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<\/a>Collecting potential grazer species for our experiments in the lagoon near the institute. The lagoon is formed by abrasion platforms \u2013 a unique biogenic rock formation in the Mediterranean.<\/p><\/div>\n
<\/a>The Rilov Lab group on a fun trip in April.<\/p><\/div>\n
Same as the other GAME teams all around the world, we investigated the effects of ocean warming on marine grazers by measuring their consumption rates, faeces production, respiration and activity in different thermal environments. This allows us to generate performance curves for each species. The global focus of our research is on \u201cgrazing in a warmer world\u201d and each team used delicious ulva pellets for running feeding trials that allows to assess grazer consumption rates. Here in the IORL, we have a small algae farm where we grow and harvest local Ulva<\/em> spp. to dry and grind it. The resulting fine algae powder was the main ingredient of our food pellets.<\/p>\n Ulva pellets after a feeding trial \u2013 our fish seem to like the them.<\/p><\/div>\n Israel is a very good place to be a marine biologist, because of the access to both the subtropical Mediterranean and the tropical Red Sea. Many interesting phenomena occur here at the moment, such as the tropicalization of the local communities in the Eastern Mediterranean by the enormous number of invaders that enter the system from the Red Sea via the Suez Canal. In addition, the Eastern Mediterranean is extremely affected by global climate change \u2013 the average \u00a0sea surface temperature increased by more than 3\u00b0C in the last 30 years.<\/p>\n Since Erez\u2019s PhD project is about the impacts of climate change on herbivorous fish, we already knew one of the two species we wanted to work with right from the start. It was quite adventurous to collect a share of the needed Siganus rivulatus<\/em> specimens by night snorkelling just next to the institute. These medium sized, schooling fish are common in shallow rocky reefs and during the night they rest on the seafloor in large numbers. To catch them, it requires three things \u2013 flash lights, nets and good gloves since the fish have a row of painful spikes on their back. In the ideal case, the light confuses the fish so much that it tries to hide itself by pressing flat to the ground without moving. If this happens you must be quick in covering it with the net and transfer it to the collection cage without letting it escape. In most nights we caught around 50-60 specimens in a 2-hours-snorkelling session.<\/p>\n Our fish grazing experiment took place in the mesocosm facilities, which are in the outside area of the institute. It is a computer controlled system consisting of 16 large water tanks which are equipped with heaters and chillers that can precisely hold a targeted temperature.<\/p>\n Siganus rivulatus can change between three different skin patterns \u2013 overall marbled like in this photo, silver with a black middle line or silver with narrow yellow lines.<\/p><\/div>\n A normal morning for Erez in the mesocosm facilities.<\/p><\/div>\n Also, our second grazer species was quickly identified \u2013 after some feeding pilots with different snail species such as Columbella rustica<\/em> and Cerithium sp.<\/em> we decided to work with the gastropod Conomurex persicus<\/em>. This is a quite large marine snail that is one of the most prominent animals of the rocky shores near Haifa and as soon as you can tell the difference between them and an overgrown stone you can spot them everywhere. Conomurex persicus<\/em> as well as the fish S. rivulatus<\/em> are invasive species that now occur in large numbers along Israel\u2019s Mediterranean coast line.<\/p>\n For our first grazer experiment, we worked in a facility called \u2018The Microcosm\u2019 which is basically a smaller version of the mesocosm system with 11 instead of 16 controlled water tanks. Unfortunately, after the first experiment this experimental system was not available for us for further trials and because of this Luisa restored an old acidification system in the basement of the institute and modified it to become a temperature controlled system. It had the big advantage \u2013 in contrast to the microcosm- to be a flow through system, which saved us 3 hours of water replacement time every day and allowed us to have a larger number of replicates.<\/p>\n Our second grazer and probably the cutest snail ever with their long proboscis and big eyes \u2013 Conomurex persicus. They also have a quite strong foot which they use to jump over the sea floor or to escape from your hand.<\/p><\/div>\n Our first system, \u2018The Microcosms\u2019, in which we exposed our snails to 11 different temperature levels ranging from 15 to 35 \u00b0C. We exchanged the water in the jars every day to ensure a good water quality.<\/p><\/div>\n A flow through system makes life much easier and snails happy \ud83d\ude0a Here we could apply 5 different temperatures simultaneously. In the first experiment in this system, we pushed our grazers to their thermal limit and in the second we narrowed in the point of maximum consumption.<\/p><\/div>\n The summer here seems endless. Basically all the time from May to September it\u2019s hot and sunny, \u00a0what also means that Israeli people are quite spoiled when it comes to their comfort temperature to enter the water \ud83d\ude09 Erez\u2019s personal rule is never go without a 5 mm suit when the water has less than 25\u00b0C. In the summer peak months July and August, the ocean is more like a bathtub with a constant temperature of 31 \u00b0C. Here you also never need to worry about rain or what kind of cloth to put on, because we can assure you \u2013 the only thing you need are shorts, t-shirt and sandals or beachwear.<\/p>\n Haifa is Israel\u2019s third largest city and situated on the slopes of Mount Carmel in the north of the country. The city is very multicultural and famous for the beautiful Bah\u2019ai Gardens. From our neighbourhood \u201cBat Galim\u201d it\u2019s only a short 5 min car ride or a beautiful 20 min walk along the sea to reach the institute. It worked well to find a flat share for Luisa for her time here and Bat Galim is a lovely place to live \u2013 directly at the beach with a nice promenade and good connection to public transportations. The nearby shore is popular for water sport activities such as wave surfing, kayaking and snorkelling. Sting rays and sea turtles are common visitors here and there is even a ship wreck in the shallow water. Luisa felt welcome here from the first day on since the atmosphere in the neighbourhood is very friendly and communal, many of the students and workers of the institute live here so there is a busy social life with frequent gathering in the local bar as well as a weekly poker night.<\/p>\n<\/a><\/a><\/a><\/a><\/a><\/a>