Distribution of phytoplankton along the thermohaline gradient in the north-eastern Adriatic channel; winter aspect

Viličić, Damir; Kuzmić, Milivoj; Bosak, Sunčica; Šilović, Tina; Hrustić, Enis; Burić, Zrinka

doi:10.5697/oc.51-4.495

Cited by 15 publications

(9 citation statements)

References 14 publications

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“…This is particularly critical in the Zaton Bay region, resulting in the frequent occurrence of phytoplankton bloom (Šupraha et al, ). Based on the example of KRE, SGD most likely plays a significant role for the nutrient budgets along the entire eastern coast of the Adriatic Sea where numerous karstic estuaries (Benac et al, ; Viličić et al, ) and marine lakes (Hrustić & Bobanović‐Ćolić, ; Wunsam et al, ) are under the influence of SGD.…”

Section: Discussionmentioning

confidence: 99%

Net Submarine Groundwater‐Derived Dissolved Inorganic Nutrients and Carbon Input to the Oligotrophic Stratified Karstic Estuary of the Krka River (Adriatic Sea, Croatia)

Liu

Hrustić

et al. 2019

JGR Oceans

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Submarine groundwater discharge (SGD) is a significant source of biogenic elements in estuaries, and relevant studies in karstic estuaries are scarce. Krka River Estuary (KRE), located on the eastern Adriatic Sea (Croatia), is a typical oligotrophic stratified karstic estuary. In this study, based on 226Ra and 228Ra, the total SGD flux into the KRE surface layer was estimated to be (12.8–16.2) × 105 m3/day. A conservative estimation of the fresh groundwater flux was (5.0–8.3) × 105 m3/day, which accounts for 10–17% of the Krka River discharge into the estuary. By establishing water and nutrient budgets in the KRE surface layer, we found that SGD dominated the nutrient sources, although it accounted for a small portion of the total inflow water. Specifically, net SGD‐derived dissolved inorganic nitrogen (DIN) and silicates contributed 58–90% and 24–64%, respectively, to the total input fluxes. These results indicate that SGD was a major external nutrient source, in which net SGD‐derived high DIN flux and high DIN to dissolved inorganic phosphorus ratio may affect productivity in the KRE ecosystem and nearby Adriatic Sea. Additionally, net SGD‐derived dissolved inorganic carbon (DIC) flux in the KRE (1.53 mol · m2 · day) was much higher than those in most estuaries worldwide, suggesting that the DIC‐enriched karst aquifers are important sources for global carbon cycle. Therefore, the impact of net SGD‐derived DIC from karst aquifers on coastal seas will likely become more evident and substantial with further development of global climate change, such as sea level rise.

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Section: Discussionmentioning

confidence: 99%

Net Submarine Groundwater‐Derived Dissolved Inorganic Nutrients and Carbon Input to the Oligotrophic Stratified Karstic Estuary of the Krka River (Adriatic Sea, Croatia)

Liu

Hrustić

et al. 2019

JGR Oceans

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“…However, even a modest, but continuous groundwater discharge can have certain trophic influence on coastal water, since natural nutrient concentration can be several orders of magnitude greater than in the seawater (Moore 2006), particularly in a carbonate and oligotrophic environment such as the Mediterranean (Basterretxea et al 2010). In the studied area, rich mussel colonies (Mytilus galloprovincialis) in Vrulja Zečica and Vrulja Modrič submarine springs (Petricioli et al 1995), several mussel farms nearby, and successful fishing activities in otherwise oligotrophic waters (Viličić et al 2009) clearly demonstrate nutrient enrichment via SGD. Furthermore, SGD-borne clastic material significantly changes the geomorphology of the coves by shallowing usually quite steep coast (Fig.…”

Section: Other Impacts Of Sgdmentioning

confidence: 93%

“…Winter isothermy of the water column is regular along the eastern Adriatic coast, with values ranging between 10 and 12°C (Viličić et al 2009). Locally, winter stratification with decreased sea surface temperatures (SST) is regulated by the cold bora wind and the freshwater influx from the SGD and the coastal springs.…”

Section: Winter Settingsmentioning

confidence: 98%

Influence of submarine groundwater discharge on seawater properties in Rovanjska-Modrič karst region (Croatia)

et al. 2015

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Coastal karst aquifers are dynamic hydrogeological systems with substantial hydrological, geomorphological and ecological impacts on the marine and coastal karst ecosystems, mostly induced by the submarine groundwater discharge (SGD). This paper presents complex hydrogeological settings of the Rovanjska-Modrič coastal karst region on the eastern Adriatic coast characterized by: (1) high temporal and spatial variations in seawater properties; (2) significantly reshaped coastal bottom morphology, and (3) plethora of associated biocenoses from fresh water, brackish, marine and cave assemblages. With the aim of resolving spatiotemporal interconnections of SGD and marine environment changes, we conducted field prospection and seasonal measurements of different water properties on-and off-shore. Obtained results pointed to: (1) the composite recharge system consisting of numerous sinking rivers in the distant hinterland (with different climate settings) and local precipitation input; (2) specific discharge settings highly governed by a complicated karst conduits network, the hydrological situation in the hinterland and local meteorological conditions, i.e. one system that permanently feeds coastal and probably submarine springs, while the other operates periodically; (3) disturbed winter isothermy and threelayered summer stratification of the seawater column, and (4) slightly changed trophic settings. All of that is the consequence of extreme heterogeneity of the coastal karst aquifer, characteristic for the eastern Adriatic coast.

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“…These freshwater discharges normally come through occasional floods that accumulate over the 150 km long and 1600 m high mountain ridge of Velebit (Perica and Orešić, 1997) and a large number of submarine karstic springs (Sekulić and Vertačnik, 1996;Bonacci, 2001;Benac et al, 2003;Surić et al, 2015). Further, thanks to occasional oceanographic campaigns, the inner area of the Velebit Channel has been classified as a two-layer system, and the surface salinity exhibits much lower values (∼ 1.0) than that in the open Adriatic (Viličić et al, 2009). Additionally, it has been identified that a strong northern Adriatic thermohaline front (Lee et al, 2005;Poulain et al, 2011) has its starting point in the northeastern coastal Adriatic, specifically in Kvarner Bay, with coastal waters advected towards the open sea, particularly during strong bora events (Pullen et al, 2003;Lee et al, 2005;Beg Paklar et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Wintertime dynamics in the coastal northeastern Adriatic Sea: the NAdEx 2015 experiment

et al. 2018

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Abstract. The paper investigates the wintertime dynamics of the coastal northeastern Adriatic Sea and is based on numerical modelling and in situ data collected through field campaigns executed during the winter and spring of 2015. The data were collected with a variety of instruments and platforms (acoustic Doppler current profilers, conductivity–temperature–depth probes, glider, profiling float) and are accompanied by the atmosphere–ocean ALADIN/ROMS modelling system. The research focused on the dense-water formation (DWF), thermal changes, circulation, and water exchange between the coastal and open Adriatic. According to both observations and modelling results, dense waters are formed in the northeastern coastal Adriatic during cold bora outbreaks. However, the dense water formed in this coastal region has lower densities than the dense water formed in the open Adriatic due to lower salinities. Since the coastal area is deeper than the open Adriatic, the observations indicate (i) balanced inward–outward exchange at the deep connecting channels of denser waters coming from the open Adriatic DWF site and less-dense waters coming from the coastal region and (ii) outward flow of less-dense waters dominating in the intermediate and surface layers. The latter phenomenon was confirmed by the model, even if it significantly underestimates the currents and transports in the connecting channels. The median residence time of the coastal area is estimated to be approximately 20 days, indicating that the coastal area may be renewed relatively quickly by the open Adriatic waters. The data that were obtained represent a comprehensive marine dataset that can be used to calibrate atmospheric and oceanic numerical models and point to several interesting phenomena to be investigated in the future.

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Distribution of phytoplankton along the thermohaline gradient in the north-eastern Adriatic channel; winter aspect

Cited by 15 publications

References 14 publications

Net Submarine Groundwater‐Derived Dissolved Inorganic Nutrients and Carbon Input to the Oligotrophic Stratified Karstic Estuary of the Krka River (Adriatic Sea, Croatia)

Net Submarine Groundwater‐Derived Dissolved Inorganic Nutrients and Carbon Input to the Oligotrophic Stratified Karstic Estuary of the Krka River (Adriatic Sea, Croatia)

Influence of submarine groundwater discharge on seawater properties in Rovanjska-Modrič karst region (Croatia)

Wintertime dynamics in the coastal northeastern Adriatic Sea: the NAdEx 2015 experiment

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