Question: Which Sumerian city was very powerful and influential during the Early Dynastic period and once a coastal city?

Context paragraphs:
Ištaran: Ištaran (also Gusilim) was the local deity of the city of Der, a Sumerian city state positioned east of the Tigris on the border between Sumer and Elam.  His cult flourished from the Early Dynastic III Period until the Middle Babylonian Period, after which his name is no longer attested in the personal names of individuals.  The beast and symbol of Ištaran, as frequently represented on kudurrus, is a snake (presumably representing Nirah, the snake god who acted as Ištaran's minister).  The consort of Ištaran was known simply as Šarrat-Deri: "the queen of Der".

Ur-Nanshe: Ur-Nanshe (or Ur-Nina) was the first king of the First Dynasty of Lagash (approx. 2500 BCE) in the Sumerian Early Dynastic Period III.  He is known through inscriptions to have commissioned many buildings projects, including canals and temples, in the state of Lagash, and defending Lagash from its rival state Umma.  He was probably not from royal lineage, being the son of Gunidu who was recorded without an accompanying royal title.  He was the father of Akurgal, who succeeded him, and grandfather of Eanatum.  Eanatum expanded the kingdom of Lagash by defeating Umma as illustrated in the Stele of the Vultures and continue building and renovation of Ur-Nanshe’s original buildings.

Imports to Ur: Imports to Ur reflect the cultural and trade connections of the Sumerian city of Ur.  During the period of the Early Dynastic III royal cemetery (ca. 2600 BC), Ur was importing elite goods from geographically distant places.  These objects include precious metals such as gold and silver, and semi-precious stones, namely lapis lazuli and carnelian.  These objects are all the more impressive considering the distance from which they traveled to reach Mesopotamia and Ur specifically.

Early Dynastic Period (Mesopotamia): The Early Dynastic period (abbreviated ED period or ED) is an archaeological culture in Mesopotamia (modern-day Iraq) that is generally dated to "c." 2900—2350 BC.  It was preceded by the Uruk and Jemdet Nasr periods, and saw the invention of writing and the formation of the first cities and states.  The ED itself was characterized by the existence of multiple city-states: small states with a relatively simple structure that developed and solidified over time.  This development ultimately led to the unification of much of Mesopotamia under the rule of Sargon, the first monarch of the Akkadian Empire.  Despite this political fragmentation, the ED city-states shared a relatively homogeneous material culture.  Sumerian cities like Uruk, Ur, Lagash, Umma and Nippur, located in Lower Mesopotamia, were very powerful and influential.  To the north and west stretched states centered on cities such as Kish, Mari, Nagar and Ebla.

Mehit: Mehit or Mehyt was an Ancient Egyptian goddess.  In the Early Dynastic period she was depicted as a reclining lioness with three bent poles projecting from her back.  In that era she appears in numerous early dynastic sealings and ivory artifacts, usually together with a representation of an Upper Egyptian shrine.  Her main places of worship were Hierakonpolis and Thinis.

Temple of Satet: The Temple of Satet or Satis was an Ancient Egyptian temple dedicated to the goddess Satet, a personification of the Nile inundation.  The temple was located on the Nile Valley island of Elephantine, Egypt.  Founded during the late Predynastic Period around 3200 BC, it was enlarged and renovated several times from the Early Dynastic Period onwards over the next 3000 years until the Ptolemaic Period.  The temple of Satet is the best example of an Ancient Egyptian temple whose construction is attested over the entire pharaonic period.

Abu Salabikh: The low tells at Abu Salabikh, around 20 km northwest of the site of ancient Nippur in Al-Qādisiyyah Governorate, Iraq mark the site of a small Sumerian city of the mid third millennium BCE, with cultural connections to the cities of Kish, Mari and Ebla.  Its contemporary name is uncertain: perhaps this was Eresh.  Kesh has also been suggested.  The Euphrates was the city's highway and lifeline; when it shifted its old bed, in the middle third millennium BCE, the city dwindled away.  Only eroded traces remain on the site's surface of habitation after the Early Dynastic Period.

Prehistoric Egypt: The prehistory of Egypt spans the period from earliest human settlement to the beginning of the Early Dynastic Period of Egypt around 3100 BC, starting with the first Pharaoh, Narmer for some egyptologists, Hor-Aha for others, (also known as Menes).  This Predynastic era is traditionally equivalent to the final part of the Neolithic period beginning c. 6000 BC, and corresponds to the Naqada III period.

Ur: Ur (Sumerian: "Urim"; Sumerian Cuneiform: URIM or URIM ; Akkadian: "Uru"; Arabic: أور‎ ‎ ) was an important Sumerian city-state in ancient Mesopotamia, located at the site of modern Tell el-Muqayyar (Arabic: تل المقير‎ ‎ ) in south Iraq's Dhi Qar Governorate.  Although Ur was once a coastal city near the mouth of the Euphrates on the Persian Gulf, the coastline has shifted and the city is now well inland, on the south bank of the Euphrates, 16 kilometres (9.9 mi) from Nasiriyah in modern-day Iraq.

Early Dynastic Period (Egypt): The Archaic or Early Dynastic Period of Egypt is the era immediately following the unification of Upper and Lower Egypt  "c." 3100 BC.  It is generally taken to include the First and Second Dynasties, lasting from the end of the Naqada III archaeological period until about 2686 BC, or the beginning of the Old Kingdom.  With the First Dynasty, the capital moved from Thinis to Memphis with a unified Egypt ruled by an Egyptian god-king.  Abydos remained the major holy land in the south.  The hallmarks of ancient Egyptian civilization, such as art, architecture and many aspects of religion, took shape during the Early Dynastic period.

Supporting paragraphs: Early Dynastic Period (Mesopotamia) Ur
Answer: Ur