If a new island emerges in a part of an ocean, what would be the first expected new arrival organisms into the island? I mean the order of changes in that ecosystem which includes migration of both unicellular as well as plants and animals.
This depends in part on the climate of the island and it's proximity to any neighbouring landmasses. Excluding micro-organisms that would arrive via wind or bird faeces, I would expect wind blown seeds and invertebrates to arrive first. Famously the first organism identified on the Krakatoa archipelago after the 1883 eruption was a spider. Early permanent colonisers of most newly emerged islands usually are grasses and lichens. The proportions and species depend on climate and rock type/substrate, etc. Transient visitors such as sea birds will add guano and potentially the seeds of other land plants.
If the island is tropical you might expect coconuts to wash ashore and soon colonise the seafront. Tropical reptiles such as snakes and lizards may also arrive by swimming or by transport on floating vegetation. Once plants are established invertebrates soon follow, pursued by predatory species. At this point some bird species will make permanent homes. Thornton's study of Krakatoa is well worth looking at for detail. There are other studies of Surtsey (Iceland) which provide analogous examination of succession in a temperate climate. Hope that helps!
This depends in part on the climate of the island and it's proximity to any neighbouring landmasses. Excluding micro-organisms that would arrive via wind or bird faeces, I would expect wind blown seeds and invertebrates to arrive first. Famously the first organism identified on the Krakatoa archipelago after the 1883 eruption was a spider. Early permanent colonisers of most newly emerged islands usually are grasses and lichens. The proportions and species depend on climate and rock type/substrate, etc. Transient visitors such as sea birds will add guano and potentially the seeds of other land plants.
If the island is tropical you might expect coconuts to wash ashore and soon colonise the seafront. Tropical reptiles such as snakes and lizards may also arrive by swimming or by transport on floating vegetation. Once plants are established invertebrates soon follow, pursued by predatory species. At this point some bird species will make permanent homes. Thornton's study of Krakatoa is well worth looking at for detail. There are other studies of Surtsey (Iceland) which provide analogous examination of succession in a temperate climate. Hope that helps!
To add to what David has said, bats (like birds) will be fairly early vertebrate colonizers as flying aids dispersal over water.
Bryophytes are often among the first plants to appear, see Pocs, T. 2006. Bryophyte colonization and speciation on oceanic islands: an overview. Lindbergia 31 (1/2): 54–62.
As David pointed out the likelihood that an organism will arrive at a newly emerged island will depend on the island's proximity to source populations, but add to that the organisms' powers of dispersal, their method of dispersal (passive/active/mix of both). However arrival and survival are two different things. So a spider was the first macroorganism found on Krakatoa, but if its prey were not present then it would not survive. So I would expect that the first colonisers that establish viable populations will be primary producers and their associated micro-organisms, followed by organisms that feed on the primary producers, decomposers, followed by carnivores. If an organism from a higher trophic level arrives on the island before its prey does, it is a question how long can it survive until its prey arrives and builds up numbers that can support it. It is a neat complex problem.
I forgot to qualify what I wrote and others have already pointed it out. The species that colonise and establish viable populations depends on the species composition of the region in which the newly emerged island is in. I think that Simberloff et al. has done some work on recolonisation of small islands after they eliminated the flora and fauna from them. Bert Jenkins also studied the colonisation of artificial tree holes and the build up of food webs in them. Those studies may give you specific data on order of colonisation and establishment of viable populations.
This has been part of research on the island of Surtsey. You can contact the Museum in Reykajvik, they have a library of the events on the island. I have been interested in drift disseminules an I suspect that these will be one of the first arrivals apart from insects and wind blown seeds and bird wastes.
..depending on the nature of the substrate on the new island i.e. rocky or sandy floating plants or algae may likely be the first arrivals on that island. Microbes and vermins from bird droppings are also likely first arrivals.
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