Directional swimming patterns in jellyfish aggregations.

Having a profound influence on marine and coastal environments worldwide, jellyfish hold significant scientific, economic, and public interest. The predictability of outbreaks and dispersion of jellyfish is limited by a fundamental gap in our understanding of their movement. Although there is evidence that jellyfish may actively affect their position, the role of active swimming in controlling jellyfish movement, and the characteristics of jellyfish swimming behavior, are not well understood.

Monitoring jellyfish outbreaks along Israel's Mediterranean coast using digital footprints.

With mounting global concerns about jellyfish outbreaks, monitoring their occurrence remains challenging. Tapping into the wealth of digital data that internet users share online, which includes reports of jellyfish sightings, may provide an alternative or complement to more conventional expert-based or citizen science monitoring. Here, we explore digital footprints as a data source to monitor jellyfish outbreaks along the Israeli Mediterranean coast.

Spatiotemporal Variation of Microbial Communities in the Ultra-Oligotrophic Eastern Mediterranean Sea.

Marine microbial communities vary seasonally and spatially, but these two factors are rarely addressed together. In this study, the temporal and spatial patterns of the bacterial and archaeal community were studied along a coast-to-offshore transect in the Eastern Mediterranean Sea (EMS) over six cruises, in three seasons of 2 consecutive years. Amplicon sequencing of 16S rRNA genes and transcripts was performed to determine presence and activity, respectively.

Patterns of exposure to SARS-CoV-2 carriers manifest multiscale association between urban landscape morphology and human activity.

The outbreak of the Coronavirus disease 2019 (COVID-19), and the drastic measures taken to mitigate its spread through imposed social distancing, have brought forward the need to better understand the underlying factors controlling spatial distribution of human activities promoting disease transmission. Focusing on results from 17,250 epidemiological investigations performed during early stages of the pandemic outbreak in Israel, we show that the distribution of carriers of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which causes COVID-19, is spatially correlated with two satellite-derived surface metrics: night light intensity and landscape patchiness, the latter being a measure to the urban landscape's scale-dependent spatial heterogeneity. We find that exposure to SARS-CoV-2 carriers was significantly more likely to occur in "patchy" parts of the city, where the urban landscape is characterized by high levels of spatial heterogeneity at relatively small, tens of meters scales.

Particle-associated and free-living bacterial communities in an oligotrophic sea are affected by different environmental factors.

In the oceans and seas, environmental conditions change over multiple temporal and spatial scales. Here, we ask what factors affect the bacterial community structure across time, depth and size fraction during six seasonal cruises (2 years) in the ultra-oligotrophic Eastern Mediterranean Sea. The bacterial community varied most between size fractions (free-living (FL) vs.

Impact of dust storm on phytoplankton bloom over the Arabian Sea: a case study during March 2012.

Dust storms affect the primary productivity of the ocean by providing necessary micronutrients to the surface layer. One such dust storm during March 2012 led to a substantial reduction in visibility and enhancement in aerosol optical depth (AOD) up to ~ 0.8 (AOD increased from 0.

Shallow Convective Cloud Field Lifetime as a Key Factor for Evaluating Aerosol Effects.

Clouds control much of the Earth's energy and water budgets. Aerosols, suspended in the atmosphere, interact with clouds and affect their properties. Recent studies have suggested that the aerosol effect on warm convective cloud systems evolve in time and eventually approach a steady state for which the overall effects of aerosols can be considered negligible.

Coccolithovirus facilitation of carbon export in the North Atlantic.

Marine phytoplankton account for approximately half of global primary productivity , making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon , which can stimulate nutrient regeneration, primary production and upper ocean respiration via lytic infection and the 'virus shunt'. Ultimately, this limits the trophic transfer of carbon and energy to both higher food webs and the deep ocean .

Expression profiling of host and virus during a coccolithophore bloom provides insights into the role of viral infection in promoting carbon export.

The cosmopolitan coccolithophore Emiliania huxleyi is a unicellular eukaryotic alga that forms vast blooms in the oceans impacting large biogeochemical cycles. These blooms are often terminated due to infection by the large dsDNA virus, E. huxleyi virus (EhV).

A Satellite-Based Lagrangian View on Phytoplankton Dynamics.

The well-lit upper layer of the open ocean is a dynamical environment that hosts approximately half of global primary production. In the remote parts of this environment, distant from the coast and from the seabed, there is no obvious spatially fixed reference frame for describing the dynamics of the microscopic drifting organisms responsible for this immense production of organic matter-the phytoplankton. Thus, a natural perspective for studying phytoplankton dynamics is to follow the trajectories of water parcels in which the organisms are embedded.

Dispersion/dilution enhances phytoplankton blooms in low-nutrient waters.

Spatial characteristics of phytoplankton blooms often reflect the horizontal transport properties of the oceanic turbulent flow in which they are embedded. Classically, bloom response to horizontal stirring is regarded in terms of generation of patchiness following large-scale bloom initiation. Here, using satellite observations from the North Pacific Subtropical Gyre and a simple ecosystem model, we show that the opposite scenario of turbulence dispersing and diluting fine-scale (∼1-100 km) nutrient-enriched water patches has the critical effect of regulating the dynamics of nutrients-phytoplankton-zooplankton ecosystems and enhancing accumulation of photosynthetic biomass in low-nutrient oceanic environments.

Metagenomic analysis reveals unusually high incidence of proteorhodopsin genes in the ultraoligotrophic Eastern Mediterranean Sea.

Sunlight can be directly harvested by photoheterotrophic bacteria to create a pH gradient across the membrane, which can then be utilized to produce ATP. Despite the potential importance of this trophic strategy, when and where such organisms are found in the seas and oceans is poorly described. Here, we describe the abundance and taxonomy of bacteria with different trophic strategies (heterotrophs, phototrophs and photoheterotrophs) in contrasting water masses of the ultra-oligotrophic eastern Mediterranean Sea.

Infection of phytoplankton by aerosolized marine viruses.

Marine viruses constitute a major ecological and evolutionary driving force in the marine ecosystems. However, their dispersal mechanisms remain underexplored. Here we follow the dynamics of Emiliania huxleyi viruses (EhV) that infect the ubiquitous, bloom-forming phytoplankton E.

Marine aerosol as a possible source for endotoxins in coastal areas.

Marine aerosols, that are very common in the highly populated coastal cities and communities, may contain biological constituents. Some of this biological fraction of marine aerosols, such as cyanobacteria and plankton debris, may influence human health by inflammation and allergic reactions when inhaled. In this study we identify and compare sources for endotoxins sampled on filters in an on-shore and more-inland site.

Decoupling physical from biological processes to assess the impact of viruses on a mesoscale algal bloom.

Phytoplankton blooms are ephemeral events of exceptionally high primary productivity that regulate the flux of carbon across marine food webs [1-3]. Quantification of bloom turnover [4] is limited by a fundamental difficulty to decouple between physical and biological processes as observed by ocean color satellite data. This limitation hinders the quantification of bloom demise and its regulation by biological processes [5, 6], which has important consequences on the efficiency of the biological pump of carbon to the deep ocean [7-9].