Shore Sites Research Articles

Pollution of the Main Components of the Natural Environment of the Most Developed Part of the Southwestern Coast of Lake Baikal (within the Baikal Municipal Formation)

The data of landscape-geochemical studies of the main components of the environment (snow, surface water, soils and vegetation) near the sedimentation ponds of the industrial site of the former Baikal pulp and paper mill, Baikalsk, at the mouth of the Kharlakta and Babkha rivers on the southwestern coast of Lake Baikal are presented. Increased content of heavy (HM) and alkaline-earth metals, SO42–, NO3–, NH4+, PO43– was detected in the snow near the Baikalsk town, exceeding background readings. Concentrations of F–, NO3–, NH4+, Pb, Mo, Mn, Zn, Sr and V in surface waters of local lake shore sites exceed sanitary and hygienic norms. Soil contamination with HM in the recreational and industrial zone located on the shore of Lake Baikal has been revealed. Correlations between the concentrations of macro- and microelements in soils and their indicators such as the content of organic carbon and physical clay fraction have been established, which indicates the presence of biogeochemical barriers on which Na, Ni, Cu, Zn, Sr, Co accumulate in values above the background readings and MAC.

Predicted ecological consequences of wave energy extraction and climate-related changes in wave exposure on rocky shore communities

Abstract Wave energy has the potential to contribute in the transition to decarbonized electricity generation. Extracting wave energy might be expected to have ecological impacts on rocky shore intertidal communities where exposure is one of the most important factors determining species structure and composition. With global climatic change, coastal exposure is predicted to increase with greater significant wave height. The wave-exposed west coast of Orkney, Scotland, UK, is the site of pre-commercial wave device testing. Surveys of 39 rocky shore sites along this coast identified key species and abundances, and quantified exposure-modifying topographic variables. A spectral wave model was constructed to compare baseline, wave extraction, climate change, and combined scenarios. Generalized additive modelling was used to describe the relationship between species, topography, and exposure. Results show that individual species differentially respond to exposure changes with ‘winners’ and ‘losers’ at site level. Overall, community responses are expected to be far greater following predicted climatic change than to industrial-scale wave energy extraction, depending on spatial scale. In combination, energy extraction may reduce the effects of climate-change-related increases in wave exposure of rocky shores. Predicting how location-specific biotic assemblages respond to changes in wave energy as a result of long-term forcing agents provides a valuable marine resource management tool.

Invertebrate trophic structure on marine ferromanganese and phosphorite hardgrounds

AbstractThe Southern California Borderland hosts a variety of geologic and oceanographic features that allow for diverse habitats to occur in a restricted region with a strong oxygen minimum zone (OMZ) and hard substrates. These include ferromanganese (FeMn) crusts and phosphorites targeted for deep‐seabed mining in other regions. Baseline studies regarding hardground macro‐ (> 0.3 mm) and megafaunal (> 2 cm) invertebrates are lacking, although they contribute to understanding nutrient cycling and resilience of deep‐sea communities to ocean deoxygenation, fishing, or mineral extraction. With the goal of understanding how substrate type, depth, and dissolved oxygen concentration influence invertebrate trophic structure, we surveyed δ13C and δ15N values of invertebrates on hard substrates on the Southern California Borderland margin along a depth gradient (120–2400 m) through the OMZ at inshore (< 100 km from shore) and offshore (100–250 km from shore) sites, using generalized additive models and community‐level metrics. Macrofaunal isotopic values correlate with substrate type, exhibiting higher trophic diversity on FeMn crusts and specialized communities on phosphorites. Megafaunal isotopic values correlate with proximity to shore; animals offshore seem to depend more on phytoplanktonic production than animals inshore. In general, δ15N increased with decreasing dissolved oxygen and increasing depth, possibly due to remineralization processes within the OMZ and with depth. We discuss how feeding modes and community composition might influence the observed patterns. This study elucidates the importance of the environmental context in shaping invertebrate trophic structure on continental margins and provides baseline knowledge that may be useful in regions where these minerals are targeted for extraction.

Drivers of CO2-carbonate system variability in the coastal ocean south of Honolulu, Hawai’i

This study examines carbonate chemistry variability from 2008 to 2021 in subtropical coastal waters adjacent to Honolulu, Hawai’i. We use surface seawater carbon dioxide partial pressure (pCO2sw) measurements obtained every three hours from two buoys located along the south shore of O’ahu near anthropogenically impacted fringing reefs. The Ala Wai buoy was located 200 m offshore of a canal draining most of Honolulu, while the Kilo Nalu buoy was 1.3 miles (2 km) to the northwest, at a similar distance from shore with fewer terrestrial inputs. We compare pCO2sw variability from diurnal to interannual time scales. A trend analysis reveals a statistically significant increase in pCO2sw of +1.84 ± 0.27 µatm per year over the 11-year period. This rate is slightly lower than the average atmospheric growth rate observed during the same timeframe. In contrast to a nearby open-ocean site, the coastal sites experience amplified shorter-term variability, while seasonal to inter-annual variability is comparable to the open ocean. Ala Wai exhibits greater ranges than Kilo Nalu in all carbonate system variables due to its proximity to the Ala Wai Canal outflow. We examine the drivers that may explain both the similarities and contrasts in carbon dynamics observed between the two locations. Drivers of aragonite saturation state (ΩAr), an important variable for quantifying ocean acidification, are isolated from the in-situ time-series. Interannual salinity variations both due to freshwater pulses and large-scale regional salinity changes have a larger impact on ΩAr than temperature changes, which mostly have an effect seasonally. A large biological contribution to ΩAr is suspected, and further investigated using TA/DIC ratios normalized to median salinity and their slopes. Observed ratios at the south shore sites are evaluated relative to expected ratios derived from an open-ocean reference. Results suggest that dissolution and respiration are the primary biogeochemical processes occurring at these coastal sites. This highlights the significance of carbonate dissolution in anthropogenically impacted coastal waters, which is likely buffering acidification due to anthropogenic CO2 and freshwater inputs at these sites.

Microbial decomposition of biodegradable plastics on the deep-sea floor

Microbes can decompose biodegradable plastics on land, rivers and seashore. However, it is unclear whether deep-sea microbes can degrade biodegradable plastics in the extreme environmental conditions of the seafloor. Here, we report microbial decomposition of representative biodegradable plastics (polyhydroxyalkanoates, biodegradable polyesters, and polysaccharide esters) at diverse deep-sea floor locations ranging in depth from 757 to 5552 m. The degradation of samples was evaluated in terms of weight loss, reduction in material thickness, and surface morphological changes. Poly(l-lactic acid) did not degrade at either shore or deep-sea sites, while other biodegradable polyesters, polyhydroxyalkanoates, and polysaccharide esters were degraded. The rate of degradation slowed with water depth. We analysed the plastic-associated microbial communities by 16S rRNA gene amplicon sequencing and metagenomics. Several dominant microorganisms carried genes potentially encoding plastic-degrading enzymes such as polyhydroxyalkanoate depolymerases and cutinases/polyesterases. Analysis of available metagenomic datasets indicated that these microorganisms are present in other deep-sea locations. Our results confirm that biodegradable plastics can be degraded by the action of microorganisms on the deep-sea floor, although with much less efficiency than in coastal settings.

Lake Superior's summer cooling of shorelines and adjacent inland forests: Implications for refugia of boreal forests and disjunct arctic-alpine plants.

Climate refugia can serve as remnant habitat for cold-adapted species and delay forest transitions. The world's largest freshwater lake by surface area, Lake Superior, serves as a model system for understanding cooling-mediated refugia effects, as its cool summer water temperatures have maintained disjunct populations of arctic-alpine plants on its shoreline since deglaciation. It is known to affect local inland climates by providing a summer cooling effect; however, the inland temperature gradient and spatial patterns of cooling have not been well quantified. Here, we describe the extent, degree, and patterns of temperature buffering and examine drivers of buffering and disjunct plant occurrence for Lake Superior's north shore over a 3-year period at distances of 10, 100 m, 1, 10, and 100 km inland. We analyzed temperature data by year, month, summer maximum (July), and growing degree days (GDD0) for each site. Average summertime cooling at shore sites (10 m) was ~5°C cooler than reference sites (100 km inland), with a maximum difference of -19.2°C. The magnitude of cooling varied geographically, with sites further west and southeast showing little to no cooling effect, while the exposed north-central shore showed the highest degree of buffering (5.8°C cooler) and had a shorter growing season than reference sites. Finally, north-central shorelines had fewer days above 16°C, a threshold above which disjunct plants are unlikely to grow. These sites also showed the highest proportion of disjunct arctic-alpine species, reflecting the highest buffering from inland sites. On north-central shores, sites up to 10 km inland had less than 10 days per year warmer than 20°C, a threshold identified for boreal forest transition. An understanding of the extent of lake-mediated cooling on adjacent forests can better inform the risk to disjunct species, inland forests, and vegetation transition models on Lake Superior's north shore.

The Role of FAS Receptor Methylation in Osteosarcoma Metastasis.

Osteosarcoma is the most frequent primary malignant bone tumor with an annual incidence of about 400 cases in the United States. Osteosarcoma primarily metastasizes to the lungs, where FAS ligand (FASL) is constitutively expressed. The interaction of FASL and its cell surface receptor, FAS, triggers apoptosis in normal cells; however, this function is altered in cancer cells. DNA methylation has previously been explored as a mechanism for altering FAS expression, but no variability was identified in the CpG island (CGI) overlapping the promoter. Analysis of an expanded region, including CGI shores and shelves, revealed high variability in the methylation of certain CpG sites that correlated significantly with FAS mRNA expression in a negative manner. Bisulfite sequencing revealed additional CpG sites, which were highly methylated in the metastatic LM7 cell line but unmethylated in its parental non-metastatic SaOS-2 cell line. Treatment with the demethylating agent, 5-azacytidine, resulted in a loss of methylation in CpG sites located within the FAS promoter and restored FAS protein expression in LM7 cells, resulting in reduced migration. Orthotopic implantation of 5-azacytidine treated LM7 cells into severe combined immunodeficient mice led to decreased lung metastases. These results suggest that DNA methylation of CGI shore sites may regulate FAS expression and constitute a potential target for osteosarcoma therapy, utilizing demethylating agents currently approved for the treatment of other cancers.

How climate-driven changes in disturbance frequency affect the recovery of intertidal mussel beds

Community and population recovery from disturbance depends on the intensity, spatial scales, and frequency of disturbance events. Moreover, foundation species, like bed-forming mussels in rocky intertidal shores, are especially prone to disturbance associated with extreme climatic events. The aim of the present study was to experimentally evaluate how the frequency of physical disturbances that generate gaps in beds of the mussel Brachidontes rodriguezii affects mussel recolonization and the succession process on two rocky shore sites of the Southwestern Atlantic. Experimental disturbances (removal of mussels and other forms of biotic cover) were applied to small plots (14 cm × 14 cm) at three different frequencies over two years: 1) only at the beginning of the experiment (i.e., 1× removal frequency), 2) at the beginning of the experiment and 12 months later (2× removal frequency) and, 3) at the beginning of the experiment and 6, 12, and 18 later (4× removal frequency). Unmanipulated areas were maintained as controls. Before applying the experimental disturbance, we measured the abundance of all organisms present in all plots, obtaining data every 6 months. The data were analyzed considering two factors associated with the disturbance frequency: the time since the last removal and the number of removals on the same plot. Our results indicate that increases in disturbance frequencies were sufficient to maintain mussel bed recovery below control levels and increased the cover of crustose algae at the end of the two-year experimental period in one of the rocky shores studied. The decreases observed in the mussel recovery rates under increased disturbance scenarios are expected to have cascading consequences on rocky shore biodiversity, such as reductions in the overall abundance of interstitial invertebrate species that depend on mussel bed habitats and increases in the abundance of sessile organisms that preferentially occur in gaps and are otherwise excluded by mussels, such as the non-native barnacle Balanus glandula.

Invasion of rocky shores by a mytilid mussel reveals an abundant‐centre distribution coupled with moderate increases in densities at its absolute range limits

AbstractSemimytilus patagonicus is an invasive mussel on the coast of southern Africa and has extended its range in recent years. We asked whether its distribution and abundance are consistent with the abundant‐centre hypothesis (ACH). Marginal populations were located by monitoring 33 rocky shore sites in South Africa and southern Namibia in 2021. This revealed no changes to its distributional limits since 2020. At nine of these sites, population demography was measured to allow a comparison of their densities and size structure. Four were central populations on the west coast of South Africa (including the site where the species was first detected in 2009). Four were marginal populations in South Africa: two towards the cold range edge in the north and two towards the warm range edge to the south. The ninth population was in southern Namibia, representing a recent invasion event first detected in 2014. Across the species' South African range, the distribution of its abundance was generally consistent with the ACH, with the greatest abundance at its range centre and a gradual decrease towards the range edges. However, the ultimate marginal population at both its cold and warm range edges showed moderate upticks in abundance compared to the penultimate marginal populations. Additionally, marginal populations in South Africa typically included a greater proportion of large individuals. Recruitment intensity was greater in warm range edge populations than cold range edge populations. The size structure of the population in Namibia resembled those of central populations in South Africa. Moderate increases in densities at the absolute range limits suggest that the species is currently undergoing spread into regions associated with moderately optimal environmental conditions (ultimate range edge sites) after encountering regions associated with suboptimal environmental conditions (penultimate range edge sites).

Confirmation of the southern African distribution of the marine sponge Hymeniacidon perlevis (Montagu, 1814) in the context of its global dispersal.

Intertidal rocky shore surveys along the South African coastline (∼3,000 km) have demonstrated the presence and abundance of the encrusting orange sponge Hymeniacidon perlevis (Montagu, 1814), a well-known globally distributed species. After analysing the southern African populations, we gained a better understanding of the genetic structure of this now-accepted global species. Apart from confirming the presence of a single population of H. perlevis, we also determined its distribution in the southern African intertidal rocky shore ecosystem, compared its genetic diversity to congeners, predict its global distribution via environmental niche modelling, and discussed possible underlying mechanisms controlling the species' global distribution. We surveyed the South African coastline and sampled sponges at 53 rocky shore sites spanning over 3,000 km, from Grosse Bucht south of Lüderitz (Namibia) to Kosi Bay on the east coast of South Africa. DNA sequences of the nuclear rDNA internal transcribed spacer (ITS1) and the COI mitochondrial gene were obtained from 61 samples and compared them to a world-wide sample of other H. perlevis sequences. Using environmental predictor variables from the global dataset BIO-ORACLE, we predicted the probability of global occurrence of the species using an ensemble of eight distribution models. South African specimens were found to be 99-100% identical to other populations of H. perlevis (=H. sinapium) from other world-wide regions. The presence of a single population of H. perlevis in southern Africa is supported by genetic data, extending its distribution to a relatively wide geographical range spanning more than 4,000 km along the temperate southern African coast. The predicted global occurrence by ensemble model matched well with the observed distribution. Surface temperature mean and range were the most important predictor variables. While H. perlevis appears to have been introduced in many parts of the world, its origins in Europe and southern Africa are unclear.

Himalayan Elecampane, Inula racemosa (Asteraceae), in North America

Inula racemosa is reported as new to Canada, with occurrences in Ontario and Québec. It is also reported as new for several states in the United States. It was first reported for North America in 2020, based on a 2017 collection in Vermont. Earlier collections from Québec (2004) and Michigan (2014) were subsequently found, however. Its distinctive appearance led to the identification of additional records on the web page iNaturalist, the postings often initially misidentified as the common I. helenium. Almost two dozen North American occurrences are now known from Illinois, New Hampshire, New York, Ontario (the largest cluster of occurrences), Québec, Washington, and Wisconsin. Several of these populations contain hundreds to thousands of plants. All populations are considered to likely be of recent origin. At least some represent escapes from cultivation for medicinal or ornamental purposes. Inula racemosa may show a preference for calcareous substrate and river shore sites in the wild. It does not appear to have substantial potential to be invasive into native plant communities.

Habitat properties and invertebrate composition in mussel-dominated rocky shores: A test of edge effects

Mussels form dense three-dimensional beds that serve as habitat to other species. In rocky shores, these beds are often interspersed by gaps due to patchy dislodgement/mortality caused by the action of waves, predators, and/or extreme temperatures. Although mussel beds and gaps are known to support distinctive invertebrate communities, variations in invertebrate habitat function between the interior and edges of mussel beds and gaps were not yet examined. Here, we evaluated variations in habitat properties and invertebrate composition between the edge and interior of mussel (Brachidontes rodriguezii) beds and gaps at three rocky shore sites in the Southwestern Atlantic. Our results indicate that the interior and edge of mussel-covered areas differ in terms of mussel size, density and orientation relative to the rock surface (all surrogates of habitat structure), and in the quantity of sediments they accumulate. However, this does not directly translated into differences in temperature, desiccation, and invertebrate composition within the mussel bed. As it concerns to gaps, we generally observed increased limpet (Siphonaria lesonii) densities at their edges, which suggests that they encounter favourable conditions by the perimeter of mussel beds. The general lack of edge effects on the invertebrates inhabiting mussel beds suggests that their species composition would remain largely unaffected by expected increases in gap and edge habitat formation due to ongoing increases in the frequency and magnitude of storms and heat waves. Yet, if increased availability of edge habitats leads to increased overall density of limpets in these rocky shores, then changes could be expected in algal production, composition, and dynamics.

On the Nile Fan's wave power potential and controlling factors integrating spectral and geostatistical techniques

Wave energy is foreseen to contribute largely to the renewable energy projected to supply 20% of Egypt's electricity budget to meet burgeoning energy demand. Therefore, this research analyses the Nile Fan wave energy forecasted from numerical modeling for 2020 of the Copernicus Marine Environment Monitoring Service (CMEMS) database, hourly spatially sampled at 0.042° as the finest scale remotely-sensed data available. Wave energy spatial distribution is analyzed using data from 259 points proposed as Wave Energy Converters (WECs). Spectral analyses techniques were appraised for disclosing the frequency and energy return periods of the significant wave height and peak periods and to understand the similarity among selected WECs of varied conditions. Factor analysis is conducted to investigate the magnitude of factors controlling the wave dynamic and energy potential. K-means clustering was used to distinguish energy classes with large inter-class variances. The obtained resources (average wave energy density, around 5.32 KWh/m; maximum recorded value of 112.9 KWh/m; annual wave energy density sum of about 46.96 MWh/m) are among the largest found in the Mediterranean Sea. Spectral analysis clarified a strong periodicity at 21 days, intermittent periods of 2.66 days, and 7.5 days dominate over the year while a 22.6 hourly period dominates in summer. January attained the strongest peak frequency of 8.4 in the west, 6.6 between the NW and SE sites, 5.20 for the near shore sites. Directional analysis indicated a bimodal wave system (325° and 285°-295°) in the west and unimodal (285°295°) in the east, while the central area showed combined distribution; bimodal in the deep water and unimodal near the shore. The 285°-295° wave direction showed largest contribution to the wave energy density. The northwest is the most energetic and most productive area. Monthly and seasonal wave energy clarified maximum of 9.98 MWh/m in January and 22.6 MWh/m in winter that contributes to 21% and 53% of the yearly mean, respectively. The wave energy resource is more than 3.5 times greater in winter than in summer. Exploitable energy density level exceeding 2 KWh/m are recorded for 250 sites out of the 259 site. Factor and detrended correspondence analyses confirmed that more than 98% of the Nile Fan's wave energy variance is controlled, in decreasing order of influence, by the depth, distance to shore, significant wave height, wave peak period, and wave principal direction. Four classes of varied statistics and hence different wave behavior were distinguished affected by the depth, morphology of the shoreline, and the dominating wave direction. Deepest water and near shore classes attained the largest wave energy. Further details on the effect of the environmental factors on the wave shape and corresponding energy are concluded.

Assessing the morphological impacts of long-term harvesting in intertidal gastropods using historical data and morphometric tools

ABSTRACTSize-selective harvesting of intertidal molluscs is a common practice. However, the effects of long-term traditional harvesting remain unclear. Changes in mean shell size are generally taken as evidence of changes in harvesting intensity. However, mean shell size is also influenced by environmental pressures, which may confound the analysis of size variation over time. In this study, we apply geometric morphometrics to historical data from two shell middens, in an attempt to classify Littorina littorea shells to their environmental origins, prior to carrying out shell size analysis. Using this method, shell shape was found to be consistent within and between the midden sites. Based on comparison with modern populations from shores of known wave exposure, the midden shells were found to be more consistent with sheltered shores, and to differ most from the very exposed shore sites, the latter of which are located adjacent to the midden remains. The mean shell size was significantly smaller in the more recent midden site. We hypothesize this reduction is caused by an increase in harvesting intensity over this period. It is also possible, given the very slight reduction in shell size, coupled with certain life-history traits of L. littorea, that the change in shell size was caused by slight differences in environmental conditions. The use of midden shells and morphometrics has the potential to provide an insight into previous environmental conditions and past harvesting practices, which may be used to inform current harvesting practices.

A Flexible, Multi-fidelity Levelised Cost of Energy Model for Floating Offshore Wind Turbines Multidisciplinary Design, Analysis and Optimisation Approaches

As the UK takes a step towards a greener, cleaner future aiming to be net zero by 2050, continuous development of the power network is required. A clear solution is offshore wind, having already proved its feasibility and success in nearshore sites. However, a large majority of near shore sites in the UK are already being utilised. The next step is to move into deeper waters and utilise the stronger, more consistent wind resources. A solution could be floating offshore wind which is still in its infancy, with only a few operational floating wind farms installed. Building upon the multidisciplinary design, analysis, and optimisation framework (MDAO) for floating offshore wind turbines (FOWT) being developed at the University of Strathclyde, called FEDORA, the aim of this work is to refine the LCoE model adopted by FEDORA, and applying it to perform the optimisation of the floating offshore OC3 SPAR. There is limited data on cost, therefore Hywind Scotland Pilot Park will be used as a basis for the LCoE model, allowing the results to be validated. This model is not restricted to SPARs, as it establishes a general methodology to calculate the life cycle cost of floating offshore wind farms. Utilising the improved cost model this work finds four optimised SPAR structures for four different maximum angles of inclination which can be experienced in the wind turbines operation. The improved cost model has a much higher accuracy, highlighting the initial cost model underestimates the cost of the SPAR structure by around half.

New Assessment of Wave Energy in Relation to Geomorphological and Demographic Characteristics on the Pacific Coast of Baja California, Mexico

The electrical grid of the Baja California peninsula, Mexico, operates separately from the National Interconnected System, with Baja California connected to the Western Electricity Coordinating Council of the USA; and Baja California Sur having an isolated, independent network. Based on the need for alternative renewable sources of electricity generation in the region, this work evaluates the wave energy power at specific locations on the Pacific coast of the peninsula, and identifies wave generation sites (WEGS). The WEGS were defined as rocky shore sites associated with a wave energy potential of over 10 kW/m (where the installation of oscillating water columns (OWC) is feasible) and the presence of coastal settlements that are less than 10 km from the shoreline. It was found that 370 km of the Pacific coast of the peninsula have characteristics suitable for the installation of OWC, and up to 1.4 million inhabitants could be benefited by this wave energy harvesting.

Släktskap och neolitiska kulturer

Kinship and Neolithic cultures. As a result of their alkaline soil, due to limestone bedrock, the two Swedish islands of Öland and Gotland, are locations where bone is well preserved. Stable isotope investigations have shown that there were two contemporary populations during Middle Neolithic on the islands. One population was buried in megalithic graves, and shows evidence of a subsistence lifestyle with high proportion of terrestrial food, most probable from agriculture. The other population has had a lifestyle based on marine subsistence, and buried their dead in earth graves at shore sites. Ancient DNA investigations now show that the two populations may also have different origins. The hunter-gathers of the ”Pitted Ware Culture” might descend from a Mesolithic population, while the supposed farmers buried in the megaliths and affiliated with the ”Funnel Beaker Culture”, are more likely to descend from immigrants that arrived in the Ewarly Neolithic and brought agriculture to the islands.

Neumark-Nord 2 – A multiphase Middle Palaeolithic open-air site in the Geisel Valley (Central Germany)

The lake basin Neumark-Nord 2 (NN 2) is located in the Geisel Valley in Saxony-Anhalt (Germany). It was scientifically investigated between 2003 and 2008. The sediment sequence, which is about 10 to 11m thick, consists of limnic deposits, mostly silts mixed with clays and sands. Sedimentological as well as palynological, malacological and palaeomagnetic investigations, supported by absolute datings, date the entire sequence into the Eemian and Early Weichselian. Within the deposits several archaeological find horizons were discovered. Neumark-Nord 2/2 (NN 2/2) at the beginning of the Eemian and Neumark-Nord 2/0 (NN 2/0) with an early Weichselian were the most important archaeological horizons. Both find horizons represent former lake shore sites, where numerous crushed animal bones and other faunal debris were found, which can be regarded as remains of hunted game. With regard to the rich lithic material, both find horizons differ remarkably. In NN2/2, a simple artefact spectrum with a certain Levallois component and a dominance of denticulated, notched and laterally retouched specimens. In NN 2/0, on the other hand, bifacial tools such as backed knives and sometimes finely retouched scrapers are dominant, while the Levallois component fades completely into the background. Thus, NN 2 is one of the few open-air sites in archaeological landscape of Central German where several middle Palaeolithic find horizons occur in superposition.

Humpback whale abundance in Hawai‘i: Temporal trends and response to climatic drivers

AbstractIn 2001, we began long‐term monitoring using scan sampling methodology to study the relative abundance and distribution of humpback whales (Megaptera novaeangliae) on their Hawaiian breeding grounds. Samples were collected annually (2001–2019) from a shore site overlooking Kawaihae Bay, Hawaiʻi Island. Each sample included the number of whales, pod composition, and position. Whale numbers increased from 2001 to 2015, with increasing variability after 2010. Numbers then declined, including a precipitous 60% drop between 2015 and 2016. Crude birth rate fell from 6.5% in 2015 to 1.1% in 2016. We used generalized additive models, including predictor variables of year, date, observational conditions, and observer, to establish a base model. Climatic indices were individually added to base models, and their contributions were evaluated using Akaike information criteria. Models indicated that whale numbers and crude birth rate fell when climate indices reflected warmer water on high latitude feeding grounds in the North Pacific. Our results show that oceanographic conditions during prior feeding seasons correspond with the reproductive rate and the number of whales in Hawaiʻi. Continued long‐term monitoring of whale populations is essential to documenting and understanding marine ecosystem responses to global climate change.

Utility of environmental DNA analysis for effective monitoring of invasive fish species in reservoirs

AbstractDam‐mediated biological invasions are a serious problem all over the world. Once established in reservoirs, the invasive species have catastrophic impacts on the river ecosystems downstream, and thus, rapid monitoring of invasive species is an urgent issue for the effective removal of them and the conservation management of native ecosystems. Here, we verified the utility of environmental DNA (eDNA) analysis as a tool to effectively monitor three invasive fish species (bluegill, largemouth bass, and smallmouth bass) in reservoirs using multiplex real‐time PCR. First, to determine the optimal sampling location and season to detect eDNA from these species, we analyzed the eDNA in water samples from shore and offshore sites in three reservoirs all year around. We found that eDNA detection rates either did not differ between sampling locations or were higher for shore than offshore sites. In addition, eDNA detection rates were higher in spring (breeding season of target species) and/or summer than winter. Second, we extensively surveyed the distribution of the three species in 30 reservoirs in Japan using eDNA analysis. Consequently, a single eDNA‐based surveillance in summer allowed to match approximately 90% of the presence/absence of the invasive fish species known from 27 yr of administrative capture‐based surveillances. Given these results, we recommend collecting the replicated water samples from shore sites in summer or the breeding season for the effective detection of invasive fish eDNA in reservoirs. Our eDNA assays with multiplex real‐time PCR enable the rapid and sensitive monitoring of invasive fish distribution in reservoirs.