Littoral Processes

This paper examines the relationship between anthropogenic and coastal geomorphologic processes in relation to archaeological site formation processes for foreshore maritime infrastructure such as piers and baths. The natural and cultural history of Queenscliff, a nineteenth-century Victorian township, is explored to understand the historical reasoning for the development of many diverse types of coastal architecture associated with use of the sea in the area. The effects of environmental processes on these structures are demonstrated, along with the role these structures play in subsequently shaping the environment. It is demonstrated that changing coastal dynamics play a major role in shaping the final locations and condition of archaeological maritime infrastructure sites. By understanding these processes it is possible to make predictive statements about the, often unexpected location and integrity of these sites.

The Piedras River marshland and El Rompido spit bar is a Natural Site in close proximity to two of the most polluted rivers in the world: the Tinto and Odiel Rivers. The aim of this study is to determine the degree of contamination of this Natural Site using a variety of pollution indices. At this site the Holocene infilling sequence is recorded and applied to a study of the pollution history and the possible impacts of human activity. The deposi-tional history of the Piedras River estuary during the Holocene recorded open marine conditions at ca. 6500 calBP when sea-level was at its Holocene maximum. To study the pollution of the estuary during the Holocene, catchment background geochemistry was established using samples that pre-date human activity (agriculture and mining). Additionally, the sedimentary environment was reconstructed throughout the Holocene; comparison of pollution levels is interpreted to be more reliable if the sedimentary environment has remained similar throughout the depositional record. Results show that, despite being located nearby very polluted estuaries, the Piedras River marshland contains unpolluted sediments mainly because of the small catchment area relative to that of neighbouring more polluted rivers, and thus has not been affected by human activity such as mining.

To relate tectonic impact to the environmental history of ancient populated areas, human archives and geo-archives must be analyzed, evaluated and compared. Aside from historical references, the most common human record of large earthquakes is the generation of horizons of destruction (and/or demolition) among the different archaeological layers of ancient cities. However, in spite of the conspicuous interferences of large seismic events with human activities in the Mediterranean, permanent landscape changes linked to active tectonics are extremely rare

Modern Age (1453-1789) coincides approximately with a time of low temperatures through most of the world, a period called Little Ice Age (LIA). So, much of the ports history during this time must be understood inside a framework of a cold period, with river discharges, sea level, possible coastal advance and estuaries evolution that may be, in some sense, the opposite of the situations that we face today. Our main objective is to emphasize this idea because we believe that it may be a clue for the understanding of seaports evolution during that time. Natural circumstances are interrelated with the man's influence modifying them (agricultural practices, forest exploitation, river embankment and dam's construction). For these reasons the correct investigation must not rely merely on a deductive model approach. However, the utilization of this inferential approach may be helpful, awaking new ideas and hypothesis that may guide the necessary historical investigation.

This article presents a new proposal for the geomorphological evolution of the Barcelona seafront, between Mount Tàber and Ciutadella Park, based on the integration of new  sedimentological information, radiocarbon datings and
archaeological data. This data reveals the existence of a
pre-Roman cove at the foot of Mount Tàber which would be straightened with the sedimentary deposits of the river Besòs from the Roman period, when the offshore bar of Santa Maria
del Mar–El Born market was formed. During the medieval period, the formation of offshore bars shaped protected areas that would be used as port zones. The gradual effect of the
deltaic progradation of the river Besòs marks the coastal dynamic of this area with the arrival of a river channel in the
16th century. The construction of successive wharf sections throughout the 17th century accelerated the coastal progradation and gave way to La Barceloneta plain.

We carried out 2 experimental simulations in which natural planktonic communities were subjected to a combination of turbulence and variable nutrient forcing. Nutrient addition was varied both in terms of total nutrient load and in the balance of elements. Unbalanced nutrient inputs (with regard to Redfield values) and varying nitrogen sources are frequent in coastal areas heavily exposed to human perturbations. The relative abundance of nitrate and ammonium has been related to shifts in the size distribution of the planktonic community, so we explored whether uneven inputs of ammonium and nitrate could be major factors driving plankton dynamics in coastal environments. The occasional uncoupling between turbulence and nutrient pulses is also a distinctive feature of nearshore waters compared with open ocean environments. Thus, we further tested the match–mismatch between nutrient enrichments and turbulent mixing. Both turbulence and nutrient inputs had a significant positive effect on the growth of planktonic organisms, with some synergistic effects. Shifts in community composition appeared to be mostly related to the interplay between turbulence and N partitioning. Under still conditions, ammonium-rich waters favoured small organisms and reinforced the microbial loop, whereas nitrate mostly
favoured diatom growth. Turbulence added complexity to the final outcome, because mixing tended to favour large over small osmotrophs. Accordingly, the rapid growth of small autotrophs and heterotrophic bacteria in ammonium-rich waters may be partly counteracted by diatom increases if nutrient pulses are coupled with turbulent mixing; diatom bursts after nitrate enrichments may also be enhanced by concomitant turbulence.

1. Global freshwater demand is increasing dramatically, with water withdrawal rates more than tripling in the last five decades. Consequently, alteration of water level regimes, particularly in the form of amplified water level fluctuations (WLF), is rapidly becoming one of the major disturbances of aquatic ecosystems globally. However, even though the impacts of WLF are likely to be strongest in littoral zones, little is known about their effects on the structure and functioning of littoral assemblages in standing water systems.
2. We established an experiment in large outdoor pond mesocosms to examine the effects of WLF on littoral assemblages and explore the potential for development of ecological indicators of WLF.
3. Water level fluctuations reduced benthic algal biomass and the density and taxonomic distinctness of benthic invertebrate assemblages. Both the taxonomic and trophic structure of
benthic assemblages were altered significantly in ponds with WLF and homogenized along the depth gradient.
4. Synthesis and applications. Our results indicate that water level fluctuations (WLF) can reduce considerably the productivity and biological diversity of lake littoral zones. Given that the problem is likely to be exacerbated by predicted increases in climatic variability and enhanced demand for water and hydropower, our findings have important implications for
the conservation and management of global aquatic biodiversity. We identified several specific ways that WLF modify littoral assemblages along the depth gradient. This ability to identify separate pressures is an important requirement of robust ecological assessment tools. This
study confers potential for development of ecological indicators of WLF in standing waters, provides indication of sampling strategies to be employed and demonstrates the need to
mitigate the most extreme water withdrawals.