On earth the phytoplankton in the ocean are a big share of photosyntheses.
As an alternative, suppose that the process that produces tectonic plates is balanced toward more plates. You can have the same amount of water, but overall smaller deeper oceans. Current average ocean depth is about 12,000 feet. If you divided the area of the oceans by a factor of 3, you'd run 25% of the surface as water, 75% land, and you'd need 40-50 thousand foot deep oceans.
Your second factor to play with is the distribution of water: If you have many Black sea sized puddles, instead of a few north Atlantics, you end up with a somewhat more moderate climate. (I don't know if rock is strong enough to have a 50,000 foot deep Black Sea. Slope too steep?) Small puddles may require just less water.
You may want to make your world just somewhat drier instead of lots drier. Typically under 10 inches of rain per year is considered desert, but it will still support an ecology. Vegetation is sparse, and separated by patches of bare ground.
Much of the western U.S. is semi-desert with about 12-16 inches of rain a year. Grass and bush is present, but there are sp,e spaces of bare earth between plants. Water is the limiting factor. Somewhere between 16 and 20 inches a year you get tall grass prairie -- vegetation cover is continuous. At 25 inches per year depending on temperature you get forests.
Geology affects deserts: Look at Australia. At that latitude the prevailing wind is from the east. Hits the mountainous east coast, which wrings most of the water out of it, and behind that range you have an awful lot of not much. If you rotated the continent by 180 degrees, you would have a grassy interior. Or if you moved it south 15 degrees latitude to where the winds come from the north west.
Another factor in developing civilization: Water transport. Water is by far the cheaper way to move stuff, and to travel in a hurry. With more land than water, fast movement is relays of horses. The Pony Express could get a letter across the U.S. in 10 days. And it cost 10 bucks to do it -- a few weeks pay. Rome shipped tin from England, and grain from all over the Mediterranean.
Compare the early settlement of Canada vs the U.S. The Hudson Bay Co. had a network of fur trading posts that spread from York Factory on the Bay to the mouth of the Columbia. The trade cycle took 4 years between goods shipped from England to furs from the remote regions arriving back. A York Boat could carry 6 tons of cargo and had a crew of 6-8. Their competition, the North West company, used large (up to 36 feet) canoes. They could carry about half the cargo at with about half again more crew -- overall about 1/3 the tonnage per crew. They were MUCH easier to portage however. Tons per crew man year favoured the canoe except on the Hayes, Saskatchewan, Athabasca and Slave Rivers, where the lack of portages and where the river size allowed the use of sail at times.
George Simpson had a crack crew of Iroquois when he was chief Factor. He could travel from the depot at Thunder Bay to Lower Fort Garry, a distance of about 700 miles in 11 days. Freight canoes took about twice this.
In the U.S. with the only really comparable east-west river being the upper Missouri, along with the Great Lakes. Most goods moved by wagon. Tonnage per person was on par with the northern methods, but where the typical York boat or Canot du Maitre did 40 miles a day, wagons typically did 10. Where trails were rough in the mountains, early traders used pack horses or mules. This isn't efficient: each animal can carry only a couple hundred pounds, and needs hours to graze. It also requires considerable time harnessing and unharnesing.
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Later, in eastern America there was a flurry of canal building. One horse pulling a canal boat moved many times the freight of a horse and wagon.
Having limited water doesn't mean no water transport: Canals moving water from where it does rain to where it's used. Then boats on the canals. Wars could be fought over the control of locks. Conventions that you don't damage the lock itself
Continental U.S. wheel and foot transport.
Northern Canada -- water transport.
The rainfall regimes are't much different. However much of Canada is granite shield -- not very water absorbent. And with every glaciation the hydrology gets messed up, so what water that is there sits in puddles. Cooler temperatures reduce evaporation.
So: You could have wet or dry depending on the geologic history of the place.
Rivers in deserts and steppes are also possible. Look at the Jordan River in the middle east, and the Tigris-Euphrates. In both cases the water sources are in the mountains with higher precipitation. There are similar rivers on coastal Peru, one of the driest deserts in the world.
A world is a big place. Lots of room for variations.
