NAF-IOLR

Underwater Gardening – Saving Coral Reefs

The health of the coral reef in Eilat, like many reef sites worldwide, has declined over the past four decades. More than a decade ago, IOLR-NIO scientist, Dr. Buki Rinkevich suggested a novel approach for reef restoration that may stem the reef’s decline. He presents himself as a coral reef gardener, but in fact he came up with an innovative two-step protocol “planting” coral-nubbins (less than a half inch in length) in mid-water floating coral nurseries. In nurseries installed in sheltered zones, the nubbins grow until they reach an adequate size for transplantation. Then the nursery-grown corals are transplanted in degraded reefs. The strategy is similar to forestry schemes for forest restoration.

In the decade following the initial studies in Eilat, several studies conducted in Southeast Asia (the Philippines, Thailand and Singapore), Jamaica and Zanzibar, tested the applicability, feasibility and the detailed developed protocols for attaching and growing corals in floating nurseries. The research has been supported by the US-AID, the European Community and the World Bank.

Two years ago the first batch of several hundred nursery-farmed coral colonies were “planted” onto a denuded area at Dekel Beach, Eilat. For each coral, a hole was drilled in the rock and a coral-bearing plastic pin was inserted and held into place with underwater epoxy glue. Two years passed and the colonies survived and flourished - high growth rates and high reproduction rates attest to their excellent health. The nursery-grown colonies became nursery sites for coral fishes and many crabs, bivalves, worms and other invertebrates that live in close association with the transplanted corals. Researchers continue to study the coral gardens and watch for new recruitment at the site.

The coral nurseries in Southeast Asia, Jamaica and Zanzibar are highly successful as well. In some sites researchers have already employed both the nursery stage and the transplantation stage, in others researchers are still working at the nursery stage. Most of the nurseries are mid-water, using floating devices of various types. The nurseries each hold thousands of coral colonies. Of course, at each location the nursery is adapted to the local conditions and the local coral species that have been “planted”.

The IOLR scientists working hypothesis is that conventional management tools employed in coral reef restoration do not achieve conservation objectives as coral reefs continue to degrade. Improved reef management helps in reducing the degradation pace but global changes foretell a dismal fate for the coral reefs. We believe that the future of the reefs is dependent on ‘active’ management - the establishment of large-scale nurseries and transplantation of their products. Active management in addition to conventional reef management is needed to help stem reef degradation.

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A Generic Integrated Mariculture System for the Mediterranean & Red Sea

A new project financed by US-AID (MERC) aims to improve land-based integrated mariculture. The integrated system is based on recycling fish excretions into feed for other valuable crops such as oysters, clams and seaweed. The goal of the project is to increase efficiency of the land-based system and reduce nutrient effluents that negatively effect both the Mediterranean and Red Sea. Two similar pilot systems employing new techniques to maximize nutrient conversion to edible products are in the final stages of construction on the Mediterranean coast of Egypt and in Eilat, Israel. Once in operation, scientists will evaluate the production of fish and shellfish while monitoring the nutrient flow. After an economic feasibility evaluation following two operational seasons, models will be developed for conversion of nutrients into fish, shellfish and seaweed biomass. This information will help researchers plan for commercialization of the integrated system.

The kickoff meeting of the new MERC project was held at Taba, Egypt, in January 2008. Drs. Muki Shpigel and George Kissil of the National Center for Mariculture (NCM) in Eilat head the Israeli team. They collaborate with their counterparts from the National Institute of Oceanography and Fisheries (NIOF), Alexandria, Egypt. NIOF and NCM have cooperated on mariculture projects since the Camp David accords in the early 1980s. This project is the late Dr. Bob Abel’s final achievement in fostering scientific cooperation between Israeli and Egyptian scientists.

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Invisible Particles Foul Up Desalination Plants

Several years ago, former KLL Director Dr. Tom Berman conducted a 3 year pioneering study of small transparent organic particles (Transparent Exopolymer Particles (TEP)) in Lake Kinneret. This research showed that the lake water contained as many as 25 million tiny sugar and/or protein containing particles per liter regardless of the season and that these organic particles were important players in the lake’s ecosystem. In fact, since their discovery in the ocean in 1993, TEP have been found in almost all naturally created bodies of water: seas, lakes and rivers.

Now it seems that TEP could also have a down side. These microscopic particles are ubiquitous, very numerous, small and sticky. Many of them carry loads of bacteria. Consequently, they have just the characteristics needed to cause biofouling–the attachment of biofilm, a thin usually resistant layer of bacteria, on all kinds of wet surfaces. Biofilm means big headaches in various types of water treatment plants. For example, both desalination plants and water treatment facilities generally use filtration through membranes as a final water purification step. During operation, layers of biofilm develop on these membranes and eventually clog them. To minimize biofilm build up on these surfaces, source water is filtered and chemically treated prior to final filtration through the membranes. This additional process makes biofilm a major and very expensive problem for the desalination and water treatment industry.

Based on the probable involvement of TEP in biofilm formation, Dr. Berman proposed that checking TEP levels would be a good way to monitor the efficiency of pretreatment in these plants. KLL researchers are working together with IDE Technologies Ltd on a new approach called Microbial Support Capacity to measure how effectively various pretreatments lower the potential for biofilm to develop on sensitive filtration membranes. The Microbial Support Capacity index is based on measuring the levels of TEP and a few other “biologically based” parameters in treated water. This new evaluation procedure is being tested at the KLL using water samples from the newly commissioned Ashkelon Desalination facility; presently the world’s largest operating desalination plant. The KLL team hopes to simplify the tests and make them more user-friendly and suitable for application in the filtration and water treatment industries. Optimizing the Microbial Support Capacity index for industrial use will allow plant designers, managers and operators to routinely evaluate the efficiency of various treatment stages in plants that are susceptible to problems caused by microbial biofouling.

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Revealing the Red-Tide-Like Phenomenon in Lake Kinneret

In Lake Kinneret, the dinoflagellate (a single cell alga with two flagellates) Peridinium gatunense forms spring blooms of intensities comparable to those of red tides. A typical Peridinium bloom is characterized by distinct spatial heterogeneity (or patchiness) of the Peridinium population, as well as daily vertical migration of the population from near the surface during the day time to deeper water during the night. Horizontally, Peridinium population is typically distributed in patches scaling hundreds of meters to several kilometers, and is visible from shore as coffee-brown regions within the bluer surrounding water. Using remote sensing devices on board a satellite, the bloom of Peridinium in Lake Kinneret is visible and quantifiable. The Satellite-based Information System on Coastal Areas and Lakes (SISCAL), initiated and operated by Dr. Gideon Tibor (NIO-IOLR), was used to process the satellite images and distribution data obtained by the satellite. This data was then used to determine the relative distribution of chlorophyll in Lake Kinneret which is attributed to the developed population of Peridinium.

For many years, the spring blooms of Peridinium were considered an indicator of the stability of the lake ecosystem and the lake’s water quality. Dinoflagellates are important components of the marine food web. However, when these blooms occur in high numbers resulting in a red-tide-like phenomenon, they can have a detrimental effect on marine life and also introduce toxins into the animals that are meant for human consumption. In the past decade the seasonal blooms were substantially reduced: 2000, 2001, 2005, 2006 and 2008 were characterized by a substantially reduced spring population of Peridinium while in the years 2003, 2004 and 2007 a normal and in some cases very high density bloom occurred. KLL scientists pay great attention to these bloom events, the reasons for their discontinuity, and their biological characteristics.

The Peridinium bloom event of spring 2007 was studied by the KLL scientists during a comprehensive effort coordinated by IOLR scientist Dr. Assaf Sukenik. The team studied the spatial distribution and dynamic variations of Peridinium population in the northern area of Lake Kinneret for three consecutive days (day and night) during the last week of March 2007. The main goal of the study was to characterize the patchy nature of Peridinium blooms in the lake and to identify and quantify the physical and/or biological processes that control this patchy nature.

The large database collected during that extended expedition suggests quantitative relationships between the size of the Peridinium population and the amount of Jordan River water diluted in the lake due to flood events. Satellite images and earlier studies indicated that the Peridinium patches occur mainly in the northern part of the lake where Jordan River enters the lake. Therefore, this area was proposed as the site of population development and growth. Such a growth is supported by nutrients and chemical conditions provided by the river inflow. The distribution of the developed Peridinium population to other locations is facilitated as the population “tracks” the Jordan River plume in Lake Kinneret. Based on the unique database collected during this study, KLL scientists postulate that a bulk of water enriched with Peridinium population is disintegrated from the “hatching” and “nursing” area (Jordan River inlet area) and starts its migration in the lake in accordance with the existing waves, currents and streams.

The patch migration continues along the “Jordan River” trail in Lake Kinneret, from the north area, the site of the population emergence, along the northwest coast and to the lake center, in accordance with the results of a circulation simulation model of Lake Kinneret operated by Dr. Alon Rimer (KLL). Based on this model, KLL scientists speculate that a single Peridinium patch migrating in the lake is of different age or developmental stage then another patch.

This study demonstrated once again the capabilities of the Kinneret Limnological Laboratory to identify crucial aspects of the lake ecosystem and to study them in a cooperative effort to better understand trends and changes in the lake’s ecosystem.

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