CLIMATE | OCEAN | CHANGE

FLASH TALKS AND VIDEO RECORDINGS

The potential effect of the Nile damming and global change processes on lightning flash intensity over the Mediterranean Sea

Karin Pitlik, Mustafa Asfur, Colin Price, Yoav Yair, Jacob Silverman
Faculty of Marine Sciences, Ruppin Academic Center, Mikhmoret

In the last century the Mediterranean Sea has undergone significant changes due to the effects of global and regional anthropogenic changes. Global warming and the erection of the Aswan High Dam (AHD) have caused substantial changes in the chemical and physical properties of seawater. The combined effects of these changes resulted in salinization of Levantine Surface Waters (LSW) from ~38.95 to ~39.4 PSU since the erection of the AHD. During the same period the increase of atmospheric CO2 resulted in ocean acidification (OA) of LSW on the order of -0.1 pH units. In this study we tested the combined effects of salinity, total alkalinity and pH on the intensity of laboratory generated electrical sparks, which are considered to be analogous to cloud to sea-surface intensity of lightning discharges. Based on these experimental results we estimate that LFI in the Levantine Sea may have increased by as much as 16±14% since the1960’s. Furthermore, assuming that salinization and acidification of LSW will continue at current trends, the LFI is predicted to increase by 25±13% relative to the pre 1960’s values by the year 2050.

Data Driven Doppler Velocity Log Navigation for Autonomous Underwater Vehicles

Nadav Cohen, Itzik Klein
The Hatter Department of Marine Technologies, Charney School of Marine Sciences, University of Haifa

Autonomous underwater vehicles (AUV) perform a wide range of applications. Commonly, an inertial navigation system (INS) aided by a Doppler velocity log (DVL) is used to provide the vehicle’s navigation solution. In such fusion, the DVL provides the velocity vector of the AUV, which determines the accuracy of the navigation solution and helps to estimate the navigation states. In this work, instead of using model based approaches, we propose BeamsNet, an end-to-end deep learning framework to regress the estimated DVL velocity vector. The data driven network uses DVL beam measurements and inertial sensors data for the regression process. Sea experiments, with the Snapir AUV, were made to validate the proposed learning approach relative to the model based approaches. Our results, evaluated on four hours of collected data, showed that BeamsNet achieved an improvement of more than 60% in estimating the DVL velocity vector. We further, elaborate the proposed BeamsNet framework to cope with situations of partial DVL beam measurements and regress the DVL velocity vector. Such scenarios occur, for example, when passing over fish and other sea creatures and passing over trenches in the seafloor.

Spatio-temporal variability of free gas content in sediments of Lake Kinneret, Israel

Ernst Uzhansky, Andrey Lunkov Prokhorov, Regina Katsman, Boris Katsnelson
Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa

Shallow gassy aquatic sediments, abundantly found in Israel and worldwide, are a source of major concern for their contribution to destabilization of coastal and marine infrastructure, ecological balance, and global warming. Here we study the spatial and temporal variability of free gas (methane) content (θ) in shallow sediments of Lake Kinneret. We implemented a recently developed noninvasive acoustic methodology that allows estimating θ in sediment based on measurements of bottom reflections of sound signals and subsequent assessment of sound speed in the bottom. The experiments were carried out in the lake in April and August 2021. Preliminary estimated θ at the 21-22 m isobath was 0.02−0.04% and 0.04−0.12% in April and August, respectively. Analysis of acoustic measurements shows distinct changes in θ in comparison to θ assessed in previous acoustic experiments carried out by our team in 2015-2018, when an inverse relationship between θ and lake level was found. Here we discuss other possible mechanisms, which may pre-determine the spatial and temporal variability in θ, such as ebullition of methane at the 21-22 m isobath and variability in deposited organic matter content, which vary both spatially and seasonally.

The potential contribution of SAR11 to global warming via methyl-phosphonate biosynthesis

Alhan Abu Hamoud, Rinat Bar-Shalom, Gustavo Ramirez, and Laura Steindler
Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa

SAR11, the most abundant marine heterotrophic bacterium on Earth, may play a role in global warming via methyl-phosphonate biosynthesis. Methyl-phosphonate is an important source of phosphate for bacteria when inorganic phosphate is limited. Interestingly, when methyl-phosphonate is degraded, both inorganic phosphate and methane are released, and the latter is a potent greenhouse gas. Greenhouse gases are causing an increase in temperature that causes ocean stratification, which in turn results in phosphate limitation and further methyl-phosphonate degradation. We postulate that some SAR11 strains are responsible for most of the MPn biosynthesis in the ocean. Our aim is to test this hypothesis and to investigate what environmental conditions trigger MPn biosynthesis.

High-resolution screening for taxa with preference for plastic surfaces

Katherine Marsay¹, Yuri Kochrov¹, Keren Davidov¹, Catarina Silva², Paula Sobral², Matan Oren¹¹Ariel University, ²Nova University of Lisbon

Plastic pollution is an increasing concern as it jeopardizes aquatic life through entanglement and ingestion. Marine plastic debris serve as substrates for the colonization of a variety of organisms. Little is known about the community composition, its dynamics and how it affects the surrounding environment. Of interest are the microorganisms that have adapted to thrive on plastic as they may contain genes or enzymes involved in the adhesion or metabolism of plastics. We have studied the plastisphere using in situ experiments and environmental sampling. We used MinION sequencing to amplify and analyse the taxonomic composition of prokaryotes, eukaryotes and fungi on plastic vs. those of glass and the surrounding water. Using differential abundance analysis we identified 37 species that were significantly more abundant on PE and PET compared to glass. Microscopy provided information about the biofilm complexity and the relationships among species. We also compared the physical and biological composition of microplastic collected from two separate locations in Israel and Portugal in Summer and Winter. We found 29 bacterial species present on all plastic samples that may represent a plastic specific community.

INS/DVL Fusion with DVL Based Acceleration Measurements

Orzion Levy, Dr. Itzik Klein
The Hatter Department of Marine Technologies, Charney School of Marine Sciences, University of Haifa

In recent years, the use of autonomous underwater vehicles (AUV) has been increasing rapidly. It is frequently used for oceanographic surveys, mapping applications, and more. Doppler velocity log (DVL) is a well-known sensor widely used in AUV navigation systems. It measures velocity relative to the seabed without the need for prior knowledge or compatible infrastructure, making it available in almost any scenario. In some cases, DVL measurements may not be available. For example, while passing over trenches or sea creatures or operating at extreme angles. Several studies offer ways to cope with this problem and enable continuous velocity updates, usually by utilizing partial raw data and previous measurements. In one of such algorithms, besides the AUV velocity, the AUV acceleration vector is also estimated yet was not used for further process. Based on that work, an enhanced fusion between inertial navigation system (INS) and DVL utilizing the estimated acceleration vector is proposed. Simulation-based, preliminary results show proposed approach improves the estimation of the accelerometer bias by an average of 38\%. As a consequence, the navigation performance also improves.

Humans and Coastlines

Ofakim Honors Program
Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa

As part of a course with Prof. Beverly Goodman Tchernov about Humans and Coastlines, we aim to explore the relashionship bewteen the two in Caesaria. We set out to document some of the aspects that involve the life around ancient artifacts and the place and impact they have. In our project, we created videos that would provide information and promote knowledge for the public on topics that include the historical, archeological, environmental and preservational aspects of the Roman aqueduct area.

Mining social media for Elasmobranch fishery data in conflict zones:
The Gaza strip as a case study

Re’em Neri¹, Adi Barash²¹Sharks in Israel, ²Ben Gurion University of the Negev

A huge gap in environmental information exists between developed and developing regions of the world. The issue is emphasized in conflict regions where environmental access to scientists ranges from unsafe to impossible. Previously unknown knowledge of Elasmobranchii presence, composition and distribution can provide valuable information regarding the exploitation of elasmobranch species and for creating comprehensive conservation strategies. However, the diversity, ecology, behavior, and many other characteristics of these species in conflict zones remain virtually unknown, which is a major cause for concern. Traditional species surveys rely on in-situ observations and municipality regulations forcing fisheries to report their catch. Conflict areas present a unique challenge, lacking formal regulation or scientific access. Here, we report the first use of social media monitoring (“iEcology”) of the extent of the Elasmobranch fishery in the Gaza strip, a conflict region previously lacking any information. Our database consists of 3 years of daily reported catch from 8 markets in the Gaza strip. We collected 584 data points belonging to 2348 individuals of 14 species. analysis of the data suggests that elasmobranch catch distribution are affected by changes in the access to maritime areas due to local conflict escalations and de-escalations. We demonstrate this approach as a relatively accurate and inexpensive procedure, allowing the quantification of multiple unrelated observations of caught and targeted fish into a uniformed geo-spatial-temporal system- making it a prime candidate for future endeavors in other conflict zones in coastal regions.

Spatial and temporal assessment of oil spills in the Mediterranean Sea

Semion Polinov¹, Revital Bookman¹, Noam Levin²¹Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa
²The Department of Geography, The Hebrew University of Jerusalem

Ship-generated oil pollution is a significant threat to the Mediterranean Sea. We present a geostatistical analysis of oil spills using three databases for the Mediterranean Sea: REMPEC (1977-2000) with 385 spills (17/year), ITOPF (1970-2018) with 167 spills (3.5/year) and EMSA (2015-2017) with 2066 detections (688/year). It was found that 88% of spills reported by REMPEC occurred near coastline areas, while 65% of the spills detected by EMSA occurred within a range of 22-100 km from the coastline. At the Exclusive Economic Zone (EEZ) level, EMSA oil spills densities were positively correlated with shipping and port activity. We conclude that there is a need to develop an open-access database of oil spills that will be based on both reports and remote sensing acquisition methods. Such a database will facilitate more efficient enforcement of international conventions in offshore areas and will increase the likelihood of effective response.

Development of portable point of detection device for the estimation of Morpholine
A Xenobiotic Pollutant in Parts per Million

Rupak Kumar
Central Drugs Standard Control Organization, New Delhi

Every second 310 Kg of toxic chemicals (annularly 10 million tons) are released into our air, land,and water around the globe. Of these, about 20% i.e., 65 Kg per second toxic chemicals are recognized carcinogens. Morpholine and its derivatives is one such chemical contaminant which is extensively used in myriad of industries like in crude oil, rubber industry, plating industry, boiler water additive, textile industry, nuclear power plant and others. The large-scale annual usage of morpholine (25,000 CA) and its potentially carcinogenic effects (due to nitrosation) thus have environmental interest for its detection in natural resource and industrial effluents. In this regard, an analytical technique which should be efficient, economical and rapidly deployable for estimating minute ranges of this analyte has been developed. Herein, a spectrophotometric method based point of detection device has been prototyped for the quantification of morpholine of 2-10 ppm and in near future, it is amenable for automation to enable handling large number of point samples.