Marine and saltmarshes ecology

The Peel-Harvey saltmarshes are important locally and regionally, because they support extensive food web and act as a biological filter for the receiving waters. This study was undertaken to examine the ecology and extent of saltmarshes of the Peel-Harvey. The extent and composition of the samphire saltmarshes was investigated over the period of 37 years (from 1957 to 1994), using aerial photography over the whole estuary, and detailed field surveys at ten sites.

The coastal dunes have almost disappeared from the Italian sandy shores as consequence of both human settlement and tourist exploitation of littoral areas. The few localities stillpartially preserved are therefore considered of particular environmental value, in reason
of the characteristic biocenosis they are exclusive depositary of, composed of highly specialised floro-faunistic taxa.
Three sites located in the Venetian coast and provided with beach-dune systems have been surveyed from 2007 to 2014 in order to study the specialized beetle fauna and detect any impact from the interventions for the construction of the mobile gates at the Venice lagoon inlets. The areas of interest are Ca’ Roman (CR), Alberoni (AL) and Punta
Sabbioni (PS), located besides the construction yards. Sixteen beetle taxa were selected among the typical inhabitants of beach-dune systems, belonging to the following families: Carabidae, Histeridae, Staphylinidae, Scarabaeidae, Ripiphoridae, Anthicidae, Tenebrionidae and Curculionidae.
Each site was visited 1 or 2 times a month from February to November for the first four years, then, since 2011 the number of visits decreased to 8, from April to October. Each area was divided in two sectors: the sector-A, closer to the construction yards, and the sector-B more distant.
From 2007 to 2010, semi-quantitative data of beetle abundance were distinctly recorded from the A and B sectors, in order to assess any difference in environmental quality. The environmental quality was evaluated by means of the index EIEC (Entomological Index of Environmental Conservation), specifically elaborated at the beginning of the investigations in order to compute a conservation score based on different aspects of the bio-indicators ecology and abundance.
Since 2011 the survey program was modified: at CR and AL the sector-B was abandoned, and the survey was focused on three subsectors of 50 m in width, identified in the sector-A, of which the fist was adjacent to the construction yards (subsector-A1), the second was at about 200 m (subsector-A2) and the third at about 350 m (subsector-A3).
This aimed to increase the efficacy of the survey for short distance impacts. PS was not interested by these changes because the construction yard was not in the perimeter of the investigated area.
Results showed that almost all the target species were present in surveyed sites. Among the species typical of the beach, the tiger beetles Cylindera trisignata trisignata and Calomera littoralis nemoralis were present everywhere with abundant populations, as well as the darkling beetles Phaleria bimaculata adriatica and Trachyscelis aphodioides. Other species, as Parallelomorphus laevigatus (Carabidae), Halacritus punctum (Histeridae) were recorded in two out of three stations, while no specimen of Dyschiriodes bacillus arbensis was observed.
Among the Staphylinids typically occurring on the seashore sands, Cafius xantholoma still resulted present with quite significant populations, whreas Remus sericeus, abundant in the past, is now sporadic. PS showed the poorest populations of taxa occurring on the
beach, apart from Cicindelina, with local extinction of P. laevigatus and H. punctum. The cause was mainly attributed to the frequent mechanical grooming of the beach. Among the dune beetles, only Mecynotarsus serricornis (Anthicidae) occurred with stable
and abundant populations, Otiorhynchus ferrarii (Curculionidae) was well represented at CR and AL but very sporadic at PS, while Isidus moreli (Elateridae) was recorded in all the sites with few specimens, although its density is probably underestimated. The Tenebrionidae
Xanthomus pallidus occurred with populations apparently stable, although the abundance assessment was negatively affected by the low number of visits carried out within its period of activity, especially since 2011. Ammobius rufus, a typical Mediterranean Tenebrionidae, was moderately present at CR and AL with abundance lower than
in other central-southern Italian sites, but absent at PS. The dung beetle Scarabaeus semipunctatus
(Scarabaeidae) was observed with a few specimens per year at PS while only two records were reported for AL and one for CR. Finally, Macrosiagon tricuspidatum (Ripophoridae) was recorded only at CR with few specimens per year. On the whole, the collected data suggest that the investigated stations still host partially preserved biocenosis, despite they show an environmental condition affected by relevant
human impacts, which have caused the loss of some species and are threatening the survival of others. The EIEC showed that the construction yards had an impact only on the dunes at CR, in an adjacent area limited to 50 m in width. PS suffers both the heavier
environmental changes due to human interventions and intense impacts produced by the tourist exploitation of the beach. The disappearance of D. bacillus arbensis and the risk of extinction of S. semipuntatus lack of sustainable explanations.

This study presents an analysis of the evolution of the marshes of the Autonomous Community of Andalusia, Spain, based on information available for 7 specific years: 1956, 1977, 1984, 1998, 2005, 2007 and 2013; analyzing variations in 10 marshlands using orthophotos and cartography available for this community. Overall, this study concludes that 47,008 ha (40%) of the approximately 116.141 ha of marshes in Andalucía in 1956 have been lost until 2013. The loss has occurred at an average rate of 1 - 2% per year, being Doñana (-27,516 ha), Bonanza (-12,069 ha) and San Pedro (-4.454 ha) the marshes most affected. The main causes of regression have been agriculture (75%), industrial salt mines (10%) and urbanization (5%), this reduction also leads to the loss of ecosystem services and atmospheric carbon sequestration; these was estimated using global reference values for CO2 sequestration and CH4 and N2O emissions, 5.54 tCO2-eq ha-1 year-1; 0.3874 tCO2-eq ha-1 year-1; 0.3808 tCO2-eq ha-1 year-1, respectively, published in the scientific literature for polyhaline marsh ecosystems (salinity> 18mg / l). The estimates show a net sequestration capacity between 301 and 199,165 tCO2-eq year-1 in Guadalhorce and Doñana marshes. However, the reduction of the area of the marshes between 1956 and 2013, entailed a loss of sequestration of 224,312.7 tCO2 year-1. Finally, 3,849 ha of soil were identified that could currently be reclaimed as marshes and constitute projects to offset GHG emissions, which can generate an approximate value of 1,495,829 carbon credits, which at the current carbon price (€ 5.27 / US-credit) amounts to approximately € 7,883,022 a year-1.

This study aims to determine the drivers of root decomposition and its role in carbon (C) budgets in mangroves and salt-marsh. We review the patterns of root decomposition, and its contribution to C budgets, in mangroves and saltmarsh: the impact of climatic (temperature and precipitation), geographic (latitude), temporal (decay period) and biotic (ecosystem type) drivers using multiple regression models. Best-fit models explain 50% and 48% of the variance in mangrove and saltmarsh root decay rates, respectively. A combination of biotic, climatic, geographic and temporal drivers influences root decay rates. Rainfall and latitude have the strongest influence on root decomposition rates in saltmarsh. For mangroves, forest type is the most important; decomposition is faster in riverine mangroves than other types. Mangrove species Avicennia marina and saltmarsh species Spartina maritima and Phragmites australis have the highest root decomposition rates. Root decomposition rates of mangroves were slightly higher in the Indo-west Pacific region (average 0.16% day − 1) than in the Atlantic-east Pacific region (0.13% day − 1). Mangrove root decomposition rates also show a negative exponential relationship with porewater salinity. In mangroves, global root decomposition rates are 0.15% day − 1 based on the median value of rates in individual studies (and 0.14% day − 1 after adjusting for area of mangroves at different latitudes). In saltmarsh, global root decomposition rates average 0.12% day − 1 (no adjustment for area with latitude necessary). Our global estimate of the amount of root decomposing is 10 Tg C yr − 1 in mangroves (8 Tg C yr − 1 adjusted for area by latitude) and 31 Tg C yr − 1 in saltmarsh. Local root C burial rates reported herein are 51–54 g C m − 2 yr − 1 for mangroves (58–61 Tg C yr − 1 adjusted for area by latitude) and 191 g C m − 2 yr − 1 for saltmarsh. These values account for 24.1–29.1% (mangroves) and 77.9% (saltmarsh) of the reported sediment C accumulation rates in these habitats. Globally , dead root C production is the significant source of stored sediment C in mangroves and saltmarsh.

The vegetation-environment relationships in the inland saltmarshes of two geographically distant oases of
the Western Desert of Egypt, Siwa, and Dakhla Oases, are described. Two data sets (25 species × 68 stands for Siwa
Oasis and 29 species × 89 stands for Dakhla Oasis) were analysed, using multivariate procedures, i.e., two-way indicator
species analysis (TWINSPAN), detrended correspondence analysis (DCA), and detrended canonical correspondence
analysis (DCCA), to produce a classification of plant communities in the studied areas, and to examine the
relationships of these plant communities to certain edaphic factors, namely soil reaction, total soluble salts, calcium
carbonate, organic matter, moisture content, and fine fractions. Twelve halophytic plant communities linked to two
main habitats (wet-moist and dry-mesic) were identified. Alhagi graecorum, Tamarix nilotica, Cressa cretica, Juncus
rigidus and Phragmites australis were the most common in the two oases. Whereas communities of Cyperus laevigatus,
Suaeda aegyptiaca, Suaeda vermiculata, Typha domingensis, and Aeluropus lagopoides are recorded from the Dakhla
Oasis, Cladium mariscus and Arthrocnemum macrostachyum communities are recorded from the Siwa Oasis. The
most important edaphic variables affecting the distribution and structure of the plant communities are salinity, moisture
content and fine fractions, nevertheless CaCO3 content seems to be more effective in the Dakhla Oasis. A new
agricultural strategy that minimizes the increase of salinized lands is called for.

The interaction between Cd and Zn in aquatic organisms is known to be highly variable. The purpose of this study was to use a subcellular compartmentalization approach to examine Cd and Zn interactions in the deposit-feeding polychaete Capitella capitata (sp. I). Laboratory-reared C. capitata were co-exposed to Cd (background or 50 μg Cd l− 1) and Zn (background or 86 μg Zn l− 1) with 109Cd and 65Zn as radiotracers for 1 week. After the 1-week uptake period, subsets of worms were allowed to depurate accumulated metals for an additional 1 week. Worms from both phases (uptake and loss) were then subjected to subcellular fractionation to determine the compartmentalization of metals as metal-sensitive fractions [MSF — organelles and heat-denaturable proteins (HDP)] and biologically detoxified metals [BDM — heat-stable proteins (HSP) and metal-rich granules (MRG)]. Uptake and loss of Cd and Zn in C. capitata at the whole body level were similar at bkgd-Cd/bkgd-Zn, with worms depurating the majority of accumulated metal (∼ 75% Cd and ∼ 64% Zn). When exposure of Zn or Cd was increased (bkgd-Cd/86-Zn; bkgd-Zn/50-Cd), uptake of background levels of Cd or Zn, respectively, was suppressed by ∼ 50%. These accumulated metals, however, were retained during the loss phase resulting in ∼ 40–50% greater Cd and Zn whole body tissue burdens than those of bkgd-Cd/bkgd-Zn worms. Beyond exhibiting similar patterns of uptake and loss at the whole body level, Cd and Zn behaved similarly at the subcellular level. Under background levels (bkgd-Cd/bkgd-Zn), after uptake, worms partitioned a majority of Cd (∼ 65%) and Zn (∼ 55%) to the HSP and organelles fractions. The HDP and MRG fractions contained less than ∼ 6% of both metals. Following depuration, at bkgd-Cd/bkgd-Zn, Cd and Zn were lost from all subcellular fractions; loss from HSP was the greatest contributor to whole body loss. When exposed to elevated concentrations of Zn or Cd, the suppression in uptake of bkgd-Cd or bkgd-Zn observed in whole body uptake was largely due to suppressions in the storage of Cd and Zn to HSP. These results suggest that Cd–Zn interactions reduce partitioning of both Cd and Zn to HSP, indicating that metal-binding proteins such as metallothioneins play a key role in these interactions.

From September 1994 through October 1995 aboveground and belowground production ofSarcocornia fruticosa andPhragmites australis was studied at two sites in the Po Delta. In 1995, aboveground production forS. fruticosa in an intertidal site was 678 g dw m−2 yr−1 with a peak live biomass of 1,008 g m−2; belowground production was 1,260 g m−2 with a peak live biomass of 3,735 g m−2. A litter bag decomposition study showed that after 69 wk there were 3.7%, 64.3%, and 66.6% of the original mass of leafy stems, woody stems, and roots, respectively. In a reed bed, which experiences brackish conditions,P. australis aboveground production was 876 g m−2 with a peak live biomass of 780 g m−2; belowground production was 2,263 g m−2 with a peak live biomass of 4,087 g m−2. After 65 wk, there was 45.4%, 50.4%, and 29.3%, respectively, of leaves, stems, and rhizomes remaining of the initial biomass. At both sites, regular submersion by salt water probably leads to lower aboveground biomass and higher belowground biomass than reported for other Mediterranean coastal sites. The high belowground biomass can contribute to accretion to offset rising sea level.

We report on a decadal trend of accretionary dynamics in the wetlands of several northwestern Mediterranean deltas and a lagoon system, all of them with high rates of wetland loss. Wetland vertical accretion and surface elevation change were measured at 55 riverine, marine, and impounded sites in four coastal systems: the Ebro delta, Spain; the Rhône delta, France; and the Po delta and Venice Lagoon, Italy. Vertical accretion and elevation change ranged between 0 and 25 mm year−1 and were strongly correlated. The highest rates of elevation gain occurred at riverine sites where vertical accretion was highest. We conclude that areas with high sediment input, mainly riverine, are the only ones likely to survive accelerated sea-level rise, especially if recent higher estimates of 1 m or more in the twenty-first century prove to be accurate. This is the first study where the importance of river input on wetland survival has been demonstrated at a decadal time scale over a broad geographical area.

Adult and juvenile fish utilise salt marshes for food and shelter at high tide, moving into adjacent sublittoral regions during low tide. Understanding whether there are high levels of site fidelity for different species of coastal fish has important implications for habitat conservation and the design of marine protected areas. We hypothesised that common salt marsh fish species would demonstrate a high site fidelity, resulting in minimal inter-marsh connectivity. Carbon (13C) and nitrogen (15N) stable isotope ratios of larvae and juveniles of five common salt marsh fish (Atherina presbyter, Chelon labrosus, Clupea harengus, Dicentrarchus labrax, Pomatoschistus microps), seven types of primary producer and seven secondary consumer food sources were sampled in five salt marshes within two estuary complexes along the coast of south-east England. Significant differences in 13C and 15N signatures between salt marshes indicated distinct sub-populations utilising the area of estuary around each salt marsh, and limited connectivity, even within the same estuary complex. 15N ratios were responsible for the majority of inter-marsh differences for each species and showed similar site-specific patterns in ratios in primary producers, secondary consumers and fish. Fish diets (derived from isotope mixing models) varied between species but were mostly consistent between marsh sites, indicating that dietary shifts were not the source of variability of the inter-marsh isotopic signatures within species. These results demonstrate that for some common coastal fish species, high levels of site fidelity result in individual salt marshes operating as discrete habitats for fish assemblages.

The Peel-Harvey saltmarshes are important locally and regionally, because they support extensive food web and act as a biological filter for the receiving waters. This study was undertaken to examine the ecology and extent of saltmarshes of the Peel-Harvey. The extent and composition of the samphire saltmarshes was investigated over the period of 37 years (from 1957 to 1994), using aerial photography over the whole estuary, and detailed field surveys at ten sites. Saltmarshes within the Peel-Harvey estuary are declining both in ...

The vegetation-environment relationships in the inland saltmarshes of two geographically distant oases of the Western Desert of Egypt, Siwa, and Dakhla Oases, are described. Two data sets (25 species × 68 stands for Siwa Oasis and 29 species × 89 stands for Dakhla Oasis) were analysed, using multivariate procedures, i.e., two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and detrended canonical correspondence analysis (DCCA), to produce a classification of plant communities in the studied areas, and to examine the relationships of these plant communities to certain edaphic factors, namely soil reaction, total soluble salts, calcium carbonate, organic matter, moisture content, and fine fractions. Twelve halophytic plant communities linked to two main habitats (wet-moist and dry-mesic) were identified. Alhagi graecorum, Tamarix nilotica, Cressa cretica, Juncus rigidus and Phragmites australis were the most common in the two oases. Whereas communit...

Coastal regions provide vital ecosystem services for the human well-being. Rapid economic growth and increasing population in coastal regions is exerting more pressure on coastal environments. Here we develop four plausible scenarios to the year 2050 that address above issues in the northern Adelaide coastline, South Australia. Four scenarios were named after their characteristics, Lacuna, Gold Coast SA, Down to Earth, and Green & Gold. Lacuna and Gold Coast SA. Economy declined significantly in Lacuna, whereas, there is highest annual GDP growth (3.5%) in Gold Coast SA, which was closely followed by Green & Gold scenario (3%), GDP under Down to Earth grows at moderate 1.5%. There is highest population growth in Gold Coast SA followed by Green & Gold, Down to Earth and Lacuna. Gold Coast SA scenario led to high inequality as estimated by the Gini co-efficient of 0.45 compared to the current value of 0.33. Ecosystem services declined rapidly under Green & Gold and Lacuna as compared ...

Identification guide for samphires found in the saltmarshes of the greater Adelaide and Fleurieu Peninsula regions. A replacement for an earlier guide, with extra information on saltmarsh flora and fauna, the blue carbon values of these habitats and several new drawings and photographs

The biochemical composition of salt marsh grass, Porteresia coarctata was investigated in this present study along with subsequent analysis of relevant physico-chemical variables. In this study, the relationship between the nutritive components of the species and the ambient environmental parameters was established. P. coarctata collected from regions of high salinity showed significant decrease in protein content.