in the period from the mid-1980s to the mid-1990s. Phytoplankton biomass showed bimodal seasonal cycles, with winter and spring maxima, which did not change over the past 30 years. Diatoms were the most abundant functional group and they prevailed during the colder part of the year while the dinoflagellate contribution to the phytoplankton community increased in the warmer period from May to August. Diatoms showed a significant negative correlation with sea surface temperature (SST), while dinoflagellates were positively correlated with SST. An increase of phytoplankton abundance, particularly dinoflagellate, in the period from the mid-1980s to the mid-1990s coincided with years characterized by a high North Atlantic Oscillation (NAO) index. Primary production and chlorophyll a concentration in the spring period were negatively correlated with the NAO winter (DJFM) index, probably caused by increased precipitation associated with a low or negative NAO index. PP in winter during the mixing period was positively related to the NAO winter index associated with higher temperatures and dry conditions which brought more clear days and increased input of solar radiation.

Inter-decadal Variability in Phytoplankton Community in the Middle Adriatic (Kaštela Bay) in Relation to the North Atlantic Oscillation

Eutrophication influence on phytoplankton community composition in three bays on the eastern Adriatic coast

Summary Based on the mechanism of food collection, bivalves can be suspension–feeders or deposit–feeders, or even utilize both feeding methods. Although some authors describe bivalve feeding as “automatized” process, recent studies show that some bivalves species have ability to regulate filtration and select particles based on their size, shape, nutritive value or chemical component on the surface of the particle. Several recent studies also showed that phytoplankton is not necessary primary food source for bivalves and pointed out the importance of other food sources such as bacteria, detritus and even zooplankton, including bivalve larvae. Ingestion of bivalve larvae indicates that adult bivalve grazing influence different life stages of these organisms and could have impact on bivalve stocks. Due to these process bivalves have great influence in energy and nutrient flux between benthic and pelagic communities, what makes them important part of marine food webs. This paper gives us the overview of current literature and understanding of bivalve feeding mechanisms, particle selection and food sources.

/pdf/bivalve-feeding-how-and-what-they-eat-2tqgn4ah83.pdf

Bivalve feeding — how and what they eat?

Interannual variability of the primary production in the middle Adriatic Sea for the period 1961-2002 was examined and correlated to the various atmospheric and oceanographic parameters. The Locally-weighted scatter plot smoothing (LOWESS) method (Cleveland, 1979) and Sequential algorithm for regime shift detection (SARS, Rodinov, 2004) were applied to the primary production mean annual and spring-summer values, revealing the three periods with significantly different mean productivity rate: 1961-1979, 1980-1996 and 1997-2002. Moreover, the period from 1980 to 1996, with the highest primary production, consists of the two distinguished regimes: periods of increasing (1980-1986) and decreasing (1987-1996) primary production. Whereas in the first period the ecosystem was under the influence of warmer and nutrient richer Levantine Intermediate Water (LIW) intrusions into the Adriatic, in the second period, which started with cold winter 1987, the Eastern Mediterranean Transient (EMT) occurred in the Mediterranean. The new circulation regime prevented the LIW intrusions in the Adriatic, causing its reduced productivity. Weak ventilation in the Adriatic was evidenced in the lower than normal sea temperature and oxygen concentrations bellow the thermocline depth. Analysed atmospheric data: air temperature, precipitation, evaporation, air-sea fluxes and the North Atlantic Oscillation (NAO) index showed similar fluctuation pattern as oceanographic data. Changed regime in the ecosystem, observed around 1980s till the end of 1996 can be also associated to the lower than normal precipitation rate, which is connected with more clear days and higher solar radiation input in the sea. Our analysis connected the shifts in primary production with changes in the climate system via changes in the atmosphere and confirmed the hypothesis that atmospheric variability can trigger the ecosystem changes.

/pdf/the-relationship-between-the-atmospheric-variability-and-3femb7wjir.pdf

The relationship between the atmospheric variability and productivity in the Adriatic Sea area

Mesozooplankton was sampled during one year in the eutrophicated Vranjic Basin and the influence of environmental variables on its abundance and distribution was analysed. Parallel microzooplankton samples were collected in order to asses trophic relationships within the zooplankton community. Total mesozooplankton abundances were high, exceeding 2 x 104 ind. m-3 in the warmer part of the year, but the biodiversity was low. The annual variability of this assemblage was mostly influenced by temperature. Copepods were dominant among net plankton groups, while ciliates dominated the protozoan community. The key species of the copepod community were Acartia clausi, Oithona nana and Euterpina acutifrons, occurring simultaneously throughout the year. High abundances of small copepod Oithona nana were determined in both meso- and microzooplankton samples, and comparisons of the catches from 125 μ m net and 5 l Niskin bottles revealed no significant differences between them. Significant correlation determined between Acartia clausi and oligotrich ciliates indicates predator-pray relationship and the importance of the ciliate community in the energy transfer through the trophic web of this area.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315406012811

Živana Ninčević Gladan

Papers

Inter-decadal Variability in Phytoplankton Community in the Middle Adriatic (Kaštela Bay) in Relation to the North Atlantic Oscillation

Eutrophication influence on phytoplankton community composition in three bays on the eastern Adriatic coast

Bivalve feeding — how and what they eat?

The relationship between the atmospheric variability and productivity in the Adriatic Sea area

Annual variability and trophic relations of the mesozooplankton community in the eutrophicated coastal area (Vranjic Basin, eastern Adriatic Sea)