Ecosystem Services

6.4 Provisioning services
6.4.1 Resource utilization and bioprospecting
Although the ecosystem components found in bays and inlets of the northern Baltic Sea
are, to our knowledge, today not used as medicinal resources, there may be future potential.
Charophytes may effectively remove organic chemicals, such as hexachlorobenzene
(Schneider and Nizzetto 2012), and metals, such as uranium (Kalin et al. 2005), nickel,
cadmium, lead and zinc, from the water (Baker et al. 2012, Gao and Yan 2012, Sooksawat
et al. 2013, Clabeaux et al. 2013, Laffont-Schwob et al. 2015). Charophytes may mitigate
cyanobacterial blooms in surface waters (Pakdel et al. 2013), reduce the viability of
Pythium (a parasitic oomycete that can cause rotting of plant roots, Juan et al. 2014), as
well as reduce the development of benthic biofilms (Gette-Bouvarot et al. 2015).
In contrast to the use today, charophytes have previously been of larger importance.
Zaneveld (1940) summarized nine ways in which charophytes have been of
more or less economic value. These included fish culture, water purification, food for
aquatic animals as well as farm stock, fertilizers, polishes, mud baths, therapeutic applications,
sugar purification, and insect control. For example, between the 18th and
the 20th century, charophytes were harvested in Lake Constance in the Alps, dried, and
used as fertilizer on vegetable fields (Schmieder 2004). However, this is not a common
practice any longer.
6.4.2 Commercial and subsistence fishery
Both commercial and subsistence fisheries are dependent on recruitment of the target
species, most of which are spring spawners. Perch, pike (Esox lucius), roach (Rutilus rutilus),
rudd (Scardinius erythropthal-mus), tench (Tinca tinca), breams (Abramis brama
and A. bjoerkna) and other cyprinids, generally benefit from warm water temperatures
due to positive effects on egg development and growth, and the enclosed bays and inlets
thus provide suitable reproduction areas as the water quickly warms with the onset
of spring (Karås 1996a, Karås and Hudd 1993). The juvenile fish spend their first summer
in these habitats, and first year growth is critical for survival and year-class-strength
(Hudd et al. 1996, Kjellman et al. 2003). On a larger scale (10–30 km) the amount of
suitable spawning and nursery habitats has been shown to be a limiting factor for the
abundance of large fish, explaining almost half of the variation in adult fish abundance
(Sundblad et al. 2014).
Ecosystem Services 87