Roelof van der Merwe, who has died in Pretoria at the age of 57, was a modest, unassuming and extraordinarily generous benefactor of conservation. He donated tens of millions of rands to biodiversity conservation projects - especially those involving penguins, seabirds and other marine life - from a trust fund set up by his father Charl, a civil engineer who made a fortune constructing cooling towers in the 1960s.When his father died in 2002, at the age of 72, Roelof took over the management of the fund with his accountant sister Betsie as chairwoman.The family trust contributed to the conservation of the African penguin and supported BirdLife South Africa's work to improve the status of threatened birds and their natural environment.It supported WWF-SA's marine conservation work and the Endangered Wildlife Trust's raptor conservation work in the eastern Karoo, as well as conservation work on the southern ground hornbill.Of the many marine conservation projects the trust funded, perhaps the most important was Africa's first offshore marine protected area, the 180000km² Prince Edward Island Marine Protected Area, roughly the size of the Free State, Lesotho and Swaziland combined.Van der Merwe was born in Sasolburg on May 13 1958 and matriculated at Hoërskool Vryburger in Germiston. After two years of national service he completed a BSc in geology and maths, eventually gaining an MSc and PhD in geology, all at the then Rand Afrikaans University.He lectured in geology at the University of Pretoria until 2002 when he took early retirement to manage the trust and pursue conservation, travel and wildlife photography.Van der Merwe snr was particularly fascinated by the emperor penguin and took the family on several trips to the Antarctic aboard a Russian icebreaker to view birds of the biggest penguin species.Van der Merwe said that being in the Antarctic was a life-changing experience. It was his favourite place on earth and he would have left for his 13th visit there next month.Unlike many conservation funders who want quick, dramatic results, Van der Merwe was in it for the long term and took a close interest in the time-consuming science involved.His support for marine work in particular was carefully chosen, and the projects he funded were among the most influential of all nongovernment-driven initiatives in shaping fishing, consumer awareness and broad marine conservation work.Under his management from 2002, the trust donated more than $250000 (R38-million at today's exchange rate) for BirdLife South Africa's seabird conservation work alone.He received the BirdLife International Conservation Achievement Award in Ottawa, Canada, in 2013, one of seven recipients acknowledged for making an "exceptional contribution" to the body's work.At the time of his death he was involved in discussions to challenge the government's decision to open the Tsitsikamma Marine Protected Area to recreational fishing.In a Christmas card to friends he said he expected 2016 to be "rather more gloomy and ominous" for conservation than previous years. "We hope to see you in some wild places around the globe in 2016 and beyond," he wrote shortly before he died in his sleep.He is survived by his wife, Willene, whom he married at the age of 53, and two stepdaughters.1958 - 2015..