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Este artículo contiene 18 páginas, 4 figuras., Climate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015–2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems' health and functioning. Overall, we show that increasing the resolution of empirical observation is critical to enhancing our ability to more effectively understand and manage the consequences of climate change., This paper was supported by Euromarine. Joaquim Garrabou acknowledges the funding by the “Severo Ochoa Centre of Excellence” (CEX2019-000928-S), the MCIU/AEI/FEDER [HEATMED; RTI2018-095346-B-I00], Interreg-Med Programme MPA-Engage (1MED15_3.2_M2_337), the European Union Horizon 2020 research and innovation programme (Futuremares SEP-210597628). Nuria Teixido acknowledges the French National Research Agency (4Oceans-MOPGA grant, ANR-17-MPGA-0001) and internal funds from the Stazione Zoologica Anton Dohrn. Gil Rilov was supported by the Israel Ministry of Environmental Protection. Hocein Bazairi, Free Spinosa, and Vasilis Gerovasileiou acknowledge the funding by the MAVA Fondation (MedKeyHabitats I Project) and the European Commission (Ecap-MED II Project; projects implemented by UNEP/MAP-RAC/SPA). Alfonso Ramos was supported the CIESM “Tropical Signals,” Stelios Katsanevakis and Maria Sini were supported by the Project “Coastal Environment Observatory and Risk Management in Island Regions AEGIS+” (MIS 5047038), implemented within the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020), co-financed by the Hellenic Government (Ministry of Development and Investments) and the European Union (European Regional Development Fund, Cohesion Fund), Stelios Katsanevakis, Maria Sini and Vasilis Gerovasileiou acknowledge the support of the MARISCA Project, co-funded by 85% by the EEA GRANTS, 2009–2014, and 15% by the Public Investments Programme (PIP) of the Hellenic Republic. Ivan Guala and Daniele Grech thanks thank the support of the project “Pinna nobilis—ricerca per la sopravvivenza: un'iniziativa di Citizen Science per tracciare la mortalità di massa di Pinna nobilis in Sardegna” project and the L/7 grant (CUP 87G17000070002) funded by the Regione Autonoma Sardegna. Jean-Baptiste Ledoux was funded by an assistant researcher contract framework of the RD Unit—UID/Multi/04423/2019—Interdisciplinary Centre of Marine and Environmental Research—financed by the European Regional Development Fund (ERDF) through COMPETE2020—Operational Program for Competitiveness and Internationalization (POCI) and national funds through FCT/MCTES (PIDDAC). This research was supported by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 through national funds provided by the FCT—Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the program PT2020. Bernat Hereu and Cristina Linares acknowledge the support of the long-term monitoring programme of the catalan Natural Parks, funded by the Departament de Territori i Sostenibilitat of the Generalitat de Catalunya. Cristina Linares acknowledges the support of the ICREA Academia programme. David Díaz acknowledges the support the research grant CTM2016-77027-R of the Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad and Program of Marines Strategies of Spain funded by MITERD. Jamila Ben Soussi was partially funded by the Fondation Albert 2 Monaco (MIMOSA Project) and the Tropical Signals Program of CIESM. Giovanni Chimienti was supported by the Italian Ministry of Education, University and Research (PON 2014–2020, AIM 1807508–1, Linea 1), by the Ente Parco Nazionale del Gargano (Research agreement with CoNISMa N. 21/2018), and by the National Geographic Society (Grant EC-176R-18). Nathaniel Bensoussan acknowledges financial support from the European Commission through the programme “Caroline Herschell” in the context of the action “Developing Downstream applications and services on BIO-PHYsical characterization of the seascape for COASTal management” (BIOPHYCOAST). Monica Montefalcone and Annalissa Azzola collected some of their data on MMEs in the frame of the project “Mare Caldo” funded by Greenpeace Italy. Núria Marbà acknowledges financial support from the Spanish Ministries of Economy and Competitiveness (CTM2012-32603, CGL2015-71809-P) and Ministerio de Ciencia, Innovación y Universidades (RTI2018-095441-B-C21). Diego K. Kersting acknowledges support by the postdoctoral fellowship programme Beatriu de Pinós funded by the Secretary of Universities and Research (Government of Catalonia) and the Horizon 2020 programme of research and innovation of the European Union under the Marie Sklodowska-Curie grant agreement No 801370.

Bite force is a key performance trait in lizards because biting is involved in many ecologically relevant tasks, including foraging, fighting and mating. Several factors have been suggested to impact bite force in lizards, such as head morphology (proximate factors), or diet, intraspecific competition and habitat characteristics (ultimate factors). However, these have been generally investigated separately and mostly at the interspecific level. Here we tested which factors drive variation in bite force at the population level and to what extent. Our study includes 20 populations of two closely related lacertid species, Podarcis melisellensis and Podarcis sicula, which inhabit islands in the Adriatic. We found that lizards with more forceful bites have relatively wider and taller heads, and consume more hard prey and plant material. Island isolation correlates with bite force, probably by driving resource availability. Bite force is only poorly explained by proxies of intraspecific competition. The linear distance from a large island and the proportion of difficult-to-reduce food items consumed are the ultimate factors that explain most of the variation in bite force. Our findings suggest that the way in which morphological variation affects bite force is species-specific, probably reflecting the different selective pressures operating on the two species.

Due to specific geomorphologic characteristics of the Dalmatian coast type, formed primarily from karst limestone, Eastern Adriatic coast shows great diversity of habitats. This diversity is also influenced by the position of the Adriatic Basin, stretching from northwest to southeast, climatic differences along its length, and the direction of sea currents. Habitats in the submerged karst characteristic for the Croatian side of the Adriatic Sea are anchihaline caves, sea caves, cold sea caves and pits with bathyal elements, vruljas, karst estuaries, submerged river canyons, submerged tuffa barriers, marine lakes, and bare karst in the sea. Though sea caves, vruljas, coralligen, marine lakes, and Posidonia beds are today threatened by direct and indirect anthropogenic influences (pollution, eutrophication, tourism, nautical tourism, coastal development, aquaculture), only a few of these habitats have been declared as areas of special interest for conservation or as threatened habitats under the relevant international conventions. There are still too few targeted studies that could contribute to better understanding of these habitats and their levels of threat. Therefore, some of these specific and valuable habitats are in danger to be destroyed before they can be investigated (1). Sea caves, vruljas, and coralligen are quite inaccessible and, therefore, there is insufficient information on the organisms living there. The mechanisms how deep-sea organisms settle into cold-water sea caves and how they survive and reproduce in these caves are insufficiently investigated. All the ecological factors which result in such a large diversity of sponges in the semi-dark cave communities are also unknown. Preliminary research of anchihaline caves shows that it might be possible that karstification processes occur just beneath the sea surface (2). Marine lakes, ecologically separate from the surrounding sea due to limited contact, are very rare at the eastern Adriatic coast and, therefore, very threatened. The benthos of these lakes includes a small number of organisms that have very large populations, which is contrary to what we find in the surrounding sea. All the preliminary research has proven these habitats to be very interesting.

The sponges Oopsacas minuta (Hexactinellida) and Asbestopluma hypogea (Demospongiae, Cladorhizidae) belong to groups that are typical of deep water, but both species have already been recorded from the shallow water Trois Pepes cave at La Ciotat (Marseille area). We here report on subsequent findings of A. hypogea in two other littoral caves: one at Garmenjak Island in the Middle Adriatic (Croatia), the other at Jarre Island (Marseille, France). The maximum temperatures experienced in situ by these populations are significantly higher than those from the deep Mediterranean Sea, but they are also up to 6°C higher than those reported for the Trois Pepes cave population, up to 23.1 °C in July 2002 for Garmenjak population and 22.8 °C in August 2004 for Jarre population (exposures from a few hours to a few days). The average summer temperature inside both caves remains several degrees lower than the outside temperature at the same depth. Long time survival of A. hypogea populations at the relatively high summer/autumn temperatures in both Jarre cave (4 years monitoring) and Garmenjak cave (5 years monitoring) indicates that the species can successfully colonise such shallow habitats in spite of its presumed deep-water origin. We also report of additional cave records of O. minuta from the Middle Adriatic (Croatia): at Hvar Island in the marine part of the Živa Voda anchialine cave, and from the marine caves at Iski Mrtovnjak, Lastovo and Fraskeric Islands. The wide distribution of this species in the deep Mediterranean is substantiated by a record on Santa Lucia Bank north of Corsica (303 m) and photographs taken by the submersible Cyana in the Central Tyrrhenian Sea (2912 m, 2845 m) and the Ionian Sea (2447 m). Possible colonisation patterns of littoral caves by both sponges are discussed.

The Croatian coastal karst abounds in submerged caves that host a variety of environmental conditions depending on the geomorphology, depth and submarine groundwater discharge. One example is the Y-Cave, a shallow, mostly submerged, horizontal cave on Dugi Otok Island, on the eastern Adriatic coast. This study was aimed at examining the temporal and spatial variability of the marine cave environment, including temperature, salinity, light intensity, cave morphology and hydrodynamism, along with the dissolutional effect caused by the mixing of sea and freshwater. The general distribution of organisms in the Y-Cave was positively correlated to the light gradient and reduced water circulation, thus the highest species diversity and abundance were recorded in the front part of the cave. The phylum Porifera was the most dominant group, and the poriferan species diversity in the cave ranks among the ten highest in the Mediterranean. The middle part of the cave, although completely dark, hosts an abundant population of the gastropod Homalopoma sanguineum and clusters of the gregarious brachiopod Novocrania anomala, whose presence could be connected to tidal hydrodynamics. The absence/scarcity of sessile marine organisms and pronounced corrosion marks at shallow depths inside the cave suggest a freshwater impact in the upper layers of the water column. A year long experiment with carbonate tablets revealed three different, independent ongoing processes affected by the position in the cave: bioaccumulation, dissolution and mechanical erosion. The results of long-term temperature readings also revealed water column stratification within the cave, which was not disturbed by either tidal or wave action. The shallow, partly submerged and relatively small Y-Cave is characterised by a suite of complex environmental conditions, which, together with the resulting distribution of organisms, are unique to this cave.

In the context of current global environmental changes, mapping and monitoring seagrass meadows have become highly important for management and preservation of coastal zone ecosystems. The purpose of this research was to determine the numerical precision of various cost-effective benthic habitat mapping techniques and their suitability for mapping and monitoring of Posidonia oceanica meadows in the Croatian Adriatic. We selected ultra-high resolution aerial imagery, single-beam echo sounder (SBES) seabed classification system from Quester Tangent Co. (QTC), and surface based underwater videography as affordable, non-destructive and simple to use systems for data acquisition. The ultra-high resolution digital imagery was capable of detecting P. oceanica meadows up to 4m depth with 94% accuracy, from 4m to 12.5m depth the accuracy dropped to app. 76%, and from 12.5 to 20 m the system was only capable of distinguishing seabed biota from substrata, though with 97% accuracy. The results of the QTC system showed over 90% detection accuracy for Cymodocea nodosa covered seabed, excellent separation capabilities (>92%) of different sediment types (slightly gravelly sand, gravelly muddy sand and slightly gravelly muddy sand) and reasonable accuracy for mapping underwater vegetation regardless of the bathymetric span. The system proved incapable of separating P. oceanica from dense macroalgae on the same type of substratum. Surface-based underwater videography demonstrated great potential for estimating P. oceanica cover in a sampled region using either a single human rater or a computer estimate. The consistency between two human scorers in evaluating P. oceanica bottom coverage was near perfect (>98%) and high between digital and human scorers (80%). The results indicate that although the selected systems are suitable for mapping seagrasses, they all display limitations in either detection accuracy or spatial coverage, which leads to a conclusion that suitable system integration is essential for producing high quality seagrass spatial distribution maps.

In late summer and early autumn of 1989 benthic mortality in the upper part of Krka estuary extended from the Skradinski buk waterfalls to approximately 5 km downstream. Dead benthic organisms were found on the bottom at depths of up to 4.5 m. During August, a freshwater phytoplankton bloom was recorded in Visovac lake (which supplies the Skradinski buk waterfalls). The green tide in the lake was composed of up to 11.9 million cells. 1--1, predominantly of Synedra acus and Dinobtyon sertularia. At that time the maximal total inflow of phytoplankton cells through the waterfalls was approx. 0.41 S-I (38000 1. d-1). Cells of these two species died after reaching the salt wedge and the cummulative effect of their decomposition apparently caused an oxygen demand sufficient enough to trigger the benthic mortality. Due to the water mass dynamics, the spreading of mortality downstream was slow (from August to October, approx. 5 km). Certain benthic fishes (like Gobius sp.) were observed on the bottom of the affected area in mid-October 1989.

The Adriatic Sea can be considered as a large, mostly shallow embayment of the Mediterranean Sea. The latitudinal SE-NW extension of the Adriatic results in considerable climate differences along its coast. In this work we compiled the listof sponges from classes Demospongiae and Homoscleromorpha recorded in the Adriatic up to now: we performed a thor-ough literature check and we added the results of our decade long research with a special emphasis on sponge fauna inmarine caves. All the records were assigned to the North, Middle or South Adriatic according to their geographic location,and the analysis showed a very high similarity among the sponge fauna of the 3 areas. The likeness between the N. andthe M. Adriatic is over 83 %, between the M. and the S. Adriatic over 76 % and between the N. and the S. Adriatic over66 %. Altogether 283 species of sponges from these two classes (our field data and literature survey) have been recordedin the whole Adriatic up to now, which is a considerably higher number than in previous reviews. Among the 125 speciesthat we found so far in our research along the Croatian coast, 77 were found in marine caves. We are still discovering spe-cies not previously found in the Adriatic Sea (especially from cryptic habitats) and here we report 15 new records for the Adriatic Sea, 9 of which were noted only in caves.

Fishing activities and other anthropogenic influences have direct and indirect effects on fish community structure. One expectation may be that with increasing fishing pressure and decreasing size selectivity of fisheries all predator populations decline and consequently fish assemblages change. Comparisons of MPAs with unprotected areas are considered valid natural experiments to test hypotheses on how predation structures communities. Here we report on the use of a lure-assisted visual census in the Central Croatian Adriatic to assess and compare fish assemblages in MPA sites (Kornati NP) with adjacent unprotected sites. We detected a significant protection effect on mesopredator abundance and overall fish diversity/richness and that protection status explained a significant portion of the fish assemblage variability, all independent of additional predictor variables, like habitat and depth. As we continue to expand the spatiotemporal scale and magnitude of the approach, we hope that it will eventually provide us with a long-term data series needed for testing many hypotheses in coastal ecology, including the effects of MPAs, coastal development, fishing and global climate change on the species interactions, abundance, diversity and assembly of animal species across multiple spatial scales., Ribolovne i druge antropogene aktivnosti izravno i neizravno utječu na sastav zajednica riba. Jedna od pretpostavki je da povećani ribolovni napor dovodi do smanjenja populacije predatorskih vrsta riba što dovodi do promjena u sastavu zajednica riba. Usporedba zaštićenih i nezaštićenih područja smatra se vjerodostojnom eksperimentalnom metodom za testiranje hipoteze na koji način struktura predatora utječe na zajednicu riba. Ovdje predstavljamo rezultate korištenja metode vizualnog cenzusa uz pomoć mamca na području srednjeg Jadrana kako bi procijenili i usporedili sastav zajednica riba u zaštićenom području (NP Kornati) i susjednim nezaštićenim područjima. Zabilježili smo značajan utjecaj zaštite na brojnost meso-predatora i na ukupnu raznolikost/brojnost riba kao i to da je zaštitom moguće objasniti značajan dio varijabilnosti u sastavu zajednica riba, neovisno o drugim faktorima poput tipa staništa ili dubine. Daljnjim proširivanjem naših istraživanja na prostornoj i vremenskoj skali, očekujemo da ćemo prikupiti vrijedne i dugotrajne podatke koji su potrebni kako bismo testirali mnoge pretpostavke u ekologiji priobalne zone, uključujući one o u utjecaju zaštićenih područja, razvoju obale, ribolovu, dostupnosti staništa te globalnim klimatskim promjenama na odnose među različitim vrstama, brojnost, raznolikost i sastav životinjskih vrsta na raznim prostornim skalama.

Anthropogenic activities that introduce an excess of nutrients and other pollutants into rivers and lakes are causing significant changes in their aquatic environment. Excessive nutrients greatly accelerate eutrophication, and lake marl formed during eutrophication differs from that formed in oligotrophic water.We analyzed recent sediment cores from Prošće and Kozjak lakes located in Plitvice National Park, central Croatia. Analyses consisted of 14C activity of calcareous lake marl, the ratio of stable isotopes (δ13C, δ18O), organic compounds in the sediment and the distribution of diatoms. Previous 14C activity measurements helped to determine the sedimentation rate and thus the time period of increased input of nutrients into lakes. We determined the increased 14C activity in lake sediments caused by nuclear bomb effect in recent depth profiles. We attributed the sudden increase in diatom species, Cyclotella operculata unipuctata and Achnanthes clevei rostrata, in the uppermost 5-cm layer, to eutrophication of the lake water.We performed a molecular characterization of hydrocarbons isolated from the sediments, and applied computer-assisted high-resolution gas chromatography/mass spectrometry to estimate contributions of biogenic, fossil and pyrolytic hydrocarbons.

A sediment trap validation study was conducted near the commercial sea bass and sea bream fish farm in order to assess the predictive capability of a particle tracking deposition model. The validation procedure consisted of two distinct phases. First, the deposition of particulate waste (i.e. fecal pellets and excess feed) was measured near a single net pen containing 19 tons of sea bass. Afterwards, the model quality was determined by statistical comparison of predicted and observed values. Goodness of fit analysis indicates that the model successfully accounts for more than 75% of variance in the observed deposition. At 5% significance level, predictions do not underestimate or overestimate observations and there is no bias. Mean absolute relative error of ±48.9% compares favorably to other published deposition models. Obtained results affirm the reliability of particle tracking techniques in modeling the aquaculture-derived benthic organic enrichment.

This study examined the impact of fish farming on foraminiferal communities in the Adriatic coastal zone. Samples were taken directly beneath the farm, near the edge of the farm, and at a reference station away from the farm. The foraminiferal community near the farm is characterized by Epistominella exigua, Globocassidulina subglobosa, Haynesina germanica and the genera Elphidium, Bulimina and Brizalina. These foraminiferal species are less abundant seaward. Asterigerinata mamilla, Neoconorbina terquemi and genus Cibicides are almost absent below the cages. Total phosphorus (TP) and total nitrogen (TN) in the sediments decrease with distance from the cages. The abundances of E. exigua, G. subglobosa, H. germanica and the genera Elphidium, Bulimina and Brizalina are correlated with TP and TN, indicating their dependence on nutrient input. The absence of A. mamilla, N. terquemi and the genus Cibicides below the cages is a due to a degraded Posidonia community. According to our study, foraminiferal community composition can be used as indicator of organic enrichment caused by fish farm activities.

With the intention of reconstructing Late Pleistocene – Holocene sea-level changes along the Eastern Adriatic coast, a series of speleothems were collected from several submerged caves and pits, in order to constrain periods of their deposition and ceased growth related to sea-level fluctuations. For that purpose, stalagmites provide more reliable records than stalactites, due to their successive layers deposited perpendicularly to the growth direction. Therefore, stalagmites have been collected preferably. But, two of 17 speleothems displayed unexpected interior morphology – speleothem L-1 collected at the depth of 1.5 m in Medvjeđa spilja Cave on Losinj Island, and speleothem M-25 from Pit near Iski Mrtovnjak Islet collected at the depth of 25 m. Both of the samples were taken from the cave floor, in the growth position of the stalagmite. But the insight into the perpendicular cut with evident central tube revealed their true (stalactitic) origin and additional confirmations were obtained by longitudinal cut and U-Th and 14C dating. Just as the causes of their breakdowns were probably different, so were their falls; speleothem M 25 (together with several other speleothems around it) stuck in the marine sediment in its primary position, while L-1 turned upside-down and even continued crystallizing during the lower sea level. These events are possible in the continental caves, as well. Evidently, it is much easier to recognize and avoid these problems in air-filled caves than in the submarine ones where the speleothems are almost always covered with marine overgrowth, which disguises their outer morphology. Additionally, the bases of the stalagmites are also sometimes covered with marine sediment, which makes correct estimation rather difficult.

We derive statistical properties of standard methods for monitoring of habitat cover worldwide, and criticize them in the context of mandated seagrass monitoring programs, as exemplified by Posidonia oceanica in the Mediterranean Sea. We report the novel result that cartographic methods with non-trivial classification errors are generally incapable of reliably detecting habitat cover losses less than about 30 to 50%, and the field labor required to increase their precision can be orders of magnitude higher than that required to estimate habitat loss directly in a field campaign. We derive a universal utility threshold of classification error in habitat maps that represents the minimum habitat map accuracy above which direct methods are superior. Widespread government reliance on blind-sentinel methods for monitoring seafloor can obscure the gradual and currently ongoing losses of benthic resources until the time has long passed for meaningful management intervention. We find two classes of methods with very high statistical power for detecting small habitat cover losses: 1) fixed-plot direct methods, which are over 100 times as efficient as direct random-plot methods in a variable habitat mosaic ; and 2) remote methods with very low classification error such as geospatial underwater videography, which is an emerging, low-cost, non-destructive method for documenting small changes at millimeter visual resolution. General adoption of these methods and their further development will require a fundamental cultural change in conservation and management bodies towards the recognition and promotion of requirements of minimal statistical power and precision in the development of international goals for monitoring these valuable resources and the ecological services they provide.

Plans are in progress to increase freshwater inflow to the Zupski Bay, in south Dalmatia (between Dubrovnik and Cavtat, Adriatic Sea) as a consequence of a need to increase hydro-electric power production. The main question is: Would the adverse environmental impacts out-weight the benefit? Following has been found: a) temperature at public beaches will decrease, but the decrease in a worse case scenario will be below 0.5 degrees C and hence will not be felt by tourists, b) the probability for subsurface phytoplankton blooms will increase, but the blooms will be very limited in extent and concentration, and will not cause hypoxia at the bottom, c) benthic community in the eu- and sub-littoral, up to 200 m sea ward from the outflow, will be replaced in part by brackish tolerant species, d) overall trophic status of the bay will increase slightly, e) category of sanitary quality on surrounding beaches will not worsen. Given the above findings, the study recommends to proceed with the plans and increase freshwater inflow from 90 to 105 m3/s.

Microphytoplankton taxonomic composition and cell density distribution were investigated at three representative stations along the highly stratified Krka River estuary on the eastern Adriatic coast. Samples were collected at approximately monthly intervals from March 1988 to April 1989. One hundred thirty six taxa were determined by light microscopy: 108 marine species (1 chrysophyte, 5 prymnesiophytes, 55 diatoms, 1 euglenophyte, 46 dinoflagellates) and 28 freshwater species (1 chrysophyte, 21 diatoms, 1 dinoflagellate, 3 chlorophytes, 2 cyanophytes). The seasonal distribution of microphytoplankton cell densities is influenced by the freshwater inflow through the Krka River and the ecological properties of the karstic salt-wedge-stratified estuary. Anthropogenic influence is notable in the lower reach of the estuary, around Šibenik., U radu je prikazan taksonomski sastav i raspodjela gustoće stanica mikrofitoplanktona na tri reprezentativne postaje u visoko stratificiranom estuariju rijeke Krke. Uzorci su sakupljeni u mjesečnim intervalima od ožujka 1988. do travnja 1989. godine. Svjetlosnim je mikroskopom određeno stotinu trideset i šest mikrofitoplanktonskih vrsta: 108 morskih (1 krizoficeja, 5 primnezioficeja, 55 dijatomeja, 1 euglenoficeja, 46 dinoflagelata) i 28 slatkovodnih vrsta (1 krizoficeja, 21 dijatomeja, 1 dinoflagelat, 3 kloroficeje, 2 cijanoficeje). Na sezonsku raspodjelu gustoće stanica mikrofitoplanktona utječe dotok vode rijeke Krke i ekološki uvjeti u estuariju. Utjecaj čovjeka vidljiv je u donjem dijelu estuarija, oko Šibenika.