 | absorption spectroscopy | |
| activity patterns | |
| airborne sensing | |
| air pollution | |
| aldrin | |
| algae | |
| algal blooms | |
| alkalinity | |
| ambient noise | |
| americium | |
| amino acids | |
| ammonium | |
| ammonium compounds | |
| analytial techniques | |
| analytical techniques | |
| Anguilla anguilla | |
| anoxic basins | |
| antifouling substances | |
| aquaculture development | |
| aquatic insects | |
| Archipelago Sea | |
| Arkona Basin | |
| Askö | |
| atmospheric precipitations |