ALBERT

Description: Background: Northern ecosystems are strongly influenced by herbivores that differ in their impacts on the ecosystem. Yet the role of herbivore diversity in shaping the structure and functioning of tundra ecosystems has been overlooked. With climate and land-use changes causing rapid shifts in Arctic species assemblages, a better understanding of the consequences of herbivore diversity changes for tundra ecosystem functioning is urgently needed. This systematic review synthesizes available evidence on the effects of herbivore diversity on different processes, functions, and properties of tundra ecosystems. Methods: Following a published protocol, our systematic review combined primary field studies retrieved from bibliographic databases, search engines and specialist websites that compared tundra ecosystem responses to different levels of vertebrate and invertebrate herbivore diversity. We used the number of functional groups of herbivores (i.e., functional group richness) as a measure of the diversity of the herbivore assemblage. We screened titles, abstracts, and full texts of studies using pre-defined eligibility criteria. We critically appraised the validity of the studies, tested the influence of different moderators, and conducted sensitivity analyses. Quantitative synthesis (i.e., calculation of effect sizes) was performed for ecosystem responses reported by at least five articles and meta-regressions including the effects of potential modifiers for those reported by at least 10 articles. Review findings: The literature searches retrieved 5944 articles. After screening titles, abstracts, and full texts, 201 articles including 3713 studies (i.e., individual comparisons) were deemed relevant for the systematic review, with 2844 of these studies included in quantitative syntheses. The available evidence base on the effects of herbivore diversity on tundra ecosystems is concentrated around well-established research locations and focuses mainly on the impacts of vertebrate herbivores on vegetation. Overall, greater herbivore diversity led to increased abundance of feeding marks by herbivores and soil temperature, and to reduced total abundance of plants, graminoids, forbs, and litter, plant leaf size, plant height, and moss depth, but the effects of herbivore diversity were difficult to tease apart from those of excluding vertebrate herbivores. The effects of different functional groups of herbivores on graminoid and lichen abundance compensated each other, leading to no net effects when herbivore effects were combined. In turn, smaller herbivores and large-bodied herbivores only reduced plant height when occurring together but not when occurring separately. Greater herbivore diversity increased plant diversity in graminoid tundra but not in other habitat types. Conclusions: This systematic review underscores the importance of herbivore diversity in shaping the structure and function of Arctic ecosystems, with different functional groups of herbivores exerting additive or compensatory effects that can be modulated by environmental conditions. Still, many challenges remain to fully understand the complex impacts of herbivore diversity on tundra ecosystems. Future studies should explicitly address the role of herbivore diversity beyond presence-absence, targeting a broader range of ecosystem responses and explicitly including invertebrate herbivores. A better understanding of the role of herbivore diversity will enhance our ability to predict whether and where shifts in herbivore assemblages might mitigate or further amplify the impacts of environmental change on Arctic ecosystems.

Description: The data presented herein originates from a mesocosm study conducted as part of the EU H2020 OceanNETs project, aimed at investigating the ecological ramifications of ocean alkalinity enhancement. Nine mesocosms were deployed in Taliarte Harbour, Gran Canaria, Spain, and systematically sampled using integrated water samplers over the period spanning from September 10th to October 25th, 2021. Alkalinity was employed in a gradient design, ranging from ambient (0 µeq kg-1 added alkalinity, OAE0) to elevated levels of 2400 µeq kg-1 additional alkalinity (OAE2400) in increments of 300 µeq kg-1. The dataset encompasses a spectrum of sediment trap particle flux data, water column biogeochemistry variables, including inorganic nutrients, carbonate chemistry parameters, and particulate matter, alongside chlorophyll a concentrations. The study and data set offer insights into impacts of alkalinity enhancement on marine ecosystems and their associated biogeochemistry.

Description: Upward transport and/or mixing of trace gas-enriched subsurface waters fosters the exchange of nitrous oxide (N2O) and methane (CH4) with the atmosphere in the Eastern-South Atlantic (ESA). To date, it is, however, unclear whether this source is maintained by local production or advection of trace-gas enriched water masses. So, the meridional and zonal variability of N2O and CH4 in the ESA were investigated to constrain the contributions of the major regional water masses to the overall budget of N2O and CH4. The fieldwork took place during the cruises M99 (July 31st - August 23rd, 2013) and M120 (October 17th - November 18th, 2015) onboard the R/V METEOR, which encompassed close-coastal and open ocean regions off Angola and Namibia. To investigate the regional concentration gradients of N2O and CH4 and corresponding sea-air fluxes, seven hydrographic sections (six zonal transects and one alongshore transect) were conducted between ~10°S and 26°S. Concentrations of dissolved N2O and CH4 in surface waters were continuously measured by using the Mobile Equilibrator Sensor System. To evaluate, the oceanic-atmospheric trace gas exchange, the atmospheric N2O and CH4 in ambient air were measured at several sporadic locations, with an inlet installed at 35 m height. The data were quality controlled by comparing with the data generated by NOAA in the nearest atmospheric sampling station (23.58° S, 15.03°E, Station NMB (Gobabeb, Namibia)). Also, to better understand the underlying patterns of the trace gas in the ESA, the vertical profiles were investigated by measuring discrete samples of N2O using the dynamic headspace method on M99. N2O and CH4 concentrations were also measured using a purge and trap system during M120 expedition.

Description: This dataset contains energy content measurements performed on zooplankton collected in the Arctic Ocean during the MOSAiC expedition (PS122) from November 2019 untill September 2020. Energy content measurements were done on Apherusa glacialis, Themisto abyssorum, Chaetognatha, Thysanoessa longicaudata and Calanus hyperboreus. These species are all known prey of polar cod (Boreogadus saida), and their energy content was measured to be included in a bioenergetic model of the growth rate of this predator and to gain insight in the differences between prey species. The meaurements were performed on freeze-dried specimens using a 6725 semi-micro oxygen calorimeter (Parr, USA) connected to a 6772 calorimetric thermometer (Parr, USA).

Description: The glider was deployed from R/V METEOR cruise M120 (17.10.-18.11. 2015) as part of a group of 4 gliders. The gliders mission was related to the PREFACE project "Enhancing prediction of tropical Atlantic climate and its impacts" (http://preface.b.uib.no) funded by the European Union within the 7th Framework programme. PREFACE is combining European and African expertise in observations, modelling, and marine ecosystems to improve our understanding and capabilities to predict Tropical Atlantic climate and its impacts. The specific objectives of the gliders mission were related to work package (WP) 3 and 4 of the project. In WP 3, the Glider data contributed to determining seasonal and interannual variability of the mixed layer heat and fresh water budgets by quantifying air-sea fluxes and diapycnal, isopycnal and advective heat and freshwater fluxes in the eastern boundary upwelling systems and the Gulf of Guinea. In WP 4, the Gilder data contributed to monitoring variability along the southern hemisphere coastal wave guide.

Description: The glider was deployed from R/V METEOR cruise M120 (17.10.-18.11. 2015) as part of a group of 4 gliders. The gliders mission was related to the PREFACE project "Enhancing prediction of tropical Atlantic climate and its impacts" (http://preface.b.uib.no) funded by the European Union within the 7th Framework programme. PREFACE is combining European and African expertise in observations, modelling, and marine ecosystems to improve our understanding and capabilities to predict Tropical Atlantic climate and its impacts. The specific objectives of the gliders mission were related to work package (WP) 3 and 4 of the project. In WP 3, the Glider data contributed to determining seasonal and interannual variability of the mixed layer heat and fresh water budgets by quantifying air-sea fluxes and diapycnal, isopycnal and advective heat and freshwater fluxes in the eastern boundary upwelling systems and the Gulf of Guinea. In WP 4, the Gilder data contributed to monitoring variability along the southern hemisphere coastal wave guide.

Description: The glider was deployed from R/V METEOR cruise M120 (17.10.-18.11. 2015) as part of a group of 4 gliders. The gliders mission was related to the PREFACE project "Enhancing prediction of tropical Atlantic climate and its impacts" (http://preface.b.uib.no) funded by the European Union within the 7th Framework programme. PREFACE is combining European and African expertise in observations, modelling, and marine ecosystems to improve our understanding and capabilities to predict Tropical Atlantic climate and its impacts. The specific objectives of the gliders mission were related to work package (WP) 3 and 4 of the project. In WP 3, the Glider data contributed to determining seasonal and interannual variability of the mixed layer heat and fresh water budgets by quantifying air-sea fluxes and diapycnal, isopycnal and advective heat and freshwater fluxes in the eastern boundary upwelling systems and the Gulf of Guinea. In WP 4, the Gilder data contributed to monitoring variability along the southern hemisphere coastal wave guide.

Description: Yellowstone Plateau Volcanic Field, USA: Ge concentrations measured by inductively coupled plasma mass spectrometry (ICP-MS), Si concentrations measured by inductively coupled plasma optical emission spectrometry (ICP-OES), Ge/Si ratio, Si isotope compositions (d30Si and standard deviation SD) measured by Multicollector ICP-MS, concentrations in Ca, Na, Mg, K measured by ICP-OES, and concentrations in SO4 and Cl measured by ion chromatography in thermal waters, major rivers draining the Yellowstone Plateau Volcanic Field, and creeks flowing into Yellowstone Lake.

Description: Since 2001, current velocities have been measured continuously as part of a multilateral collaboration, the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA), that regularly services a moored observatory located at 0°N, 23°W. Here, we present 20 years of full-depth current velocity observations at 0°N, 23°W. With the presented current velocity data product, we aim to provide an important and accessible reference data set against which models and reanalysis output could be validated. The velocity time series will also be helpful for studies focusing on long-term climate variability to search for connections with changes in the equatorial circulation over the last 20 years. Earlier versions of this data product have already been used in a variety of studies and provided a significant contribution to an overall improved understanding of equatorial ocean dynamics. The moored observatory at 0°N, 23°W is an ongoing example of a successful multinational collaboration extending over more than two decades.

Description: Plant protection products in the environment are partly responsible for the progressive loss of biodiversity. The mostly insufficient ecological status of surface waters is often explained by habitat degradation and excessive nutrient input. But what role do plant protection products play in this context? The Kleingewässermonitoring (KgM) project provides a worldwide unique quantitative assessment of the impact of pesticides from diffuse agricultural sources on small and medium-sized streams. The dataset comprises 124 monitoring stream sections all over Germany covering a wide pollution gradient where consistent measurements were carried out in 2018 and 2019 during the major pesticide application period from April to July. These measurements include event-driven sampling to record surface rainfall-induced short-term peak concentrations in addition to regular grab sampling of pesticides and a wide range of other pollutants resulting in more than 1,000 water samples. All further relevant anthropogenic and environmental parameters reigning ecological stream quality were recorded comprehensively (morphological and stream bed structure, temperature, flow velocity, dissolved oxygen, pH, catchment land use, stream profile). The dataset also contains effect monitoring data featuring sampled invertebrate communities and bioassay analyses of water samples. The data enables an assessment of pesticide exposure and related effects as well as the analysis of complex causal relationships in streams.